From fa3870b06f5f2ebd95fcaeba04d75a81c8b7064d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Guth?= <b.guth@netcon-consulting.com>
Date: Tue, 22 Jun 2021 15:11:49 +0200
Subject: [PATCH 01/29] Add a config variable for a logo path

---
 crates/mdbook-core/src/config.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/crates/mdbook-core/src/config.rs b/crates/mdbook-core/src/config.rs
index d7aa13bb89..58c2321334 100644
--- a/crates/mdbook-core/src/config.rs
+++ b/crates/mdbook-core/src/config.rs
@@ -330,6 +330,9 @@ pub struct BookConfig {
     /// The direction of text in the book: Left-to-right (LTR) or Right-to-left (RTL).
     /// When not specified, the text direction is derived from [`BookConfig::language`].
     pub text_direction: Option<TextDirection>,
+    /// A logo to be displayed on top of the navigation bar. The path is relative to the source
+    /// path
+    pub logo: Option<PathBuf>,
 }
 
 /// Helper for serde serialization.
@@ -346,6 +349,7 @@ impl Default for BookConfig {
             src: PathBuf::from("src"),
             language: Some(String::from("en")),
             text_direction: None,
+            logo: None,
         }
     }
 }
@@ -779,6 +783,8 @@ mod tests {
             src: PathBuf::from("source"),
             language: Some(String::from("ja")),
             text_direction: None,
+            // TODO: add a test logo
+            logo: None,
         };
         let build_should_be = BuildConfig {
             build_dir: PathBuf::from("outputs"),

From fb415da8caa23d39b200207bdd231d4a3de9bbbb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Guth?= <b.guth@netcon-consulting.com>
Date: Thu, 24 Jun 2021 14:43:07 +0200
Subject: [PATCH 02/29] Add a logo to the HTML template

The logo is placed at the top of the navication sidebar.
---
 crates/mdbook-html/front-end/css/chrome.css            | 7 +++++++
 crates/mdbook-html/front-end/templates/index.hbs       | 5 +++++
 crates/mdbook-html/src/html_handlebars/hbs_renderer.rs | 4 ++++
 3 files changed, 16 insertions(+)

diff --git a/crates/mdbook-html/front-end/css/chrome.css b/crates/mdbook-html/front-end/css/chrome.css
index 19b8e90f9d..18b462943a 100644
--- a/crates/mdbook-html/front-end/css/chrome.css
+++ b/crates/mdbook-html/front-end/css/chrome.css
@@ -498,6 +498,13 @@ html:not(.sidebar-resizing) .sidebar {
     right: 0;
     padding: 10px 10px;
 }
+.sidebar .sidebar-scrollbox .sidebar-book-logo img {
+    display: block;
+    margin-left: auto;
+    margin-right: auto;
+    max-width: max-content;
+    width: 100%;
+}
 .sidebar .sidebar-resize-handle {
     position: absolute;
     cursor: col-resize;
diff --git a/crates/mdbook-html/front-end/templates/index.hbs b/crates/mdbook-html/front-end/templates/index.hbs
index b1834189f9..4f982bfd0e 100644
--- a/crates/mdbook-html/front-end/templates/index.hbs
+++ b/crates/mdbook-html/front-end/templates/index.hbs
@@ -126,6 +126,11 @@
         </script>
 
         <nav id="mdbook-sidebar" class="sidebar" aria-label="Table of contents">
+            {{#if book_logo }}
+                <div class="sidebar-book-logo">
+                    <img src="{{ book_logo }}">
+                </div>
+            {{/if}}
             <!-- populated by js -->
             <mdbook-sidebar-scrollbox class="sidebar-scrollbox"></mdbook-sidebar-scrollbox>
             <noscript>
diff --git a/crates/mdbook-html/src/html_handlebars/hbs_renderer.rs b/crates/mdbook-html/src/html_handlebars/hbs_renderer.rs
index 8edac3cace..850dd811f8 100644
--- a/crates/mdbook-html/src/html_handlebars/hbs_renderer.rs
+++ b/crates/mdbook-html/src/html_handlebars/hbs_renderer.rs
@@ -478,6 +478,10 @@ fn make_data(
         "description".to_owned(),
         json!(config.book.description.clone().unwrap_or_default()),
     );
+    data.insert(
+        "book_logo".to_owned(),
+        json!(config.book.logo.clone().unwrap_or_default()),
+    );
     if theme.favicon_png.is_some() {
         data.insert("favicon_png".to_owned(), json!("favicon.png"));
     }

From db82eaba95a04079dc5592069b7acc412541a8c2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Guth?= <b.guth@netcon-consulting.com>
Date: Thu, 24 Jun 2021 14:46:23 +0200
Subject: [PATCH 03/29] Add informations about the logo to the guide

---
 guide/src/format/configuration/general.md | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/guide/src/format/configuration/general.md b/guide/src/format/configuration/general.md
index a01b0b1008..aa198dd391 100644
--- a/guide/src/format/configuration/general.md
+++ b/guide/src/format/configuration/general.md
@@ -49,16 +49,20 @@ This is general information about your book.
   This is also used to derive the direction of text (RTL, LTR) within the book.
 - **text-direction**: The direction of text in the book: Left-to-right (LTR) or Right-to-left (RTL). Possible values: `ltr`, `rtl`.
   When not specified, the text direction is derived from the book's `language` attribute.
+- **logo:** Path to a logo to shown at the top of the navigation bar. If this
+  is given as a relative path, it's base directory is the source directory.
 
 **book.toml**
+
 ```toml
 [book]
 title = "Example book"
 authors = ["John Doe", "Jane Doe"]
 description = "The example book covers examples."
 src = "my-src"  # the source files will be found in `root/my-src` instead of `root/src`
-language = "en"
+language = "en
 text-direction = "ltr"
+logo = "static/logo.png"
 ```
 
 ### Rust options

From 96de6871400c6f2848ae20921c3c608283fe2624 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Guth?= <b.guth@netcon-consulting.com>
Date: Sun, 24 Oct 2021 21:18:35 +0200
Subject: [PATCH 04/29] Fix a typo

---
 guide/src/format/configuration/general.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/guide/src/format/configuration/general.md b/guide/src/format/configuration/general.md
index aa198dd391..9b99e098e5 100644
--- a/guide/src/format/configuration/general.md
+++ b/guide/src/format/configuration/general.md
@@ -50,7 +50,7 @@ This is general information about your book.
 - **text-direction**: The direction of text in the book: Left-to-right (LTR) or Right-to-left (RTL). Possible values: `ltr`, `rtl`.
   When not specified, the text direction is derived from the book's `language` attribute.
 - **logo:** Path to a logo to shown at the top of the navigation bar. If this
-  is given as a relative path, it's base directory is the source directory.
+  is given as a relative path, its base directory is the source directory.
 
 **book.toml**
 

From f446322d89d201fb105b210eae17d2028daef138 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Guth?= <b.guth@netcon-consulting.com>
Date: Sun, 24 Oct 2021 22:51:02 +0200
Subject: [PATCH 05/29] Fix the link to the logo so it worked on every page

---
 crates/mdbook-html/front-end/templates/index.hbs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/mdbook-html/front-end/templates/index.hbs b/crates/mdbook-html/front-end/templates/index.hbs
index 4f982bfd0e..5b21acab5a 100644
--- a/crates/mdbook-html/front-end/templates/index.hbs
+++ b/crates/mdbook-html/front-end/templates/index.hbs
@@ -128,7 +128,7 @@
         <nav id="mdbook-sidebar" class="sidebar" aria-label="Table of contents">
             {{#if book_logo }}
                 <div class="sidebar-book-logo">
-                    <img src="{{ book_logo }}">
+                    <img src="{{ path_to_root }}{{ book_logo }}">
                 </div>
             {{/if}}
             <!-- populated by js -->

From a2e36aede27c1a3700c5bc875200af4cde30c8c1 Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Thu, 3 Sep 2026 16:09:04 -0400
Subject: [PATCH 06/29] fix tests

---
 tests/testsuite/config.rs       | 4 ++--
 tests/testsuite/preprocessor.rs | 3 ++-
 tests/testsuite/renderer.rs     | 3 ++-
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/tests/testsuite/config.rs b/tests/testsuite/config.rs
index f3284c0426..017b52ecac 100644
--- a/tests/testsuite/config.rs
+++ b/tests/testsuite/config.rs
@@ -176,7 +176,7 @@ ERROR Invalid configuration file
   |
 3 | foo = 123
   | ^^^
-unknown field `foo`, expected one of `title`, `authors`, `description`, `src`, `language`, `text-direction`
+unknown field `foo`, expected one of `title`, `authors`, `description`, `src`, `language`, `text-direction`, `logo`
 
 
 "#]]);
@@ -232,7 +232,7 @@ fn env_invalid_value() {
                 .expect_failure()
                 .expect_stdout(str![[""]])
                 .expect_stderr(str![[r#"
-ERROR unknown field `titlez`, expected one of `title`, `authors`, `description`, `src`, `language`, `text-direction`
+ERROR unknown field `titlez`, expected one of `title`, `authors`, `description`, `src`, `language`, `text-direction`, `logo`
 
 
 "#]]);
diff --git a/tests/testsuite/preprocessor.rs b/tests/testsuite/preprocessor.rs
index 33c320785e..037179e8cc 100644
--- a/tests/testsuite/preprocessor.rs
+++ b/tests/testsuite/preprocessor.rs
@@ -363,7 +363,8 @@ fn extension_compatibility() {
           "description": null,
           "language": "en",
           "text-direction": null,
-          "title": "extension_compatibility"
+          "title": "extension_compatibility",
+          "logo": null,
         },
         "output": {
           "html": {},
diff --git a/tests/testsuite/renderer.rs b/tests/testsuite/renderer.rs
index 2dbe272735..4c1011fc4c 100644
--- a/tests/testsuite/renderer.rs
+++ b/tests/testsuite/renderer.rs
@@ -185,11 +185,12 @@ fn backends_receive_render_context_via_stdin() {
   },
   "config": {
     "book": {
+      "title": null,
       "authors": [],
       "description": null,
       "language": "en",
       "text-direction": null,
-      "title": null
+      "logo": null
     },
     "output": {
       "cat-to-file": {

From 3c16f0f4d6622e1d7d72bd03aeb27b962d1d8998 Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Fri, 4 Sep 2026 08:54:43 -0400
Subject: [PATCH 07/29] add alt to book logo

---
 crates/mdbook-html/front-end/templates/index.hbs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/mdbook-html/front-end/templates/index.hbs b/crates/mdbook-html/front-end/templates/index.hbs
index 5b21acab5a..b1f6f5a07a 100644
--- a/crates/mdbook-html/front-end/templates/index.hbs
+++ b/crates/mdbook-html/front-end/templates/index.hbs
@@ -128,7 +128,7 @@
         <nav id="mdbook-sidebar" class="sidebar" aria-label="Table of contents">
             {{#if book_logo }}
                 <div class="sidebar-book-logo">
-                    <img src="{{ path_to_root }}{{ book_logo }}">
+                    <img src="{{ path_to_root }}{{ book_logo }}" alt="{{ book_title }}">
                 </div>
             {{/if}}
             <!-- populated by js -->

From eafe56329b61c92ca3ce6098b9e6f17e10e529e7 Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Fri, 4 Sep 2026 08:56:56 -0400
Subject: [PATCH 08/29] change logo extension from png to svg in guide
 documentation

---
 guide/src/format/configuration/general.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/guide/src/format/configuration/general.md b/guide/src/format/configuration/general.md
index 9b99e098e5..ddaacaab33 100644
--- a/guide/src/format/configuration/general.md
+++ b/guide/src/format/configuration/general.md
@@ -62,7 +62,7 @@ description = "The example book covers examples."
 src = "my-src"  # the source files will be found in `root/my-src` instead of `root/src`
 language = "en
 text-direction = "ltr"
-logo = "static/logo.png"
+logo = "static/logo.svg"
 ```
 
 ### Rust options

From 613e08eb8a0c2ca93300196dbb21b109f50f1045 Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Fri, 4 Sep 2026 09:56:34 -0400
Subject: [PATCH 09/29] fix display issue for logo ; it is now displayed in the
 center of the sidebar, at fix width of 40% the sidebar width, and actually
 shows no matter the depth level of the current page

---
 crates/mdbook-html/front-end/css/chrome.css       | 7 +++----
 crates/mdbook-html/front-end/templates/index.hbs  | 5 -----
 crates/mdbook-html/front-end/templates/toc.js.hbs | 5 ++++-
 3 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/crates/mdbook-html/front-end/css/chrome.css b/crates/mdbook-html/front-end/css/chrome.css
index 18b462943a..ed2ba74f81 100644
--- a/crates/mdbook-html/front-end/css/chrome.css
+++ b/crates/mdbook-html/front-end/css/chrome.css
@@ -500,10 +500,9 @@ html:not(.sidebar-resizing) .sidebar {
 }
 .sidebar .sidebar-scrollbox .sidebar-book-logo img {
     display: block;
-    margin-left: auto;
-    margin-right: auto;
-    max-width: max-content;
-    width: 100%;
+    height: auto;
+    margin: 10px 30%;
+    width: 40%;
 }
 .sidebar .sidebar-resize-handle {
     position: absolute;
diff --git a/crates/mdbook-html/front-end/templates/index.hbs b/crates/mdbook-html/front-end/templates/index.hbs
index b1f6f5a07a..b1834189f9 100644
--- a/crates/mdbook-html/front-end/templates/index.hbs
+++ b/crates/mdbook-html/front-end/templates/index.hbs
@@ -126,11 +126,6 @@
         </script>
 
         <nav id="mdbook-sidebar" class="sidebar" aria-label="Table of contents">
-            {{#if book_logo }}
-                <div class="sidebar-book-logo">
-                    <img src="{{ path_to_root }}{{ book_logo }}" alt="{{ book_title }}">
-                </div>
-            {{/if}}
             <!-- populated by js -->
             <mdbook-sidebar-scrollbox class="sidebar-scrollbox"></mdbook-sidebar-scrollbox>
             <noscript>
diff --git a/crates/mdbook-html/front-end/templates/toc.js.hbs b/crates/mdbook-html/front-end/templates/toc.js.hbs
index 3b0b70c365..b036361bf4 100644
--- a/crates/mdbook-html/front-end/templates/toc.js.hbs
+++ b/crates/mdbook-html/front-end/templates/toc.js.hbs
@@ -8,7 +8,10 @@ class MDBookSidebarScrollbox extends HTMLElement {
         super();
     }
     connectedCallback() {
-        this.innerHTML = '{{#toc}}{{/toc}}';
+        {{#if book_logo }}
+        this.innerHTML = '<div class="sidebar-book-logo"><img src="' + path_to_root + '{{ book_logo }}" alt="{{ book_title }}"></div>';
+        {{/if}}
+        this.innerHTML += '{{#toc}}{{/toc}}';
         // Set the current, active page, and reveal it if it's hidden
         let current_page = document.location.href.toString().split('#')[0].split('?')[0];
         if (current_page.endsWith('/')) {

From f6ad728fc4b179ffcc66451dd3894723b7eb5306 Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Fri, 4 Sep 2026 09:57:24 -0400
Subject: [PATCH 10/29] add logo to guide

---
 guide/book.toml           |  1 +
 guide/src/images/logo.svg | 22 ++++++++++++++++++++++
 2 files changed, 23 insertions(+)
 create mode 100755 guide/src/images/logo.svg

diff --git a/guide/book.toml b/guide/book.toml
index 2e6ae364c6..14fb8bd21f 100644
--- a/guide/book.toml
+++ b/guide/book.toml
@@ -3,6 +3,7 @@ title = "mdBook Documentation"
 description = "Create book from markdown files. Like Gitbook but implemented in Rust"
 authors = ["Mathieu David", "Michael-F-Bryan"]
 language = "en"
+logo = "images/logo.svg"
 
 [rust]
 edition = "2018"
diff --git a/guide/src/images/logo.svg b/guide/src/images/logo.svg
new file mode 100755
index 0000000000..90e0ea58bd
--- /dev/null
+++ b/guide/src/images/logo.svg
@@ -0,0 +1,22 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 199.7 184.2">
+  <style>
+    @media (prefers-color-scheme: dark) {
+      svg { fill: white; }
+    }
+  </style>
+<path d="M189.5,36.8c0.2,2.8,0,5.1-0.6,6.8L153,162c-0.6,2.1-2,3.7-4.2,5c-2.2,1.2-4.4,1.9-6.7,1.9H31.4c-9.6,0-15.3-2.8-17.3-8.4
+  c-0.8-2.2-0.8-3.9,0.1-5.2c0.9-1.2,2.4-1.8,4.6-1.8H123c7.4,0,12.6-1.4,15.4-4.1s5.7-8.9,8.6-18.4l32.9-108.6
+  c1.8-5.9,1-11.1-2.2-15.6S169.9,0,164,0H72.7c-1,0-3.1,0.4-6.1,1.1l0.1-0.4C64.5,0.2,62.6,0,61,0.1s-3,0.5-4.3,1.4
+  c-1.3,0.9-2.4,1.8-3.2,2.8S52,6.5,51.2,8.1c-0.8,1.6-1.4,3-1.9,4.3s-1.1,2.7-1.8,4.2c-0.7,1.5-1.3,2.7-2,3.7c-0.5,0.6-1.2,1.5-2,2.5
+  s-1.6,2-2.2,2.8s-0.9,1.5-1.1,2.2c-0.2,0.7-0.1,1.8,0.2,3.2c0.3,1.4,0.4,2.4,0.4,3.1c-0.3,3-1.4,6.9-3.3,11.6
+  c-1.9,4.7-3.6,8.1-5.1,10.1c-0.3,0.4-1.2,1.3-2.6,2.7c-1.4,1.4-2.3,2.6-2.6,3.7c-0.3,0.4-0.3,1.5-0.1,3.4c0.3,1.8,0.4,3.1,0.3,3.8
+  c-0.3,2.7-1.3,6.3-3,10.8c-1.7,4.5-3.4,8.2-5,11c-0.2,0.5-0.9,1.4-2,2.8c-1.1,1.4-1.8,2.5-2,3.4c-0.2,0.6-0.1,1.8,0.1,3.4
+  c0.2,1.6,0.2,2.8-0.1,3.6c-0.6,3-1.8,6.7-3.6,11c-1.8,4.3-3.6,7.9-5.4,11c-0.5,0.8-1.1,1.7-2,2.8c-0.8,1.1-1.5,2-2,2.8
+  s-0.8,1.6-1,2.5c-0.1,0.5,0,1.3,0.4,2.3c0.3,1.1,0.4,1.9,0.4,2.6c-0.1,1.1-0.2,2.6-0.5,4.4c-0.2,1.8-0.4,2.9-0.4,3.2
+  c-1.8,4.8-1.7,9.9,0.2,15.2c2.2,6.2,6.2,11.5,11.9,15.8c5.7,4.3,11.7,6.4,17.8,6.4h110.7c5.2,0,10.1-1.7,14.7-5.2s7.7-7.8,9.2-12.9
+  l33-108.6c1.8-5.8,1-10.9-2.2-15.5C194.9,39.7,192.6,38,189.5,36.8z M59.6,122.8L73.8,80c0,0,7,0,10.8,0s28.8-1.7,25.4,17.5
+  c-3.4,19.2-18.8,25.2-36.8,25.4S59.6,122.8,59.6,122.8z M78.6,116.8c4.7-0.1,18.9-2.9,22.1-17.1S89.2,86.3,89.2,86.3l-8.9,0
+  l-10.2,30.5C70.2,116.9,74,116.9,78.6,116.8z M75.3,68.7L89,26.2h9.8l0.8,34l23.6-34h9.9l-13.6,42.5h-7.1l12.5-35.4l-24.5,35.4h-6.8
+  l-0.8-35L82,68.7H75.3z"/>
+</svg>
+<!-- Original image Copyright Dave Gandy — CC BY 4.0 License -->

From 375fa9e5cae18809020b3617a86342ecd83d96b4 Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Fri, 4 Sep 2026 10:18:07 -0400
Subject: [PATCH 11/29] fix broken tests

---
 crates/mdbook-html/front-end/templates/toc.js.hbs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/crates/mdbook-html/front-end/templates/toc.js.hbs b/crates/mdbook-html/front-end/templates/toc.js.hbs
index b036361bf4..844f32e931 100644
--- a/crates/mdbook-html/front-end/templates/toc.js.hbs
+++ b/crates/mdbook-html/front-end/templates/toc.js.hbs
@@ -9,9 +9,10 @@ class MDBookSidebarScrollbox extends HTMLElement {
     }
     connectedCallback() {
         {{#if book_logo }}
-        this.innerHTML = '<div class="sidebar-book-logo"><img src="' + path_to_root + '{{ book_logo }}" alt="{{ book_title }}"></div>';
+        this.innerHTML = '<div class="sidebar-book-logo"><img src="' + path_to_root + '{{ book_logo }}" alt="{{ book_title }}"></div>{{#toc}}{{/toc}}';
+        {{else}}
+        this.innerHTML = '{{#toc}}{{/toc}}';
         {{/if}}
-        this.innerHTML += '{{#toc}}{{/toc}}';
         // Set the current, active page, and reveal it if it's hidden
         let current_page = document.location.href.toString().split('#')[0].split('?')[0];
         if (current_page.endsWith('/')) {

From bfa235faaecae9f2aa87524f344fc468f6dc8527 Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Fri, 4 Sep 2026 10:18:43 -0400
Subject: [PATCH 12/29] add logo path to complex test example

---
 crates/mdbook-core/src/config.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/crates/mdbook-core/src/config.rs b/crates/mdbook-core/src/config.rs
index 58c2321334..42178f1c9d 100644
--- a/crates/mdbook-core/src/config.rs
+++ b/crates/mdbook-core/src/config.rs
@@ -746,6 +746,7 @@ mod tests {
         description = "A completely useless book"
         src = "source"
         language = "ja"
+        logo = "images/logo.svg"
 
         [build]
         build-dir = "outputs"
@@ -783,8 +784,7 @@ mod tests {
             src: PathBuf::from("source"),
             language: Some(String::from("ja")),
             text_direction: None,
-            // TODO: add a test logo
-            logo: None,
+            logo: Some(PathBuf::from("images/logo.svg")),
         };
         let build_should_be = BuildConfig {
             build_dir: PathBuf::from("outputs"),

From c907143f1e520138d1065a901f145ff65940af28 Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Fri, 4 Sep 2026 10:50:41 -0400
Subject: [PATCH 13/29] add title next to logo to fill the space, rustdoc style

---
 crates/mdbook-html/front-end/css/chrome.css     | 17 +++++++++++++++--
 .../mdbook-html/front-end/templates/toc.js.hbs  |  9 +++++----
 2 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/crates/mdbook-html/front-end/css/chrome.css b/crates/mdbook-html/front-end/css/chrome.css
index ed2ba74f81..988a027348 100644
--- a/crates/mdbook-html/front-end/css/chrome.css
+++ b/crates/mdbook-html/front-end/css/chrome.css
@@ -498,12 +498,25 @@ html:not(.sidebar-resizing) .sidebar {
     right: 0;
     padding: 10px 10px;
 }
+.sidebar .sidebar-scrollbox .sidebar-book-logo {
+    align-items: center;
+    column-gap: 20px;
+    display: flex;
+    justify-content: center;
+    margin: 20px 0;
+}
 .sidebar .sidebar-scrollbox .sidebar-book-logo img {
     display: block;
     height: auto;
-    margin: 10px 30%;
-    width: 40%;
+    width: 20%;
 }
+.sidebar .sidebar-scrollbox .sidebar-book-logo h2 {
+    margin: 0;
+    max-width: 70%;
+    overflow-wrap: anywhere;
+    text-wrap: balance;
+}
+
 .sidebar .sidebar-resize-handle {
     position: absolute;
     cursor: col-resize;
diff --git a/crates/mdbook-html/front-end/templates/toc.js.hbs b/crates/mdbook-html/front-end/templates/toc.js.hbs
index 844f32e931..ba899b5c29 100644
--- a/crates/mdbook-html/front-end/templates/toc.js.hbs
+++ b/crates/mdbook-html/front-end/templates/toc.js.hbs
@@ -8,11 +8,12 @@ class MDBookSidebarScrollbox extends HTMLElement {
         super();
     }
     connectedCallback() {
-        {{#if book_logo }}
-        this.innerHTML = '<div class="sidebar-book-logo"><img src="' + path_to_root + '{{ book_logo }}" alt="{{ book_title }}"></div>{{#toc}}{{/toc}}';
-        {{else}}
+{{#if book_logo }}
+        this.innerHTML =
+            '<div class="sidebar-book-logo"><img src="' + path_to_root + '{{ book_logo }}" alt="{{ book_title }}"><h2 class="sidebar-logo-title">{{ book_title }}</h2></div>{{#toc}}{{/toc}}';
+{{else}}
         this.innerHTML = '{{#toc}}{{/toc}}';
-        {{/if}}
+{{/if}}
         // Set the current, active page, and reveal it if it's hidden
         let current_page = document.location.href.toString().split('#')[0].split('?')[0];
         if (current_page.endsWith('/')) {

From ed6c15000ae38cf2367113c3f17b0529d462db7c Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Fri, 4 Sep 2026 10:55:39 -0400
Subject: [PATCH 14/29] fix gui test

---
 crates/mdbook-html/front-end/templates/toc.js.hbs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/crates/mdbook-html/front-end/templates/toc.js.hbs b/crates/mdbook-html/front-end/templates/toc.js.hbs
index ba899b5c29..0e44a18565 100644
--- a/crates/mdbook-html/front-end/templates/toc.js.hbs
+++ b/crates/mdbook-html/front-end/templates/toc.js.hbs
@@ -10,7 +10,8 @@ class MDBookSidebarScrollbox extends HTMLElement {
     connectedCallback() {
 {{#if book_logo }}
         this.innerHTML =
-            '<div class="sidebar-book-logo"><img src="' + path_to_root + '{{ book_logo }}" alt="{{ book_title }}"><h2 class="sidebar-logo-title">{{ book_title }}</h2></div>{{#toc}}{{/toc}}';
+            '<div class="sidebar-book-logo"><img src="' + path_to_root + '{{ book_logo }}" alt="{{ book_title }}">' +
+            '<h2 class="sidebar-logo-title">{{ book_title }}</h2></div>{{#toc}}{{/toc}}';
 {{else}}
         this.innerHTML = '{{#toc}}{{/toc}}';
 {{/if}}

From 4b35b3f8b16114ac063c9de5e25e7f4bc6e3ffb1 Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Fri, 4 Sep 2026 13:58:10 -0400
Subject: [PATCH 15/29] add missing double quote

---
 guide/src/format/configuration/general.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/guide/src/format/configuration/general.md b/guide/src/format/configuration/general.md
index ddaacaab33..bef59f0d47 100644
--- a/guide/src/format/configuration/general.md
+++ b/guide/src/format/configuration/general.md
@@ -60,7 +60,7 @@ title = "Example book"
 authors = ["John Doe", "Jane Doe"]
 description = "The example book covers examples."
 src = "my-src"  # the source files will be found in `root/my-src` instead of `root/src`
-language = "en
+language = "en"
 text-direction = "ltr"
 logo = "static/logo.svg"
 ```

From 9217acc6c7d9384c2d46b8bf22aa2b4945330356 Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Fri, 4 Sep 2026 14:02:36 -0400
Subject: [PATCH 16/29] fix properties order

---
 tests/testsuite/preprocessor.rs | 4 ++--
 tests/testsuite/renderer.rs     | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/tests/testsuite/preprocessor.rs b/tests/testsuite/preprocessor.rs
index 037179e8cc..b8c0a5c78b 100644
--- a/tests/testsuite/preprocessor.rs
+++ b/tests/testsuite/preprocessor.rs
@@ -362,9 +362,9 @@ fn extension_compatibility() {
           "authors": [],
           "description": null,
           "language": "en",
-          "text-direction": null,
-          "title": "extension_compatibility",
           "logo": null,
+          "text-direction": null,
+          "title": "extension_compatibility"
         },
         "output": {
           "html": {},
diff --git a/tests/testsuite/renderer.rs b/tests/testsuite/renderer.rs
index 4c1011fc4c..27eb00bc3e 100644
--- a/tests/testsuite/renderer.rs
+++ b/tests/testsuite/renderer.rs
@@ -185,12 +185,12 @@ fn backends_receive_render_context_via_stdin() {
   },
   "config": {
     "book": {
-      "title": null,
       "authors": [],
       "description": null,
       "language": "en",
+      "logo": null,
       "text-direction": null,
-      "logo": null
+      "title": null
     },
     "output": {
       "cat-to-file": {

From 5c5d81a450c9e7580e7ba3ad5f4f69297541cc5d Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Sat, 5 Sep 2026 10:17:34 -0400
Subject: [PATCH 17/29] add tests: display, position, src, across different
 nested chapters

---
 .../front-end/templates/toc.js.hbs            |  3 +-
 tests/gui/books/sidebar-logo/book.toml        |  4 +
 tests/gui/books/sidebar-logo/src/SUMMARY.md   |  6 ++
 tests/gui/books/sidebar-logo/src/chapter_1.md |  3 +
 tests/gui/books/sidebar-logo/src/chapter_2.md |  3 +
 tests/gui/books/sidebar-logo/src/logo.svg     |  1 +
 .../src/nested/again/chapter_nested.md        |  3 +
 .../sidebar-logo/src/nested/chapter_nested.md |  3 +
 tests/gui/sidebar-logo.goml                   | 73 +++++++++++++++++++
 tests/gui/sidebar.goml                        |  3 +
 10 files changed, 101 insertions(+), 1 deletion(-)
 create mode 100644 tests/gui/books/sidebar-logo/book.toml
 create mode 100644 tests/gui/books/sidebar-logo/src/SUMMARY.md
 create mode 100644 tests/gui/books/sidebar-logo/src/chapter_1.md
 create mode 100644 tests/gui/books/sidebar-logo/src/chapter_2.md
 create mode 100644 tests/gui/books/sidebar-logo/src/logo.svg
 create mode 100644 tests/gui/books/sidebar-logo/src/nested/again/chapter_nested.md
 create mode 100644 tests/gui/books/sidebar-logo/src/nested/chapter_nested.md
 create mode 100644 tests/gui/sidebar-logo.goml

diff --git a/crates/mdbook-html/front-end/templates/toc.js.hbs b/crates/mdbook-html/front-end/templates/toc.js.hbs
index 0e44a18565..47bfcfce3f 100644
--- a/crates/mdbook-html/front-end/templates/toc.js.hbs
+++ b/crates/mdbook-html/front-end/templates/toc.js.hbs
@@ -10,7 +10,8 @@ class MDBookSidebarScrollbox extends HTMLElement {
     connectedCallback() {
 {{#if book_logo }}
         this.innerHTML =
-            '<div class="sidebar-book-logo"><img src="' + path_to_root + '{{ book_logo }}" alt="{{ book_title }}">' +
+            '<div id="sidebar-book-logo" class="sidebar-book-logo"><img src="' + path_to_root +
+            '{{ book_logo }}" alt="{{ book_title }}" logo>' +
             '<h2 class="sidebar-logo-title">{{ book_title }}</h2></div>{{#toc}}{{/toc}}';
 {{else}}
         this.innerHTML = '{{#toc}}{{/toc}}';
diff --git a/tests/gui/books/sidebar-logo/book.toml b/tests/gui/books/sidebar-logo/book.toml
new file mode 100644
index 0000000000..d828346eec
--- /dev/null
+++ b/tests/gui/books/sidebar-logo/book.toml
@@ -0,0 +1,4 @@
+[book]
+title = "sidebar-logo test"
+language = "en"
+logo = "logo.svg"
diff --git a/tests/gui/books/sidebar-logo/src/SUMMARY.md b/tests/gui/books/sidebar-logo/src/SUMMARY.md
new file mode 100644
index 0000000000..d6aa0b7c79
--- /dev/null
+++ b/tests/gui/books/sidebar-logo/src/SUMMARY.md
@@ -0,0 +1,6 @@
+# Summary
+
+- [Chapter 1](./chapter_1.md)
+- [Chapter 2](./chapter_2.md)
+- [Nested](./nested/chapter_nested.md)
+- [Deeper](./nested/again/chapter_nested.md)
diff --git a/tests/gui/books/sidebar-logo/src/chapter_1.md b/tests/gui/books/sidebar-logo/src/chapter_1.md
new file mode 100644
index 0000000000..9cfa366566
--- /dev/null
+++ b/tests/gui/books/sidebar-logo/src/chapter_1.md
@@ -0,0 +1,3 @@
+# Chapter 1
+
+This is the first chapter to test logo display at root level.
diff --git a/tests/gui/books/sidebar-logo/src/chapter_2.md b/tests/gui/books/sidebar-logo/src/chapter_2.md
new file mode 100644
index 0000000000..620fffa1ea
--- /dev/null
+++ b/tests/gui/books/sidebar-logo/src/chapter_2.md
@@ -0,0 +1,3 @@
+# Chapter 2
+
+This is the second chapter.
diff --git a/tests/gui/books/sidebar-logo/src/logo.svg b/tests/gui/books/sidebar-logo/src/logo.svg
new file mode 100644
index 0000000000..1a6c762d4e
--- /dev/null
+++ b/tests/gui/books/sidebar-logo/src/logo.svg
@@ -0,0 +1 @@
+<svg height="144" width="144" xmlns="http://www.w3.org/2000/svg"><path d="m71.05 23.68c-26.06 0-47.27 21.22-47.27 47.27s21.22 47.27 47.27 47.27 47.27-21.22 47.27-47.27-21.22-47.27-47.27-47.27zm-.07 4.2a3.1 3.11 0 0 1 3.02 3.11 3.11 3.11 0 0 1 -6.22 0 3.11 3.11 0 0 1 3.2-3.11zm7.12 5.12a38.27 38.27 0 0 1 26.2 18.66l-3.67 8.28c-.63 1.43.02 3.11 1.44 3.75l7.06 3.13a38.27 38.27 0 0 1 .08 6.64h-3.93c-.39 0-.55.26-.55.64v1.8c0 4.24-2.39 5.17-4.49 5.4-2 .23-4.21-.84-4.49-2.06-1.18-6.63-3.14-8.04-6.24-10.49 3.85-2.44 7.85-6.05 7.85-10.87 0-5.21-3.57-8.49-6-10.1-3.42-2.25-7.2-2.7-8.22-2.7h-40.6a38.27 38.27 0 0 1 21.41-12.08l4.79 5.02c1.08 1.13 2.87 1.18 4 .09zm-44.2 23.02a3.11 3.11 0 0 1 3.02 3.11 3.11 3.11 0 0 1 -6.22 0 3.11 3.11 0 0 1 3.2-3.11zm74.15.14a3.11 3.11 0 0 1 3.02 3.11 3.11 3.11 0 0 1 -6.22 0 3.11 3.11 0 0 1 3.2-3.11zm-68.29.5h5.42v24.44h-10.94a38.27 38.27 0 0 1 -1.24-14.61l6.7-2.98c1.43-.64 2.08-2.31 1.44-3.74zm22.62.26h12.91c.67 0 4.71.77 4.71 3.8 0 2.51-3.1 3.41-5.65 3.41h-11.98zm0 17.56h9.89c.9 0 4.83.26 6.08 5.28.39 1.54 1.26 6.56 1.85 8.17.59 1.8 2.98 5.4 5.53 5.4h16.14a38.27 38.27 0 0 1 -3.54 4.1l-6.57-1.41c-1.53-.33-3.04.65-3.37 2.18l-1.56 7.28a38.27 38.27 0 0 1 -31.91-.15l-1.56-7.28c-.33-1.53-1.83-2.51-3.36-2.18l-6.43 1.38a38.27 38.27 0 0 1 -3.32-3.92h31.27c.35 0 .59-.06.59-.39v-11.06c0-.32-.24-.39-.59-.39h-9.15zm-14.43 25.33a3.11 3.11 0 0 1 3.02 3.11 3.11 3.11 0 0 1 -6.22 0 3.11 3.11 0 0 1 3.2-3.11zm46.05.14a3.11 3.11 0 0 1 3.02 3.11 3.11 3.11 0 0 1 -6.22 0 3.11 3.11 0 0 1 3.2-3.11z"/><path d="m115.68 70.95a44.63 44.63 0 0 1 -44.63 44.63 44.63 44.63 0 0 1 -44.63-44.63 44.63 44.63 0 0 1 44.63-44.63 44.63 44.63 0 0 1 44.63 44.63zm-.84-4.31 6.96 4.31-6.96 4.31 5.98 5.59-7.66 2.87 4.78 6.65-8.09 1.32 3.4 7.46-8.19-.29 1.88 7.98-7.98-1.88.29 8.19-7.46-3.4-1.32 8.09-6.65-4.78-2.87 7.66-5.59-5.98-4.31 6.96-4.31-6.96-5.59 5.98-2.87-7.66-6.65 4.78-1.32-8.09-7.46 3.4.29-8.19-7.98 1.88 1.88-7.98-8.19.29 3.4-7.46-8.09-1.32 4.78-6.65-7.66-2.87 5.98-5.59-6.96-4.31 6.96-4.31-5.98-5.59 7.66-2.87-4.78-6.65 8.09-1.32-3.4-7.46 8.19.29-1.88-7.98 7.98 1.88-.29-8.19 7.46 3.4 1.32-8.09 6.65 4.78 2.87-7.66 5.59 5.98 4.31-6.96 4.31 6.96 5.59-5.98 2.87 7.66 6.65-4.78 1.32 8.09 7.46-3.4-.29 8.19 7.98-1.88-1.88 7.98 8.19-.29-3.4 7.46 8.09 1.32-4.78 6.65 7.66 2.87z" fill-rule="evenodd" stroke="#000" stroke-linecap="round" stroke-linejoin="round" stroke-width="3"/></svg>
\ No newline at end of file
diff --git a/tests/gui/books/sidebar-logo/src/nested/again/chapter_nested.md b/tests/gui/books/sidebar-logo/src/nested/again/chapter_nested.md
new file mode 100644
index 0000000000..9504f99f8e
--- /dev/null
+++ b/tests/gui/books/sidebar-logo/src/nested/again/chapter_nested.md
@@ -0,0 +1,3 @@
+# Deeper Chapter
+
+This is a nested chapter to test logo display at different nesting levels.
diff --git a/tests/gui/books/sidebar-logo/src/nested/chapter_nested.md b/tests/gui/books/sidebar-logo/src/nested/chapter_nested.md
new file mode 100644
index 0000000000..8d4948d7eb
--- /dev/null
+++ b/tests/gui/books/sidebar-logo/src/nested/chapter_nested.md
@@ -0,0 +1,3 @@
+# Nested Chapter
+
+This is a nested chapter to test logo display at different nesting levels.
diff --git a/tests/gui/sidebar-logo.goml b/tests/gui/sidebar-logo.goml
new file mode 100644
index 0000000000..931a106952
--- /dev/null
+++ b/tests/gui/sidebar-logo.goml
@@ -0,0 +1,73 @@
+// This GUI test checks that the logo is displayed when configured
+// Test cases:
+// - test if the logo is displayed when provided
+// - test it is displayed above the toc
+// - test if works in nested files (level 0, 1 and n > 1)
+
+go-to: |DOC_PATH| + "sidebar-logo/index.html"
+set-window-size: (1100, 600)
+reload:
+
+define-function: (
+    "assert-logo",
+    [],
+    block {
+        assert-css: ("#sidebar-book-logo", {"display": "flex"})
+        assert-css: ("#sidebar-book-logo img", {"display": "block"})
+    },
+)
+
+define-function: (
+    "assert-logo-src",
+    [prefix],
+    block {
+        store-attribute: (".sidebar-book-logo img", {"src": logo_src})
+        assert: |logo_src| == |prefix| + "logo.svg"
+        assert-find-text-false: "sidebar-logo test logo"
+    },
+)
+
+define-function: (
+    "assert-logo-position",
+    [],
+    block {
+        store-position: ("#sidebar-book-logo img", {"y": logo_y})
+        store-position: ("ol.chapter", {"y": chapter_y})
+        assert: |logo_y| < |chapter_y|
+    },
+)
+
+// Wait for the TOC to be populated by JavaScript
+assert-find-text: "Deeper"
+wait-for: "mdbook-sidebar-scrollbox"
+wait-for: "ol.chapter"
+wait-for: "#sidebar-book-logo"
+
+// The sidebar-book-logo should exist when logo is provided
+call-function: ("assert-logo", {})
+
+// Logo image should have the correct src path and loaded
+call-function: ("assert-logo-src", {"prefix": ""})
+
+// Logo should be above the TOC
+call-function: ("assert-logo-position", {})
+
+// Test on chapter_2, nested, and deeper
+click: ".chapter a[href='chapter_2.html']"
+wait-for-text: (".header", "Chapter 2")
+call-function: ("assert-logo", {})
+call-function: ("assert-logo-src", {"prefix": ""})
+call-function: ("assert-logo-position", {})
+
+
+click: ".chapter a[href='nested/chapter_nested.html']"
+wait-for-text: (".header", "Nested Chapter")
+call-function: ("assert-logo", {})
+call-function: ("assert-logo-src", {"prefix": "../"})
+call-function: ("assert-logo-position", {})
+
+click: ".chapter a[href='../nested/again/chapter_nested.html']"
+wait-for-text: (".header", "Deeper Chapter")
+call-function: ("assert-logo", {})
+call-function: ("assert-logo-src", {"prefix": "../../"})
+call-function: ("assert-logo-position", {})
diff --git a/tests/gui/sidebar.goml b/tests/gui/sidebar.goml
index 50dc71a940..bac0c98345 100644
--- a/tests/gui/sidebar.goml
+++ b/tests/gui/sidebar.goml
@@ -67,3 +67,6 @@ assert-local-storage: {|sidebar_storage_value|: |sidebar_storage_displayed_value
 // But the sidebar should be hidden anyway.
 assert-css: ("#mdbook-sidebar", {"display": "none"})
 assert-position: ("#mdbook-page-wrapper", {"x": 0})
+
+// The logo should not be displayed in the sidebar.
+assert-false: "#sidebar-book-logo"

From e6030edbf2a74d41b1b10b55dc187c0c8125895c Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Mon, 7 Sep 2026 19:20:07 -0400
Subject: [PATCH 18/29] Address comments

---
 crates/mdbook-html/front-end/templates/toc.js.hbs | 4 ++--
 guide/src/format/configuration/general.md         | 2 +-
 tests/gui/sidebar-logo.goml                       | 4 +---
 3 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/crates/mdbook-html/front-end/templates/toc.js.hbs b/crates/mdbook-html/front-end/templates/toc.js.hbs
index 47bfcfce3f..1796361f59 100644
--- a/crates/mdbook-html/front-end/templates/toc.js.hbs
+++ b/crates/mdbook-html/front-end/templates/toc.js.hbs
@@ -10,8 +10,8 @@ class MDBookSidebarScrollbox extends HTMLElement {
     connectedCallback() {
 {{#if book_logo }}
         this.innerHTML =
-            '<div id="sidebar-book-logo" class="sidebar-book-logo"><img src="' + path_to_root +
-            '{{ book_logo }}" alt="{{ book_title }}" logo>' +
+            '<div id="sidebar-book-logo" class="sidebar-book-logo">' +
+            '<img src="' + path_to_root + '{{ book_logo }}" alt="{{ book_title }}" logo>' +
             '<h2 class="sidebar-logo-title">{{ book_title }}</h2></div>{{#toc}}{{/toc}}';
 {{else}}
         this.innerHTML = '{{#toc}}{{/toc}}';
diff --git a/guide/src/format/configuration/general.md b/guide/src/format/configuration/general.md
index bef59f0d47..0dca16bbea 100644
--- a/guide/src/format/configuration/general.md
+++ b/guide/src/format/configuration/general.md
@@ -49,7 +49,7 @@ This is general information about your book.
   This is also used to derive the direction of text (RTL, LTR) within the book.
 - **text-direction**: The direction of text in the book: Left-to-right (LTR) or Right-to-left (RTL). Possible values: `ltr`, `rtl`.
   When not specified, the text direction is derived from the book's `language` attribute.
-- **logo:** Path to a logo to shown at the top of the navigation bar. If this
+- **logo:** Path to a logo to displayed at the top of the navigation bar. If this
   is given as a relative path, its base directory is the source directory.
 
 **book.toml**
diff --git a/tests/gui/sidebar-logo.goml b/tests/gui/sidebar-logo.goml
index 931a106952..d7b74235d8 100644
--- a/tests/gui/sidebar-logo.goml
+++ b/tests/gui/sidebar-logo.goml
@@ -21,8 +21,7 @@ define-function: (
     "assert-logo-src",
     [prefix],
     block {
-        store-attribute: (".sidebar-book-logo img", {"src": logo_src})
-        assert: |logo_src| == |prefix| + "logo.svg"
+        assert-attribute: (".sidebar-book-logo img", {"src": |prefix| + "logo.svg"})
         assert-find-text-false: "sidebar-logo test logo"
     },
 )
@@ -59,7 +58,6 @@ call-function: ("assert-logo", {})
 call-function: ("assert-logo-src", {"prefix": ""})
 call-function: ("assert-logo-position", {})
 
-
 click: ".chapter a[href='nested/chapter_nested.html']"
 wait-for-text: (".header", "Nested Chapter")
 call-function: ("assert-logo", {})

From 0aeacff7fdf48f1b06f7c5658635e6d7c38a71b4 Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Tue, 8 Sep 2026 12:05:58 -0400
Subject: [PATCH 19/29] crash after loading the config if the logo does not
 exist, add testcase supporting this claim

---
 crates/mdbook-core/src/config.rs            | 20 ++++++++++++++++++++
 crates/mdbook-driver/src/mdbook.rs          |  1 +
 tests/testsuite/main.rs                     |  1 +
 tests/testsuite/sidebar/logo/book.toml      |  2 ++
 tests/testsuite/sidebar/logo/src/SUMMARY.md |  0
 tests/testsuite/sidebar_logo.rs             | 11 +++++++++++
 6 files changed, 35 insertions(+)
 create mode 100644 tests/testsuite/sidebar/logo/book.toml
 create mode 100644 tests/testsuite/sidebar/logo/src/SUMMARY.md
 create mode 100644 tests/testsuite/sidebar_logo.rs

diff --git a/crates/mdbook-core/src/config.rs b/crates/mdbook-core/src/config.rs
index 42178f1c9d..81bf5c8071 100644
--- a/crates/mdbook-core/src/config.rs
+++ b/crates/mdbook-core/src/config.rs
@@ -303,6 +303,26 @@ impl Config {
 
         Ok(())
     }
+
+    /// The config can load properly with valid, but wrong values, for instance wrong paths.
+    /// This is the place to check for such config variables.
+    pub fn check<P: Into<PathBuf>>(&self, book_root: P) -> Result<()> {
+        // Make sure the `logo` path exists when provided.
+        if let Some(logo_cfg) = self.book.logo.clone() {
+            let logo_path = if logo_cfg.is_absolute() {
+                logo_cfg
+            } else {
+                book_root.into().join(&self.book.src).join(logo_cfg)
+            };
+            if !logo_path.exists() {
+                bail!(
+                    "invalid value for `logo`: {} does not exist",
+                    logo_path.to_str().unwrap_or(&logo_path.to_string_lossy())
+                );
+            }
+        }
+        Result::Ok(())
+    }
 }
 
 fn parse_env(key: &str) -> Option<String> {
diff --git a/crates/mdbook-driver/src/mdbook.rs b/crates/mdbook-driver/src/mdbook.rs
index 3e617de04b..92999aee6b 100644
--- a/crates/mdbook-driver/src/mdbook.rs
+++ b/crates/mdbook-driver/src/mdbook.rs
@@ -57,6 +57,7 @@ impl MDBook {
         };
 
         config.update_from_env()?;
+        config.check(book_root.clone())?;
 
         if tracing::enabled!(tracing::Level::TRACE) {
             for line in format!("Config: {config:#?}").lines() {
diff --git a/tests/testsuite/main.rs b/tests/testsuite/main.rs
index 9ef11dd76e..18d0d69a78 100644
--- a/tests/testsuite/main.rs
+++ b/tests/testsuite/main.rs
@@ -20,6 +20,7 @@ mod renderer;
 mod rendering;
 #[cfg(feature = "search")]
 mod search;
+mod sidebar_logo;
 mod test;
 mod theme;
 mod toc;
diff --git a/tests/testsuite/sidebar/logo/book.toml b/tests/testsuite/sidebar/logo/book.toml
new file mode 100644
index 0000000000..30ec31e982
--- /dev/null
+++ b/tests/testsuite/sidebar/logo/book.toml
@@ -0,0 +1,2 @@
+[book]
+logo = "does/not/exist"
diff --git a/tests/testsuite/sidebar/logo/src/SUMMARY.md b/tests/testsuite/sidebar/logo/src/SUMMARY.md
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/testsuite/sidebar_logo.rs b/tests/testsuite/sidebar_logo.rs
new file mode 100644
index 0000000000..ed4bd18ba7
--- /dev/null
+++ b/tests/testsuite/sidebar_logo.rs
@@ -0,0 +1,11 @@
+use crate::prelude::*;
+
+#[test]
+fn bad_logo_path() {
+    BookTest::from_dir("sidebar/logo").run("build", |cmd| {
+        cmd.expect_failure();
+        cmd.expect_stderr(
+            "ERROR invalid value for `logo`: [ROOT]/src/does/not/exist does not exist\n",
+        );
+    });
+}

From 024fb96d36bf9ac1f0275aafb5ccf30a1dca0090 Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Wed, 9 Sep 2026 11:26:13 -0400
Subject: [PATCH 20/29] replace logo copy with symlink

---
 guide/src/images/logo.svg | 23 +----------------------
 1 file changed, 1 insertion(+), 22 deletions(-)
 mode change 100755 => 120000 guide/src/images/logo.svg

diff --git a/guide/src/images/logo.svg b/guide/src/images/logo.svg
deleted file mode 100755
index 90e0ea58bd..0000000000
--- a/guide/src/images/logo.svg
+++ /dev/null
@@ -1,22 +0,0 @@
-<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 199.7 184.2">
-  <style>
-    @media (prefers-color-scheme: dark) {
-      svg { fill: white; }
-    }
-  </style>
-<path d="M189.5,36.8c0.2,2.8,0,5.1-0.6,6.8L153,162c-0.6,2.1-2,3.7-4.2,5c-2.2,1.2-4.4,1.9-6.7,1.9H31.4c-9.6,0-15.3-2.8-17.3-8.4
-  c-0.8-2.2-0.8-3.9,0.1-5.2c0.9-1.2,2.4-1.8,4.6-1.8H123c7.4,0,12.6-1.4,15.4-4.1s5.7-8.9,8.6-18.4l32.9-108.6
-  c1.8-5.9,1-11.1-2.2-15.6S169.9,0,164,0H72.7c-1,0-3.1,0.4-6.1,1.1l0.1-0.4C64.5,0.2,62.6,0,61,0.1s-3,0.5-4.3,1.4
-  c-1.3,0.9-2.4,1.8-3.2,2.8S52,6.5,51.2,8.1c-0.8,1.6-1.4,3-1.9,4.3s-1.1,2.7-1.8,4.2c-0.7,1.5-1.3,2.7-2,3.7c-0.5,0.6-1.2,1.5-2,2.5
-  s-1.6,2-2.2,2.8s-0.9,1.5-1.1,2.2c-0.2,0.7-0.1,1.8,0.2,3.2c0.3,1.4,0.4,2.4,0.4,3.1c-0.3,3-1.4,6.9-3.3,11.6
-  c-1.9,4.7-3.6,8.1-5.1,10.1c-0.3,0.4-1.2,1.3-2.6,2.7c-1.4,1.4-2.3,2.6-2.6,3.7c-0.3,0.4-0.3,1.5-0.1,3.4c0.3,1.8,0.4,3.1,0.3,3.8
-  c-0.3,2.7-1.3,6.3-3,10.8c-1.7,4.5-3.4,8.2-5,11c-0.2,0.5-0.9,1.4-2,2.8c-1.1,1.4-1.8,2.5-2,3.4c-0.2,0.6-0.1,1.8,0.1,3.4
-  c0.2,1.6,0.2,2.8-0.1,3.6c-0.6,3-1.8,6.7-3.6,11c-1.8,4.3-3.6,7.9-5.4,11c-0.5,0.8-1.1,1.7-2,2.8c-0.8,1.1-1.5,2-2,2.8
-  s-0.8,1.6-1,2.5c-0.1,0.5,0,1.3,0.4,2.3c0.3,1.1,0.4,1.9,0.4,2.6c-0.1,1.1-0.2,2.6-0.5,4.4c-0.2,1.8-0.4,2.9-0.4,3.2
-  c-1.8,4.8-1.7,9.9,0.2,15.2c2.2,6.2,6.2,11.5,11.9,15.8c5.7,4.3,11.7,6.4,17.8,6.4h110.7c5.2,0,10.1-1.7,14.7-5.2s7.7-7.8,9.2-12.9
-  l33-108.6c1.8-5.8,1-10.9-2.2-15.5C194.9,39.7,192.6,38,189.5,36.8z M59.6,122.8L73.8,80c0,0,7,0,10.8,0s28.8-1.7,25.4,17.5
-  c-3.4,19.2-18.8,25.2-36.8,25.4S59.6,122.8,59.6,122.8z M78.6,116.8c4.7-0.1,18.9-2.9,22.1-17.1S89.2,86.3,89.2,86.3l-8.9,0
-  l-10.2,30.5C70.2,116.9,74,116.9,78.6,116.8z M75.3,68.7L89,26.2h9.8l0.8,34l23.6-34h9.9l-13.6,42.5h-7.1l12.5-35.4l-24.5,35.4h-6.8
-  l-0.8-35L82,68.7H75.3z"/>
-</svg>
-<!-- Original image Copyright Dave Gandy — CC BY 4.0 License -->
diff --git a/guide/src/images/logo.svg b/guide/src/images/logo.svg
new file mode 120000
index 0000000000..d26ee9efe5
--- /dev/null
+++ b/guide/src/images/logo.svg
@@ -0,0 +1 @@
+../../../crates/mdbook-html/front-end/images/favicon.svg
\ No newline at end of file

From 258cce2b43b463d388c7c8bc25cf1fe4a99d7dd7 Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Thu, 10 Sep 2026 19:17:00 -0400
Subject: [PATCH 21/29] move test case

---
 tests/testsuite/sidebar/logo/{ => not_found}/book.toml      | 0
 tests/testsuite/sidebar/logo/{ => not_found}/src/SUMMARY.md | 0
 tests/testsuite/sidebar_logo.rs                             | 2 +-
 3 files changed, 1 insertion(+), 1 deletion(-)
 rename tests/testsuite/sidebar/logo/{ => not_found}/book.toml (100%)
 rename tests/testsuite/sidebar/logo/{ => not_found}/src/SUMMARY.md (100%)

diff --git a/tests/testsuite/sidebar/logo/book.toml b/tests/testsuite/sidebar/logo/not_found/book.toml
similarity index 100%
rename from tests/testsuite/sidebar/logo/book.toml
rename to tests/testsuite/sidebar/logo/not_found/book.toml
diff --git a/tests/testsuite/sidebar/logo/src/SUMMARY.md b/tests/testsuite/sidebar/logo/not_found/src/SUMMARY.md
similarity index 100%
rename from tests/testsuite/sidebar/logo/src/SUMMARY.md
rename to tests/testsuite/sidebar/logo/not_found/src/SUMMARY.md
diff --git a/tests/testsuite/sidebar_logo.rs b/tests/testsuite/sidebar_logo.rs
index ed4bd18ba7..5046cd98b4 100644
--- a/tests/testsuite/sidebar_logo.rs
+++ b/tests/testsuite/sidebar_logo.rs
@@ -2,7 +2,7 @@ use crate::prelude::*;
 
 #[test]
 fn bad_logo_path() {
-    BookTest::from_dir("sidebar/logo").run("build", |cmd| {
+    BookTest::from_dir("sidebar/logo/not_found").run("build", |cmd| {
         cmd.expect_failure();
         cmd.expect_stderr(
             "ERROR invalid value for `logo`: [ROOT]/src/does/not/exist does not exist\n",

From f59370d5fa902d7fbecf3051f9830ef96b5b9199 Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Tue, 15 Sep 2026 14:43:45 -0400
Subject: [PATCH 22/29] Rewrite check: revise failure conditions for logo
 config

Add tests and test files:
- large and tall images don't mess up layout
- logo config is validated, or error is thrown, regardless of the src
  directory
Update logo config documentation
---
 crates/mdbook-core/src/config.rs              | 42 +++++++++++++-----
 guide/src/format/configuration/general.md     |  5 +--
 tests/gui/books/sidebar-logo-large/book.toml  |  2 +
 .../books/sidebar-logo-large/src/SUMMARY.md   |  1 +
 tests/gui/books/sidebar-logo-large/src/c1.md  |  1 +
 .../gui/books/sidebar-logo-large/src/logo.svg |  3 ++
 tests/gui/books/sidebar-logo-tall/book.toml   |  2 +
 .../books/sidebar-logo-tall/src/SUMMARY.md    |  1 +
 tests/gui/books/sidebar-logo-tall/src/c1.md   |  1 +
 .../gui/books/sidebar-logo-tall/src/logo.svg  |  3 ++
 tests/gui/sidebar-logo.goml                   | 32 ++++++++++----
 .../testsuite/sidebar/logo/absolute/book.toml |  5 +++
 .../sidebar/logo/absolute/src/SUMMARY.md      |  3 ++
 .../sidebar/logo/absolute/src/chapter_1.md    |  1 +
 tests/testsuite/sidebar/logo/good/book.toml   |  4 ++
 .../sidebar/logo/good/src/SUMMARY.md          |  3 ++
 .../sidebar/logo/good/src/chapter_1.md        |  1 +
 .../testsuite/sidebar/logo/good/src/logo.svg  |  1 +
 .../sidebar/logo/other_src/book.toml          |  6 +++
 .../sidebar/logo/other_src/my-src/SUMMARY.md  |  3 ++
 .../logo/other_src/my-src/chapter_1.md        |  1 +
 .../sidebar/logo/other_src/my-src/logo.svg    | 22 ++++++++++
 .../testsuite/sidebar/logo/outside/book.toml  |  5 +++
 tests/testsuite/sidebar/logo/outside/logo.svg |  1 +
 .../sidebar/logo/outside/src/SUMMARY.md       |  3 ++
 .../sidebar/logo/outside/src/chapter_1.md     |  1 +
 tests/testsuite/sidebar_logo.rs               | 44 +++++++++++++++++++
 27 files changed, 174 insertions(+), 23 deletions(-)
 create mode 100644 tests/gui/books/sidebar-logo-large/book.toml
 create mode 100644 tests/gui/books/sidebar-logo-large/src/SUMMARY.md
 create mode 100644 tests/gui/books/sidebar-logo-large/src/c1.md
 create mode 100644 tests/gui/books/sidebar-logo-large/src/logo.svg
 create mode 100644 tests/gui/books/sidebar-logo-tall/book.toml
 create mode 100644 tests/gui/books/sidebar-logo-tall/src/SUMMARY.md
 create mode 100644 tests/gui/books/sidebar-logo-tall/src/c1.md
 create mode 100644 tests/gui/books/sidebar-logo-tall/src/logo.svg
 create mode 100644 tests/testsuite/sidebar/logo/absolute/book.toml
 create mode 100644 tests/testsuite/sidebar/logo/absolute/src/SUMMARY.md
 create mode 100644 tests/testsuite/sidebar/logo/absolute/src/chapter_1.md
 create mode 100644 tests/testsuite/sidebar/logo/good/book.toml
 create mode 100644 tests/testsuite/sidebar/logo/good/src/SUMMARY.md
 create mode 100644 tests/testsuite/sidebar/logo/good/src/chapter_1.md
 create mode 120000 tests/testsuite/sidebar/logo/good/src/logo.svg
 create mode 100644 tests/testsuite/sidebar/logo/other_src/book.toml
 create mode 100644 tests/testsuite/sidebar/logo/other_src/my-src/SUMMARY.md
 create mode 100644 tests/testsuite/sidebar/logo/other_src/my-src/chapter_1.md
 create mode 100755 tests/testsuite/sidebar/logo/other_src/my-src/logo.svg
 create mode 100644 tests/testsuite/sidebar/logo/outside/book.toml
 create mode 120000 tests/testsuite/sidebar/logo/outside/logo.svg
 create mode 100644 tests/testsuite/sidebar/logo/outside/src/SUMMARY.md
 create mode 100644 tests/testsuite/sidebar/logo/outside/src/chapter_1.md

diff --git a/crates/mdbook-core/src/config.rs b/crates/mdbook-core/src/config.rs
index 81bf5c8071..977d2cba4d 100644
--- a/crates/mdbook-core/src/config.rs
+++ b/crates/mdbook-core/src/config.rs
@@ -45,11 +45,11 @@
 
 use crate::static_regex;
 use crate::utils::{TomlExt, fs, log_backtrace};
-use anyhow::{Context, Error, Result, bail};
+use anyhow::{Context, Error, Result, anyhow, bail};
 use serde::{Deserialize, Serialize};
 use std::collections::{BTreeMap, HashMap};
 use std::env;
-use std::path::{Path, PathBuf};
+use std::path::{Component, Path, PathBuf};
 use std::str::FromStr;
 use toml::Value;
 use toml::value::Table;
@@ -307,18 +307,23 @@ impl Config {
     /// The config can load properly with valid, but wrong values, for instance wrong paths.
     /// This is the place to check for such config variables.
     pub fn check<P: Into<PathBuf>>(&self, book_root: P) -> Result<()> {
-        // Make sure the `logo` path exists when provided.
-        if let Some(logo_cfg) = self.book.logo.clone() {
-            let logo_path = if logo_cfg.is_absolute() {
-                logo_cfg
-            } else {
-                book_root.into().join(&self.book.src).join(logo_cfg)
-            };
+        if let Some(logo_path) = self.book.get_logo_absolute_path(book_root) {
+            // Forbid absolute paths and parent directory references in the config file
+            if let Some(logo_path) = &self.book.logo {
+                if logo_path.is_absolute()
+                    || logo_path.components().any(|c| c == Component::ParentDir)
+                {
+                    return Result::Err(anyhow!(
+                        "invalid value for `logo`: should live under `{}/`",
+                        self.book.src.to_string_lossy()
+                    ));
+                }
+            }
             if !logo_path.exists() {
-                bail!(
+                return Result::Err(anyhow!(
                     "invalid value for `logo`: {} does not exist",
-                    logo_path.to_str().unwrap_or(&logo_path.to_string_lossy())
-                );
+                    logo_path.to_str().unwrap_or(&logo_path.to_string_lossy()),
+                ));
             }
         }
         Result::Ok(())
@@ -384,6 +389,19 @@ impl BookConfig {
             TextDirection::from_lang_code(self.language.as_deref().unwrap_or_default())
         }
     }
+
+    /// Compute the absolute path of the book's logo, if provided, and canonicalize it
+    pub fn get_logo_absolute_path<P: Into<PathBuf>>(&self, book_root: P) -> Option<PathBuf> {
+        if let Some(logo_cfg) = self.logo.clone() {
+            Some(if logo_cfg.is_absolute() {
+                logo_cfg
+            } else {
+                book_root.into().join(&self.src).join(logo_cfg)
+            })
+        } else {
+            None
+        }
+    }
 }
 
 /// Text direction to use for HTML output
diff --git a/guide/src/format/configuration/general.md b/guide/src/format/configuration/general.md
index 0dca16bbea..89aff071e6 100644
--- a/guide/src/format/configuration/general.md
+++ b/guide/src/format/configuration/general.md
@@ -49,8 +49,7 @@ This is general information about your book.
   This is also used to derive the direction of text (RTL, LTR) within the book.
 - **text-direction**: The direction of text in the book: Left-to-right (LTR) or Right-to-left (RTL). Possible values: `ltr`, `rtl`.
   When not specified, the text direction is derived from the book's `language` attribute.
-- **logo:** Path to a logo to displayed at the top of the navigation bar. If this
-  is given as a relative path, its base directory is the source directory.
+- **logo:** Path to a logo to displayed at the top of the navigation bar, relative to `<book_root>/<src>/`.
 
 **book.toml**
 
@@ -62,7 +61,7 @@ description = "The example book covers examples."
 src = "my-src"  # the source files will be found in `root/my-src` instead of `root/src`
 language = "en"
 text-direction = "ltr"
-logo = "static/logo.svg"
+logo = "static/logo.svg"  # logo lives at `root/my-src/static/logo.svg`
 ```
 
 ### Rust options
diff --git a/tests/gui/books/sidebar-logo-large/book.toml b/tests/gui/books/sidebar-logo-large/book.toml
new file mode 100644
index 0000000000..49e60bcedc
--- /dev/null
+++ b/tests/gui/books/sidebar-logo-large/book.toml
@@ -0,0 +1,2 @@
+[book]
+logo = "logo.svg"
diff --git a/tests/gui/books/sidebar-logo-large/src/SUMMARY.md b/tests/gui/books/sidebar-logo-large/src/SUMMARY.md
new file mode 100644
index 0000000000..22fc8fc79e
--- /dev/null
+++ b/tests/gui/books/sidebar-logo-large/src/SUMMARY.md
@@ -0,0 +1 @@
+- [c1](c1.md)
diff --git a/tests/gui/books/sidebar-logo-large/src/c1.md b/tests/gui/books/sidebar-logo-large/src/c1.md
new file mode 100644
index 0000000000..3c62125d67
--- /dev/null
+++ b/tests/gui/books/sidebar-logo-large/src/c1.md
@@ -0,0 +1 @@
+# c1
diff --git a/tests/gui/books/sidebar-logo-large/src/logo.svg b/tests/gui/books/sidebar-logo-large/src/logo.svg
new file mode 100644
index 0000000000..b3b02c5efa
--- /dev/null
+++ b/tests/gui/books/sidebar-logo-large/src/logo.svg
@@ -0,0 +1,3 @@
+<svg xmlns="http://w3.org" viewBox="0 0 1000 1" width="1000" height="1">
+  <line x1="0.5" y1="0" y2="0.5" x2="1000" stroke="red" stroke-width="1" />
+</svg>
diff --git a/tests/gui/books/sidebar-logo-tall/book.toml b/tests/gui/books/sidebar-logo-tall/book.toml
new file mode 100644
index 0000000000..49e60bcedc
--- /dev/null
+++ b/tests/gui/books/sidebar-logo-tall/book.toml
@@ -0,0 +1,2 @@
+[book]
+logo = "logo.svg"
diff --git a/tests/gui/books/sidebar-logo-tall/src/SUMMARY.md b/tests/gui/books/sidebar-logo-tall/src/SUMMARY.md
new file mode 100644
index 0000000000..22fc8fc79e
--- /dev/null
+++ b/tests/gui/books/sidebar-logo-tall/src/SUMMARY.md
@@ -0,0 +1 @@
+- [c1](c1.md)
diff --git a/tests/gui/books/sidebar-logo-tall/src/c1.md b/tests/gui/books/sidebar-logo-tall/src/c1.md
new file mode 100644
index 0000000000..3c62125d67
--- /dev/null
+++ b/tests/gui/books/sidebar-logo-tall/src/c1.md
@@ -0,0 +1 @@
+# c1
diff --git a/tests/gui/books/sidebar-logo-tall/src/logo.svg b/tests/gui/books/sidebar-logo-tall/src/logo.svg
new file mode 100644
index 0000000000..e736ecb66f
--- /dev/null
+++ b/tests/gui/books/sidebar-logo-tall/src/logo.svg
@@ -0,0 +1,3 @@
+<svg xmlns="http://w3.org" viewBox="0 0 1 1000" width="1" height="1000">
+  <line x1="0.5" y1="0" x2="0.5" y2="1000" stroke="red" stroke-width="1" />
+</svg>
diff --git a/tests/gui/sidebar-logo.goml b/tests/gui/sidebar-logo.goml
index d7b74235d8..13dee066ef 100644
--- a/tests/gui/sidebar-logo.goml
+++ b/tests/gui/sidebar-logo.goml
@@ -3,10 +3,21 @@
 // - test if the logo is displayed when provided
 // - test it is displayed above the toc
 // - test if works in nested files (level 0, 1 and n > 1)
+// - large pictures are properly displayed
 
-go-to: |DOC_PATH| + "sidebar-logo/index.html"
-set-window-size: (1100, 600)
-reload:
+define-function: (
+    "load",
+    [path],
+    block {
+    go-to: |DOC_PATH| + |path|
+    set-window-size: (1100, 600)
+    reload:
+    // Wait for the TOC to be populated by JavaScript
+    wait-for: "mdbook-sidebar-scrollbox"
+    wait-for: "ol.chapter"
+    wait-for: "#sidebar-book-logo"
+    },
+)
 
 define-function: (
     "assert-logo",
@@ -36,11 +47,7 @@ define-function: (
     },
 )
 
-// Wait for the TOC to be populated by JavaScript
-assert-find-text: "Deeper"
-wait-for: "mdbook-sidebar-scrollbox"
-wait-for: "ol.chapter"
-wait-for: "#sidebar-book-logo"
+call-function: ("load", {"path": "sidebar-logo/index.html"})
 
 // The sidebar-book-logo should exist when logo is provided
 call-function: ("assert-logo", {})
@@ -69,3 +76,12 @@ wait-for-text: (".header", "Deeper Chapter")
 call-function: ("assert-logo", {})
 call-function: ("assert-logo-src", {"prefix": "../../"})
 call-function: ("assert-logo-position", {})
+
+// Large images checks
+call-function: ("load", {"path": "sidebar-logo-large/index.html"})
+store-attribute : (".sidebar-book-logo img", {"width": logo_width})
+assert: |logo_width| <= 200
+
+call-function: ("load", {"path": "sidebar-logo-tall/index.html"})
+store-attribute : (".sidebar-book-logo img", {"height": logo_height})
+assert: |logo_height| <= 200
diff --git a/tests/testsuite/sidebar/logo/absolute/book.toml b/tests/testsuite/sidebar/logo/absolute/book.toml
new file mode 100644
index 0000000000..db6f90825c
--- /dev/null
+++ b/tests/testsuite/sidebar/logo/absolute/book.toml
@@ -0,0 +1,5 @@
+[book]
+title = "outside"
+authors = ["Chocorean"]
+language = "en"
+logo = "../logo.svg"
diff --git a/tests/testsuite/sidebar/logo/absolute/src/SUMMARY.md b/tests/testsuite/sidebar/logo/absolute/src/SUMMARY.md
new file mode 100644
index 0000000000..7390c82896
--- /dev/null
+++ b/tests/testsuite/sidebar/logo/absolute/src/SUMMARY.md
@@ -0,0 +1,3 @@
+# Summary
+
+- [Chapter 1](./chapter_1.md)
diff --git a/tests/testsuite/sidebar/logo/absolute/src/chapter_1.md b/tests/testsuite/sidebar/logo/absolute/src/chapter_1.md
new file mode 100644
index 0000000000..b743fda354
--- /dev/null
+++ b/tests/testsuite/sidebar/logo/absolute/src/chapter_1.md
@@ -0,0 +1 @@
+# Chapter 1
diff --git a/tests/testsuite/sidebar/logo/good/book.toml b/tests/testsuite/sidebar/logo/good/book.toml
new file mode 100644
index 0000000000..0f4da87e18
--- /dev/null
+++ b/tests/testsuite/sidebar/logo/good/book.toml
@@ -0,0 +1,4 @@
+[book]
+title = "Passing test"
+authors = ["Chocorean"]
+language = "en"
diff --git a/tests/testsuite/sidebar/logo/good/src/SUMMARY.md b/tests/testsuite/sidebar/logo/good/src/SUMMARY.md
new file mode 100644
index 0000000000..7390c82896
--- /dev/null
+++ b/tests/testsuite/sidebar/logo/good/src/SUMMARY.md
@@ -0,0 +1,3 @@
+# Summary
+
+- [Chapter 1](./chapter_1.md)
diff --git a/tests/testsuite/sidebar/logo/good/src/chapter_1.md b/tests/testsuite/sidebar/logo/good/src/chapter_1.md
new file mode 100644
index 0000000000..b743fda354
--- /dev/null
+++ b/tests/testsuite/sidebar/logo/good/src/chapter_1.md
@@ -0,0 +1 @@
+# Chapter 1
diff --git a/tests/testsuite/sidebar/logo/good/src/logo.svg b/tests/testsuite/sidebar/logo/good/src/logo.svg
new file mode 120000
index 0000000000..4a9621e800
--- /dev/null
+++ b/tests/testsuite/sidebar/logo/good/src/logo.svg
@@ -0,0 +1 @@
+../../../../../../crates/mdbook-html/front-end/images/favicon.svg
\ No newline at end of file
diff --git a/tests/testsuite/sidebar/logo/other_src/book.toml b/tests/testsuite/sidebar/logo/other_src/book.toml
new file mode 100644
index 0000000000..b88292b563
--- /dev/null
+++ b/tests/testsuite/sidebar/logo/other_src/book.toml
@@ -0,0 +1,6 @@
+[book]
+title = "Other src"
+authors = ["Chocorean"]
+language = "en"
+src = "my-src"
+logo = "logo.svg"
diff --git a/tests/testsuite/sidebar/logo/other_src/my-src/SUMMARY.md b/tests/testsuite/sidebar/logo/other_src/my-src/SUMMARY.md
new file mode 100644
index 0000000000..7390c82896
--- /dev/null
+++ b/tests/testsuite/sidebar/logo/other_src/my-src/SUMMARY.md
@@ -0,0 +1,3 @@
+# Summary
+
+- [Chapter 1](./chapter_1.md)
diff --git a/tests/testsuite/sidebar/logo/other_src/my-src/chapter_1.md b/tests/testsuite/sidebar/logo/other_src/my-src/chapter_1.md
new file mode 100644
index 0000000000..b743fda354
--- /dev/null
+++ b/tests/testsuite/sidebar/logo/other_src/my-src/chapter_1.md
@@ -0,0 +1 @@
+# Chapter 1
diff --git a/tests/testsuite/sidebar/logo/other_src/my-src/logo.svg b/tests/testsuite/sidebar/logo/other_src/my-src/logo.svg
new file mode 100755
index 0000000000..90e0ea58bd
--- /dev/null
+++ b/tests/testsuite/sidebar/logo/other_src/my-src/logo.svg
@@ -0,0 +1,22 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 199.7 184.2">
+  <style>
+    @media (prefers-color-scheme: dark) {
+      svg { fill: white; }
+    }
+  </style>
+<path d="M189.5,36.8c0.2,2.8,0,5.1-0.6,6.8L153,162c-0.6,2.1-2,3.7-4.2,5c-2.2,1.2-4.4,1.9-6.7,1.9H31.4c-9.6,0-15.3-2.8-17.3-8.4
+  c-0.8-2.2-0.8-3.9,0.1-5.2c0.9-1.2,2.4-1.8,4.6-1.8H123c7.4,0,12.6-1.4,15.4-4.1s5.7-8.9,8.6-18.4l32.9-108.6
+  c1.8-5.9,1-11.1-2.2-15.6S169.9,0,164,0H72.7c-1,0-3.1,0.4-6.1,1.1l0.1-0.4C64.5,0.2,62.6,0,61,0.1s-3,0.5-4.3,1.4
+  c-1.3,0.9-2.4,1.8-3.2,2.8S52,6.5,51.2,8.1c-0.8,1.6-1.4,3-1.9,4.3s-1.1,2.7-1.8,4.2c-0.7,1.5-1.3,2.7-2,3.7c-0.5,0.6-1.2,1.5-2,2.5
+  s-1.6,2-2.2,2.8s-0.9,1.5-1.1,2.2c-0.2,0.7-0.1,1.8,0.2,3.2c0.3,1.4,0.4,2.4,0.4,3.1c-0.3,3-1.4,6.9-3.3,11.6
+  c-1.9,4.7-3.6,8.1-5.1,10.1c-0.3,0.4-1.2,1.3-2.6,2.7c-1.4,1.4-2.3,2.6-2.6,3.7c-0.3,0.4-0.3,1.5-0.1,3.4c0.3,1.8,0.4,3.1,0.3,3.8
+  c-0.3,2.7-1.3,6.3-3,10.8c-1.7,4.5-3.4,8.2-5,11c-0.2,0.5-0.9,1.4-2,2.8c-1.1,1.4-1.8,2.5-2,3.4c-0.2,0.6-0.1,1.8,0.1,3.4
+  c0.2,1.6,0.2,2.8-0.1,3.6c-0.6,3-1.8,6.7-3.6,11c-1.8,4.3-3.6,7.9-5.4,11c-0.5,0.8-1.1,1.7-2,2.8c-0.8,1.1-1.5,2-2,2.8
+  s-0.8,1.6-1,2.5c-0.1,0.5,0,1.3,0.4,2.3c0.3,1.1,0.4,1.9,0.4,2.6c-0.1,1.1-0.2,2.6-0.5,4.4c-0.2,1.8-0.4,2.9-0.4,3.2
+  c-1.8,4.8-1.7,9.9,0.2,15.2c2.2,6.2,6.2,11.5,11.9,15.8c5.7,4.3,11.7,6.4,17.8,6.4h110.7c5.2,0,10.1-1.7,14.7-5.2s7.7-7.8,9.2-12.9
+  l33-108.6c1.8-5.8,1-10.9-2.2-15.5C194.9,39.7,192.6,38,189.5,36.8z M59.6,122.8L73.8,80c0,0,7,0,10.8,0s28.8-1.7,25.4,17.5
+  c-3.4,19.2-18.8,25.2-36.8,25.4S59.6,122.8,59.6,122.8z M78.6,116.8c4.7-0.1,18.9-2.9,22.1-17.1S89.2,86.3,89.2,86.3l-8.9,0
+  l-10.2,30.5C70.2,116.9,74,116.9,78.6,116.8z M75.3,68.7L89,26.2h9.8l0.8,34l23.6-34h9.9l-13.6,42.5h-7.1l12.5-35.4l-24.5,35.4h-6.8
+  l-0.8-35L82,68.7H75.3z"/>
+</svg>
+<!-- Original image Copyright Dave Gandy — CC BY 4.0 License -->
diff --git a/tests/testsuite/sidebar/logo/outside/book.toml b/tests/testsuite/sidebar/logo/outside/book.toml
new file mode 100644
index 0000000000..ffee968e8f
--- /dev/null
+++ b/tests/testsuite/sidebar/logo/outside/book.toml
@@ -0,0 +1,5 @@
+[book]
+title = "outside"
+authors = ["Chocorean"]
+language = "en"
+logo = "/absolute/path/logo.svg"
diff --git a/tests/testsuite/sidebar/logo/outside/logo.svg b/tests/testsuite/sidebar/logo/outside/logo.svg
new file mode 120000
index 0000000000..718fa53dd7
--- /dev/null
+++ b/tests/testsuite/sidebar/logo/outside/logo.svg
@@ -0,0 +1 @@
+../../../../../crates/mdbook-html/front-end/images/favicon.svg
\ No newline at end of file
diff --git a/tests/testsuite/sidebar/logo/outside/src/SUMMARY.md b/tests/testsuite/sidebar/logo/outside/src/SUMMARY.md
new file mode 100644
index 0000000000..7390c82896
--- /dev/null
+++ b/tests/testsuite/sidebar/logo/outside/src/SUMMARY.md
@@ -0,0 +1,3 @@
+# Summary
+
+- [Chapter 1](./chapter_1.md)
diff --git a/tests/testsuite/sidebar/logo/outside/src/chapter_1.md b/tests/testsuite/sidebar/logo/outside/src/chapter_1.md
new file mode 100644
index 0000000000..b743fda354
--- /dev/null
+++ b/tests/testsuite/sidebar/logo/outside/src/chapter_1.md
@@ -0,0 +1 @@
+# Chapter 1
diff --git a/tests/testsuite/sidebar_logo.rs b/tests/testsuite/sidebar_logo.rs
index 5046cd98b4..48815639c4 100644
--- a/tests/testsuite/sidebar_logo.rs
+++ b/tests/testsuite/sidebar_logo.rs
@@ -9,3 +9,47 @@ fn bad_logo_path() {
         );
     });
 }
+
+#[test]
+fn outside_src_dir() {
+    BookTest::from_dir("sidebar/logo/outside").run("build", |cmd| {
+        cmd.expect_failure();
+        cmd.expect_stderr("ERROR invalid value for `logo`: should live under `src/`\n");
+    });
+}
+
+#[test]
+fn abs_path() {
+    BookTest::from_dir("sidebar/logo/absolute").run("build", |cmd| {
+        cmd.expect_failure();
+        cmd.expect_stderr("ERROR invalid value for `logo`: should live under `src/`\n");
+    });
+}
+
+#[test]
+fn good_logo() {
+    BookTest::from_dir("sidebar/logo/good")
+        .run("build", |cmd| {
+            cmd.expect_stderr(str![[r#"
+ INFO Book building has started
+ INFO Running the html backend
+ INFO HTML book written to `[ROOT]/book`
+
+"#]]);
+        })
+        .check_file_contains("book/logo.svg", "<svg");
+}
+
+#[test]
+fn logo_from_other_src() {
+    BookTest::from_dir("sidebar/logo/other_src")
+        .run("build", |cmd| {
+            cmd.expect_stderr(str![[r#"
+ INFO Book building has started
+ INFO Running the html backend
+ INFO HTML book written to `[ROOT]/book`
+
+"#]]);
+        })
+        .check_file_contains("book/logo.svg", "<svg");
+}

From 9edf1a4c6c05faf7cc9d9bf65d98c5c7864b0f41 Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Tue, 15 Sep 2026 14:56:48 -0400
Subject: [PATCH 23/29] attempt to fix gui tests

---
 tests/gui/sidebar-logo.goml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/gui/sidebar-logo.goml b/tests/gui/sidebar-logo.goml
index 13dee066ef..001051d943 100644
--- a/tests/gui/sidebar-logo.goml
+++ b/tests/gui/sidebar-logo.goml
@@ -79,9 +79,9 @@ call-function: ("assert-logo-position", {})
 
 // Large images checks
 call-function: ("load", {"path": "sidebar-logo-large/index.html"})
-store-attribute : (".sidebar-book-logo img", {"width": logo_width})
+store-property : (".sidebar-book-logo img", {"width": logo_width})
 assert: |logo_width| <= 200
 
 call-function: ("load", {"path": "sidebar-logo-tall/index.html"})
-store-attribute : (".sidebar-book-logo img", {"height": logo_height})
+store-property : (".sidebar-book-logo img", {"height": logo_height})
 assert: |logo_height| <= 200

From 59b3fb5e21f8d62c8607c12831862355ff689608 Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Tue, 15 Sep 2026 15:05:09 -0400
Subject: [PATCH 24/29] fix swapped logo paths

---
 tests/testsuite/sidebar/logo/absolute/book.toml | 2 +-
 tests/testsuite/sidebar/logo/outside/book.toml  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/testsuite/sidebar/logo/absolute/book.toml b/tests/testsuite/sidebar/logo/absolute/book.toml
index db6f90825c..ffee968e8f 100644
--- a/tests/testsuite/sidebar/logo/absolute/book.toml
+++ b/tests/testsuite/sidebar/logo/absolute/book.toml
@@ -2,4 +2,4 @@
 title = "outside"
 authors = ["Chocorean"]
 language = "en"
-logo = "../logo.svg"
+logo = "/absolute/path/logo.svg"
diff --git a/tests/testsuite/sidebar/logo/outside/book.toml b/tests/testsuite/sidebar/logo/outside/book.toml
index ffee968e8f..db6f90825c 100644
--- a/tests/testsuite/sidebar/logo/outside/book.toml
+++ b/tests/testsuite/sidebar/logo/outside/book.toml
@@ -2,4 +2,4 @@
 title = "outside"
 authors = ["Chocorean"]
 language = "en"
-logo = "/absolute/path/logo.svg"
+logo = "../logo.svg"

From dcce71bb7f470be287fb44bd5a238b3b6524b598 Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Tue, 15 Sep 2026 15:12:35 -0400
Subject: [PATCH 25/29] add logo absolute test variant for windows platforms

---
 .../logo/{absolute => absolute_unix}/book.toml       |  0
 .../logo/{absolute => absolute_unix}/src/SUMMARY.md  |  0
 .../{absolute => absolute_unix}/src/chapter_1.md     |  0
 .../sidebar/logo/absolute_windows/book.toml          |  5 +++++
 .../testsuite/sidebar/logo/absolute_windows/logo.svg |  1 +
 .../sidebar/logo/absolute_windows/src/SUMMARY.md     |  3 +++
 .../sidebar/logo/absolute_windows/src/chapter_1.md   |  1 +
 tests/testsuite/sidebar_logo.rs                      | 12 +++++++++++-
 8 files changed, 21 insertions(+), 1 deletion(-)
 rename tests/testsuite/sidebar/logo/{absolute => absolute_unix}/book.toml (100%)
 rename tests/testsuite/sidebar/logo/{absolute => absolute_unix}/src/SUMMARY.md (100%)
 rename tests/testsuite/sidebar/logo/{absolute => absolute_unix}/src/chapter_1.md (100%)
 create mode 100644 tests/testsuite/sidebar/logo/absolute_windows/book.toml
 create mode 120000 tests/testsuite/sidebar/logo/absolute_windows/logo.svg
 create mode 100644 tests/testsuite/sidebar/logo/absolute_windows/src/SUMMARY.md
 create mode 100644 tests/testsuite/sidebar/logo/absolute_windows/src/chapter_1.md

diff --git a/tests/testsuite/sidebar/logo/absolute/book.toml b/tests/testsuite/sidebar/logo/absolute_unix/book.toml
similarity index 100%
rename from tests/testsuite/sidebar/logo/absolute/book.toml
rename to tests/testsuite/sidebar/logo/absolute_unix/book.toml
diff --git a/tests/testsuite/sidebar/logo/absolute/src/SUMMARY.md b/tests/testsuite/sidebar/logo/absolute_unix/src/SUMMARY.md
similarity index 100%
rename from tests/testsuite/sidebar/logo/absolute/src/SUMMARY.md
rename to tests/testsuite/sidebar/logo/absolute_unix/src/SUMMARY.md
diff --git a/tests/testsuite/sidebar/logo/absolute/src/chapter_1.md b/tests/testsuite/sidebar/logo/absolute_unix/src/chapter_1.md
similarity index 100%
rename from tests/testsuite/sidebar/logo/absolute/src/chapter_1.md
rename to tests/testsuite/sidebar/logo/absolute_unix/src/chapter_1.md
diff --git a/tests/testsuite/sidebar/logo/absolute_windows/book.toml b/tests/testsuite/sidebar/logo/absolute_windows/book.toml
new file mode 100644
index 0000000000..35025f6d53
--- /dev/null
+++ b/tests/testsuite/sidebar/logo/absolute_windows/book.toml
@@ -0,0 +1,5 @@
+[book]
+title = "outside"
+authors = ["Chocorean"]
+language = "en"
+logo = "C:\absolute\path\logo.svg"
diff --git a/tests/testsuite/sidebar/logo/absolute_windows/logo.svg b/tests/testsuite/sidebar/logo/absolute_windows/logo.svg
new file mode 120000
index 0000000000..718fa53dd7
--- /dev/null
+++ b/tests/testsuite/sidebar/logo/absolute_windows/logo.svg
@@ -0,0 +1 @@
+../../../../../crates/mdbook-html/front-end/images/favicon.svg
\ No newline at end of file
diff --git a/tests/testsuite/sidebar/logo/absolute_windows/src/SUMMARY.md b/tests/testsuite/sidebar/logo/absolute_windows/src/SUMMARY.md
new file mode 100644
index 0000000000..7390c82896
--- /dev/null
+++ b/tests/testsuite/sidebar/logo/absolute_windows/src/SUMMARY.md
@@ -0,0 +1,3 @@
+# Summary
+
+- [Chapter 1](./chapter_1.md)
diff --git a/tests/testsuite/sidebar/logo/absolute_windows/src/chapter_1.md b/tests/testsuite/sidebar/logo/absolute_windows/src/chapter_1.md
new file mode 100644
index 0000000000..b743fda354
--- /dev/null
+++ b/tests/testsuite/sidebar/logo/absolute_windows/src/chapter_1.md
@@ -0,0 +1 @@
+# Chapter 1
diff --git a/tests/testsuite/sidebar_logo.rs b/tests/testsuite/sidebar_logo.rs
index 48815639c4..c150deef5c 100644
--- a/tests/testsuite/sidebar_logo.rs
+++ b/tests/testsuite/sidebar_logo.rs
@@ -19,8 +19,18 @@ fn outside_src_dir() {
 }
 
 #[test]
+#[cfg(not(target_os = "windows"))]
 fn abs_path() {
-    BookTest::from_dir("sidebar/logo/absolute").run("build", |cmd| {
+    BookTest::from_dir("sidebar/logo/absolute_unix").run("build", |cmd| {
+        cmd.expect_failure();
+        cmd.expect_stderr("ERROR invalid value for `logo`: should live under `src/`\n");
+    });
+}
+
+#[test]
+#[cfg(target_os = "windows")]
+fn abs_path() {
+    BookTest::from_dir("sidebar/logo/absolute_windows").run("build", |cmd| {
         cmd.expect_failure();
         cmd.expect_stderr("ERROR invalid value for `logo`: should live under `src/`\n");
     });

From 8e24b48b9871127e8af3cdcb6382247e8a62286e Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Tue, 15 Sep 2026 15:17:38 -0400
Subject: [PATCH 26/29] fix logo path for windows absolute logo path test

---
 tests/testsuite/sidebar/logo/absolute_windows/book.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/testsuite/sidebar/logo/absolute_windows/book.toml b/tests/testsuite/sidebar/logo/absolute_windows/book.toml
index 35025f6d53..b71ee32822 100644
--- a/tests/testsuite/sidebar/logo/absolute_windows/book.toml
+++ b/tests/testsuite/sidebar/logo/absolute_windows/book.toml
@@ -2,4 +2,4 @@
 title = "outside"
 authors = ["Chocorean"]
 language = "en"
-logo = "C:\absolute\path\logo.svg"
+logo = "C:/absolute/path/logo.svg"

From ae508fa59cbb63bdfe77fe1dcba4582836af8fe9 Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Tue, 15 Sep 2026 16:07:19 -0400
Subject: [PATCH 27/29] last css adjustments: logo is 20% wide and max 8rem
 tall, title is 70% wide

---
 crates/mdbook-html/front-end/css/chrome.css | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/crates/mdbook-html/front-end/css/chrome.css b/crates/mdbook-html/front-end/css/chrome.css
index 988a027348..dcdde8dbd6 100644
--- a/crates/mdbook-html/front-end/css/chrome.css
+++ b/crates/mdbook-html/front-end/css/chrome.css
@@ -507,12 +507,12 @@ html:not(.sidebar-resizing) .sidebar {
 }
 .sidebar .sidebar-scrollbox .sidebar-book-logo img {
     display: block;
-    height: auto;
+    max-height: 8rem;
     width: 20%;
 }
 .sidebar .sidebar-scrollbox .sidebar-book-logo h2 {
     margin: 0;
-    max-width: 70%;
+    width: 70%;
     overflow-wrap: anywhere;
     text-wrap: balance;
 }

From 08ef043b27e995a05d842825db1744e73e3db794 Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Tue, 15 Sep 2026 16:07:26 -0400
Subject: [PATCH 28/29] fix logo img tag

---
 crates/mdbook-html/front-end/templates/toc.js.hbs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/mdbook-html/front-end/templates/toc.js.hbs b/crates/mdbook-html/front-end/templates/toc.js.hbs
index 1796361f59..09053047c3 100644
--- a/crates/mdbook-html/front-end/templates/toc.js.hbs
+++ b/crates/mdbook-html/front-end/templates/toc.js.hbs
@@ -11,7 +11,7 @@ class MDBookSidebarScrollbox extends HTMLElement {
 {{#if book_logo }}
         this.innerHTML =
             '<div id="sidebar-book-logo" class="sidebar-book-logo">' +
-            '<img src="' + path_to_root + '{{ book_logo }}" alt="{{ book_title }}" logo>' +
+            '<img src="' + path_to_root + '{{ book_logo }}" alt="{{ book_title }}" />' +
             '<h2 class="sidebar-logo-title">{{ book_title }}</h2></div>{{#toc}}{{/toc}}';
 {{else}}
         this.innerHTML = '{{#toc}}{{/toc}}';

From 5caab23aec3fbaf70047ece2d11b57f9190d1a13 Mon Sep 17 00:00:00 2001
From: Chocorean <chocorean@pm.me>
Date: Tue, 15 Sep 2026 16:07:57 -0400
Subject: [PATCH 29/29] minor tweaks for logo large/tall tests

---
 tests/gui/books/sidebar-logo-large/book.toml    | 1 +
 tests/gui/books/sidebar-logo-large/src/logo.svg | 5 +++--
 tests/gui/books/sidebar-logo-tall/book.toml     | 1 +
 tests/gui/books/sidebar-logo-tall/src/logo.svg  | 5 +++--
 4 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/tests/gui/books/sidebar-logo-large/book.toml b/tests/gui/books/sidebar-logo-large/book.toml
index 49e60bcedc..032ad94766 100644
--- a/tests/gui/books/sidebar-logo-large/book.toml
+++ b/tests/gui/books/sidebar-logo-large/book.toml
@@ -1,2 +1,3 @@
 [book]
+title = "Large logo"
 logo = "logo.svg"
diff --git a/tests/gui/books/sidebar-logo-large/src/logo.svg b/tests/gui/books/sidebar-logo-large/src/logo.svg
index b3b02c5efa..7d4745ee7e 100644
--- a/tests/gui/books/sidebar-logo-large/src/logo.svg
+++ b/tests/gui/books/sidebar-logo-large/src/logo.svg
@@ -1,3 +1,4 @@
-<svg xmlns="http://w3.org" viewBox="0 0 1000 1" width="1000" height="1">
-  <line x1="0.5" y1="0" y2="0.5" x2="1000" stroke="red" stroke-width="1" />
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1000 10" width="1000" height="10">
+  <line x1="0" y1="5" x2="1000" y2="5" stroke="red" stroke-width="1" />
+  <rect x="0" y="0" width="1000" height="10" stroke="red" stroke-width="3" fill="none" />
 </svg>
diff --git a/tests/gui/books/sidebar-logo-tall/book.toml b/tests/gui/books/sidebar-logo-tall/book.toml
index 49e60bcedc..cc0e5b4844 100644
--- a/tests/gui/books/sidebar-logo-tall/book.toml
+++ b/tests/gui/books/sidebar-logo-tall/book.toml
@@ -1,2 +1,3 @@
 [book]
+title = "Tall logo"
 logo = "logo.svg"
diff --git a/tests/gui/books/sidebar-logo-tall/src/logo.svg b/tests/gui/books/sidebar-logo-tall/src/logo.svg
index e736ecb66f..b750ef0896 100644
--- a/tests/gui/books/sidebar-logo-tall/src/logo.svg
+++ b/tests/gui/books/sidebar-logo-tall/src/logo.svg
@@ -1,3 +1,4 @@
-<svg xmlns="http://w3.org" viewBox="0 0 1 1000" width="1" height="1000">
-  <line x1="0.5" y1="0" x2="0.5" y2="1000" stroke="red" stroke-width="1" />
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 10 1000" width="10" height="1000">
+  <line x1="5" y1="0" x2="5" y2="1000" stroke="red" stroke-width="1" />
+  <rect x="0" y="0" width="10" height="1000" stroke="red" stroke-width="3" fill="none" />
 </svg>