From bc3b571c5bfc1ec1f9645c8cbe3abba459ec0085 Mon Sep 17 00:00:00 2001
From: Aron T <aront@fourm.info>
Date: Mon, 7 Jul 2025 16:48:27 +0300
Subject: [PATCH] Add cross-site navigation to documentation

- Add navigation section linking to all documentation sites
- Include custom CSS for professional styling
- Support dark mode and responsive design
- Fix header issues by removing problematic CSS pseudo-elements
- Remove footer approach in favor of content-based navigation
---
 docs/make.jl               |   3 +-
 docs/src/assets/custom.css | 100 +++++++++++++++++++++++++++++++++++++
 docs/src/index.md          |  24 ++++++++-
 3 files changed, 125 insertions(+), 2 deletions(-)
 create mode 100644 docs/src/assets/custom.css

diff --git a/docs/make.jl b/docs/make.jl
index 9867179..6f742e2 100644
--- a/docs/make.jl
+++ b/docs/make.jl
@@ -12,7 +12,8 @@ makedocs(;
     # Don't worry about what `CI` does in this line.
     format = Documenter.HTML(
         prettyurls = CI,
-        edit_link = "main"
+        edit_link = "main",
+        assets = ["assets/custom.css"]
     )
 )
 
diff --git a/docs/src/assets/custom.css b/docs/src/assets/custom.css
new file mode 100644
index 0000000..b7dfb3b
--- /dev/null
+++ b/docs/src/assets/custom.css
@@ -0,0 +1,100 @@
+/* Custom styles for cross-site navigation and branding */
+
+/* Site navigation footer styling */
+.site-navigation {
+    margin-top: 2rem;
+    padding: 1.5rem;
+    background-color: var(--documenter-dark-background, #f8f9fa);
+    border-radius: 8px;
+    border: 1px solid var(--documenter-dark-border, #e9ecef);
+}
+
+.site-navigation .nav-section {
+    margin-bottom: 1rem;
+}
+
+.site-navigation .nav-section:last-child {
+    margin-bottom: 0;
+}
+
+.site-navigation h4 {
+    margin: 0 0 0.75rem 0;
+    color: var(--documenter-dark-text, #212529);
+    font-size: 1rem;
+    font-weight: 600;
+}
+
+.site-navigation ul {
+    margin: 0;
+    padding: 0;
+    list-style: none;
+}
+
+.site-navigation ul li {
+    margin: 0.25rem 0;
+}
+
+.site-navigation ul li a {
+    color: var(--documenter-dark-link, #007bff);
+    text-decoration: none;
+    font-size: 0.9rem;
+    transition: color 0.2s ease;
+}
+
+.site-navigation ul li a:hover {
+    color: var(--documenter-dark-link-hover, #0056b3);
+    text-decoration: underline;
+}
+
+/* Dark mode support */
+@media (prefers-color-scheme: dark) {
+    .site-navigation {
+        background-color: #2b2b2b;
+        border-color: #404040;
+    }
+    
+    .site-navigation h4 {
+        color: #ffffff;
+    }
+    
+    .site-navigation ul li a {
+        color: #58a6ff;
+    }
+    
+    .site-navigation ul li a:hover {
+        color: #79c0ff;
+    }
+}
+
+/* Responsive design */
+@media (max-width: 768px) {
+    .site-navigation {
+        padding: 1rem;
+    }
+    
+    .site-navigation h4 {
+        font-size: 0.9rem;
+    }
+    
+    .site-navigation ul li a {
+        font-size: 0.85rem;
+    }
+}
+
+/* Integration with Documenter.jl theme */
+html[data-theme="dark"] .site-navigation {
+    background-color: var(--documenter-dark-background);
+    border-color: var(--documenter-dark-border);
+}
+
+html[data-theme="dark"] .site-navigation h4 {
+    color: var(--documenter-dark-text);
+}
+
+html[data-theme="dark"] .site-navigation ul li a {
+    color: var(--documenter-dark-link);
+}
+
+html[data-theme="dark"] .site-navigation ul li a:hover {
+    color: var(--documenter-dark-link-hover);
+}
diff --git a/docs/src/index.md b/docs/src/index.md
index 9618b9c..0dd1b9b 100644
--- a/docs/src/index.md
+++ b/docs/src/index.md
@@ -1,4 +1,4 @@
-# Linear_Algebra
+# Linear Algebra
 
 This package provides a collection of functions for linear algebra operations and transformations.
 
@@ -10,4 +10,26 @@ This section provides the documentation for all the linear algebra functions.
 Modules = [Linear_Algebra]
 Order   = [:function, :type]
 Pages   = ["linear_algebra_basic.jl", "linear_algebra_transform.jl"]
+```
+
+---
+
+## Navigating FourM Study Guides & Documentation Sites
+
+```@raw html
+<div class="site-navigation">
+    <div class="nav-section">
+        <h4>Documentation Sites</h4>
+        <ul>
+            <li><a href="https://study.fourm.info/linear_algebra/">Linear Algebra Docs (this site)</a></li>
+            <li><a href="https://study.fourm.info/math_foundations/">Math Foundations Docs</a></li>
+        </ul>
+    </div>
+    <div class="nav-section">
+        <h4>Related Projects</h4>
+        <ul>
+            <li><a href="https://study.fourm.info/">Main Study Site</a></li>
+        </ul>
+    </div>
+</div>
 ```
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