From c42d01d4f46ada00a563bc5e02df2121f0abdf39 Mon Sep 17 00:00:00 2001
From: Kenneth Reitz <me@kennethreitz.org>
Date: Wed, 3 Dec 2025 14:26:39 -0500
Subject: [PATCH] Add sticky header, font size controls, and page prefetch
MIME-Version: 1.0
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1. Sticky header on scroll
   - Shows current page title and breadcrumb navigation
   - Appears when scrolling past the main breadcrumb
   - Smooth slide-down animation

2. Font size controls (A/A buttons)
   - Small, normal, large, x-large sizes
   - Persisted to localStorage
   - Positioned next to dark mode toggle

3. Prefetch next/prev pages
   - Uses requestIdleCallback for non-blocking prefetch
   - Prefetches chapter/verse/book navigation links
   - Makes page-to-page navigation feel instant

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>
---
 kjvstudy_org/static/base.js      | 102 ++++++++++++++++
 kjvstudy_org/templates/base.html | 198 +++++++++++++++++++++++++++++++
 2 files changed, 300 insertions(+)

diff --git a/kjvstudy_org/static/base.js b/kjvstudy_org/static/base.js
index 519a5fa..e5fad6d 100644
--- a/kjvstudy_org/static/base.js
+++ b/kjvstudy_org/static/base.js
@@ -12,6 +12,31 @@ function toggleDarkMode() {
   localStorage.setItem('theme', newTheme);
 }
 
+// Font size functionality
+(function() {
+  const sizes = ['small', 'normal', 'large', 'x-large'];
+  const savedSize = localStorage.getItem('fontSize') || 'normal';
+  if (savedSize !== 'normal') {
+    document.documentElement.setAttribute('data-font-size', savedSize);
+  }
+})();
+
+function changeFontSize(direction) {
+  const sizes = ['small', 'normal', 'large', 'x-large'];
+  const currentSize = document.documentElement.getAttribute('data-font-size') || 'normal';
+  const currentIndex = sizes.indexOf(currentSize);
+  const newIndex = Math.max(0, Math.min(sizes.length - 1, currentIndex + direction));
+  const newSize = sizes[newIndex];
+
+  if (newSize === 'normal') {
+    document.documentElement.removeAttribute('data-font-size');
+    localStorage.removeItem('fontSize');
+  } else {
+    document.documentElement.setAttribute('data-font-size', newSize);
+    localStorage.setItem('fontSize', newSize);
+  }
+}
+
 // Red letter toggle functionality
 (function() {
   // Check for saved red letter preference or default to enabled
@@ -34,6 +59,41 @@ function toggleRedLetters() {
   }
 }
 
+// Sticky header on scroll
+(function() {
+  var stickyHeader = document.getElementById('sticky-header');
+  var breadcrumb = document.querySelector('.breadcrumb');
+  if (!stickyHeader || !breadcrumb) return;
+
+  var lastScrollY = 0;
+  var ticking = false;
+  var threshold = 150; // Show after scrolling 150px past breadcrumb
+
+  function updateStickyHeader() {
+    var breadcrumbBottom = breadcrumb.getBoundingClientRect().bottom;
+    var scrollY = window.scrollY;
+
+    // Show sticky header when breadcrumb is scrolled out of view
+    if (breadcrumbBottom < -threshold) {
+      stickyHeader.classList.add('visible');
+      stickyHeader.setAttribute('aria-hidden', 'false');
+    } else {
+      stickyHeader.classList.remove('visible');
+      stickyHeader.setAttribute('aria-hidden', 'true');
+    }
+
+    ticking = false;
+  }
+
+  window.addEventListener('scroll', function() {
+    lastScrollY = window.scrollY;
+    if (!ticking) {
+      window.requestAnimationFrame(updateStickyHeader);
+      ticking = true;
+    }
+  }, { passive: true });
+})();
+
 // Sidebar collapse state persistence (mobile only)
 (function() {
   var toggle = document.getElementById('sidebar-toggle');
@@ -1410,3 +1470,45 @@ function showKeyboardHelp() {
   });
 })();
 
+// Prefetch next/prev pages for faster navigation
+(function() {
+  // Wait for page to be fully loaded and idle
+  if ('requestIdleCallback' in window) {
+    requestIdleCallback(prefetchNavigationLinks, { timeout: 2000 });
+  } else {
+    setTimeout(prefetchNavigationLinks, 1000);
+  }
+
+  function prefetchNavigationLinks() {
+    // Find navigation links (next/prev chapter, verse, book)
+    var prefetchSelectors = [
+      'a[rel="next"]',
+      'a[rel="prev"]',
+      '.chapter-nav a',
+      '.verse-nav a',
+      '.book-nav a',
+      '.nav-btn[href*="/chapter/"]',
+      '.nav-btn[href*="/verse/"]'
+    ];
+
+    var links = document.querySelectorAll(prefetchSelectors.join(', '));
+    var prefetched = new Set();
+
+    links.forEach(function(link) {
+      var href = link.href;
+      if (!href || prefetched.has(href)) return;
+      if (href.includes('#')) return; // Skip anchor links
+      if (!href.startsWith(window.location.origin)) return; // Skip external links
+
+      prefetched.add(href);
+
+      // Use link prefetch hint
+      var prefetchLink = document.createElement('link');
+      prefetchLink.rel = 'prefetch';
+      prefetchLink.href = href;
+      prefetchLink.as = 'document';
+      document.head.appendChild(prefetchLink);
+    });
+  }
+})();
+
diff --git a/kjvstudy_org/templates/base.html b/kjvstudy_org/templates/base.html
index 801ca0b..a7c60b7 100644
--- a/kjvstudy_org/templates/base.html
+++ b/kjvstudy_org/templates/base.html
@@ -346,6 +346,184 @@
             padding-bottom: 1rem;
         }
 
+        /* Sticky header on scroll */
+        .sticky-header {
+            position: fixed;
+            top: 0;
+            left: 140px;
+            right: 0;
+            background: var(--bg-color);
+            border-bottom: 1px solid var(--border-color);
+            padding: 0.6rem 2rem;
+            z-index: 99;
+            transform: translateY(-100%);
+            transition: transform 0.2s ease;
+            box-shadow: 0 2px 8px rgba(0,0,0,0.05);
+        }
+
+        .sticky-header.visible {
+            transform: translateY(0);
+        }
+
+        .sticky-header-content {
+            display: flex;
+            align-items: center;
+            justify-content: space-between;
+            max-width: 800px;
+            gap: 1rem;
+        }
+
+        .sticky-header-title {
+            font-size: 0.95rem;
+            font-weight: 500;
+            color: var(--text-color);
+            white-space: nowrap;
+            overflow: hidden;
+            text-overflow: ellipsis;
+        }
+
+        .sticky-header-breadcrumb {
+            font-size: 0.8rem;
+            color: var(--text-secondary);
+            display: flex;
+            align-items: center;
+            gap: 0.5rem;
+        }
+
+        .sticky-header-breadcrumb a {
+            color: var(--text-secondary);
+            text-decoration: none;
+            border-bottom: none;
+        }
+
+        .sticky-header-breadcrumb a:hover {
+            color: var(--link-color);
+        }
+
+        .sticky-header-breadcrumb .sep {
+            color: var(--text-quaternary);
+        }
+
+        [data-theme="dark"] .sticky-header {
+            box-shadow: 0 2px 8px rgba(0,0,0,0.2);
+        }
+
+        @media (max-width: 1200px) {
+            .sticky-header {
+                left: 0;
+            }
+        }
+
+        /* Font size controls */
+        .font-size-controls {
+            position: fixed;
+            top: 2rem;
+            right: 4rem;
+            z-index: 101;
+            margin: -25px 0 0 0;
+            display: flex;
+            gap: 0.25rem;
+        }
+
+        .font-size-btn {
+            width: 24px;
+            height: 24px;
+            cursor: pointer;
+            background: transparent;
+            border: 1px solid var(--border-color-darker);
+            border-radius: 3px;
+            display: flex;
+            align-items: center;
+            justify-content: center;
+            font-size: 0.75rem;
+            font-weight: 600;
+            color: var(--text-secondary);
+            transition: all 0.2s;
+            font-family: inherit;
+        }
+
+        .font-size-btn:hover {
+            border-color: var(--text-tertiary);
+            color: var(--link-hover);
+        }
+
+        .font-size-btn.decrease {
+            font-size: 0.65rem;
+        }
+
+        .font-size-btn.increase {
+            font-size: 0.85rem;
+        }
+
+        /* Font size scale classes */
+        [data-font-size="small"] article {
+            font-size: 0.9rem;
+        }
+
+        [data-font-size="small"] article p,
+        [data-font-size="small"] article li {
+            font-size: 1.2rem;
+        }
+
+        [data-font-size="small"] article h1 {
+            font-size: 2.4rem;
+        }
+
+        [data-font-size="small"] article h2 {
+            font-size: 1.7rem;
+        }
+
+        [data-font-size="large"] article {
+            font-size: 1.1rem;
+        }
+
+        [data-font-size="large"] article p,
+        [data-font-size="large"] article li {
+            font-size: 1.6rem;
+            line-height: 2.2;
+        }
+
+        [data-font-size="large"] article h1 {
+            font-size: 3.2rem;
+        }
+
+        [data-font-size="large"] article h2 {
+            font-size: 2.3rem;
+        }
+
+        [data-font-size="x-large"] article {
+            font-size: 1.2rem;
+        }
+
+        [data-font-size="x-large"] article p,
+        [data-font-size="x-large"] article li {
+            font-size: 1.8rem;
+            line-height: 2.4;
+        }
+
+        [data-font-size="x-large"] article h1 {
+            font-size: 3.5rem;
+        }
+
+        [data-font-size="x-large"] article h2 {
+            font-size: 2.6rem;
+        }
+
+        @media (max-width: 768px) {
+            .font-size-controls {
+                top: 1rem;
+                right: 3.5rem;
+                margin: 0;
+            }
+        }
+
+        @media (max-width: 480px) {
+            .font-size-controls {
+                top: 0.5rem;
+                right: 3rem;
+            }
+        }
+
         .breadcrumb a {
             color: var(--link-color);
             text-decoration: none;
@@ -1306,9 +1484,29 @@
     <p class="sidebar-toggle-container">
         <label for="sidebar-toggle" class="sidebar-toggle-btn" title="Toggle sidebar" aria-label="Toggle navigation sidebar"></label>
     </p>
+    <div class="font-size-controls">
+        <button class="font-size-btn decrease" title="Decrease font size" onclick="changeFontSize(-1)" aria-label="Decrease font size">A</button>
+        <button class="font-size-btn increase" title="Increase font size" onclick="changeFontSize(1)" aria-label="Increase font size">A</button>
+    </div>
     <p class="dark-mode-toggle">
         <button class="dark-mode-btn" title="Toggle dark mode" onclick="toggleDarkMode()" aria-label="Toggle dark mode"></button>
     </p>
+
+    <!-- Sticky header (appears on scroll) -->
+    {% if breadcrumbs %}
+    <header class="sticky-header" id="sticky-header" aria-hidden="true">
+        <div class="sticky-header-content">
+            <span class="sticky-header-title">{{ breadcrumbs[-1].text if breadcrumbs else '' }}</span>
+            <nav class="sticky-header-breadcrumb">
+                {% for crumb in breadcrumbs[:-1] %}
+                <a href="{{ crumb.url }}">{{ crumb.text }}</a>
+                {% if not loop.last %}<span class="sep">›</span>{% endif %}
+                {% endfor %}
+            </nav>
+        </div>
+    </header>
+    {% endif %}
+
     <article role="main" id="main-content">
         {% if breadcrumbs %}
         <nav class="breadcrumb" aria-label="Breadcrumb">