style: 完全移除章节导航按钮和面板

- 删除章节导航按钮HTML元素
- 删除章节导航面板HTML元素
- 删除相关的CSS样式
- 删除响应式样式中的章节导航部分

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Maynor996

_layouts/default.html

@@ -768,148 +768,6 @@
       min-width: 0;
     }
 
-    /* ── 章节导航按钮 ── */
-    .chapter-nav-toggle {
-      position: fixed;
-      bottom: 2rem;
-      right: 6rem;
-      width: 48px;
-      height: 48px;
-      background: var(--color-primary);
-      color: #fff;
-      border: none;
-      border-radius: var(--radius-full);
-      cursor: pointer;
-      display: flex;
-      align-items: center;
-      justify-content: center;
-      font-size: 1.5rem;
-      box-shadow: var(--shadow-lg);
-      transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
-      z-index: 9998;
-    }
-
-    .chapter-nav-toggle:hover {
-      background: var(--color-primary-dark);
-      transform: scale(1.1);
-      box-shadow: var(--shadow-xl);
-    }
-
-    .chapter-nav-toggle:active {
-      transform: scale(0.95);
-    }
-
-    /* ── 章节导航面板 ── */
-    .chapter-nav-panel {
-      position: fixed;
-      top: 50%;
-      right: -400px;
-      transform: translateY(-50%);
-      width: 360px;
-      max-height: 80vh;
-      background: var(--color-bg);
-      border: 2px solid var(--color-border);
-      border-radius: var(--radius-lg);
-      box-shadow: var(--shadow-xl);
-      overflow: hidden;
-      transition: right 0.3s cubic-bezier(0.4, 0, 0.2, 1);
-      z-index: 9997;
-      display: flex;
-      flex-direction: column;
-    }
-
-    .chapter-nav-panel.open {
-      right: 2rem;
-    }
-
-    .chapter-nav-header {
-      padding: 1.25rem;
-      background: var(--color-bg-alt);
-      border-bottom: 1px solid var(--color-border);
-      display: flex;
-      justify-content: space-between;
-      align-items: center;
-    }
-
-    .chapter-nav-header h3 {
-      margin: 0;
-      font-size: 1.1rem;
-      color: var(--color-text);
-    }
-
-    .chapter-nav-close {
-      background: none;
-      border: none;
-      font-size: 1.5rem;
-      cursor: pointer;
-      color: var(--color-text-muted);
-      padding: 0.25rem;
-      line-height: 1;
-      transition: color 0.2s;
-    }
-
-    .chapter-nav-close:hover {
-      color: var(--color-accent);
-    }
-
-    .chapter-nav-content {
-      overflow-y: auto;
-      flex: 1;
-      padding: 1rem;
-    }
-
-    .chapter-nav-content::-webkit-scrollbar {
-      width: 6px;
-    }
-
-    .chapter-nav-content::-webkit-scrollbar-track {
-      background: var(--color-bg-alt);
-    }
-
-    .chapter-nav-content::-webkit-scrollbar-thumb {
-      background: var(--color-border);
-      border-radius: 3px;
-    }
-
-    .chapter-nav-content::-webkit-scrollbar-thumb:hover {
-      background: var(--color-text-muted);
-    }
-
-    .chapter-nav-section {
-      margin-bottom: 1.5rem;
-    }
-
-    .chapter-nav-section-title {
-      font-size: 0.9rem;
-      font-weight: 600;
-      color: var(--color-text-secondary);
-      margin-bottom: 0.75rem;
-      text-transform: uppercase;
-      letter-spacing: 0.05em;
-    }
-
-    .chapter-nav-link {
-      display: block;
-      padding: 0.5rem 0.75rem;
-      color: var(--color-text);
-      text-decoration: none;
-      border-radius: var(--radius-sm);
-      margin-bottom: 0.25rem;
-      transition: all 0.2s;
-      font-size: 0.9rem;
-    }
-
-    .chapter-nav-link:hover {
-      background: var(--color-bg-alt);
-      color: var(--color-primary);
-      transform: translateX(4px);
-    }
-
-    .chapter-nav-link.current {
-      background: var(--color-primary);
-      color: #fff;
-    }
-
     /* ── 返回顶部按钮 ── */
     .back-to-top {
       position: fixed;
@@ -946,20 +804,6 @@
 
     /* 响应式调整 */
     @media screen and (max-width: 42em) {
-      .chapter-nav-panel {
-        width: calc(100vw - 2rem);
-        max-width: 360px;
-      }
-
-      .chapter-nav-panel.open {
-        right: 1rem;
-      }
-
-      .chapter-nav-toggle {
-        bottom: 1rem;
-        right: 4.5rem;
-      }
-
       .back-to-top {
         bottom: 1rem;
         right: 1rem;
@@ -1231,21 +1075,6 @@
   </script>
 </head>
 <body>
-  <!-- 章节导航按钮 -->
-  <button class="chapter-nav-toggle" id="chapter-nav-toggle" aria-label="章节导航">
-  </button>
-
-  <!-- 章节导航面板 -->
-  <div class="chapter-nav-panel" id="chapter-nav-panel">
-    <div class="chapter-nav-header">
-      <h3>章节导航</h3>
-      <button class="chapter-nav-close" id="chapter-nav-close" aria-label="关闭">×</button>
-    </div>
-    <div class="chapter-nav-content" id="chapter-nav-content">
-      <!-- 内容将由 JavaScript 动态生成 -->
-    </div>
-  </div>
-
   <header class="page-header" role="banner">
     <!-- 主题切换按钮 -->
     <button class="theme-toggle" id="theme-toggle" aria-label="切换主题">