/* 计算与推断思维 - 中文版样式 */
:root {
  --bg: #ffffff;
  --text: #1a1a1a;
  --text-muted: #666;
  --accent: #2b6cb0;
  --accent-light: #ebf4ff;
  --border: #e2e8f0;
  --code-bg: #f7f8fa;
  --code-text: #2d3748;
  --output-bg: #f0fdf4;
  --max-width: 800px;
  --font-sans: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: "Fira Code", "Cascadia Code", "JetBrains Mono", Consolas, monospace;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
  font-family: var(--font-sans);
  color: var(--text);
  background: var(--bg);
  line-height: 1.8;
  font-size: 16px;
}

.page-wrapper {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

.page-header {
  padding: 20px 0;
  border-bottom: 1px solid var(--border);
  margin-bottom: 30px;
}

.logo-link {
  font-size: 18px;
  font-weight: 700;
  color: var(--accent);
  text-decoration: none;
}

.logo-link:hover { text-decoration: underline; }

.page-content { min-height: 60vh; }

.page-footer {
  padding: 20px 0;
  margin-top: 40px;
  border-top: 1px solid var(--border);
  text-align: center;
  color: var(--text-muted);
  font-size: 14px;
}


/* ===== 侧边栏 ===== */
.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: 300px;
  height: 100vh;
  background: #f8f9fa;
  border-right: 1px solid var(--border);
  overflow-y: auto;
  z-index: 1000;
  transform: translateX(-100%);
  transition: transform 0.3s ease;
}

.sidebar.open {
  transform: translateX(0);
}

.sidebar-toggle {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 1001;
  background: var(--accent);
  color: white;
  border: none;
  border-radius: 4px;
  padding: 6px 12px;
  font-size: 18px;
  cursor: pointer;
  opacity: 0.8;
  transition: opacity 0.2s;
}

.sidebar-toggle:hover { opacity: 1; }

.sidebar.open ~ .sidebar-toggle,
.sidebar-toggle:focus + .sidebar { transform: translateX(0); }

.sidebar-content {
  padding: 60px 12px 20px;
}

.sidebar-header {
  font-size: 16px;
  font-weight: 700;
  color: var(--accent);
  padding: 8px 12px;
  margin-bottom: 12px;
  border-bottom: 2px solid var(--accent);
}

.sidebar-toc, .sidebar-sublist {
  list-style: none;
  padding: 0;
  margin: 0;
}

.sidebar-item { margin: 2px 0; }

.sidebar-link {
  display: block;
  padding: 6px 12px;
  color: var(--text);
  text-decoration: none;
  font-size: 14px;
  border-radius: 4px;
  transition: background 0.15s;
}

.sidebar-link:hover {
  background: var(--accent-light);
  color: var(--accent);
}

.sidebar-link.active {
  background: var(--accent);
  color: white;
  font-weight: 600;
}

.sidebar-sublist { display: none; }
.sidebar-item.expanded > .sidebar-sublist { display: block; }

.sidebar-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0,0,0,0.3);
  z-index: 999;
}

.sidebar.open ~ .sidebar-overlay { display: block; }

/* ===== 调整页面布局 ===== */
.page-wrapper { position: relative; }

.page-nav {
  display: flex;
  justify-content: space-between;
  padding: 15px 0;
  margin: 20px 0;
}

.nav-link {
  color: var(--accent);
  text-decoration: none;
  font-size: 15px;
  max-width: 45%;
  padding: 8px 16px;
  border: 1px solid var(--accent);
  border-radius: 6px;
  transition: all 0.15s;
}

.nav-link:hover {
  background: var(--accent);
  color: white;
  text-decoration: none;
}

.nav-disabled {
  visibility: hidden;
  border-color: transparent;
}

/* ===== 索引页 ===== */
.index-hero {
  text-align: center;
  padding: 60px 0 40px;
}

.index-hero h1 {
  font-size: 36px;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 10px;
}

.subtitle {
  font-size: 20px;
  color: var(--text-muted);
  margin-bottom: 10px;
}

.authors {
  font-size: 14px;
  color: var(--text-muted);
  margin-bottom: 5px;
}

.note {
  font-size: 13px;
  color: var(--text-muted);
}

.index-toc { margin: 30px 0; }

.index-toc h2 {
  font-size: 22px;
  margin-bottom: 20px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--accent);
}

.toc { list-style: none; }
.toc li { margin: 6px 0; }
.toc a {
  color: var(--accent);
  text-decoration: none;
  font-size: 15px;
}
.toc a:hover { text-decoration: underline; }
.toc-sublist { margin-left: 20px; }
.toc-sublist .toc-sublist { margin-left: 20px; }

.index-info {
  margin: 30px 0;
  padding: 20px;
  background: var(--accent-light);
  border-radius: 8px;
}

.index-info h3 { margin-bottom: 10px; font-size: 18px; }
.index-info p { font-size: 14px; line-height: 1.8; color: #4a5568; }
.index-info a { color: var(--accent); }

/* ===== 内容样式 ===== */
.page-content h1 {
  font-size: 28px;
  font-weight: 700;
  margin: 30px 0 20px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--accent);
}

.page-content h2 {
  font-size: 22px;
  font-weight: 600;
  margin: 25px 0 15px;
}

.page-content h3 {
  font-size: 18px;
  font-weight: 600;
  margin: 20px 0 12px;
}

.page-content p {
  margin: 12px 0;
  text-align: justify;
}

.page-content ul, .page-content ol {
  margin: 12px 0;
  padding-left: 24px;
}

.page-content li { margin: 6px 0; }

.page-content a {
  color: var(--accent);
  text-decoration: none;
}

.page-content a:hover { text-decoration: underline; }

.page-content strong { font-weight: 600; }

.page-content em { font-style: italic; }

/* ===== 代码样式 ===== */
.page-content code {
  font-family: var(--font-mono);
  background: var(--code-bg);
  padding: 2px 6px;
  border-radius: 3px;
  font-size: 0.9em;
  color: #c7254e;
}

.page-content pre {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 16px;
  overflow-x: auto;
  margin: 16px 0;
}

.page-content pre code {
  background: none;
  padding: 0;
  color: var(--code-text);
  font-size: 14px;
  line-height: 1.6;
}

/* ===== 表格 ===== */
.page-content table {
  border-collapse: collapse;
  width: 100%;
  margin: 16px 0;
  font-size: 14px;
}

.page-content th, .page-content td {
  border: 1px solid var(--border);
  padding: 8px 12px;
  text-align: left;
}

.page-content th {
  background: var(--accent-light);
  font-weight: 600;
}

.page-content tr:nth-child(even) { background: #fafafa; }

/* ===== Notebook 单元格 ===== */
.cell { margin: 20px 0; }

.code-cell {
  background: #1e1e1e;
  border-radius: 6px;
  overflow: hidden;
}

.code-header {
  background: #333;
  color: #999;
  padding: 4px 12px;
  font-size: 12px;
  font-family: var(--font-mono);
}

.code-input {
  background: #1e1e1e !important;
  border: none !important;
  margin: 0 !important;
  padding: 16px !important;
}

.code-input code {
  color: #d4d4d4 !important;
  background: none !important;
  font-size: 14px !important;
  line-height: 1.6 !important;
}

.code-output {
  background: var(--output-bg) !important;
  border: 1px solid #c6f6d5 !important;
  border-top: none !important;
  border-radius: 0 0 6px 6px !important;
  margin: 0 !important;
  padding: 12px 16px !important;
}

.code-output code {
  color: #276749 !important;
  background: none !important;
}

.error-output {
  background: #fff5f5;
  border: 1px solid #feb2b2;
  border-radius: 6px;
  padding: 12px;
  margin: 12px 0;
}

.error-type {
  color: #c53030;
  font-weight: 600;
  margin-bottom: 8px;
}

.error-output pre {
  background: none;
  border: none;
  padding: 0;
  margin: 0;
}

.error-output code {
  color: #c53030;
}

/* ===== 引用块 ===== */
.page-content blockquote {
  border-left: 4px solid var(--accent);
  padding: 10px 16px;
  margin: 16px 0;
  background: var(--accent-light);
  border-radius: 0 6px 6px 0;
}

.page-content blockquote p { margin: 6px 0; }

/* ===== 数学公式 ===== */
.page-content .math { overflow-x: auto; }

/* ===== 响应式 ===== */
@media (max-width: 640px) {
  body { font-size: 15px; }
  .page-wrapper { padding: 0 12px; }
  .index-hero h1 { font-size: 28px; }
  .page-content h1 { font-size: 24px; }
  .page-content h2 { font-size: 20px; }
}