/* ========== 基础样式模板 - 莫兰迪色系 ========== */
:root {
  /* 主色调 - 莫兰迪绿 */
  --primary: #6b8e6b;
  --primary-light: #8aaa8a;
  --primary-dark: #4a6b4a;
  
  /* 背景色 */
  --bg-main: #f5f2ed;
  --bg-sidebar: #ebe6df;
  --bg-card: #ffffff;
  --bg-code: #f0ede8;
  
  /* 文字色 */
  --text-primary: #3a3a3a;
  --text-secondary: #6b6b6b;
  --text-muted: #9a9a9a;
  
  /* 边框 */
  --border: #d8d2c9;
  --border-light: #e8e3dc;
  
  /* 提示框颜色 */
  --info-bg: #e8eff5;
  --info-border: #7a9ab8;
  --warning-bg: #f5ede0;
  --warning-border: #c4a574;
  --success-bg: #e5f0e5;
  --success-border: #7aab7a;
  --danger-bg: #f5e0e0;
  --danger-border: #c47474;
  
  /* 阴影 */
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
  --shadow-md: 0 2px 8px rgba(0,0,0,0.1);
  --shadow-lg: 0 4px 16px rgba(0,0,0,0.12);
  
  /* 圆角 */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg-main);
  color: var(--text-primary);
  line-height: 1.7;
  font-size: 15px;
}

/* ========== 布局 ========== */
.app-container {
  display: flex;
  min-height: 100vh;
}

.sidebar {
  width: 280px;
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border);
  overflow-y: auto;
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  z-index: 100;
}

.main-content {
  margin-left: 280px;
  flex: 1;
  padding: 30px 40px;
  max-width: 1100px;
}

/* ========== 侧边栏 ========== */
.sidebar-header {
  padding: 24px 20px 16px;
  border-bottom: 1px solid var(--border);
}

.logo {
  font-size: 18px;
  font-weight: 700;
  color: var(--primary-dark);
}

.logo-sub {
  font-size: 11px;
  color: var(--text-muted);
  margin-top: 4px;
  letter-spacing: 0.5px;
}

.progress-section {
  padding: 16px 20px;
  border-bottom: 1px solid var(--border-light);
}

.progress-label {
  font-size: 12px;
  color: var(--text-secondary);
  margin-bottom: 6px;
}

.progress-bar {
  height: 6px;
  background: var(--border);
  border-radius: 3px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: var(--primary);
  border-radius: 3px;
  transition: width 0.3s;
  width: 0%;
}

/* 导航 */
.nav-menu { padding: 12px 0; }

.nav-part {
  padding: 8px 20px;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 1px;
  cursor: pointer;
  user-select: none;
}

.nav-chapter {
  padding: 8px 20px;
  font-size: 14px;
  font-weight: 600;
  color: var(--text-primary);
  cursor: pointer;
}

.nav-chapter:hover { background: var(--bg-main); }

.nav-lesson {
  padding: 6px 20px 6px 36px;
  font-size: 13px;
  color: var(--text-secondary);
  cursor: pointer;
  border-left: 3px solid transparent;
}

.nav-lesson:hover {
  background: var(--bg-main);
  color: var(--primary-dark);
}

.nav-lesson.active {
  background: var(--bg-main);
  color: var(--primary-dark);
  border-left-color: var(--primary);
  font-weight: 500;
}

.nav-lesson.completed::after {
  content: '✓';
  color: var(--success-border);
  float: right;
  font-size: 12px;
}

/* ========== 章节头部 ========== */
.chapter-header {
  color: white;
  padding: 32px 36px;
  border-radius: var(--radius-lg);
  margin-bottom: 24px;
  box-shadow: var(--shadow-md);
}

.chapter-num {
  font-size: 12px;
  letter-spacing: 2px;
  opacity: 0.8;
  margin-bottom: 8px;
}

.chapter-header h1 {
  font-size: 28px;
  margin-bottom: 8px;
}

.chapter-desc {
  font-size: 14px;
  opacity: 0.9;
}

/* ========== 内容排版 ========== */
.lesson-content h2 {
  font-size: 22px;
  color: var(--primary-dark);
  margin: 32px 0 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--border-light);
}

.lesson-content h3 {
  font-size: 17px;
  color: var(--text-primary);
  margin: 24px 0 12px;
}

.lesson-content h4 {
  font-size: 15px;
  color: var(--text-secondary);
  margin: 16px 0 8px;
}

.lesson-content p {
  margin-bottom: 12px;
  color: var(--text-primary);
}

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

.lesson-content li {
  margin-bottom: 6px;
}

.lesson-content strong {
  color: var(--primary-dark);
}

/* ========== 代码块 ========== */
.code-block {
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 16px 20px;
  margin: 16px 0;
  overflow-x: auto;
}

.code-block pre {
  margin: 0;
  font-family: "Consolas", "Monaco", "Courier New", monospace;
  font-size: 13px;
  line-height: 1.6;
  color: var(--text-primary);
  white-space: pre;
}

.code-block code {
  font-family: inherit;
}

/* 行内代码 */
.lesson-content code {
  background: var(--bg-code);
  padding: 2px 6px;
  border-radius: 3px;
  font-size: 13px;
  font-family: "Consolas", monospace;
  color: var(--primary-dark);
}

/* ========== 数据表格 ========== */
.data-table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0;
  font-size: 14px;
  background: var(--bg-card);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.data-table th {
  background: var(--bg-sidebar);
  color: var(--text-primary);
  font-weight: 600;
  padding: 10px 14px;
  text-align: left;
  border-bottom: 2px solid var(--border);
}

.data-table td {
  padding: 10px 14px;
  border-bottom: 1px solid var(--border-light);
}

.data-table tr:last-child td { border-bottom: none; }

.data-table tr:hover td { background: var(--bg-main); }

/* ========== 提示框 ========== */
.callout {
  border-radius: var(--radius-md);
  padding: 16px 20px;
  margin: 16px 0;
  display: flex;
  gap: 12px;
  align-items: flex-start;
}

.callout-icon {
  font-size: 20px;
  flex-shrink: 0;
  margin-top: 2px;
}

.callout > div { flex: 1; }
.callout p { margin-bottom: 8px; }
.callout p:last-child { margin-bottom: 0; }
.callout ul, .callout ol { margin: 8px 0; }

.callout-info {
  background: var(--info-bg);
  border-left: 4px solid var(--info-border);
}

.callout-warning {
  background: var(--warning-bg);
  border-left: 4px solid var(--warning-border);
}

.callout-success {
  background: var(--success-bg);
  border-left: 4px solid var(--success-border);
}

.callout-danger {
  background: var(--danger-bg);
  border-left: 4px solid var(--danger-border);
}

/* ========== 建设中提示 ========== */
.lesson-coming-soon {
  text-align: center;
  padding: 60px 20px;
  color: var(--text-muted);
}

.lesson-coming-soon .icon {
  font-size: 48px;
  margin-bottom: 16px;
}

.lesson-coming-soon h3 {
  font-size: 20px;
  margin-bottom: 12px;
  color: var(--text-secondary);
}

/* ========== 响应式 ========== */
@media (max-width: 768px) {
  .sidebar {
    transform: translateX(-100%);
    transition: transform 0.3s;
  }
  .sidebar.open { transform: translateX(0); }
  .main-content {
    margin-left: 0;
    padding: 20px;
  }
}