:root {
  --bg: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-tertiary: #f1f3f5;
  --text: #1a1a2e;
  --text-secondary: #6c757d;
  --text-tertiary: #adb5bd;
  --border: #e9ecef;
  --border-strong: #dee2e6;
  --accent: #1D9E75;
  --accent-light: #E1F5EE;
  --accent-dark: #0F6E56;
  --blue: #378ADD;
  --blue-light: #E6F1FB;
  --amber: #BA7517;
  --amber-light: #FAEEDA;
  --radius: 8px;
  --radius-lg: 12px;
  --max-width: 960px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  --mono: "SF Mono", Monaco, "Cascadia Code", "Roboto Mono", Consolas, monospace;
}

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

body {
  font-family: var(--font);
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  font-size: 15px;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
  padding: 0 24px;
}
.navbar-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
}
.logo {
  font-size: 18px;
  font-weight: 600;
  letter-spacing: -0.5px;
  color: var(--text);
  cursor: pointer;
}
.logo .dot { color: var(--accent); }
.nav-links { display: flex; gap: 24px; align-items: center; }
.nav-links a {
  color: var(--text-secondary);
  font-size: 14px;
  cursor: pointer;
  transition: color 0.15s;
}
.nav-links a:hover { color: var(--text); text-decoration: none; }
.nav-links a.active { color: var(--text); font-weight: 500; }
.nav-links .btn-admin {
  background: var(--accent-light);
  color: var(--accent-dark);
  padding: 4px 14px;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 500;
}
.nav-links .btn-login {
  color: var(--text-secondary);
  padding: 4px 14px;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 500;
  border: 1px solid var(--border-strong);
}
.nav-links .btn-login:hover { color: var(--text); border-color: var(--text-secondary); }

.login-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.06);
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 32px 24px;
}

.hero {
  text-align: center;
  padding: 48px 24px 40px;
}
.hero .tagline {
  font-size: 12px;
  color: var(--accent-dark);
  font-weight: 600;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  margin-bottom: 12px;
}
.hero h1 {
  font-size: 32px;
  font-weight: 600;
  letter-spacing: -0.5px;
  margin-bottom: 12px;
}
.hero p {
  font-size: 16px;
  color: var(--text-secondary);
  max-width: 480px;
  margin: 0 auto 20px;
}
.hero-actions { display: flex; gap: 12px; justify-content: center; }
.btn {
  display: inline-block;
  padding: 8px 20px;
  border-radius: var(--radius);
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  border: none;
  transition: all 0.15s;
}
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-dark); text-decoration: none; }
.btn-outline { background: var(--bg); border: 1px solid var(--border-strong); color: var(--text); }
.btn-outline:hover { border-color: var(--accent); color: var(--accent); text-decoration: none; }
.btn-sm { padding: 4px 12px; font-size: 13px; }
.btn-danger { background: #fff; border: 1px solid #e24b4a; color: #e24b4a; }
.btn-danger:hover { background: #fcebeb; }

.stats-bar {
  display: flex;
  justify-content: center;
  gap: 32px;
  padding: 16px 0;
  margin-bottom: 8px;
}
.stat-item { text-align: center; }
.stat-item .num { font-size: 22px; font-weight: 600; color: var(--accent); }
.stat-item .label { font-size: 12px; color: var(--text-tertiary); }

.three-col {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 20px;
  margin-top: 16px;
}
@media (max-width: 768px) {
  .three-col { grid-template-columns: 1fr; }
  .hero h1 { font-size: 24px; }
}

.col-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
}
.col-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 16px;
  border-bottom: 1px solid var(--border);
}
.col-header .title { display: flex; align-items: center; gap: 8px; font-weight: 600; font-size: 14px; }
.col-header .dot { width: 8px; height: 8px; border-radius: 2px; }
.col-header .more { font-size: 12px; color: var(--text-tertiary); cursor: pointer; }
.col-header .more:hover { color: var(--accent); }
.col-body { padding: 8px 0; }
.col-item {
  padding: 10px 16px;
  cursor: pointer;
  transition: background 0.1s;
  border-bottom: 1px solid var(--border);
}
.col-item:last-child { border-bottom: none; }
.col-item:hover { background: var(--bg-secondary); }
.col-item .item-title { font-size: 14px; font-weight: 500; margin-bottom: 2px; }
.col-item .item-meta { font-size: 12px; color: var(--text-tertiary); }
.col-empty { padding: 24px 16px; text-align: center; color: var(--text-tertiary); font-size: 13px; }

.page-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 24px;
}
.page-header h2 { font-size: 22px; font-weight: 600; }
.page-header .actions { display: flex; gap: 8px; }

.list-item {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 16px 20px;
  margin-bottom: 12px;
  cursor: pointer;
  transition: border-color 0.15s;
}
.list-item:hover { border-color: var(--border-strong); }
.list-item .li-title { font-size: 16px; font-weight: 600; margin-bottom: 4px; }
.list-item .li-excerpt { font-size: 13px; color: var(--text-secondary); margin-bottom: 8px; line-height: 1.5; }
.list-item .li-meta { font-size: 12px; color: var(--text-tertiary); display: flex; gap: 12px; flex-wrap: wrap; }
.tag {
  display: inline-block;
  font-size: 11px;
  padding: 1px 8px;
  border-radius: 4px;
  background: var(--bg-tertiary);
  color: var(--text-secondary);
}
.tag-cat { background: var(--accent-light); color: var(--accent-dark); }

.article-detail, .doc-detail, .qa-detail {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px 40px;
}
@media (max-width: 768px) {
  .article-detail, .doc-detail, .qa-detail { padding: 20px; }
}
.detail-title { font-size: 26px; font-weight: 600; margin-bottom: 8px; line-height: 1.3; }
.detail-meta { font-size: 13px; color: var(--text-tertiary); margin-bottom: 24px; display: flex; gap: 16px; flex-wrap: wrap; }
.detail-content { font-size: 15px; line-height: 1.8; }
.detail-content h1 { font-size: 22px; margin: 24px 0 12px; font-weight: 600; }
.detail-content h2 { font-size: 19px; margin: 20px 0 10px; font-weight: 600; }
.detail-content h3 { font-size: 16px; margin: 16px 0 8px; font-weight: 600; }
.detail-content p { margin-bottom: 12px; }
.detail-content ul, .detail-content ol { margin: 8px 0 12px 24px; }
.detail-content li { margin-bottom: 4px; }
.detail-content code {
  font-family: var(--mono);
  font-size: 13px;
  background: var(--bg-tertiary);
  padding: 2px 6px;
  border-radius: 4px;
}
.detail-content pre {
  background: #1e1e2e;
  color: #cdd6f4;
  padding: 16px;
  border-radius: var(--radius);
  overflow-x: auto;
  margin: 12px 0;
  font-size: 13px;
  line-height: 1.5;
}
.detail-content pre code { background: none; padding: 0; color: inherit; }
.detail-content blockquote {
  border-left: 3px solid var(--accent);
  padding: 8px 16px;
  margin: 12px 0;
  background: var(--bg-secondary);
  border-radius: 0 var(--radius) var(--radius) 0;
  color: var(--text-secondary);
}
.detail-content img { max-width: 100%; border-radius: var(--radius); margin: 12px 0; }
.detail-content table { border-collapse: collapse; width: 100%; margin: 12px 0; }
.detail-content th, .detail-content td { border: 1px solid var(--border); padding: 8px 12px; text-align: left; }
.detail-content th { background: var(--bg-secondary); font-weight: 600; }
.detail-content a { color: var(--blue); }

.back-link { margin-bottom: 16px; }
.back-link a { font-size: 13px; color: var(--text-secondary); }
.back-link a:hover { color: var(--accent); }

.admin-layout { display: flex; gap: 0; min-height: calc(100vh - 56px); }
.admin-sidebar {
  width: 200px;
  border-right: 1px solid var(--border);
  padding: 16px 0;
  flex-shrink: 0;
}
.admin-sidebar .section-label {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-tertiary);
  padding: 8px 20px;
}
.admin-sidebar a {
  display: block;
  padding: 8px 20px;
  font-size: 14px;
  color: var(--text-secondary);
  cursor: pointer;
}
.admin-sidebar a:hover, .admin-sidebar a.active { color: var(--accent); background: var(--accent-light); text-decoration: none; }
.admin-main { flex: 1; padding: 24px; overflow-x: hidden; }

.editor-form { max-width: 640px; }
.form-group { margin-bottom: 16px; }
.form-group label { display: block; font-size: 13px; font-weight: 500; margin-bottom: 6px; color: var(--text-secondary); }
.form-group input, .form-group select, .form-group textarea {
  width: 100%;
  padding: 8px 12px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius);
  font-size: 14px;
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  outline: none;
  transition: border-color 0.15s;
}
.form-group input:focus, .form-group select:focus, .form-group textarea:focus { border-color: var(--accent); }
.form-group textarea { resize: vertical; min-height: 120px; }
.form-row { display: flex; gap: 12px; }
.form-row .form-group { flex: 1; }
.editor-toolbar { display: flex; gap: 8px; margin-bottom: 8px; }
.editor-toolbar button {
  padding: 4px 10px;
  font-size: 13px;
  border: 1px solid var(--border-strong);
  background: var(--bg);
  border-radius: 4px;
  cursor: pointer;
  color: var(--text-secondary);
}
.editor-toolbar button:hover { border-color: var(--accent); color: var(--accent); }
.markdown-editor {
  font-family: var(--mono);
  font-size: 13px;
  min-height: 320px;
  line-height: 1.6;
}
.preview-toggle { display: flex; gap: 0; margin-bottom: 12px; border-bottom: 1px solid var(--border); }
.preview-toggle button {
  padding: 8px 16px;
  font-size: 13px;
  border: none;
  background: none;
  cursor: pointer;
  color: var(--text-secondary);
  border-bottom: 2px solid transparent;
}
.preview-toggle button.active { color: var(--accent); border-bottom-color: var(--accent); }

.admin-list-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 8px;
}
.admin-list-item .ali-info { flex: 1; }
.admin-list-item .ali-title { font-size: 14px; font-weight: 500; }
.admin-list-item .ali-meta { font-size: 12px; color: var(--text-tertiary); }
.admin-list-item .ali-actions { display: flex; gap: 6px; }
.status-badge { font-size: 11px; padding: 1px 6px; border-radius: 4px; }
.status-published { background: var(--accent-light); color: var(--accent-dark); }
.status-draft { background: var(--bg-tertiary); color: var(--text-secondary); }

.answer-card {
  background: var(--bg-secondary);
  border-radius: var(--radius);
  padding: 14px 16px;
  margin-bottom: 10px;
}
.answer-card .ac-meta { font-size: 12px; color: var(--text-tertiary); margin-bottom: 6px; }
.answer-card .ac-content { font-size: 14px; }
.answer-form { margin-top: 16px; }
.answer-form textarea { min-height: 80px; }

.loading { text-align: center; padding: 40px; color: var(--text-tertiary); }
.empty-state { text-align: center; padding: 48px 24px; color: var(--text-tertiary); }
.empty-state .icon { font-size: 32px; margin-bottom: 8px; opacity: 0.5; }

.doc-tree { font-size: 14px; }
.doc-tree .doc-node { padding: 6px 0; cursor: pointer; }
.doc-tree .doc-node:hover { color: var(--accent); }
.doc-tree .doc-children { padding-left: 20px; border-left: 1px solid var(--border); margin-left: 4px; }

.footer {
  border-top: 1px solid var(--border);
  padding: 20px 24px;
  text-align: center;
  font-size: 12px;
  color: var(--text-tertiary);
  max-width: var(--max-width);
  margin: 0 auto;
}

.toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--text);
  color: #fff;
  padding: 10px 20px;
  border-radius: var(--radius);
  font-size: 13px;
  z-index: 999;
  opacity: 0;
  transition: opacity 0.3s;
  pointer-events: none;
}
.toast.show { opacity: 1; }

/* ===== 文档目录 (TOC) ===== */
.doc-layout {
  display: flex;
  gap: 28px;
  align-items: flex-start;
}
.doc-toc {
  width: 220px;
  flex-shrink: 0;
  position: sticky;
  top: 72px;
  max-height: calc(100vh - 90px);
  overflow-y: auto;
}
.doc-toc .toc-title {
  font-size: 13px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 10px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}
.toc-link {
  display: block;
  font-size: 13px;
  color: var(--text-secondary);
  cursor: pointer;
  padding: 4px 10px;
  border-radius: 4px;
  transition: all 0.15s;
  line-height: 1.5;
  margin-bottom: 2px;
}
.toc-link:hover {
  color: var(--accent);
  background: var(--accent-light);
  text-decoration: none;
}
.toc-level-1 { font-weight: 500; color: var(--text); }
.toc-level-3 { font-size: 12px; }
.toc-level-4 { font-size: 12px; opacity: 0.8; }
.doc-heading { scroll-margin-top: 80px; }
.doc-toc-mobile { display: none; margin-bottom: 16px; }
.toc-toggle-btn {
  width: 100%;
  padding: 10px 14px;
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  background: var(--bg-secondary);
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  text-align: left;
  color: var(--text);
}
.toc-toggle-btn:hover { border-color: var(--accent); }
.toc-mobile-body {
  margin-top: 8px;
  padding: 8px;
  border: 1px solid var(--border);
  border-radius: 8px;
  max-height: 300px;
  overflow-y: auto;
}

/* ===== 图片拖拽高亮 ===== */
.markdown-editor.drag-over {
  border-color: var(--accent) !important;
  background: var(--accent-light);
}

/* ===== 汉堡菜单按钮（桌面隐藏，移动端显示）===== */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 4px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
  z-index: 101;
}
.nav-toggle span {
  width: 22px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: 0.25s;
}
.nav-toggle.active span:nth-child(1) { transform: rotate(45deg) translate(5px, 4px); }
.nav-toggle.active span:nth-child(2) { opacity: 0; }
.nav-toggle.active span:nth-child(3) { transform: rotate(-45deg) translate(5px, -4px); }

/* ===== 移动端适配 ===== */
@media (max-width: 768px) {
  /* 汉堡按钮显示 */
  .nav-toggle { display: flex; }

  /* 导航链接收为下拉面板 */
  .nav-links {
    position: fixed;
    top: 56px;
    left: 0;
    right: 0;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    gap: 0;
    padding: 8px 0;
    transform: translateY(-120%);
    transition: transform 0.25s ease;
    z-index: 99;
    box-shadow: 0 4px 16px rgba(0,0,0,0.1);
  }
  .nav-links.nav-open { transform: translateY(0); }
  .nav-links a {
    padding: 14px 24px;
    width: 100%;
    font-size: 15px;
  }
  .nav-links .btn-admin, .nav-links .btn-login {
    margin: 4px 24px;
    width: fit-content;
  }

  /* 导航栏 */
  .navbar { padding: 0 16px; }

  /* 容器 */
  .container { padding: 16px; }

  /* Hero */
  .hero { padding: 28px 16px 24px; }
  .hero h1 { font-size: 22px; }
  .hero p { font-size: 14px; max-width: 100%; }
  .hero-actions { flex-wrap: wrap; }
  .hero-actions .btn { font-size: 13px; padding: 7px 16px; }

  /* 统计栏 */
  .stats-bar { gap: 12px; flex-wrap: wrap; }
  .stat-item .num { font-size: 18px; }
  .stat-item .label { font-size: 11px; }

  /* 三栏 → 单栏 */
  .three-col { grid-template-columns: 1fr; gap: 12px; }

  /* 页面标题 */
  .page-header { flex-wrap: wrap; gap: 8px; margin-bottom: 16px; }
  .page-header h2 { font-size: 18px; }

  /* 列表项 */
  .list-item { padding: 14px 16px; }
  .list-item .li-title { font-size: 15px; }
  .list-item .li-meta { gap: 8px; font-size: 11px; }

  /* 详情页 */
  .article-detail, .doc-detail, .qa-detail { padding: 18px 16px; }
  .detail-title { font-size: 20px; }
  .detail-content { font-size: 14px; }
  .detail-content h1 { font-size: 19px; }
  .detail-content h2 { font-size: 17px; }
  .detail-content pre { padding: 12px; font-size: 12px; }
  .detail-content table { display: block; overflow-x: auto; -webkit-overflow-scrolling: touch; }

  /* ===== 后台管理 ===== */
  /* 侧边栏 → 顶部横向条 */
  .admin-layout { flex-direction: column; }
  .admin-sidebar {
    width: 100%;
    border-right: none;
    border-bottom: 1px solid var(--border);
    padding: 0;
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0;
    position: sticky;
    top: 56px;
    background: var(--bg);
    z-index: 50;
    overflow-x: auto;
  }
  .admin-sidebar .section-label {
    width: auto;
    padding: 6px 10px 6px 16px;
    font-size: 10px;
    white-space: nowrap;
  }
  .admin-sidebar .section-label[style*="margin-top"] { margin-top: 0 !important; width: auto; }
  .admin-sidebar a {
    padding: 8px 12px;
    white-space: nowrap;
    font-size: 13px;
  }
  .admin-main { padding: 14px; }

  /* 后台列表项 → 竖排 */
  .admin-list-item {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
    padding: 12px 14px;
  }
  .admin-list-item .ali-info { width: 100%; }
  .admin-list-item .ali-actions {
    width: 100%;
    flex-wrap: wrap;
    gap: 6px;
  }
  .admin-list-item .ali-actions .btn { font-size: 12px; padding: 3px 10px; }

  /* 表单行 → 竖排 */
  .form-row { flex-direction: column; gap: 0; }
  .editor-form { max-width: 100%; }

  /* 编辑器工具栏 → 横向滚动 */
  .editor-toolbar {
    overflow-x: auto;
    flex-wrap: nowrap;
    -webkit-overflow-scrolling: touch;
    padding-bottom: 4px;
  }
  .editor-toolbar button { flex-shrink: 0; }

  /* Markdown 编辑器 */
  .markdown-editor { min-height: 220px; font-size: 13px; }

  /* 预览区 */
  #previewArea { font-size: 14px; }

  /* 保存按钮区 */
  .editor-form > div[style*="display:flex"] { flex-wrap: wrap; }

  /* 登录页 */
  .login-card { padding: 24px 20px; }

  /* 回答区 */
  .answer-card { padding: 12px 14px; }
  .answer-form textarea { font-size: 14px; }

  /* 页脚 */
  .footer { padding: 16px; font-size: 11px; }

  /* Toast */
  .toast { bottom: 16px; font-size: 12px; padding: 8px 16px; left: 16px; right: 16px; transform: none; text-align: center; }
}

/* ===== 超小屏 (≤375px) ===== */
@media (max-width: 375px) {
  .hero h1 { font-size: 19px; }
  .hero .tagline { font-size: 10px; letter-spacing: 1px; }
  .stat-item .num { font-size: 16px; }
  .detail-title { font-size: 18px; }
  .col-item { padding: 8px 12px; }
  .col-item .item-title { font-size: 13px; }
}

/* ===== 文档 TOC 移动端 ===== */
@media (max-width: 768px) {
  .doc-layout { flex-direction: column; }
  .doc-toc { display: none; }
  .doc-toc-mobile { display: block; }
}