* { box-sizing: border-box; }
  :root {
    --bg: #f8fafc;
    --surface: #ffffff;
    --border: #e2e8f0;
    --border-strong: #cbd5e1;
    --text: #0f172a;
    --sub: #334155;
    --mute: #64748b;
    --accent: #2563eb;
    --accent-soft: #eff6ff;
    --star: #dc2626;
    --warn-bg: #fffbeb;
    --warn-bar: #d97706;
    --err-bg: #fef2f2;
    --err-bar: #dc2626;
    --ok: #16a34a;
  }
  @media (prefers-color-scheme: dark) {
    :root {
      --bg: #0f172a;
      --surface: #1e293b;
      --border: #334155;
      --border-strong: #475569;
      --text: #f1f5f9;
      --sub: #cbd5e1;
      --mute: #94a3b8;
      --accent: #3b82f6;
      --accent-soft: #1e3a5f;
      --star: #fca5a5;
      --warn-bg: #422006;
      --warn-bar: #fbbf24;
      --err-bg: #450a0a;
      --err-bar: #f87171;
      --ok: #4ade80;
    }
    mark { background: #854d0e; }
    .topbar { background: rgba(15,23,42,.88); }
    .back-top { background: var(--surface); }
    .back-top:hover { background: var(--border); }
    .bell-head { background: linear-gradient(135deg, #450a0a, #1e293b); }
    .bell-ok { background: linear-gradient(135deg, #052e16, #1e293b); }
    .loading-mask { background: rgba(15,23,42,.8); }
    .toast { background: #e2e8f0; color: #0f172a; }
  }
  html, body { margin: 0; padding: 0; background: var(--bg); color: var(--text);
    font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Segoe UI", Roboto, sans-serif;
    font-size: 14px; line-height: 1.55; -webkit-font-smoothing: antialiased; }
  a { color: inherit; text-decoration: none; }
  a:hover { color: var(--accent); }
  button { font-family: inherit; }
  mark { background: #fef08a; color: inherit; padding: 0 2px; border-radius: 2px; }

  /* 自定义滚动条 */
  ::-webkit-scrollbar { width: 6px; height: 6px; }
  ::-webkit-scrollbar-track { background: transparent; }
  ::-webkit-scrollbar-thumb { background: var(--border-strong); border-radius: 3px; }
  ::-webkit-scrollbar-thumb:hover { background: var(--mute); }
  * { scrollbar-width: thin; scrollbar-color: var(--border-strong) transparent; }

  /* Toast 提醒 */
  .toast {
    position: fixed; bottom: 24px; left: 50%; transform: translateX(-50%) translateY(20px);
    padding: 10px 20px; background: #1e293b; color: #fff; border-radius: 8px;
    font-size: 13px; opacity: 0; transition: all .3s ease; z-index: 9999;
    pointer-events: none; box-shadow: 0 4px 12px rgba(0,0,0,.15);
  }
  .toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

  /* 回到顶部按钮 */
  .back-top {
    position: fixed; bottom: 24px; right: 24px; width: 40px; height: 40px;
    border: none; border-radius: 50%; background: #fff; color: var(--text);
    box-shadow: 0 2px 10px rgba(0,0,0,.12); cursor: pointer; z-index: 99;
    display: flex; align-items: center; justify-content: center;
    opacity: 0; pointer-events: none; transition: opacity .25s, transform .25s;
    transform: translateY(8px);
  }
  .back-top.show { opacity: 1; pointer-events: auto; transform: translateY(0); }
  .back-top:hover { background: var(--bg); }

  /* 容器：全宽，保留 16-24px 安全边距，1600px 上限避免在 4K 上过宽 */
  .app { width: 100%; max-width: 1600px; margin: 0 auto; padding: 0 24px 72px; }

  /* ===== 顶栏（扁平、毛玻璃底、底线分隔） ===== */
  .topbar {
    position: sticky; top: 0; z-index: 20;
    background: rgba(250,250,250,.88);
    backdrop-filter: saturate(180%) blur(8px);
    border-bottom: 1px solid var(--border);
    display: flex; align-items: center; justify-content: space-between;
    padding: 13px 0 12px;
    margin: 0 -24px;
    padding-left: 24px; padding-right: 24px;
  }
  .brand { display: flex; align-items: baseline; gap: 10px; }
  .brand .logo { font-size: 16px; font-weight: 700; letter-spacing: .2px; }
  .brand .logo b { color: var(--accent); font-weight: 700; }
  .brand .sub { font-size: 12px; color: var(--mute); }
  .top-actions { display: flex; align-items: center; gap: 14px; }
  .live { display: inline-flex; align-items: center; gap: 6px; font-size: 12px; color: var(--sub); cursor: pointer; user-select: none; }
  .live .dot { width: 7px; height: 7px; border-radius: 50%; background: var(--ok); }
  .live.off .dot { background: var(--mute); }
  .refresh-btn { height: 36px; padding: 0 12px; border: 1px solid var(--border-strong); background: var(--surface);
    border-radius: 6px; cursor: pointer; font-size: 12.5px; color: var(--sub); transition: .12s; display: inline-flex; align-items: center; gap: 5px; }
  .refresh-btn:hover { background: var(--accent-soft); color: var(--accent); border-color: var(--accent); }

  /* ===== 小铃铛告警 ===== */
  .bell-wrap { position: relative; }
  .bell-btn {
    position: relative; display: flex; align-items: center; justify-content: center;
    width: 36px; height: 36px; border: 1px solid var(--border-strong);
    background: var(--surface); border-radius: 6px; cursor: pointer;
    color: var(--sub); transition: .12s;
  }
  .bell-btn:hover { background: var(--accent-soft); color: var(--accent); border-color: var(--accent); }
  .bell-badge {
    position: absolute; top: -4px; right: -4px;
    min-width: 16px; height: 16px; padding: 0 4px;
    background: var(--err-bar); color: #fff; font-size: 10px; font-weight: 700;
    border-radius: 8px; display: none; line-height: 16px; text-align: center;
  }
  .bell-badge.show { display: block; }
  .bell-dropdown {
    position: absolute; top: 100%; right: 0; margin-top: 8px;
    width: 260px; background: var(--surface); border: 1px solid var(--border);
    border-radius: 12px; box-shadow: 0 8px 24px rgba(0,0,0,.12); z-index: 100;
    overflow: hidden;
  }
  .bell-dropdown.collapsed { display: none; }
  .bell-head {
    padding: 12px 14px; font-size: 13px; font-weight: 600; color: var(--text);
    background: linear-gradient(135deg, #fef2f2, #fff5f5);
    border-bottom: 1px solid var(--border);
  }
  .bell-ok {
    padding: 20px 14px; color: var(--ok); font-size: 12.5px;
    display: flex; align-items: center; gap: 8px; justify-content: center;
    background: linear-gradient(135deg, #f0fdf4, #ecfdf5);
  }
  .bell-ok svg { color: var(--ok); }

  /* ===== 设置面板 ===== */
  .settings-body { padding: 0; max-height: 420px; overflow-y: auto; }
  .settings-section { padding: 12px 14px; border-bottom: 1px solid var(--border); }
  .settings-section:last-child { border-bottom: 0; }
  .settings-title { font-size: 12px; font-weight: 600; color: var(--text); margin-bottom: 10px; }
  .settings-row { display: flex; align-items: center; justify-content: space-between; padding: 6px 0; }
  .settings-row.column { flex-direction: column; align-items: stretch; gap: 6px; }
  .settings-label { font-size: 12px; color: var(--sub); }
  .settings-input-wrap { display: flex; align-items: center; gap: 6px; }
  .settings-input { width: 70px; height: 28px; padding: 0 8px; border: 1px solid var(--border-strong);
    border-radius: 4px; font-size: 12px; color: var(--text); background: var(--surface); outline: none; }
  .settings-input:focus { border-color: var(--accent); }
  .settings-input.full { width: 100%; }
  .settings-unit { font-size: 11px; color: var(--mute); white-space: nowrap; }
  .settings-btn { padding: 6px 12px; border: 1px solid var(--border-strong); border-radius: 4px;
    background: var(--surface); color: var(--sub); font-size: 12px; cursor: pointer; transition: .15s; }
  .settings-btn:hover { background: var(--bg); border-color: var(--accent); color: var(--accent); }

  /* Toggle 开关 */
  .toggle { position: relative; display: inline-block; width: 36px; height: 20px; cursor: pointer; }
  .toggle input { opacity: 0; width: 0; height: 0; }
  .toggle .slider { position: absolute; inset: 0; background: #cbd5e1; border-radius: 20px; transition: .2s; }
  .toggle .slider::before { content: ""; position: absolute; left: 2px; top: 2px;
    width: 16px; height: 16px; border-radius: 50%; background: #fff; transition: .2s; }
  .toggle input:checked + .slider { background: var(--accent); }
  .toggle input:checked + .slider::before { transform: translateX(16px); }

  /* ===== 筛选区（与下方内容直接相连，无卡片包裹） ===== */
  .filters { padding: 12px 0 0; }
  .filters .row { display: flex; align-items: center; gap: 10px; }
  .filters .row + .row { margin-top: 10px; padding-bottom: 12px; border-bottom: 1px solid var(--border); }
  .search { flex: 1; min-width: 180px; max-width: 480px; position: relative; }
  .search input { width: 100%; height: 32px; padding: 0 10px 0 32px; background: var(--surface);
    border: 1px solid var(--border-strong); border-radius: 6px; font-size: 13.5px; color: var(--text); outline: none; transition: .12s; }
  .search input:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }
  .search::before { content: ""; position: absolute; left: 10px; top: 50%; transform: translateY(-50%);
    width: 14px; height: 14px; pointer-events: none;
    background: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%2399a3b0' stroke-width='2' stroke-linecap='round'><circle cx='11' cy='11' r='7'/><path d='m21 21-4.35-4.35'/></svg>") center/contain no-repeat; }
  .seg {
    display: inline-flex; background: var(--border); border-radius: 20px;
    padding: 2px; gap: 2px;
  }
  .seg button {
    padding: 6px 14px; border: 0; background: transparent; border-radius: 18px;
    cursor: pointer; font-size: 12.5px; color: var(--sub); transition: .2s;
    font-weight: 500;
  }
  .seg button:hover { background: rgba(255,255,255,.5); }
  .seg button.on { background: var(--surface); color: var(--accent); box-shadow: 0 1px 3px rgba(0,0,0,.1); }
  .seg .cnt { font-size: 10.5px; opacity: .8; margin-left: 3px; font-weight: 600; }

  .chips { display: flex; flex-wrap: wrap; gap: 4px 10px; align-items: center; }
  .chip { display: inline-flex; align-items: center; gap: 5px; padding: 5px 10px;
    border: 1px solid transparent; border-radius: 12px; font-size: 12px; color: var(--sub);
    cursor: pointer; user-select: none; transition: .12s; background: transparent; line-height: 1.5; }
  .chip:hover { background: var(--surface); border-color: var(--border-strong); }
  .chip.sel .name { color: var(--accent); font-weight: 600; }
  .chip .st-dot { width: 7px; height: 7px; border-radius: 50%; flex: none; background: #d1d5db; }
  .chip .st-dot.ok { background: var(--ok); }
  .chip .st-dot.err { background: var(--err-bar); animation: blink 1.6s ease-in-out infinite; }
  @keyframes blink { 50% { opacity: .35; } }
  .src-hint { font-size: 11.5px; color: var(--mute); margin-left: 6px; white-space: nowrap; }

  /* ===== 时间轴信息流（核心） ===== */
  .stream { padding: 4px 0 24px; -webkit-user-select: none; user-select: none; -webkit-touch-callout: none; }
  .day-head {
    font-size: 12px; font-weight: 600; color: var(--mute);
    padding: 20px 0 6px; letter-spacing: .4px;
  }
  .item {
    display: grid;
    grid-template-columns: 76px 22px 1fr;
    column-gap: 6px;
    padding: 12px 0;
    border-bottom: 1px solid var(--border);
    position: relative;
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    user-select: none;
  }
  .item:last-child { border-bottom: 0; }
  .item .t-time {
    text-align: right;
    font-size: 12px;
    color: var(--mute);
    font-variant-numeric: tabular-nums;
    padding-top: 2px;
    line-height: 1.5;
    user-select: none;
  }
  .item .t-rail {
    position: relative;
  }
  .item .t-rail::before {
    content: "";
    position: absolute;
    left: 50%;
    top: 0; bottom: 0;
    width: 1px;
    background: var(--border);
    transform: translateX(-0.5px);
  }
  .item .t-rail .dot {
    display: block;
    width: 7px; height: 7px;
    border-radius: 50%;
    background: var(--border-strong);
    margin: 8px auto 0;
    position: relative;
    z-index: 1;
  }
  .item.starred .t-rail .dot { background: var(--star); }
  .item .t-body { min-width: 0; }
  .item .t-title {
    font-size: 15px;
    line-height: 1.5;
    color: var(--text);
    font-weight: 500;
    word-break: break-word;
  }
  .item.starred .t-title { color: var(--star); font-weight: 600; }
  .item .t-content {
    font-size: 13px;
    line-height: 1.7;
    color: var(--sub);
    margin-top: 4px;
    word-break: break-word;
  }
  .item .t-content.collapsed {
    display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical;
    overflow: hidden; cursor: pointer;
  }
  .item .t-content.expanded { display: block; cursor: pointer; }
  .item .t-meta {
    display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 6px;
    margin-top: 5px; font-size: 12px; color: var(--mute);
  }
  .item .t-meta .src { color: var(--mute); }
  .item .t-meta .actions { display: flex; gap: 14px; }
  .item .t-meta a, .item .t-meta button {
    color: var(--mute); font-size: 12px; padding: 4px 0;
    background: transparent; border: 0; cursor: pointer;
    display: inline-flex; align-items: center; gap: 3px;
  }
  .item .t-meta a:hover, .item .t-meta button:hover { color: var(--accent); }

  /* 合并的文章（缩进、左线） */
  .item .t-dups {
    margin-top: 8px;
    border-left: 2px solid var(--border);
    padding: 4px 0 4px 10px;
  }
  .item .t-dups-title {
    font-size: 11.5px; color: var(--mute); font-weight: 600;
    margin-bottom: 4px; letter-spacing: .3px;
  }
  .item .t-dups-list { display: flex; flex-direction: column; gap: 1px; }
  .item .t-dup {
    display: grid; grid-template-columns: 56px 76px 1fr; column-gap: 8px;
    font-size: 12.5px; color: var(--sub);
    padding: 2px 4px; border-radius: 4px;
  }
  .item .t-dup:not(.nolink):hover { background: var(--accent-soft); }
  .item .t-dup:not(.nolink):hover .dti { color: var(--accent); }
  .item .t-dup .dt { color: var(--mute); font-variant-numeric: tabular-nums; font-size: 11.5px; }
  .item .t-dup .ds { color: var(--mute); font-size: 11.5px; }
  .item .t-dup .dti { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

  .empty { text-align: center; padding: 60px 0; color: var(--mute); font-size: 13px; }
  .empty .e { font-size: 24px; margin-bottom: 6px; opacity: .5; }

  /* ===== Loading 骨架屏 ===== */
  .skeleton { padding: 12px 0; border-bottom: 1px solid var(--border); }
  .skeleton-row { display: grid; grid-template-columns: 76px 22px 1fr; column-gap: 6px; }
  .skeleton-time { height: 14px; background: var(--border); border-radius: 4px; margin-top: 4px; }
  .skeleton-dot { width: 7px; height: 7px; border-radius: 50%; background: var(--border); margin: 8px auto 0; }
  .skeleton-content { }
  .skeleton-title { height: 18px; background: var(--border); border-radius: 4px; width: 60%; margin-bottom: 8px; }
  .skeleton-text { height: 14px; background: var(--border); border-radius: 4px; width: 90%; margin-bottom: 6px; }
  .skeleton-text:last-child { width: 40%; }
  .loading-mask {
    position: fixed; top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(250,250,250,.8); display: flex; align-items: center; justify-content: center;
    z-index: 999; opacity: 0; pointer-events: none; transition: opacity .2s;
  }
  .loading-mask.show { opacity: 1; pointer-events: auto; }
  .loading-spinner {
    width: 32px; height: 32px; border: 3px solid var(--border);
    border-top-color: var(--accent); border-radius: 50%; animation: spin .8s linear infinite;
  }
  @keyframes spin { to { transform: rotate(360deg); } }
  .load-more { display: flex; align-items: center; justify-content: center; gap: 8px;
    padding: 16px 0; color: var(--mute); font-size: 12.5px; }
  .load-more .mini-spinner {
    width: 16px; height: 16px; border: 2px solid var(--border);
    border-top-color: var(--accent); border-radius: 50%; animation: spin .8s linear infinite;
  }

  @media (max-width: 720px) {
    .app { padding: 0 14px 60px; }
    .topbar { margin: 0 -14px; padding-left: 14px; padding-right: 14px; }
    .brand .sub { display: none; }
    .seg button { padding: 6px 12px; font-size: 12px; min-height: 36px; }
    /* 信源横向滚动 */
    .chips { flex-wrap: nowrap; overflow-x: auto; -webkit-overflow-scrolling: touch; scrollbar-width: none; padding-bottom: 2px; }
    .chips::-webkit-scrollbar { display: none; }
    .chip { white-space: nowrap; flex-shrink: 0; }
    /* 状态文字：单独一行，精简显示 */
    .filters .row + .row { flex-wrap: wrap; }
    .src-hint { width: 100%; margin-left: 0; margin-top: 4px; font-size: 11px; }
    /* 列表项：时间移到标题上方 */
    .item { display: flex; flex-direction: column; gap: 4px; padding: 12px 0; }
    .item .t-time { text-align: left; font-size: 11px; order: 0; }
    .item .t-rail { display: none; }
    .item .t-body { order: 1; }
    .item .t-title { font-size: 14.5px; }
    .item .t-content { font-size: 12.5px; }
    .item .t-meta { flex-direction: column; align-items: flex-start; gap: 2px; }
    .item .t-meta .actions { gap: 12px; }
    .item .t-dup { grid-template-columns: 46px 64px 1fr; font-size: 12px; column-gap: 6px; }
    .item .t-dup .dti { white-space: normal; }
  }