/* ======================================================
   22408 公共样式 — 设计令牌 + 复用组件
   所有子页面均可引用此文件，各自只保留科目特有样式
   ====================================================== */

/* ----- 设计令牌 (Design Tokens) ----- */
:root {
    --primary: #d9730d;
    --primary-light: rgba(217,115,13,0.08);
    --primary-hover: rgba(217,115,13,0.14);

    --accent: #2eaadc;
    --accent-light: rgba(46,170,220,0.08);

    --success: #0f7b6c;
    --success-light: rgba(15,123,108,0.08);

    --danger: #eb5757;
    --danger-light: rgba(235,87,87,0.08);

    --purple: #7c3aed;
    --purple-light: rgba(124,58,237,0.08);

    --bg: #f7f6f3;
    --card: #ffffff;
    --text: #37352f;
    --text-secondary: #9b9a97;
    --border: rgba(55,53,47,0.09);
    --border-light: rgba(55,53,47,0.04);

    --header-height: 52px;
    --sidebar-width: 260px;

    --radius-sm: 8px;
    --radius: 12px;
    --radius-lg: 14px;

    --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
    --font-mono: "SF Mono", Consolas, "Source Code Pro", monospace;

    --ease: cubic-bezier(0.16,1,0.3,1);
}

/* ----- Reset ----- */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

body {
    font-family: var(--font);
    background: var(--bg);
    color: var(--text);
    line-height: 1.7;
}

/* ----- SVG Icons ----- */
.icon-svg {
    width: 16px; height: 16px;
    display: inline-block;
    vertical-align: middle;
    flex-shrink: 0;
}

/* ----- Header (fixed top bar) ----- */
.header {
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 1000;
    height: var(--header-height);
    background: rgba(255,255,255,0.85);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    padding: 0 20px;
    gap: 12px;
}
.header h1 {
    font-size: 16px;
    font-weight: 700;
    letter-spacing: 0.5px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}
.header .subtitle {
    font-size: 11px;
    color: var(--text-secondary);
    margin-left: 4px;
}

/* ----- Back link ----- */
.back-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 13px;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 4px;
    flex-shrink: 0;
    transition: color 0.2s;
}
.back-link:hover { color: var(--primary); }

/* ----- Menu toggle (mobile) ----- */
.menu-toggle {
    display: none;
    background: none;
    border: none;
    color: var(--text);
    font-size: 20px;
    cursor: pointer;
    padding: 4px;
    border-radius: var(--radius-sm);
    line-height: 1;
    flex-shrink: 0;
}
.menu-toggle:hover { background: rgba(0,0,0,0.04); }

/* ----- Sidebar ----- */
.sidebar {
    position: fixed;
    top: var(--header-height);
    left: 0;
    bottom: 0;
    width: var(--sidebar-width);
    background: var(--card);
    border-right: 1px solid var(--border);
    overflow-y: auto;
    z-index: 100;
    padding: 12px 0;
    transition: transform 0.3s var(--ease);
}
.sidebar::-webkit-scrollbar { width: 4px; }
.sidebar::-webkit-scrollbar-thumb { background: rgba(0,0,0,0.08); border-radius: 4px; }

.sidebar-section {
    padding: 8px 0;
    border-bottom: 1px solid var(--border-light);
}
.sidebar-section:last-child { border-bottom: none; }

.sidebar-title {
    font-size: 10px;
    text-transform: uppercase;
    letter-spacing: 3px;
    color: var(--primary);
    font-weight: 800;
    padding: 0 18px;
    margin-bottom: 6px;
    user-select: none;
}

/* Sidebar overlay (mobile) */
.sidebar-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.3);
    z-index: 99;
}
.sidebar-overlay.show { display: block; }

/* ----- Pill (sidebar navigation item) ----- */
.pill {
    display: block;
    margin: 4px 12px;
    width: calc(100% - 24px);
    text-align: left;
    padding: 6px 12px;
    border-radius: var(--radius-sm);
    font-size: 13px;
    cursor: pointer;
    border: 1px solid transparent;
    background: transparent;
    color: var(--text-secondary);
    transition: 0.2s;
}
.pill:hover {
    background: var(--primary-light);
    color: var(--primary);
}
.pill.active {
    background: var(--primary-light);
    color: var(--primary);
    border-color: rgba(217,115,13,0.15);
    font-weight: 600;
}
.pill .icon-svg {
    width: 14px; height: 14px;
    display: inline-block;
    vertical-align: middle;
    margin-right: 4px;
    flex-shrink: 0;
}
.pill .count {
    font-size: 11px;
    color: var(--text-secondary);
    margin-left: 4px;
}
.pill.active-sub {
    background: rgba(217,115,13,0.12);
    color: var(--primary);
    border-color: rgba(217,115,13,0.2);
}
.pill.gp {
    background: var(--primary-light);
    color: var(--primary);
    border-color: rgba(217,115,13,0.12);
    font-weight: 600;
}

/* ----- Tag ----- */
.tag {
    display: inline-block;
    font-size: 11px;
    font-weight: 700;
    padding: 2px 10px;
    border-radius: 12px;
    margin: 0 3px;
}
.tag.must { background: rgba(192,57,43,0.08); color: #c0392b; }
.tag.hot  { background: rgba(211,84,0,0.08);   color: #d35400; }
.tag.new  { background: rgba(13,148,136,0.08);  color: #0d9488; }

/* ----- Search box ----- */
.search-box {
    width: 100%;
    padding: 10px 16px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 14px;
    margin-bottom: 16px;
    transition: border-color 0.3s var(--ease);
    background: var(--card);
    font-family: var(--font);
    outline: none;
}
.search-box:focus { border-color: var(--primary); }
.search-box::placeholder { color: #ccc; }

/* ----- Card base ----- */
.card {
    background: var(--card);
    border-radius: var(--radius-lg);
    padding: 24px;
    margin-bottom: 20px;
    border: 1px solid var(--border);
}

/* ----- Tab buttons (通用) ----- */
.tab-btn {
    padding: 5px 14px;
    border: 1px solid var(--border);
    border-radius: 20px;
    background: var(--card);
    cursor: pointer;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-secondary);
    transition: 0.2s;
    font-family: var(--font);
}
.tab-btn:hover {
    border-color: rgba(217,115,13,0.3);
    color: var(--primary);
}
.tab-btn.active {
    background: var(--primary-light);
    color: var(--primary);
    border-color: rgba(217,115,13,0.2);
}

/* Tab content panels */
.tab-content { display: none; }
.tab-content.active { display: block; }

.tabs {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    margin-bottom: 16px;
}

/* ----- Clickable card (grid) ----- */
.kc-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(170px, 1fr));
    gap: 14px;
    margin: 16px 0;
}
.kc-card {
    border-radius: var(--radius);
    padding: 16px;
    text-align: center;
    border: 1px solid var(--border);
    transition: 0.3s var(--ease);
    cursor: pointer;
}
.kc-card:hover {
    transform: translateY(-2px);
    border-color: rgba(217,115,13,0.15);
}
.kc-card .kc-icon { font-size: 32px; margin-bottom: 8px; }
.kc-card .kc-title { font-weight: 700; font-size: 14px; margin-bottom: 4px; }
.kc-card .kc-desc { font-size: 12px; color: var(--text-secondary); }

/* ----- Empty state ----- */
.empty {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-secondary);
    font-size: 15px;
}

/* ----- Stats grid ----- */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
    gap: 14px;
    margin-bottom: 24px;
}
.stat-card {
    background: var(--card);
    border-radius: var(--radius);
    padding: 18px;
    text-align: center;
    border: 1px solid var(--border);
    position: relative;
    overflow: hidden;
}
.stat-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 3px;
}
.stat-card .stat-number { font-size: 36px; font-weight: 800; }
.stat-card .stat-label { font-size: 12px; color: var(--text-secondary); margin-top: 2px; }

/* ----- Tip boxes ----- */
.tip-box {
    padding: 14px 18px;
    border-radius: var(--radius);
    margin: 14px 0;
    display: flex;
    align-items: flex-start;
    gap: 10px;
    font-size: 14px;
}
.tip-box.info    { background: rgba(52,152,219,0.04); border: 1px solid rgba(52,152,219,0.12); }
.tip-box.warning { background: rgba(211,84,0,0.04);    border: 1px solid rgba(211,84,0,0.12); }
.tip-box.danger  { background: rgba(192,57,43,0.04);   border: 1px solid rgba(192,57,43,0.12); }
.tip-box.success { background: rgba(39,174,96,0.04);   border: 1px solid rgba(39,174,96,0.12); }
.tip-box .tip-icon { font-size: 18px; flex-shrink: 0; line-height: 1.5; }

/* ----- Formula boxes ----- */
.formula-box {
    background: rgba(217,115,13,0.02);
    border: 1px solid rgba(217,115,13,0.08);
    border-radius: var(--radius);
    padding: 18px;
    margin: 14px 0;
    overflow-x: auto;
}
.formula-box.important {
    background: rgba(211,84,0,0.03);
    border-color: rgba(211,84,0,0.15);
    border-left: 4px solid var(--accent);
}
.formula-box.success {
    background: rgba(39,174,96,0.03);
    border-color: rgba(39,174,96,0.12);
}
.formula-box.purple {
    background: rgba(124,58,237,0.03);
    border-color: rgba(124,58,237,0.12);
    border-left: 4px solid var(--purple);
}

/* ----- Tables ----- */
.table-scroll {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    margin: 14px 0;
}
table {
    width: 100%;
    border-collapse: collapse;
    font-size: 13px;
}
th {
    background: rgba(217,115,13,0.06);
    color: var(--primary);
    padding: 10px 14px;
    text-align: left;
    font-size: 13px;
    font-weight: 700;
}
td {
    padding: 9px 14px;
    border-bottom: 1px solid var(--border-light);
}
tr:nth-child(even) { background: rgba(0,0,0,0.01); }
tr:hover { background: var(--primary-light); }

/* ----- Example blocks ----- */
.example {
    background: rgba(217,115,13,0.02);
    border-left: 4px solid var(--primary);
    padding: 18px;
    margin: 14px 0;
    border-radius: 0 var(--radius) var(--radius) 0;
}
.example.exercise {
    border-left-color: var(--accent);
    background: rgba(46,170,220,0.02);
}
.example-title {
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 8px;
    font-size: 14px;
}
.example.exercise .example-title { color: var(--accent); }

/* ----- Answer toggle ----- */
.answer-toggle {
    background: var(--primary);
    color: white;
    border: none;
    padding: 6px 16px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 13px;
    margin-top: 10px;
    font-family: var(--font);
    transition: 0.2s;
}
.answer-toggle:hover { filter: brightness(1.1); }
.answer-content {
    display: none;
    margin-top: 10px;
    padding: 14px;
    background: var(--primary-light);
    border-radius: var(--radius-sm);
    border: 1px dashed rgba(217,115,13,0.15);
}
.answer-content.show { display: block; }

/* ----- Progress ----- */
.progress-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 10px;
    margin: 14px 0;
}
.progress-item {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 10px 14px;
    cursor: pointer;
    transition: 0.3s var(--ease);
    font-size: 13px;
}
.progress-item:hover { border-color: rgba(217,115,13,0.2); }
.progress-item.done {
    background: var(--success-light);
    border-color: rgba(15,123,108,0.2);
}
.progress-item label { cursor: pointer; display: flex; align-items: center; gap: 6px; }
.progress-item input { accent-color: var(--primary); }

/* ----- Flowchart ----- */
.flowchart {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0;
    padding: 20px 0;
}
.fc-step {
    padding: 12px 24px;
    border-radius: var(--radius);
    font-size: 14px;
    font-weight: 600;
    text-align: center;
    max-width: 350px;
    position: relative;
}
.fc-step.start    { background: rgba(217,115,13,0.06); color: var(--primary); border-radius: 24px; }
.fc-step.process  { background: rgba(217,115,13,0.03); color: var(--primary); border: 1px solid rgba(217,115,13,0.12); }
.fc-step.end      { background: var(--success-light); color: var(--success); border: 1px solid rgba(15,123,108,0.12); border-radius: 24px; }
.fc-arrow {
    width: 2px;
    height: 24px;
    background: rgba(0,0,0,0.06);
    position: relative;
}
.fc-arrow::after {
    content: '';
    position: absolute;
    bottom: -4px; left: -4px;
    border-left: 5px solid transparent;
    border-right: 5px solid transparent;
    border-top: 6px solid rgba(0,0,0,0.08);
}
.fc-row {
    display: flex;
    gap: 16px;
    align-items: flex-start;
    flex-wrap: wrap;
    justify-content: center;
}
.fc-box {
    flex: 1;
    min-width: 140px;
    max-width: 200px;
    padding: 12px;
    border-radius: var(--radius);
    text-align: center;
    font-size: 13px;
    font-weight: 600;
}
.fc-label {
    font-size: 11px;
    color: var(--text-secondary);
    margin: -8px 0;
    padding: 2px 8px;
    background: var(--card);
    border-radius: 4px;
}

/* ----- Content area (next to sidebar) ----- */
.content-area {
    margin-left: var(--sidebar-width);
    padding-top: var(--header-height);
    min-height: 100vh;
}

/* ----- Responsive (mobile) ----- */
@media (max-width: 768px) {
    .sidebar {
        transform: translateX(-100%);
        width: 280px;
    }
    .sidebar.open { transform: translateX(0); }
    .sidebar .pill { font-size: 14px; padding: 8px 14px; }

    .menu-toggle { display: block; }

    .content-area {
        margin-left: 0;
        padding: var(--header-height) 16px 24px;
    }

    .header h1 { font-size: 14px; }
    .header .subtitle { display: none; }
    .back-link { font-size: 12px; margin-right: 6px; }

    .stats-grid { grid-template-columns: repeat(2, 1fr); }
    .stat-card .stat-number { font-size: 28px; }
    .kc-grid { grid-template-columns: repeat(2, 1fr); gap: 8px; }
    .kc-card { padding: 12px; }
    .kc-card .kc-icon { font-size: 24px; }
    .card { padding: 18px; }

    .tab-btn { font-size: 12px; padding: 4px 10px; }
    .tabs { gap: 4px; }

    table { font-size: 12px; }
    th, td { padding: 6px 8px; }
    .formula-box { padding: 12px; font-size: 13px; }

    .fc-step { padding: 10px 16px; font-size: 13px; max-width: 280px; }
    .fc-box { min-width: 100px; padding: 8px; font-size: 12px; }
    .fc-row { flex-direction: column; align-items: center; }
}