:root {
    /* 主色系（同蓝色系内微调） */
    --brand: #1b3f8e;
    --brand-600: #163674;
    --brand-50: #eef3fb;
    --brand-100: #e3ecf8;
    /* 中性灰阶分层 */
    --page-bg: #f4f6fb; /* 页面底色，略冷一档 */
    --section-alt-bg: #eef1f6; /* 区块交替底色，与页面底色拉开 */
    --surface: #ffffff;
    --border: #e6eaf1;
    --border-soft: #eef1f6;
    --divider: #f1f4f9;
    /* 文字层级 */
    --text-1: #1a2233; /* 主标题/强调 */
    --text-2: #3a4357; /* 正文 */
    --text-3: #6b7589; /* 次要 */
    --text-4: #9aa3b5; /* 辅助 */
    /* 阴影：双层柔和，外层带蓝调 */
    --shadow-sm: 0 1px 2px rgba(23,43,92,0.04), 0 1px 3px rgba(23,43,92,0.05);
    --shadow-md: 0 4px 14px rgba(23,43,92,0.06), 0 2px 6px rgba(23,43,92,0.04);
    --shadow-lg: 0 12px 32px rgba(23,43,92,0.12), 0 4px 10px rgba(23,43,92,0.06);
}

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

body {
    font-family: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Arial, sans-serif;
    color: var(--text-2);
    background: var(--page-bg);
    line-height: 1.75;
    font-size: 15px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    font-feature-settings: "tnum" 0;
}

a {
    text-decoration: none;
    color: inherit;
    transition: color 0.2s ease;
}

/* 数字与英文更锐利、等宽对齐 */
.num, .price, .unit, td, th, canvas {
    font-variant-numeric: tabular-nums;
}



/* Hero */
.hero {
    background: linear-gradient(135deg, var(--brand) 0%, #2a56b5 100%);
    padding: 92px 0 88px;
    text-align: center;
    position: relative;
    overflow: hidden;
}

    .hero::after {
        content: '';
        position: absolute;
        right: -120px;
        top: -120px;
        width: 360px;
        height: 360px;
        border-radius: 50%;
        background: rgba(255,255,255,0.06);
    }

    .hero::before {
        content: '';
        position: absolute;
        left: -80px;
        bottom: -100px;
        width: 260px;
        height: 260px;
        border-radius: 50%;
        background: rgba(255,255,255,0.05);
    }

    .hero .container {
        position: relative;
        z-index: 1;
    }

    .hero h1 {
        font-size: 46px;
        color: #fff;
        font-weight: 700;
        margin-bottom: 24px;
        letter-spacing: 3px;
        line-height: 1.3;
    }

    .hero p {
        font-size: 17px;
        color: rgba(255,255,255,0.88);
        max-width: 720px;
        margin: 0 auto;
        line-height: 1.9;
        font-weight: 350;
    }

/* Section common */
.section {
    padding: 56px 0;
}

.section-alt {
    background: var(--section-alt-bg);
}

.section-header {
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    margin-bottom: 36px;
}

.section-title {
    font-size: 26px;
    font-weight: 650;
    color: var(--text-1);
    display: flex;
    align-items: center;
    gap: 14px;
    letter-spacing: 0.5px;
}

    .section-title::before {
        content: '';
        display: inline-block;
        width: 4px;
        height: 28px;
        background: var(--brand);
        border-radius: 2px;
    }

.section-subtitle {
    font-size: 14px;
    color: var(--text-4);
    margin-top: 8px;
    font-weight: 350;
}

.section-more {
    color: var(--brand);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: opacity 0.2s ease;
}

    .section-more:hover {
        opacity: 0.7;
    }

/* Region cards */
.region-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 20px;
}

.region-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 26px;
    cursor: pointer;
    transition: box-shadow 0.25s ease, border-color 0.25s ease, transform 0.25s ease;
    box-shadow: var(--shadow-sm);
}

    .region-card:hover {
        box-shadow: var(--shadow-lg);
        border-color: var(--brand-100);
        transform: translateY(-3px);
    }

    .region-card .city {
        font-size: 21px;
        font-weight: 650;
        color: var(--brand);
        margin-bottom: 20px;
        letter-spacing: 0.5px;
    }

    .region-card .info {
        display: flex;
        align-items: center;
        justify-content: space-between;
        font-size: 13px;
        color: var(--text-4);
    }

    .region-card .arrow {
        font-size: 18px;
        color: var(--brand);
        transition: transform 0.25s ease;
    }

    .region-card:hover .arrow {
        transform: translateX(4px);
    }

/* Latest updates */
.updates-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}

.update-table {
    width: 100%;
    background: var(--surface);
    border-radius: 12px;
    overflow: hidden;
    border: 1px solid var(--border);
    box-shadow: var(--shadow-sm);
}

    .update-table table {
        width: 100%;
        border-collapse: collapse;
    }

    .update-table th {
        background: var(--brand-50);
        padding: 13px 22px;
        text-align: left;
        font-size: 13px;
        color: var(--text-3);
        font-weight: 600;
        letter-spacing: 0.3px;
        border-bottom: 1px solid var(--border-soft);
    }

    .update-table td {
        padding: 14px 22px;
        font-size: 14px;
        color: var(--text-2);
        border-bottom: 1px solid var(--divider);
    }

    .update-table tbody tr {
        transition: background 0.15s ease;
    }

        .update-table tbody tr:nth-child(even) td {
            background: #fafbfd;
        }

        .update-table tbody tr:hover td {
            background: var(--brand-50);
        }

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

    .update-table .link {
        color: var(--brand);
        cursor: pointer;
        transition: opacity 0.2s ease;
        font-weight: 500;
    }

        .update-table .link:hover {
            opacity: 0.7;
        }

/* Price trend */
.trend-content {
    display: grid;
    grid-template-columns: 1fr 340px;
    gap: 24px;
}

.trend-chart-box {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 28px;
    box-shadow: var(--shadow-sm);
}

.trend-chart-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 20px;
    flex-wrap: wrap;
    gap: 12px;
}

.trend-chart-title {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-1);
}

.trend-chart-legend {
    display: flex;
    gap: 22px;
    font-size: 13px;
    color: var(--text-3);
}

.legend-dot {
    display: inline-block;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    margin-right: 6px;
    vertical-align: middle;
}

    .legend-dot.blue {
        background: var(--brand);
    }

    .legend-dot.gray {
        background: #b0b8d0;
    }

.trend-chart-actions {
    display: flex;
    gap: 12px;
}

.btn-outline {
    border: 1px solid var(--brand);
    color: var(--brand);
    background: var(--surface);
    padding: 7px 18px;
    border-radius: 8px;
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.2s ease;
}

    .btn-outline:hover {
        background: var(--brand-50);
    }

.btn-primary {
    background: var(--brand);
    color: #fff;
    border: none;
    padding: 7px 18px;
    border-radius: 8px;
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.2s ease;
}

    .btn-primary:hover {
        background: var(--brand-600);
    }

.chart-area {
    width: 100%;
    height: 280px;
    position: relative;
}

    .chart-area canvas {
        width: 100%;
        height: 100%;
        display: block;
    }

/* Price sidebar */
.price-sidebar {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 24px;
    box-shadow: var(--shadow-sm);
}

.price-sidebar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 18px;
    padding-bottom: 14px;
    border-bottom: 1px solid var(--border-soft);
}

.price-sidebar-title {
    font-size: 15px;
    font-weight: 600;
    color: var(--text-1);
}

.price-sidebar-detail {
    font-size: 13px;
    color: var(--brand);
    cursor: pointer;
    font-weight: 500;
}

.price-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 7px 0;
    border-bottom: 1px solid var(--divider);
}

    .price-item:last-of-type {
        border-bottom: none;
    }

.price-item-name {
    font-size: 15px;
    font-weight: 600;
    color: var(--text-1);
}

.price-item-spec {
    font-size: 12px;
    color: var(--text-4);
    margin-top: 3px;
}

.price-item-value {
    text-align: right;
}

    .price-item-value .price {
        font-size: 20px;
        font-weight: 700;
        color: var(--brand);
    }

    .price-item-value .unit {
        font-size: 12px;
        color: var(--text-4);
    }

.btn-full {
    width: 100%;
    background: var(--brand-50);
    color: var(--brand);
    border: none;
    padding: 12px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.2s ease;
    margin-top: 18px;
}

    .btn-full:hover {
        background: var(--brand-100);
    }

/* CTA */
.cta {
    background: linear-gradient(135deg, var(--brand) 0%, #2a56b5 100%);
    padding: 52px 56px;
    border-radius: 14px;
    margin-bottom: 52px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    box-shadow: var(--shadow-md);
}

.cta-text h2 {
    font-size: 28px;
    color: #fff;
    font-weight: 700;
    margin-bottom: 14px;
    letter-spacing: 0.5px;
}

.cta-text p {
    font-size: 15px;
    color: rgba(255,255,255,0.82);
    max-width: 600px;
    line-height: 1.8;
    font-weight: 350;
}

.cta-actions {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 14px;
}

.btn-cta {
    background: #fff;
    color: var(--brand);
    padding: 14px 40px;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    border: none;
    transition: background 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease;
}

    .btn-cta:hover {
        background: var(--brand-50);
        transform: translateY(-1px);
        box-shadow: var(--shadow-md);
    }

.cta-login {
    font-size: 13px;
    color: rgba(255,255,255,0.7);
}

    .cta-login a {
        color: #fff;
        text-decoration: underline;
        transition: opacity 0.2s ease;
    }

        .cta-login a:hover {
            opacity: 0.8;
        }



/* Container */
.container {
    max-width: 1280px;
    margin: 0 auto;
    width: 100%;
    padding: 0 48px;
}

/* Tablet: <= 1024px */
@media (max-width: 1024px) {
    .container {
        padding: 0 24px;
    }

    .hero {
        padding: 64px 0 56px;
    }

        .hero h1 {
            font-size: 34px;
            letter-spacing: 2px;
        }

        .hero p {
            font-size: 16px;
        }

    .section {
        padding: 44px 0;
    }

    .section-title {
        font-size: 22px;
    }

    .region-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: 18px;
    }

    .trend-content {
        grid-template-columns: 1fr;
    }

    .cta {
        margin-bottom: 40px;
        padding: 40px 36px;
    }

    .cta-text h2 {
        font-size: 24px;
    }

    .footer {
        padding: 40px 0 20px;
    }
}

/* Mobile: <= 768px */
@media (max-width: 768px) {
    .container {
        padding: 0 16px;
    }

    .hero {
        padding: 48px 0 40px;
    }

        .hero h1 {
            font-size: 26px;
            letter-spacing: 1px;
        }

        .hero p {
            font-size: 15px;
        }

    .section {
        padding: 32px 0;
    }

    .section-title {
        font-size: 21px;
    }

    .section-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }

    .trend-chart-actions {
        align-self: flex-end;
    }

    .region-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 14px;
    }

    .region-card {
        padding: 22px;
    }

    .updates-grid {
        grid-template-columns: 1fr;
        gap: 18px;
    }

    .update-table {
        overflow-x: auto;
    }

        .update-table table {
            min-width: 360px;
        }

    .trend-chart-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }

    .trend-chart-legend {
        flex-wrap: wrap;
    }

    .cta {
        margin-bottom: 32px;
        padding: 32px 24px;
        flex-direction: column;
        text-align: center;
        gap: 28px;
    }

    .cta-text h2 {
        font-size: 22px;
    }

    .cta-text p {
        font-size: 15px;
    }

    .footer {
        padding: 32px 0 16px;
    }

    .footer-grid {
        grid-template-columns: 1fr 1fr;
        gap: 28px;
    }

    .footer-bottom {
        flex-direction: column;
        gap: 10px;
        text-align: center;
    }

    .footer-bottom-links {
        justify-content: center;
        flex-wrap: wrap;
    }
}

/* Small mobile: <= 480px */
@media (max-width: 480px) {
    .header .container {
        flex-wrap: nowrap;
    }

    .hero h1 {
        font-size: 22px;
    }

    .region-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 10px;
    }

    .section-title {
        font-size: 18px;
    }

    .trend-chart-title {
        font-size: 14px;
    }

    .trend-chart-box {
        padding: 16px;
    }

    .chart-area {
        height: 220px;
    }

    .price-sidebar {
        padding: 16px;
    }

    .price-sidebar-title {
        font-size: 15px;
    }

    .footer-grid {
        grid-template-columns: 1fr;
    }

    .footer-bottom-links {
        gap: 14px;
    }

    .cta {
        padding: 28px 20px;
    }

    .cta-text h2 {
        font-size: 21px;
    }
}