:root {
    --primary: #667eea;
    --primary-dark: #764ba2;
    --accent: #ff3d71;
    --text-main: #1a202c;
    --text-secondary: #4a5568;
    --text-light: #718096;
    --bg-body: #f7fafc;
    --bg-white: #ffffff;
    --line: #e2e8f0;
    --container-width: 1180px;
    --shadow: 0 14px 40px rgba(26, 32, 44, 0.08);
}

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

body {
    background: var(--bg-body);
    color: var(--text-main);
    font-family: "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
    line-height: 1.75;
}

a {
    color: inherit;
    text-decoration: none;
}

.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 20px;
}

.site-header {
    position: sticky;
    top: 0;
    z-index: 20;
    background: rgba(255, 255, 255, 0.92);
    border-bottom: 1px solid rgba(226, 232, 240, 0.8);
    backdrop-filter: blur(12px);
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    min-height: 72px;
    gap: 24px;
}

.brand {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 22px;
    font-weight: 800;
    color: var(--primary-dark);
}

.brand-mark {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 34px;
    height: 34px;
    border-radius: 10px;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: #ffffff;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 24px;
    color: var(--text-secondary);
    font-size: 15px;
    font-weight: 600;
}

.nav-links a:hover {
    color: var(--primary-dark);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 44px;
    padding: 0 20px;
    border-radius: 10px;
    border: 1px solid transparent;
    font-weight: 700;
}

.btn-primary {
    background: var(--text-main);
    color: #ffffff;
}

.btn-light {
    background: #ffffff;
    border-color: var(--line);
    color: var(--text-main);
}

.hero {
    padding: 84px 0 56px;
    background:
        radial-gradient(circle at 12% 10%, rgba(102, 126, 234, 0.18), transparent 32%),
        radial-gradient(circle at 90% 20%, rgba(255, 61, 113, 0.12), transparent 30%),
        #ffffff;
    border-bottom: 1px solid var(--line);
}

.eyebrow {
    display: inline-flex;
    margin-bottom: 14px;
    color: var(--primary-dark);
    font-size: 14px;
    font-weight: 800;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.hero-grid {
    display: grid;
    grid-template-columns: minmax(0, 1.2fr) minmax(320px, 0.8fr);
    gap: 42px;
    align-items: center;
}

h1 {
    max-width: 840px;
    font-size: 46px;
    line-height: 1.18;
    letter-spacing: 0;
}

.hero-text {
    max-width: 760px;
    margin-top: 20px;
    color: var(--text-secondary);
    font-size: 18px;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
    margin-top: 30px;
}

.fact-panel {
    background: #ffffff;
    border: 1px solid var(--line);
    border-radius: 8px;
    box-shadow: var(--shadow);
    padding: 28px;
}

.fact-panel h2 {
    margin-bottom: 16px;
    font-size: 22px;
}

.fact-list {
    display: grid;
    gap: 12px;
}

.fact-item {
    display: grid;
    grid-template-columns: 92px 1fr;
    gap: 12px;
    padding-bottom: 12px;
    border-bottom: 1px solid #edf2f7;
    color: var(--text-secondary);
}

.fact-item:last-child {
    border-bottom: 0;
    padding-bottom: 0;
}

.fact-item strong {
    color: var(--text-main);
}

.section {
    padding: 68px 0;
}

.section-white {
    background: #ffffff;
}

.section-title {
    max-width: 780px;
    margin-bottom: 30px;
}

.section-title h2 {
    margin-bottom: 12px;
    font-size: 32px;
    line-height: 1.25;
}

.section-title p {
    color: var(--text-secondary);
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 20px;
}

.grid-2 {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 20px;
}

.card {
    background: #ffffff;
    border: 1px solid var(--line);
    border-radius: 8px;
    padding: 24px;
}

.card h3 {
    margin-bottom: 10px;
    font-size: 20px;
}

.card p,
.card li {
    color: var(--text-secondary);
}

.card ul {
    display: grid;
    gap: 8px;
    padding-left: 18px;
}

.table-wrap {
    overflow-x: auto;
    background: #ffffff;
    border: 1px solid var(--line);
    border-radius: 8px;
}

table {
    width: 100%;
    border-collapse: collapse;
    min-width: 720px;
}

th,
td {
    padding: 16px;
    border-bottom: 1px solid var(--line);
    text-align: left;
    vertical-align: top;
}

th {
    background: #f8fafc;
    font-weight: 800;
}

td {
    color: var(--text-secondary);
}

.faq-list {
    display: grid;
    gap: 16px;
}

.faq-item {
    background: #ffffff;
    border: 1px solid var(--line);
    border-radius: 8px;
    padding: 22px 24px;
}

.faq-item h2,
.faq-item h3 {
    margin-bottom: 8px;
    font-size: 20px;
}

.faq-item p {
    color: var(--text-secondary);
}

.cta {
    background: linear-gradient(135deg, var(--text-main), #2d3748);
    color: #ffffff;
    padding: 54px 0;
}

.cta p {
    max-width: 720px;
    margin-top: 10px;
    color: rgba(255, 255, 255, 0.76);
}

.cta .btn {
    margin-top: 24px;
}

.article-layout {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 280px;
    gap: 30px;
    align-items: start;
}

.article-main {
    background: #ffffff;
    border: 1px solid var(--line);
    border-radius: 8px;
    padding: 30px;
}

.article-main h2 {
    margin: 28px 0 12px;
    font-size: 26px;
    line-height: 1.28;
}

.article-main h2:first-child {
    margin-top: 0;
}

.article-main h3 {
    margin: 22px 0 8px;
    font-size: 20px;
}

.article-main p,
.article-main li {
    color: var(--text-secondary);
}

.article-main ul,
.article-main ol {
    display: grid;
    gap: 8px;
    margin: 10px 0 0 20px;
}

.toc {
    position: sticky;
    top: 92px;
    background: #ffffff;
    border: 1px solid var(--line);
    border-radius: 8px;
    padding: 20px;
}

.toc h2 {
    margin-bottom: 12px;
    font-size: 18px;
}

.toc a {
    display: block;
    padding: 7px 0;
    color: var(--text-secondary);
    font-size: 14px;
}

.toc a:hover {
    color: var(--primary-dark);
}

.note {
    margin-top: 18px;
    padding: 16px;
    border-left: 4px solid var(--primary);
    background: #f8fafc;
    color: var(--text-secondary);
}

.site-footer {
    background: #ffffff;
    border-top: 1px solid var(--line);
    padding: 34px 0;
    color: var(--text-light);
    font-size: 14px;
}

.footer-grid {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    gap: 16px;
}

@media (max-width: 860px) {
    .nav {
        align-items: flex-start;
        flex-direction: column;
        padding: 16px 0;
    }

    .nav-links {
        flex-wrap: wrap;
        gap: 14px;
    }

    .hero {
        padding: 56px 0 42px;
    }

    .hero-grid,
    .grid-2,
    .grid-3,
    .article-layout {
        grid-template-columns: 1fr;
    }

    .toc {
        position: static;
    }

    h1 {
        font-size: 34px;
    }

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

    .fact-item {
        grid-template-columns: 1fr;
        gap: 2px;
    }
}