:root {
    color-scheme: light;
    --ink: #111827;
    --muted: #657086;
    --line: #e5e9f0;
    --paper: #f7f8fb;
    --panel: #ffffff;
    --dark: #111827;
    --cyan: #18a7b5;
    --lime: #71a322;
    --amber: #db8b17;
    --violet: #7b61ff;
    --rose: #d84b6a;
    --blue: #3578e5;
    --shadow: 0 22px 70px rgba(17, 24, 39, 0.12);
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: "Inter", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
    color: var(--ink);
    background: var(--paper);
    letter-spacing: 0;
}

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

.site-header {
    position: sticky;
    top: 0;
    z-index: 20;
    display: flex;
    align-items: center;
    justify-content: space-between;
    min-height: 72px;
    padding: 0 clamp(18px, 5vw, 72px);
    border-bottom: 1px solid rgba(229, 233, 240, 0.82);
    background: rgba(247, 248, 251, 0.86);
    backdrop-filter: blur(18px);
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-weight: 800;
}

.brand span {
    display: grid;
    width: 38px;
    height: 38px;
    place-items: center;
    border-radius: 8px;
    color: #fff;
    background: var(--dark);
    font-size: 14px;
}

.site-nav {
    display: flex;
    align-items: center;
    gap: 28px;
    color: var(--muted);
    font-size: 14px;
    font-weight: 700;
}

.site-nav a:hover {
    color: var(--ink);
}

.nav-toggle {
    display: none;
    width: 42px;
    height: 42px;
    border: 1px solid var(--line);
    border-radius: 8px;
    background: #fff;
}

.nav-toggle span {
    display: block;
    width: 18px;
    height: 2px;
    margin: 4px auto;
    background: var(--ink);
}

.hero {
    display: grid;
    grid-template-columns: minmax(0, 1.05fr) minmax(320px, 0.95fr);
    gap: clamp(28px, 5vw, 72px);
    align-items: center;
    min-height: calc(100svh - 72px);
    padding: clamp(42px, 7vw, 92px) clamp(18px, 5vw, 72px) clamp(28px, 5vw, 64px);
}

.eyebrow {
    margin: 0 0 14px;
    color: var(--cyan);
    font-size: 12px;
    font-weight: 900;
    letter-spacing: 0;
    text-transform: uppercase;
}

.hero h1 {
    max-width: 780px;
    margin: 0;
    font-size: clamp(42px, 6vw, 82px);
    line-height: 1.02;
    letter-spacing: 0;
}

.hero-copy > p:not(.eyebrow) {
    max-width: 660px;
    margin: 24px 0 0;
    color: var(--muted);
    font-size: clamp(16px, 2vw, 20px);
    line-height: 1.85;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-top: 34px;
}

.primary-btn,
.ghost-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 46px;
    padding: 0 20px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 800;
}

.primary-btn {
    color: #fff;
    background: var(--ink);
}

.ghost-btn {
    border: 1px solid var(--line);
    background: #fff;
}

.hero-panel {
    display: grid;
    gap: 14px;
}

.feature-card {
    min-height: 158px;
    padding: 22px;
    border: 1px solid rgba(255, 255, 255, 0.5);
    border-radius: 8px;
    color: #fff;
    background: var(--dark);
    box-shadow: var(--shadow);
    transition: transform 180ms ease, box-shadow 180ms ease;
}

.feature-card:hover,
.article-card:hover,
.related-card:hover {
    transform: translateY(-3px);
}

.feature-card strong {
    display: block;
    margin: 14px 0 10px;
    font-size: clamp(20px, 2.4vw, 28px);
    line-height: 1.28;
}

.feature-card span:last-child {
    display: block;
    color: rgba(255, 255, 255, 0.76);
    line-height: 1.7;
}

.card-kicker {
    color: rgba(255, 255, 255, 0.78);
    font-size: 12px;
    font-weight: 900;
}

.accent-cyan { --accent: var(--cyan); }
.accent-lime { --accent: var(--lime); }
.accent-amber { --accent: var(--amber); }
.accent-violet { --accent: var(--violet); }
.accent-rose { --accent: var(--rose); }
.accent-blue { --accent: var(--blue); }

.accent-cyan,
.accent-lime,
.accent-amber,
.accent-violet,
.accent-rose,
.accent-blue {
    background:
        linear-gradient(135deg, rgba(255, 255, 255, 0.14), rgba(255, 255, 255, 0)),
        linear-gradient(135deg, var(--accent), #141827 66%);
}

.metrics {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1px;
    margin: 0 clamp(18px, 5vw, 72px);
    overflow: hidden;
    border: 1px solid var(--line);
    border-radius: 8px;
    background: var(--line);
}

.metrics div {
    padding: 26px;
    background: #fff;
}

.metrics strong {
    display: block;
    font-size: 34px;
}

.metrics span {
    color: var(--muted);
    font-weight: 700;
}

.section-head {
    max-width: 1180px;
    margin: clamp(54px, 7vw, 88px) auto 22px;
    padding: 0 clamp(18px, 5vw, 0px);
}

.section-head h2 {
    margin: 0;
    font-size: clamp(28px, 4vw, 44px);
    line-height: 1.18;
}

.article-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
    max-width: 1180px;
    margin: 0 auto;
    padding: 0 clamp(18px, 5vw, 0px);
}

.article-card {
    overflow: hidden;
    border: 1px solid var(--line);
    border-radius: 8px;
    background: #fff;
    box-shadow: 0 16px 45px rgba(17, 24, 39, 0.07);
    transition: transform 180ms ease, box-shadow 180ms ease;
}

.title-tile {
    display: flex;
    min-height: 210px;
    flex-direction: column;
    justify-content: space-between;
    padding: 22px;
    color: #fff;
}

.title-tile span,
.article-visual span,
.related-card span {
    font-size: 12px;
    font-weight: 900;
}

.title-tile strong {
    font-size: 25px;
    line-height: 1.25;
}

.article-card-body {
    padding: 22px;
}

.article-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    color: var(--muted);
    font-size: 13px;
    font-weight: 800;
}

.article-card h3 {
    margin: 16px 0 10px;
    font-size: 21px;
    line-height: 1.35;
}

.article-card p {
    margin: 0;
    color: var(--muted);
    line-height: 1.8;
}

.read-link,
.back-link {
    display: inline-flex;
    margin-top: 18px;
    color: var(--cyan);
    font-weight: 900;
}

.newsletter {
    max-width: 1180px;
    margin: clamp(56px, 8vw, 100px) auto;
    padding: clamp(32px, 5vw, 54px);
    border: 1px solid var(--line);
    border-radius: 8px;
    background: #fff;
}

.newsletter h2 {
    max-width: 680px;
    margin: 0;
    font-size: clamp(28px, 4vw, 48px);
}

.newsletter p:last-child {
    max-width: 720px;
    color: var(--muted);
    font-size: 17px;
    line-height: 1.8;
}

.site-footer {
    display: flex;
    justify-content: space-between;
    gap: 16px;
    padding: 30px clamp(18px, 5vw, 72px);
    border-top: 1px solid var(--line);
    color: var(--muted);
    font-weight: 800;
}

.reading-progress {
    position: fixed;
    top: 0;
    left: 0;
    z-index: 40;
    width: 0;
    height: 3px;
    background: var(--cyan);
}

.article-shell {
    max-width: 1180px;
    margin: 0 auto;
    padding: 34px clamp(18px, 5vw, 0px) 70px;
}

.article-layout {
    display: grid;
    grid-template-columns: minmax(260px, 360px) minmax(0, 1fr);
    gap: clamp(28px, 5vw, 64px);
    align-items: start;
}

.article-visual {
    position: sticky;
    top: 104px;
    display: flex;
    min-height: 430px;
    flex-direction: column;
    justify-content: space-between;
    padding: 28px;
    border-radius: 8px;
    color: #fff;
    box-shadow: var(--shadow);
}

.article-visual strong {
    font-size: clamp(29px, 3.2vw, 42px);
    line-height: 1.16;
}

.article-visual small {
    color: rgba(255, 255, 255, 0.78);
    font-weight: 800;
}

.article-main {
    padding: clamp(26px, 4vw, 48px);
    border: 1px solid var(--line);
    border-radius: 8px;
    background: #fff;
}

.article-main h1 {
    margin: 18px 0;
    font-size: clamp(34px, 5vw, 58px);
    line-height: 1.12;
}

.lead {
    margin: 0 0 34px;
    color: var(--muted);
    font-size: 18px;
    line-height: 1.85;
}

.article-content {
    color: #263247;
    font-size: 17px;
    line-height: 1.92;
}

.article-content h2 {
    margin: 42px 0 14px;
    padding-top: 18px;
    border-top: 1px solid var(--line);
    color: var(--ink);
    font-size: clamp(23px, 3vw, 32px);
    line-height: 1.32;
}

.article-content p {
    margin: 0 0 20px;
}

.related {
    margin-top: 64px;
}

.related .section-head {
    margin: 0 0 22px;
    padding: 0;
}

.related-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
}

.related-card {
    display: flex;
    min-height: 170px;
    flex-direction: column;
    justify-content: space-between;
    padding: 22px;
    border-radius: 8px;
    color: #fff;
    transition: transform 180ms ease;
}

.related-card strong {
    font-size: 21px;
    line-height: 1.35;
}

.to-top {
    position: fixed;
    right: 18px;
    bottom: 18px;
    display: none;
    width: 44px;
    height: 44px;
    border: 0;
    border-radius: 8px;
    color: #fff;
    background: var(--ink);
    font-size: 18px;
    font-weight: 900;
    box-shadow: 0 14px 34px rgba(17, 24, 39, 0.22);
}

.to-top.is-visible {
    display: block;
}

@media (max-width: 980px) {
    .hero,
    .article-layout {
        grid-template-columns: 1fr;
    }

    .hero {
        min-height: auto;
    }

    .article-grid,
    .related-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .article-visual {
        position: relative;
        top: auto;
        min-height: 300px;
    }
}

@media (max-width: 720px) {
    .site-header {
        min-height: 64px;
    }

    .nav-toggle {
        display: block;
    }

    .site-nav {
        position: absolute;
        top: 64px;
        right: 18px;
        left: 18px;
        display: none;
        flex-direction: column;
        align-items: stretch;
        gap: 0;
        padding: 8px;
        border: 1px solid var(--line);
        border-radius: 8px;
        background: #fff;
        box-shadow: var(--shadow);
    }

    .site-nav.is-open {
        display: flex;
    }

    .site-nav a {
        padding: 14px;
    }

    .hero h1 {
        font-size: 42px;
    }

    .metrics,
    .article-grid,
    .related-grid {
        grid-template-columns: 1fr;
    }

    .metrics {
        margin: 0 18px;
    }

    .article-main {
        padding: 24px 20px;
    }

    .article-main h1 {
        font-size: 34px;
    }

    .site-footer {
        flex-direction: column;
    }
}