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

:root {
    --primary: #3b82f6;
    --primary-dark: #2563eb;
    --accent: #7c3aed;
    --text: #1e293b;
    --text-muted: #64748b;
    --bg: #f8fafc;
    --card: #ffffff;
    --border: #e2e8f0;
    --star: #f59e0b;
    --footer-bg: #1e293b;
}

html { scroll-behavior: smooth; }

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", "PingFang SC", sans-serif;
    line-height: 1.6;
    color: var(--text);
    background: var(--bg);
    -webkit-font-smoothing: antialiased;
}

a { color: inherit; }

.container {
    max-width: 1080px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ── 导航栏 ───────────────────────────── */

.navbar {
    background: var(--card);
    box-shadow: 0 1px 3px rgba(0,0,0,.08);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 56px;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 18px;
    font-weight: 700;
    color: var(--primary-dark);
    text-decoration: none;
}

.nav-logo {
    width: 28px;
    height: 28px;
    border-radius: 6px;
}

.nav-links {
    display: flex;
    gap: 28px;
}

.nav-links a {
    text-decoration: none;
    color: var(--text);
    font-size: 15px;
    transition: color .2s;
}

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

/* ── Hero ─────────────────────────────── */

.hero {
    background: linear-gradient(135deg, #1e3a8a 0%, #7c3aed 100%);
    padding: 80px 0 72px;
    color: #fff;
    text-align: center;
}

.hero-center {
    max-width: 720px;
    margin: 0 auto;
}

.hero h1 {
    font-size: 48px;
    font-weight: 800;
    margin-bottom: 16px;
    letter-spacing: .5px;
}

.hero-desc {
    font-size: 18px;
    opacity: .92;
    margin-bottom: 40px;
    line-height: 1.7;
}

.hero-buttons {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 14px;
    margin-bottom: 16px;
}

.btn {
    display: inline-block;
    text-decoration: none;
    font-size: 15px;
    font-weight: 500;
    border-radius: 8px;
    cursor: pointer;
    transition: background .2s, transform .15s, box-shadow .2s, color .2s, border-color .2s;
}

.btn-hero {
    padding: 12px 28px;
    border: 2px solid rgba(255,255,255,.65);
    color: #fff;
    background: rgba(255,255,255,.08);
}

.btn-hero:hover {
    background: #fff;
    color: var(--primary-dark);
    border-color: #fff;
    transform: translateY(-2px);
    box-shadow: 0 4px 14px rgba(0,0,0,.15);
}

.hero-hint {
    font-size: 13px;
    opacity: .6;
}

/* ── 通用区块标题 ─────────────────────── */

.section-title {
    text-align: center;
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 40px;
    color: var(--text);
}

/* ── 用户评价 ─────────────────────────── */

.reviews {
    padding: 72px 0;
    background: #f1f5f9;
}

.reviews-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.review-card {
    background: var(--card);
    border-radius: 12px;
    padding: 28px 24px;
    box-shadow: 0 1px 4px rgba(0,0,0,.06);
}

.review-stars {
    color: var(--star);
    font-size: 18px;
    margin-bottom: 14px;
    letter-spacing: 2px;
}

.review-text {
    font-size: 15px;
    color: var(--text);
    line-height: 1.75;
    margin-bottom: 20px;
}

.review-user {
    display: flex;
    align-items: center;
    gap: 12px;
}

.review-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    object-fit: cover;
}

.review-name {
    font-size: 14px;
    font-weight: 600;
    color: var(--text);
}

.review-meta {
    font-size: 12px;
    color: var(--text-muted);
}

/* ── 知识卡片 ─────────────────────────── */

.knowledge {
    padding: 72px 0;
    background: var(--bg);
}

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

.knowledge-card {
    background: var(--card);
    border-radius: 12px;
    padding: 24px 28px;
    box-shadow: 0 1px 4px rgba(0,0,0,.05);
    transition: box-shadow .2s;
}

.knowledge-card:hover {
    box-shadow: 0 4px 16px rgba(0,0,0,.1);
}

.knowledge-card h3 {
    font-size: 17px;
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--primary-dark);
}

.knowledge-card p {
    font-size: 14px;
    line-height: 1.75;
    color: var(--text-muted);
}

/* ── 下载页头部 ───────────────────────── */

.download-header {
    background: linear-gradient(135deg, #1e3a8a 0%, #7c3aed 100%);
    padding: 64px 0 56px;
    color: #fff;
    text-align: center;
}

.download-header h1 {
    font-size: 30px;
    font-weight: 700;
    margin-bottom: 12px;
}

.download-header p {
    font-size: 16px;
    opacity: .85;
}

/* ── 平台下载卡片 ─────────────────────── */

.platforms {
    padding: 56px 0 72px;
}

.platforms-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
}

.platform-card {
    background: var(--card);
    border-radius: 14px;
    padding: 36px 32px;
    box-shadow: 0 2px 8px rgba(0,0,0,.06);
    text-align: center;
    transition: box-shadow .25s, transform .2s;
}

.platform-card:hover {
    box-shadow: 0 8px 28px rgba(0,0,0,.12);
    transform: translateY(-4px);
}

.platform-card h2 {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 8px;
    color: var(--text);
}

.platform-version {
    display: inline-block;
    font-size: 13px;
    color: var(--primary);
    font-weight: 600;
    background: var(--bg);
    padding: 2px 10px;
    border-radius: 4px;
    margin-bottom: 10px;
}

.platform-req,
.platform-size,
.platform-date {
    font-size: 13px;
    color: var(--text-muted);
    margin-bottom: 4px;
}

.platform-date { margin-bottom: 20px; }

.btn-download {
    display: inline-block;
    padding: 12px 32px;
    background: var(--primary);
    color: #fff;
    border: none;
    border-radius: 8px;
    font-size: 15px;
    font-weight: 600;
    text-decoration: none;
}

.btn-download:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(37,99,235,.35);
}

.platform-card small {
    display: block;
    font-size: 12px;
    color: var(--text-muted);
    margin-top: 8px;
    margin-bottom: 16px;
}

.platform-variants {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
    gap: 6px;
    font-size: 13px;
    padding-top: 16px;
    border-top: 1px solid var(--border);
}

.platform-variants a {
    color: var(--primary);
    text-decoration: none;
}

.platform-variants a:hover { text-decoration: underline; }

.platform-variants .sep { color: var(--border); }

.platform-variants .variant-note {
    color: var(--text-muted);
    font-size: 12px;
}

/* ── 页脚 ─────────────────────────────── */

.footer {
    background: var(--footer-bg);
    color: #94a3b8;
    padding: 40px 0;
    text-align: center;
    font-size: 13px;
    line-height: 1.9;
}

/* ── 响应式 ───────────────────────────── */

@media (max-width: 768px) {
    .hero h1 { font-size: 32px; }
    .hero-desc { font-size: 16px; }

    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }

    .btn-hero {
        width: 100%;
        max-width: 280px;
        text-align: center;
    }

    .reviews-grid { grid-template-columns: 1fr; }
    .knowledge-grid { grid-template-columns: 1fr; }
    .platforms-grid { grid-template-columns: 1fr; }

    .download-header h1 { font-size: 22px; }
    .section-title { font-size: 24px; }
    .platform-card { padding: 28px 20px; }
}