:root {
    --primary-color: #e53e3e;
    --primary-hover: #c53030;
    --text-dark: #2a2a2d;
    --text-muted: #4b5563;
    --bg-light: #f8fafc;
    --bg-gradient: radial-gradient(circle at 50% 50%, #e0f2fe 0%, #ffffff 100%);
    --card-bg: #ffffff;
    --border-color: #e2e8f0;
    --accent-blue: #2563eb;
}
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
body {
    font-family: 'Noto Sans SC', sans-serif;
    color: var(--text-dark);
    background-color: #ffffff;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    line-height: 1.7;
}
.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 40px;
    margin: 0 auto;
    width: 100%;
    position: fixed;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    z-index: 10;
    background: #eff8ff;
    border-bottom: 1px solid rgba(62, 95, 255, 0.1);
}
.header-left, .header-right {
    display: flex;
    align-items: center;
    gap: 32px;
}
.logo {
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 700;
    font-size: 22px;
    color: #0640b7;
    text-decoration: none;
}
.logo img {
    height: 32px;
    width: auto;
    display: block;
}
.nav-links {
    display: flex;
    gap: 24px;
    list-style: none;
}
.nav-item {
    display: flex;
    align-items: center;
    gap: 4px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
}
.nav-item a {
    color: var(--text-dark);
    text-decoration: none;
}
.nav-secondary {
    display: flex;
    align-items: center;
    gap: 20px;
    list-style: none;
    font-size: 14px;
}
.nav-secondary a {
    color: var(--text-dark);
    text-decoration: none;
}
.nav-secondary li {
    display: flex;
    align-items: center;
    gap: 4px;
}
.lang-selector {
    display: flex;
    align-items: center;
    cursor: pointer;
}
.btn-primary {
    background-color: var(--primary-color);
    color: #ffffff;
    padding: 10px 24px;
    border-radius: 9999px;
    font-weight: 700;
    text-decoration: none;
    font-size: 14px;
    transition: background-color 0.2s;
    border: none;
    cursor: pointer;
    display: inline-block;
    text-align: center;
}
.btn-primary:hover {
    background-color: var(--primary-hover);
}
.download-hero {
    background: var(--bg-gradient);
    padding: 180px 20px 80px 20px;
    text-align: center;
    border-bottom: 1px solid var(--border-color);
}
.hero-container {
    max-width: 720px;
    margin: 0 auto;
}
.hero-badge {
    color: var(--accent-blue);
    font-size: 14px;
    font-weight: 700;
    letter-spacing: 0.05em;
    margin-bottom: 16px;
    display: inline-block;
    text-transform: uppercase;
}
.hero-title {
    font-size: 46px;
    font-weight: 700;
    line-height: 1.25;
    color: #0f172a;
    margin-bottom: 24px;
}
.hero-desc {
    font-size: 18px;
    color: var(--text-muted);
    margin-bottom: 40px;
}
.action-box {
    max-width: 480px;
    margin: 0 auto 32px auto;
}
.btn-download-full {
    display: block;
    width: 100%;
    background-color: var(--primary-color);
    color: #ffffff;
    padding: 18px 32px;
    border-radius: 12px;
    font-weight: 700;
    font-size: 18px;
    text-decoration: none;
    transition: background-color 0.2s, transform 0.1s;
    border: none;
    cursor: pointer;
    box-shadow: 0 4px 14px rgba(229, 62, 62, 0.3);
    text-align: center;
}
.btn-download-full:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
}
.btn-download-full:active {
    transform: translateY(1px);
}
.hero-meta {
    font-size: 13px;
    color: var(--text-muted);
    display: flex;
    justify-content: center;
    gap: 24px;
}
.platforms-section {
    padding: 80px 40px;
    background-color: #ffffff;
}
.section-container {
    max-width: 1200px;
    margin: 0 auto;
}
.section-title {
    font-size: 32px;
    font-weight: 700;
    color: #0f172a;
    text-align: center;
    margin-bottom: 56px;
}
.platform-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 32px;
}
.platform-card {
    background: #ffffff;
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 32px;
    text-align: center;
    transition: transform 0.2s, box-shadow 0.2s;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}
.platform-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 20px -3px rgba(0, 0, 0, 0.05);
    border-color: #cbd5e1;
}
.platform-icon {
    width: 48px;
    height: 48px;
    margin: 0 auto 20px auto;
    color: var(--accent-blue);
}
.platform-name {
    font-size: 20px;
    font-weight: 700;
    color: #1e293b;
    margin-bottom: 12px;
}
.platform-version {
    font-size: 13px;
    color: var(--text-muted);
    margin-bottom: 24px;
}
.btn-outline {
    display: block;
    border: 1px solid #cbd5e1;
    color: var(--text-dark);
    padding: 10px 20px;
    border-radius: 8px;
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
    transition: background-color 0.2s, border-color 0.2s;
}
.btn-outline:hover {
    background-color: var(--bg-light);
    border-color: var(--text-dark);
}

/* ---------- 新增创意版块：安装指南 & 升级亮点 ---------- */
.install-guide-section {
    padding: 80px 40px;
    background-color: #f8fafc;
    border-top: 1px solid var(--border-color);
}
.guide-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
    margin-bottom: 64px;
}
.guide-card {
    background: #ffffff;
    border-radius: 16px;
    padding: 32px;
    text-align: center;
    border: 1px solid var(--border-color);
    transition: box-shadow 0.2s;
}
.guide-card:hover {
    box-shadow: 0 8px 16px rgba(0,0,0,0.04);
}
.guide-step {
    width: 48px;
    height: 48px;
    background-color: #e0f2fe;
    color: var(--accent-blue);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    font-weight: 700;
    margin: 0 auto 20px auto;
}
.guide-title {
    font-size: 20px;
    font-weight: 700;
    color: #0f172a;
    margin-bottom: 12px;
}
.guide-desc {
    font-size: 14px;
    color: var(--text-muted);
    line-height: 1.6;
}
.upgrade-highlight {
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
    border-radius: 20px;
    padding: 48px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    color: #ffffff;
    gap: 40px;
}
.upgrade-content {
    flex: 1;
}
.upgrade-badge {
    display: inline-block;
    background: rgba(255,255,255,0.1);
    padding: 6px 16px;
    border-radius: 20px;
    font-size: 13px;
    font-weight: 500;
    margin-bottom: 16px;
    color: #a5b4fc;
}
.upgrade-content h3 {
    font-size: 26px;
    font-weight: 700;
    margin-bottom: 16px;
}
.upgrade-content p {
    font-size: 15px;
    color: #cbd5e1;
    line-height: 1.6;
    margin-bottom: 24px;
    max-width: 600px;
}
.upgrade-content .btn-outline {
    display: inline-block;
    width: auto;
    padding: 10px 24px;
    border-color: #475569;
    color: #e2e8f0;
    background: transparent;
}
.upgrade-content .btn-outline:hover {
    background: rgba(255,255,255,0.05);
    border-color: #94a3b8;
}
.upgrade-image {
    flex-shrink: 0;
}

.site-footer {
    background-color: #0b0e17;
    color: #9ca3af;
    padding: 80px 40px 40px 40px;
    margin-top: 0;
}
.footer-container {
    max-width: 1200px;
    margin: 0 auto;
}
.footer-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 40px;
    border-bottom: 1px solid #22293a;
    padding-bottom: 48px;
}
.footer-col h4 {
    color: #ffffff;
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 24px;
}
.footer-links {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 16px;
}
.footer-links a {
    color: #9ca3af;
    text-decoration: none;
    font-size: 14px;
    transition: color 0.2s;
}
.footer-links a:hover {
    color: #ffffff;
}

/* 响应式调整 */
@media (max-width: 1024px) {
    .platform-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    .guide-grid {
        grid-template-columns: 1fr;
    }
    .upgrade-highlight {
        flex-direction: column;
        text-align: center;
    }
    .upgrade-content p {
        max-width: 100%;
    }
    .footer-grid {
        grid-template-columns: 1fr 1fr;
    }
}
@media (max-width: 768px) {
    .nav-links, .nav-secondary {
        display: none;
    }
    .download-hero {
        padding: 140px 20px 60px 20px;
    }
    .hero-title {
        font-size: 32px;
    }
    .hero-desc {
        font-size: 16px;
        margin-bottom: 32px;
    }
    .platform-grid {
        grid-template-columns: 1fr;
    }
    .footer-grid {
        grid-template-columns: 1fr;
    }
}