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

:root {
    --bg-dark: #05050a;
    --bg-card: rgba(255, 255, 255, 0.03);
    --border: rgba(255, 255, 255, 0.08);
    --text-primary: #ffffff;
    --text-secondary: rgba(255, 255, 255, 0.6);
    --text-muted: rgba(255, 255, 255, 0.4);
    --accent-blue: #5b8cff;
    --accent-cyan: #6dd5fa;
    --accent-glow: rgba(91, 140, 255, 0.4);
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--bg-dark);
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 32px;
}

.starfield {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
    pointer-events: none;
    background: radial-gradient(ellipse at bottom, #0d111c 0%, #05050a 70%);
}

/* 导航 */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 24px 0;
    background: linear-gradient(180deg, rgba(5, 5, 10, 0.9) 0%, rgba(5, 5, 10, 0) 100%);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-primary);
    text-decoration: none;
    letter-spacing: 4px;
    opacity: 0.9;
}

.nav-links {
    display: flex;
    gap: 48px;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
    letter-spacing: 1px;
    transition: color 0.3s ease;
}

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

/* 通用 */
.gradient-text {
    background: linear-gradient(135deg, var(--accent-blue) 0%, var(--accent-cyan) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.section {
    position: relative;
    z-index: 1;
    padding: 140px 0;
}

.section-header {
    margin-bottom: 64px;
}

.section-header.center {
    text-align: center;
}

.section-label {
    display: block;
    font-size: 12px;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 4px;
    margin-bottom: 24px;
}

.section-title {
    font-size: 44px;
    font-weight: 700;
    line-height: 1.25;
    color: var(--text-primary);
}

/* 首屏 */
.hero {
    position: relative;
    z-index: 1;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 160px 0 120px;
}

.hero-subtitle {
    font-size: 13px;
    color: var(--text-muted);
    letter-spacing: 3px;
    margin-bottom: 32px;
    text-transform: uppercase;
}

.hero h1 {
    font-size: 72px;
    font-weight: 800;
    line-height: 1.15;
    margin-bottom: 32px;
    color: var(--text-primary);
}

.hero-desc {
    font-size: 18px;
    color: var(--text-secondary);
    max-width: 560px;
    margin: 0 auto 48px;
    line-height: 1.8;
}

.btn-primary {
    display: inline-block;
    background: linear-gradient(135deg, var(--accent-blue) 0%, var(--accent-cyan) 100%);
    color: #ffffff;
    padding: 16px 40px;
    border-radius: 50px;
    text-decoration: none;
    font-size: 15px;
    font-weight: 600;
    letter-spacing: 1px;
    transition: all 0.3s ease;
    box-shadow: 0 4px 24px var(--accent-glow);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 32px rgba(91, 140, 255, 0.5);
}

.btn-large {
    padding: 20px 56px;
    font-size: 17px;
}

/* 关于 */
.about-desc {
    font-size: 17px;
    color: var(--text-secondary);
    max-width: 720px;
    line-height: 1.9;
    margin-bottom: 80px;
}

.stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
}

.stat-card {
    padding: 48px 32px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 16px;
    text-align: center;
    backdrop-filter: blur(10px);
    transition: all 0.4s ease;
}

.stat-card:hover {
    border-color: rgba(91, 140, 255, 0.3);
    box-shadow: 0 0 40px rgba(91, 140, 255, 0.15);
    transform: translateY(-4px);
}

.stat-number {
    font-size: 64px;
    font-weight: 800;
    line-height: 1;
    background: linear-gradient(135deg, var(--accent-blue) 0%, var(--accent-cyan) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 8px;
}

.stat-unit {
    font-size: 16px;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.stat-label {
    font-size: 14px;
    color: var(--text-muted);
}

/* 功能 */
.features-desc {
    font-size: 17px;
    color: var(--text-secondary);
    max-width: 640px;
    line-height: 1.8;
    margin-bottom: 64px;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}

.feature-card {
    padding: 40px 32px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 20px;
    backdrop-filter: blur(10px);
    transition: all 0.4s ease;
}

.feature-card:hover {
    border-color: rgba(91, 140, 255, 0.25);
    box-shadow: 0 0 48px rgba(91, 140, 255, 0.12);
    transform: translateY(-6px);
}

.feature-icon {
    width: 48px;
    height: 48px;
    margin-bottom: 20px;
}

.feature-icon svg {
    width: 100%;
    height: 100%;
    display: block;
}

.feature-card h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.feature-card p {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.7;
}

/* 下载 */
.download {
    text-align: center;
}

.download .section-header {
    margin-bottom: 40px;
}

.download-desc {
    font-size: 17px;
    color: var(--text-secondary);
    max-width: 520px;
    margin: 0 auto 48px;
    line-height: 1.8;
}

.download-tip {
    margin-top: 24px;
    font-size: 13px;
    color: var(--text-muted);
}

/* 底部 */
.footer {
    position: relative;
    z-index: 1;
    background: rgba(0, 0, 0, 0.3);
    border-top: 1px solid var(--border);
    padding: 80px 0 30px;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    margin-bottom: 60px;
}

.footer-logo {
    font-size: 20px;
    font-weight: 600;
    letter-spacing: 4px;
    color: var(--text-primary);
    margin-bottom: 12px;
}

.footer-brand p {
    color: var(--text-muted);
    font-size: 14px;
}

.footer-contact h4 {
    font-size: 15px;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.footer-contact p {
    margin-bottom: 8px;
    color: var(--text-secondary);
    font-size: 14px;
}

.footer-contact a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-contact a:hover {
    color: var(--accent-blue);
}

.footer-bottom {
    border-top: 1px solid var(--border);
    padding-top: 30px;
    text-align: center;
}

.footer-bottom p {
    color: var(--text-muted);
    font-size: 13px;
}

/* 响应式 */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }

    .hero {
        min-height: auto;
        padding: 140px 0 100px;
    }

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

    .section {
        padding: 100px 0;
    }

    .section-title {
        font-size: 32px;
    }

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

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

    .footer-content {
        flex-direction: column;
        gap: 40px;
    }
}