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

:root {
    --black: #000000;
    --white: #ffffff;
    --gray-50: #fafafa;
    --gray-100: #f5f5f5;
    --gray-200: #e5e5e5;
    --gray-300: #d4d4d4;
    --gray-400: #a3a3a3;
    --gray-500: #737373;
    --gray-600: #525252;
    --gray-700: #404040;
    --gray-800: #262626;
    --gray-900: #171717;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    color: var(--gray-900);
    background: var(--white);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.header {
    background: var(--white);
    border-bottom: 1px solid var(--gray-200);
    padding: 20px 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-wrapper {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    font-size: 24px;
    font-weight: 700;
    color: var(--black);
}

.nav {
    display: flex;
    gap: 32px;
}

.nav a {
    color: var(--gray-700);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
}

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

.actions {
    display: flex;
    gap: 16px;
    align-items: center;
}

.btn-text {
    color: var(--gray-700);
    text-decoration: none;
    padding: 8px 16px;
}

.btn-primary {
    background: var(--black);
    color: var(--white);
    padding: 10px 24px;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 500;
    transition: background 0.3s;
}

.btn-primary:hover {
    background: var(--gray-800);
}

/* Hero */
.hero {
    padding: 80px 0;
    text-align: center;
    background: var(--gray-50);
    border-bottom: 1px solid var(--gray-200);
}

.hero h1 {
    font-size: 48px;
    font-weight: 700;
    margin-bottom: 16px;
    color: var(--black);
}

.hero-desc {
    font-size: 20px;
    color: var(--gray-600);
    margin-bottom: 48px;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 80px;
    margin-bottom: 48px;
}

.stat {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.stat strong {
    font-size: 32px;
    font-weight: 700;
    color: var(--black);
}

.stat span {
    font-size: 14px;
    color: var(--gray-500);
}

.btn-hero {
    display: inline-block;
    background: var(--black);
    color: var(--white);
    padding: 16px 48px;
    border-radius: 8px;
    text-decoration: none;
    font-size: 18px;
    font-weight: 600;
    transition: transform 0.3s;
}

.btn-hero:hover {
    transform: translateY(-2px);
}

/* Download */
.download {
    padding: 80px 0;
}

.download h2 {
    text-align: center;
    font-size: 36px;
    font-weight: 700;
    margin-bottom: 48px;
    color: var(--black);
}

.download-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}

.download-card {
    border: 1px solid var(--gray-200);
    padding: 32px 24px;
    text-align: center;
    border-radius: 8px;
    transition: all 0.3s;
}

.download-card:hover {
    border-color: var(--black);
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.download-card .icon {
    font-size: 48px;
    margin-bottom: 16px;
}

.download-card h3 {
    font-size: 20px;
    margin-bottom: 8px;
    color: var(--black);
}

.download-card p {
    color: var(--gray-600);
    margin-bottom: 16px;
    font-size: 14px;
}

.btn-download {
    display: inline-block;
    background: var(--black);
    color: var(--white);
    padding: 10px 32px;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 500;
    transition: background 0.3s;
}

.btn-download:hover {
    background: var(--gray-800);
}

/* Features */
.features {
    padding: 80px 0;
    background: var(--gray-50);
}

.features h2 {
    text-align: center;
    font-size: 36px;
    font-weight: 700;
    margin-bottom: 48px;
    color: var(--black);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 32px;
}

.feature {
    background: var(--white);
    padding: 32px;
    border-radius: 8px;
    border: 1px solid var(--gray-200);
}

.feature h3 {
    font-size: 20px;
    margin-bottom: 12px;
    color: var(--black);
}

.feature p {
    color: var(--gray-600);
    line-height: 1.7;
}

/* Content */
.content {
    padding: 80px 0;
}

.article h2 {
    font-size: 32px;
    font-weight: 700;
    margin-bottom: 32px;
    color: var(--black);
}

.article-body {
    max-width: 800px;
    margin: 0 auto;
}

.article-body h3 {
    font-size: 24px;
    font-weight: 600;
    margin: 32px 0 16px;
    color: var(--black);
}

.article-body p {
    margin-bottom: 16px;
    color: var(--gray-700);
    line-height: 1.8;
}

.article-body ul,
.article-body ol {
    margin: 16px 0;
    padding-left: 32px;
}

.article-body li {
    margin-bottom: 8px;
    color: var(--gray-700);
}

.article-body strong {
    font-weight: 600;
    color: var(--black);
}

/* Footer */
.footer {
    background: var(--gray-900);
    color: var(--white);
    padding: 60px 0 30px;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 48px;
    margin-bottom: 48px;
}

.footer-col h4 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 16px;
}

.footer-col {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.footer-col a {
    color: var(--gray-400);
    text-decoration: none;
    transition: color 0.3s;
}

.footer-col a:hover {
    color: var(--white);
}

.footer-bottom {
    text-align: center;
    padding-top: 32px;
    border-top: 1px solid var(--gray-700);
}

.footer-bottom p {
    color: var(--gray-500);
    font-size: 14px;
}

/* Responsive */
@media (max-width: 968px) {
    .nav {
        display: none;
    }
    
    .hero h1 {
        font-size: 32px;
    }
    
    .hero-stats {
        gap: 40px;
    }
    
    .download-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 640px) {
    .hero-stats {
        flex-direction: column;
        gap: 24px;
    }
    
    .download-grid {
        grid-template-columns: 1fr;
    }
}