:root {
    --primary-color: #0a0a0a;
    --secondary-color: #f5f5f7;
    --accent-color: #0071e3;
    --text-color: #1d1d1f;
    --text-secondary: #86868b;
    --bg-color: #ffffff;
    --nav-height: 60px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    color: var(--text-color);
    background-color: var(--bg-color);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

a {
    text-decoration: none;
    color: inherit;
    transition: color 0.3s ease;
}

header {
    height: var(--nav-height);
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 40px;
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px);
    z-index: 1000;
    border-bottom: 1px solid #d2d2d7;
}

.logo img {
    height: 30px;
}

nav ul {
    display: flex;
    list-style: none;
    gap: 30px;
}

nav ul li a {
    font-size: 14px;
    font-weight: 400;
    color: var(--text-color);
}

nav ul li a:hover {
    color: var(--accent-color);
}

.hero {
    padding: 160px 40px 80px;
    text-align: center;
    max-width: 1000px;
    margin: 0 auto;
}

.hero h1 {
    font-size: 56px;
    font-weight: 700;
    letter-spacing: -0.005em;
    margin-bottom: 24px;
}

.hero p {
    font-size: 24px;
    color: var(--text-secondary);
    margin-bottom: 40px;
}

.section {
    padding: 100px 40px;
    max-width: 1200px;
    margin: 0 auto;
}

.section-title {
    font-size: 40px;
    font-weight: 600;
    margin-bottom: 48px;
    text-align: center;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 40px;
}

.card {
    background: var(--secondary-color);
    padding: 40px;
    border-radius: 20px;
    transition: transform 0.3s ease;
}

.card:hover {
    transform: translateY(-5px);
}

.card h3 {
    font-size: 24px;
    margin-bottom: 16px;
}

.card p {
    color: var(--text-secondary);
}

footer {
    background: var(--primary-color);
    color: #ffffff;
    padding: 80px 40px;
    text-align: center;
}

footer .footer-links {
    display: flex;
    justify-content: center;
    gap: 40px;
    margin-bottom: 40px;
}

footer .footer-links a {
    color: #86868b;
}

footer .footer-links a:hover {
    color: #ffffff;
}

footer p {
    color: #86868b;
    font-size: 12px;
}

/* 响应式 */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 40px;
    }
    .hero p {
        font-size: 18px;
    }
}