/* 基础样式 */
* { margin:0; padding:0; box-sizing:border-box; }
body { font-family:Arial,sans-serif; line-height:1.6; color:#333; background:#f5f5f5; }
.container { width:90%; max-width:1200px; margin:0 auto; padding:0 20px; }

/* 导航 */
header { background:#2c5282; color:white; padding:1rem 0; position:fixed; width:100%; top:0; }
.logo { font-size:1.8rem; color:#ff6b6b; text-decoration:none; }
nav { display:flex; justify-content:space-between; align-items:center; }
.nav-links { display:flex; list-style:none; gap:1.5rem; }
.nav-links a { color:white; text-decoration:none; padding:0.5rem 1rem; }
.nav-links a.active { background:rgba(255,255,255,0.2); border-radius:20px; }

/* 主内容 */
main { margin-top:80px; padding:2rem 0; min-height:80vh; }

/* 英雄区域 */
.hero { background:linear-gradient(135deg,#1e3c72,#2a5298); color:white; text-align:center; padding:4rem 2rem; border-radius:15px; margin-bottom:3rem; }
.hero h1 { font-size:3rem; margin-bottom:1rem; }
.hero p { font-size:1.2rem; margin-bottom:2rem; max-width:800px; margin-left:auto; margin-right:auto; }

/* 按钮 */
.btn { display:inline-block; background:#e53e3e; color:white; padding:1rem 2rem; text-decoration:none; border-radius:50px; font-weight:bold; }
.btn:hover { background:#c53030; }
.btn-secondary { background:#2d3748; }

/* 卡片 */
.features { display:grid; grid-template-columns:repeat(auto-fit, minmax(300px, 1fr)); gap:2rem; margin:3rem 0; }
.card { background:white; border-radius:15px; overflow:hidden; box-shadow:0 5px 15px rgba(0,0,0,0.1); }
.card-img { width:100%; height:200px; display:flex; align-items:center; justify-content:center; color:white; font-size:2rem; font-weight:bold; text-shadow:2px 2px 4px rgba(0,0,0,0.3); }
.card-content { padding:1.5rem; }
.card h3 { color:#2c5282; margin-bottom:1rem; }
.card p { color:#666; margin-bottom:0.5rem; }

/* 号召行动 */
.cta { background:white; padding:3rem; text-align:center; border-radius:15px; margin:3rem 0; }
.cta h2 { color:#2c5282; margin-bottom:1rem; }
.cta p { color:#666; margin-bottom:2rem; }

/* 页脚 */
footer { background:#2c5282; color:white; padding:3rem 0 1.5rem; margin-top:4rem; }
.footer-content { display:flex; justify-content:space-between; align-items:center; margin-bottom:2rem; }
.footer-links { display:flex; gap:1.5rem; }
.footer-links a { color:#cbd5e0; text-decoration:none; }
.copyright { text-align:center; padding-top:1.5rem; border-top:1px solid #4a5568; color:#a0aec0; }

/* 响应式 */
@media (max-width:768px) {
    .hero h1 { font-size:2rem; }
    .hero { padding:3rem 1rem; }
    .nav-links { display:none; }
    .footer-content { flex-direction:column; text-align:center; gap:1.5rem; }
    .features { grid-template-columns:1fr; }
}