/* 全局重置与基础样式 */
* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif; background: #f5f5f7; color: #1d1d1f; line-height: 1.6; transition: background 0.3s, color 0.3s; }
a { color: #0070c9; text-decoration: none; transition: color 0.2s; }
a:hover { text-decoration: underline; color: #005bb5; }
img, svg { max-width: 100%; height: auto; display: block; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }

/* 导航吸顶与毛玻璃效果 */
.navbar { position: sticky; top: 0; z-index: 1000; background: rgba(255,255,255,0.85); backdrop-filter: blur(16px); -webkit-backdrop-filter: blur(16px); border-bottom: 1px solid rgba(229,229,234,0.5); padding: 10px 0; transition: background 0.3s, border-color 0.3s; }
.navbar .container { display: flex; align-items: center; justify-content: space-between; }
.logo { font-size: 1.5rem; font-weight: 700; color: #1a1a2e; transition: color 0.3s; }
.logo span { color: #e74c3c; }
.nav-links { display: flex; gap: 20px; list-style: none; }
.nav-links a { color: #1d1d1f; font-size: 0.95rem; font-weight: 500; position: relative; }
.nav-links a::after { content: ''; position: absolute; left: 0; bottom: -2px; width: 0; height: 2px; background: #e74c3c; transition: width 0.3s; }
.nav-links a:hover::after { width: 100%; }
.search-box input { padding: 8px 16px; border: 1px solid #d1d1d6; border-radius: 20px; font-size: 0.9rem; width: 200px; background: rgba(255,255,255,0.6); backdrop-filter: blur(4px); transition: border-color 0.3s, box-shadow 0.3s; }
.search-box input:focus { outline: none; border-color: #0070c9; box-shadow: 0 0 0 3px rgba(0,112,201,0.15); }
.dark-toggle { cursor: pointer; background: none; border: none; font-size: 1.2rem; padding: 4px 8px; border-radius: 50%; transition: background 0.3s; }
.dark-toggle:hover { background: rgba(0,0,0,0.05); }

/* 移动菜单 */
.menu-toggle { display: none; background: none; border: none; font-size: 1.8rem; cursor: pointer; color: #1d1d1f; transition: color 0.3s; }
@media (max-width: 768px) {
    .nav-links { display: none; flex-direction: column; background: rgba(255,255,255,0.95); backdrop-filter: blur(16px); -webkit-backdrop-filter: blur(16px); position: absolute; top: 60px; left: 0; right: 0; padding: 20px; border-bottom: 1px solid #e5e5ea; box-shadow: 0 8px 24px rgba(0,0,0,0.08); }
    .nav-links.active { display: flex; }
    .menu-toggle { display: block; }
    .search-box input { width: 140px; }
}

/* 面包屑 */
.breadcrumb { padding: 15px 0; font-size: 0.9rem; color: #86868b; }
.breadcrumb a { color: #0070c9; }

/* 首屏区域 - 渐变Banner */
.hero { background: linear-gradient(135deg, #1a1a2e 0%, #16213e 40%, #0f3460 100%); color: white; padding: 70px 0; text-align: center; position: relative; overflow: hidden; }
.hero::before { content: ''; position: absolute; top: -50%; left: -50%; width: 200%; height: 200%; background: radial-gradient(circle, rgba(231,76,60,0.15) 0%, transparent 60%); animation: heroGlow 8s ease-in-out infinite alternate; }
@keyframes heroGlow { 0% { transform: translate(0,0); } 100% { transform: translate(20%,20%); } }
.hero h1 { font-size: 2.8rem; margin-bottom: 20px; font-weight: 700; position: relative; z-index: 1; text-shadow: 0 2px 10px rgba(0,0,0,0.3); }
.hero p { font-size: 1.2rem; max-width: 700px; margin: 0 auto 30px; opacity: 0.9; position: relative; z-index: 1; }
.hero .btn { display: inline-block; background: linear-gradient(135deg, #e74c3c, #c0392b); color: white; padding: 14px 36px; border-radius: 30px; font-weight: 600; font-size: 1rem; position: relative; z-index: 1; transition: transform 0.3s, box-shadow 0.3s; box-shadow: 0 4px 15px rgba(231,76,60,0.3); }
.hero .btn:hover { transform: translateY(-2px); box-shadow: 0 8px 25px rgba(231,76,60,0.4); text-decoration: none; }

/* 轮播 */
.carousel { position: relative; overflow: hidden; margin: 30px 0; border-radius: 16px; background: #ffffff; box-shadow: 0 4px 24px rgba(0,0,0,0.06); transition: background 0.3s; }
.carousel-track { display: flex; transition: transform 0.5s cubic-bezier(0.25, 0.46, 0.45, 0.94); }
.carousel-slide { min-width: 100%; padding: 50px 40px; text-align: center; }
.carousel-slide h3 { font-size: 1.6rem; margin-bottom: 12px; color: #1a1a2e; }
.carousel-slide p { font-size: 1rem; color: #515154; max-width: 600px; margin: 0 auto; }
.carousel-btn { position: absolute; top: 50%; transform: translateY(-50%); background: rgba(0,0,0,0.25); color: white; border: none; padding: 14px 18px; cursor: pointer; border-radius: 50%; font-size: 1.3rem; backdrop-filter: blur(4px); transition: background 0.3s, transform 0.3s; }
.carousel-btn:hover { background: rgba(0,0,0,0.45); transform: translateY(-50%) scale(1.1); }
.carousel-btn.prev { left: 12px; }
.carousel-btn.next { right: 12px; }

/* 网格布局 */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 30px; margin: 40px 0; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 25px; margin: 40px 0; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; margin: 40px 0; }
@media (max-width: 768px) {
    .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
}

/* 圆角卡片与hover动画 */
.card { background: white; border-radius: 16px; padding: 28px; box-shadow: 0 2px 16px rgba(0,0,0,0.06); transition: transform 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94), box-shadow 0.3s; }
.card:hover { transform: translateY(-6px); box-shadow: 0 12px 32px rgba(0,0,0,0.1); }
.card h3 { font-size: 1.2rem; margin-bottom: 10px; color: #1a1a2e; }
.card p { font-size: 0.95rem; color: #515154; }
.card .meta { font-size: 0.85rem; color: #86868b; margin-top: 10px; }

/* 数字动画区 */
.stats { background: linear-gradient(135deg, #1a1a2e, #16213e); color: white; padding: 50px 0; text-align: center; }
.stats .grid-4 { margin: 0; }
.stat-item { padding: 20px; }
.stat-number { font-size: 2.8rem; font-weight: 700; background: linear-gradient(135deg, #e74c3c, #f39c12); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.stat-label { font-size: 1rem; opacity: 0.85; margin-top: 4px; }

/* FAQ */
.faq-item { border-bottom: 1px solid #e5e5ea; padding: 18px 0; cursor: pointer; transition: background 0.2s; }
.faq-item:hover { background: rgba(0,0,0,0.02); }
.faq-question { font-weight: 600; font-size: 1.05rem; display: flex; justify-content: space-between; align-items: center; color: #1d1d1f; }
.faq-question::after { content: '+'; font-size: 1.3rem; color: #86868b; transition: transform 0.3s; }
.faq-item.active .faq-question::after { transform: rotate(45deg); }
.faq-answer { max-height: 0; overflow: hidden; transition: max-height 0.4s ease, padding 0.3s; color: #515154; padding-top: 0; }
.faq-item.active .faq-answer { max-height: 500px; padding-top: 12px; }

/* HowTo 步骤 */
.step { display: flex; gap: 16px; margin-bottom: 20px; align-items: flex-start; }
.step-number { background: linear-gradient(135deg, #0070c9, #005bb5); color: white; width: 42px; height: 42px; border-radius: 50%; display: flex; align-items: center; justify-content: center; font-weight: 700; flex-shrink: 0; font-size: 1.1rem; }

/* 联系方式 */
.contact-info p { margin: 6px 0; }

/* 页脚 */
.footer { background: #1d1d1f; color: #a1a1a6; padding: 45px 0; font-size: 0.9rem; }
.footer a { color: #a1a1a6; transition: color 0.2s; }
.footer a:hover { color: #ffffff; }
.footer .grid-4 { margin: 0; }
.footer h4 { color: white; margin-bottom: 12px; font-size: 1rem; }
.footer ul { list-style: none; padding: 0; }
.footer ul li { margin-bottom: 6px; }

/* 暗黑模式 */
.dark-mode { background: #1c1c1e; color: #f5f5f7; }
.dark-mode .navbar { background: rgba(28,28,30,0.9); backdrop-filter: blur(16px); -webkit-backdrop-filter: blur(16px); border-bottom-color: rgba(44,44,46,0.6); }
.dark-mode .card { background: #2c2c2e; color: #f5f5f7; }
.dark-mode .card h3 { color: #f5f5f7; }
.dark-mode .card p { color: #c7c7cc; }
.dark-mode .carousel { background: #2c2c2e; }
.dark-mode .carousel-slide h3 { color: #f5f5f7; }
.dark-mode .carousel-slide p { color: #c7c7cc; }
.dark-mode .breadcrumb { color: #86868b; }
.dark-mode .faq-item { border-bottom-color: #3a3a3c; }
.dark-mode .faq-question { color: #f5f5f7; }
.dark-mode .faq-answer { color: #c7c7cc; }
.dark-mode .footer { background: #000; }
.dark-mode .search-box input { background: rgba(44,44,46,0.6); border-color: #3a3a3c; color: #f5f5f7; }
.dark-mode .search-box input:focus { border-color: #0070c9; }
.dark-mode .menu-toggle { color: #f5f5f7; }
.dark-mode .nav-links a { color: #f5f5f7; }
.dark-mode .logo { color: #f5f5f7; }

/* 返回顶部 */
.back-to-top { position: fixed; bottom: 30px; right: 30px; background: linear-gradient(135deg, #0070c9, #005bb5); color: white; border: none; padding: 14px 18px; border-radius: 50%; cursor: pointer; font-size: 1.3rem; display: none; z-index: 999; box-shadow: 0 4px 16px rgba(0,112,201,0.3); transition: transform 0.3s, box-shadow 0.3s; }
.back-to-top.show { display: block; }
.back-to-top:hover { transform: translateY(-3px); box-shadow: 0 8px 24px rgba(0,112,201,0.4); }

/* 滚动动画 */
.fade-in { opacity: 0; transform: translateY(30px); transition: opacity 0.7s cubic-bezier(0.25, 0.46, 0.45, 0.94), transform 0.7s cubic-bezier(0.25, 0.46, 0.45, 0.94); }
.fade-in.visible { opacity: 1; transform: translateY(0); }

/* 图片懒加载占位 */
.lazy-placeholder { background: #e5e5ea; border-radius: 8px; min-height: 100px; display: flex; align-items: center; justify-content: center; color: #86868b; }

/* 通用标题样式 */
h2 { font-size: 2rem; margin: 30px 0 20px; color: #1a1a2e; position: relative; display: inline-block; }
h2::after { content: ''; display: block; width: 60px; height: 3px; background: linear-gradient(135deg, #e74c3c, #f39c12); margin-top: 8px; border-radius: 2px; }
.dark-mode h2 { color: #f5f5f7; }

/* 友情链接样式 */
.fade-in a { color: #0070c9; transition: color 0.2s; }
.fade-in a:hover { color: #e74c3c; }

/* 小屏幕适配 */
@media (max-width: 480px) {
    .hero h1 { font-size: 2rem; }
    .hero p { font-size: 1rem; }
    .carousel-slide { padding: 30px 20px; }
    .card { padding: 20px; }
    .step { flex-direction: column; align-items: center; text-align: center; }
}