/* 全局重置与基础 */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,'Helvetica Neue',Arial,sans-serif;line-height:1.6;color:#1a1a2e;background:#f8f9fa;transition:background .3s,color .3s}
body.dark{background:#0f0f1a;color:#e0e0e0}
.container{max-width:1200px;margin:0 auto;padding:0 20px}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
.skip-link{position:absolute;top:-40px;left:0;background:#c8102e;color:#fff;padding:8px 16px;z-index:1000;transition:top .2s}
.skip-link:focus{top:0}

/* 头部 */
header{position:sticky;top:0;z-index:100;background:rgba(255,255,255,.95);backdrop-filter:blur(10px);-webkit-backdrop-filter:blur(10px);border-bottom:1px solid rgba(0,0,0,.08);transition:background .3s}
body.dark header{background:rgba(15,15,26,.95);border-bottom-color:rgba(255,255,255,.08)}
.header-inner{display:flex;align-items:center;justify-content:space-between;height:64px}
.logo{display:flex;align-items:center;gap:10px;text-decoration:none;color:inherit;font-weight:700;font-size:1.25rem}
.logo svg{flex-shrink:0}
.logo span{color:#c8102e}
.nav{display:flex;gap:24px;list-style:none}
.nav a{text-decoration:none;color:inherit;font-size:.95rem;font-weight:500;padding:6px 0;border-bottom:2px solid transparent;transition:border-color .2s,color .2s}
.nav a:hover,.nav a.active{border-bottom-color:#c8102e;color:#c8102e}
.nav-toggle{display:none;background:none;border:none;font-size:1.5rem;cursor:pointer;color:inherit;padding:4px}
@media(max-width:768px){
  .nav{display:none;position:absolute;top:64px;left:0;right:0;background:inherit;flex-direction:column;padding:16px 20px;gap:12px;border-bottom:1px solid rgba(0,0,0,.08)}
  .nav.open{display:flex}
  .nav-toggle{display:block}
}

/* Hero 渐变Banner */
.hero{background:linear-gradient(135deg,#c8102e 0%,#8b0000 50%,#1a1a2e 100%);color:#fff;padding:80px 0 60px;text-align:center;position:relative;overflow:hidden}
.hero::after{content:'';position:absolute;bottom:0;left:0;right:0;height:4px;background:linear-gradient(90deg,#ffd700,#c8102e,#ffd700)}
.hero h1{font-size:2.8rem;font-weight:800;margin-bottom:16px;letter-spacing:-.5px;opacity:0;animation:fadeInUp .8s ease forwards}
.hero p{font-size:1.2rem;max-width:700px;margin:0 auto 32px;opacity:0;animation:fadeInUp .8s ease .2s forwards}
.hero .btn-group{display:flex;gap:16px;justify-content:center;flex-wrap:wrap;opacity:0;animation:fadeInUp .8s ease .4s forwards}
@keyframes fadeInUp{from{opacity:0;transform:translateY(30px)}to{opacity:1;transform:translateY(0)}}

/* 按钮 */
.btn{display:inline-flex;align-items:center;gap:8px;padding:14px 32px;border-radius:8px;font-weight:600;font-size:1rem;text-decoration:none;transition:transform .2s,box-shadow .2s;cursor:pointer;border:none}
.btn:hover{transform:translateY(-2px);box-shadow:0 8px 24px rgba(0,0,0,.2)}
.btn-primary{background:#ffd700;color:#1a1a2e}
.btn-secondary{background:rgba(255,255,255,.15);color:#fff;backdrop-filter:blur(4px);-webkit-backdrop-filter:blur(4px)}
.btn-outline{background:transparent;border:2px solid #ffd700;color:#ffd700}
@media(max-width:600px){
  .hero h1{font-size:2rem}
  .hero p{font-size:1rem}
}

/* 通用区块 */
section{padding:64px 0}
.section-title{font-size:2rem;font-weight:700;margin-bottom:8px;color:inherit}
.section-subtitle{font-size:1.1rem;color:#666;margin-bottom:40px}
body.dark .section-subtitle{color:#aaa}

/* 网格 */
.grid{display:grid;gap:24px}
.grid-2{grid-template-columns:1fr 1fr}
.grid-3{grid-template-columns:1fr 1fr 1fr}
.grid-4{grid-template-columns:1fr 1fr 1fr 1fr}
@media(max-width:768px){.grid-2,.grid-3,.grid-4{grid-template-columns:1fr}}

/* 卡片 - 圆角 + 毛玻璃 + 滚动动画 */
.card{background:rgba(255,255,255,.85);backdrop-filter:blur(8px);-webkit-backdrop-filter:blur(8px);border-radius:12px;padding:24px;box-shadow:0 2px 12px rgba(0,0,0,.06);transition:transform .3s,box-shadow .3s,background .3s;opacity:0;transform:translateY(20px);animation:cardFadeIn .6s ease forwards}
.card:nth-child(1){animation-delay:.1s}
.card:nth-child(2){animation-delay:.2s}
.card:nth-child(3){animation-delay:.3s}
.card:nth-child(4){animation-delay:.4s}
.card:nth-child(5){animation-delay:.5s}
.card:nth-child(6){animation-delay:.6s}
@keyframes cardFadeIn{to{opacity:1;transform:translateY(0)}}
body.dark .card{background:rgba(26,26,46,.85);backdrop-filter:blur(8px);-webkit-backdrop-filter:blur(8px);box-shadow:0 2px 12px rgba(0,0,0,.3)}
.card:hover{transform:translateY(-6px);box-shadow:0 12px 32px rgba(0,0,0,.12)}
.card h3{font-size:1.2rem;margin-bottom:8px}
.card p{color:#555;font-size:.95rem;line-height:1.5}
body.dark .card p{color:#bbb}
.card .meta{font-size:.85rem;color:#888;margin-top:12px}

/* 关于 */
.about-content{max-width:800px;margin:0 auto;text-align:center}
.about-content p{margin-bottom:16px;font-size:1.05rem}
.trust-badges{display:flex;gap:32px;justify-content:center;flex-wrap:wrap;margin-top:32px}
.trust-badges span{display:flex;align-items:center;gap:8px;font-weight:500}

/* FAQ 手风琴 */
.faq-item{border-bottom:1px solid #e0e0e0;padding:16px 0}
body.dark .faq-item{border-bottom-color:#333}
.faq-question{display:flex;justify-content:space-between;align-items:center;width:100%;background:none;border:none;font-size:1.05rem;font-weight:600;color:inherit;cursor:pointer;padding:8px 0;text-align:left;transition:color .2s}
.faq-question:hover{color:#c8102e}
.faq-question::after{content:'+';font-size:1.3rem;transition:transform .3s}
.faq-item.open .faq-question::after{content:'−';transform:rotate(180deg)}
.faq-answer{padding:8px 0 16px;color:#555;line-height:1.6;display:none}
body.dark .faq-answer{color:#bbb}
.faq-item.open .faq-answer{display:block;animation:slideDown .3s ease}
@keyframes slideDown{from{opacity:0;max-height:0}to{opacity:1;max-height:500px}}

/* HowTo 步骤 */
.howto-step{display:flex;gap:16px;margin-bottom:24px;align-items:flex-start;opacity:0;transform:translateX(-20px);animation:stepSlide .5s ease forwards}
.howto-step:nth-child(1){animation-delay:.1s}
.howto-step:nth-child(2){animation-delay:.2s}
.howto-step:nth-child(3){animation-delay:.3s}
.howto-step:nth-child(4){animation-delay:.4s}
@keyframes stepSlide{to{opacity:1;transform:translateX(0)}}
.howto-step .step-num{background:#c8102e;color:#fff;width:32px;height:32px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:700;flex-shrink:0}
.howto-step .step-content h4{font-size:1.1rem;margin-bottom:4px}
.howto-step .step-content p{color:#555;font-size:.95rem}
body.dark .howto-step .step-content p{color:#bbb}

/* 联系 */
.contact-grid{display:grid;grid-template-columns:1fr 1fr;gap:32px}
@media(max-width:768px){.contact-grid{grid-template-columns:1fr}}
.contact-info p{margin-bottom:8px;display:flex;align-items:center;gap:8px}

/* 页脚 */
footer{background:#1a1a2e;color:#ccc;padding:48px 0 24px}
.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:32px;margin-bottom:32px}
@media(max-width:768px){.footer-grid{grid-template-columns:1fr 1fr}}
.footer-grid h4{color:#fff;margin-bottom:12px;font-size:1rem}
.footer-grid a{color:#aaa;text-decoration:none;display:block;margin-bottom:6px;font-size:.9rem;transition:color .2s}
.footer-grid a:hover{color:#ffd700}
.footer-bottom{border-top:1px solid #333;padding-top:16px;display:flex;justify-content:space-between;flex-wrap:wrap;gap:12px;font-size:.85rem}
.footer-bottom a{color:#aaa;text-decoration:none;transition:color .2s}
.footer-bottom a:hover{color:#ffd700}

/* 回到顶部 */
.back-to-top{position:fixed;bottom:24px;right:24px;width:44px;height:44px;border-radius:50%;background:#c8102e;color:#fff;border:none;font-size:1.2rem;cursor:pointer;display:none;align-items:center;justify-content:center;box-shadow:0 4px 12px rgba(0,0,0,.2);z-index:99;transition:opacity .3s,transform .2s}
.back-to-top.visible{display:flex}
.back-to-top:hover{transform:scale(1.1)}

/* Banner 轮播 */
.banner-slider{position:relative;overflow:hidden;border-radius:12px;height:320px;background:#1a1a2e}
.banner-slide{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;flex-direction:column;color:#fff;padding:32px;text-align:center;opacity:0;transition:opacity .6s}
.banner-slide.active{opacity:1}
.banner-slide h2{font-size:1.8rem;margin-bottom:12px}
.banner-slide p{max-width:500px;font-size:1rem;opacity:.9}
.banner-dots{display:flex;justify-content:center;gap:8px;margin-top:16px}
.banner-dots button{width:12px;height:12px;border-radius:50%;border:2px solid #c8102e;background:transparent;cursor:pointer;transition:background .3s,transform .2s}
.banner-dots button.active{background:#c8102e}
.banner-dots button:hover{transform:scale(1.2)}

/* 统计 */
.stat-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:24px;text-align:center}
@media(max-width:600px){.stat-grid{grid-template-columns:repeat(2,1fr)}}
.stat-item .stat-number{font-size:2.5rem;font-weight:800;color:#c8102e}
.stat-item .stat-label{font-size:.95rem;color:#666;margin-top:4px}
body.dark .stat-item .stat-label{color:#aaa}

/* 搜索 */
.search-box{max-width:400px;margin:0 auto 32px}
.search-box input{width:100%;padding:12px 16px;border:2px solid #ddd;border-radius:8px;font-size:1rem;background:#fff;color:#1a1a2e;transition:border-color .2s,box-shadow .2s}
body.dark .search-box input{background:#1a1a2e;border-color:#444;color:#e0e0e0}
.search-box input:focus{outline:none;border-color:#c8102e;box-shadow:0 0 0 3px rgba(200,16,46,.2)}

/* 主题切换 */
.theme-toggle{background:none;border:none;font-size:1.2rem;cursor:pointer;color:inherit;padding:4px 8px;transition:transform .2s}
.theme-toggle:hover{transform:rotate(15deg)}

img{max-width:100%;height:auto;display:block}