/* ==========================================
   U体育 · 无限运动可能
   Design System — 运动活力 · 渐变流体
   Color: 活力橙 + 天空蓝渐变 + 纯净白
   ========================================== */

/* 基础重置 */
*, *::before, *::after { margin:0; padding:0; box-sizing:border-box; }
body { 
    font-family: system-ui, 'PingFang SC', 'Microsoft YaHei', sans-serif; 
    overflow-x:hidden; 
    background: linear-gradient(135deg, #fff6f0 0%, #f0f7ff 100%);
    color: #1a2a3a;
}

/* 核心布局 — 必须居中 */
.container { max-width:1200px; margin:0 auto; padding:0 24px; }
.section { padding:80px 0; position: relative; }
.section:nth-child(even) { 
    background: linear-gradient(135deg, rgba(255,118,0,0.03) 0%, rgba(0,150,255,0.03) 100%);
}

/* 导航 — 固定顶部 */
.site-header { 
    position:fixed; top:0; left:0; width:100%; z-index:1000; 
    background: rgba(255,255,255,0.92); 
    backdrop-filter:blur(10px); 
    border-bottom: 1px solid rgba(255,118,0,0.15);
    box-shadow: 0 2px 20px rgba(0,150,255,0.06);
}
.header-inner { 
    display:flex; align-items:center; justify-content:space-between; 
    height:68px; max-width:1200px; margin:0 auto; padding:0 24px; 
}
.logo { 
    display:flex; align-items:center; gap:10px; 
    font-weight:800; font-size:1.3rem; text-decoration:none; 
    background: linear-gradient(135deg, #ff7600, #0096ff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.logo-icon { 
    width:38px; height:38px; 
    border-radius: 12px; 
    background: linear-gradient(135deg, #ff7600, #0096ff);
    display:flex; align-items:center; justify-content:center; 
    font-size:1.1rem; 
    color: #fff;
    box-shadow: 0 4px 12px rgba(255,118,0,0.25);
}
.main-nav { display:flex; align-items:center; gap:28px; list-style:none; }
.main-nav a { 
    text-decoration:none; font-size:0.9rem; font-weight:500; 
    transition:0.3s; color: #2a3a4a;
    position: relative;
}
.main-nav a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: linear-gradient(135deg, #ff7600, #0096ff);
    transition: width 0.3s;
}
.main-nav a:hover::after { width: 100%; }
.main-nav a:hover { color: #ff7600; }
.nav-cta { 
    padding:8px 22px; border-radius:50px; 
    background: linear-gradient(135deg, #ff7600, #0096ff);
    color:#fff!important; font-weight:600; 
    box-shadow: 0 4px 15px rgba(255,118,0,0.3);
    transition: transform 0.3s, box-shadow 0.3s;
}
.nav-cta:hover { 
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0,150,255,0.35);
}
.nav-cta::after { display: none !important; }
.menu-toggle { display:none; }

/* 首页Hero */
.hero { 
    min-height:75vh; display:flex; align-items:center; 
    position: relative;
    overflow: hidden;
}
.hero::before {
    content: '';
    position: absolute;
    top: -30%;
    right: -20%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(255,118,0,0.08), transparent 70%);
    border-radius: 50%;
    pointer-events: none;
}
.hero::after {
    content: '';
    position: absolute;
    bottom: -20%;
    left: -10%;
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(0,150,255,0.06), transparent 70%);
    border-radius: 50%;
    pointer-events: none;
}
.hero-content { max-width:720px; position: relative; z-index: 1; }
.hero-eyebrow { 
    display:inline-block; font-size:0.85rem; font-weight:700; 
    padding:6px 18px; border-radius:50px; margin-bottom:16px; 
    background: linear-gradient(135deg, rgba(255,118,0,0.12), rgba(0,150,255,0.12));
    color: #ff7600;
    letter-spacing: 1px;
}
.hero h1 { 
    font-size:3rem; line-height:1.15; margin-bottom:20px; 
    background: linear-gradient(135deg, #1a2a3a, #ff7600);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.hero p { 
    font-size:1.15rem; opacity:0.7; max-width:560px; margin-bottom:36px; 
    line-height: 1.7;
}
.hero-buttons { display:flex; gap:16px; }
.hero-image { border-radius:16px; overflow:hidden; }
.hero-image img { width:100%; height:auto; }

/* 按钮 */
.btn { 
    display:inline-flex; align-items:center; gap:8px; 
    padding:14px 32px; border-radius:50px; font-weight:600; 
    cursor:pointer; border:none; text-decoration:none; 
    transition:0.3s; font-size: 0.95rem;
}
.btn-primary { 
    background: linear-gradient(135deg, #ff7600, #0096ff);
    color:#fff; 
    box-shadow: 0 4px 20px rgba(255,118,0,0.3);
}
.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 30px rgba(0,150,255,0.4);
}
.btn-outline { 
    background:transparent; border:2px solid;
    border-image: linear-gradient(135deg, #ff7600, #0096ff) 1;
    color: #ff7600;
}
.btn-outline:hover {
    background: linear-gradient(135deg, #ff7600, #0096ff);
    color: #fff;
    transform: translateY(-2px);
}

/* 标签/标题 */
.section-label { 
    display:inline-block; font-size:0.8rem; font-weight:700; 
    letter-spacing:3px; margin-bottom:12px; 
    background: linear-gradient(135deg, #ff7600, #0096ff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-transform: uppercase;
}
.section-title { 
    font-size:2.2rem; margin-bottom:14px; 
    color: #1a2a3a;
    font-weight: 800;
}
.section-desc { max-width:600px; opacity:0.7; margin-bottom:40px; font-size: 1.05rem; }

/* 卡片网格 */
.cards-grid { display:grid; grid-template-columns:repeat(auto-fill,minmax(260px,1fr)); gap:28px; }
.category-card { 
    border-radius:16px; padding:32px; 
    background: rgba(255,255,255,0.85);
    backdrop-filter: blur(8px);
    border: 1px solid rgba(255,118,0,0.1);
    transition:0.4s; 
    position: relative;
    overflow: hidden;
}
.category-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(135deg, #ff7600, #0096ff);
    opacity: 0;
    transition: opacity 0.4s;
}
.category-card:hover { 
    transform:translateY(-6px); 
    box-shadow:0 12px 40px rgba(255,118,0,0.12);
    border-color: transparent;
}
.category-card:hover::before { opacity: 1; }
.card-icon { 
    width:52px; height:52px; 
    border-radius:14px; 
    background: linear-gradient(135deg, rgba(255,118,0,0.1), rgba(0,150,255,0.1));
    display:flex; align-items:center; justify-content:center; 
    margin-bottom:18px; font-size:1.4rem; 
    color: #ff7600;
}
.card-link { 
    font-weight:700; font-size:0.85rem; text-decoration:none; 
    color: #0096ff;
    transition: 0.3s;
}
.card-link:hover { color: #ff7600; gap: 12px; }

/* 特性块 */
.feature-block { display:grid; grid-template-columns:1fr 1fr; gap:56px; align-items:center; }
.feature-image { 
    border-radius:16px; overflow:hidden; 
    box-shadow: 0 8px 30px rgba(0,0,0,0.06);
}
.feature-image img { width:100%; height:auto; transition: transform 0.5s; }
.feature-image:hover img { transform: scale(1.03); }
.feature-text { }
.feature-list { list-style:none; }
.feature-list li { 
    padding:8px 0; display:flex; align-items:center; gap:10px; 
    font-size: 1rem;
}
.feature-list li::before { 
    content:'✓'; font-weight:700; 
    background: linear-gradient(135deg, #ff7600, #0096ff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-size: 1.2rem;
}

/* 数据条 */
.stats-bar { 
    display:grid; grid-template-columns:repeat(4,1fr); gap:24px; text-align:center; 
    position: relative;
}
.stat-item { 
    padding:32px 24px; 
    border-radius:16px; 
    background: rgba(255,255,255,0.8);
    backdrop-filter: blur(6px);
    border: 1px solid rgba(0,150,255,0.08);
    transition: 0.3s;
}
.stat-item:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 30px rgba(0,150,255,0.1);
}
.stat-number { 
    font-size:2.6rem; font-weight:800; 
    background: linear-gradient(135deg, #ff7600, #0096ff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.stat-label { font-size:0.9rem; opacity:0.6; margin-top:8px; font-weight: 500; }

/* 内容墙 */
.content-wall { display:grid; grid-template-columns:repeat(auto-fill,minmax(280px,1fr)); gap:28px; }
.content-wall-item { 
    border-radius:16px; overflow:hidden; 
    background: rgba(255,255,255,0.85);
    backdrop-filter: blur(6px);
    border: 1px solid rgba(255,118,0,0.08);
    transition:0.4s; 
}
.content-wall-item:hover { 
    transform:translateY(-6px); 
    box-shadow:0 12px 40px rgba(0,150,255,0.1);
    border-color: transparent;
}
.content-wall-item img { 
    width:100%; height:200px; object-fit:cover; 
    transition: transform 0.5s;
}
.content-wall-item:hover img { transform: scale(1.05); }
.content-wall-body { padding:24px; }
.content-wall-body h3 { font-size: 1.1rem; margin-bottom: 8px; }

/* FAQ */
.faq-list { max-width:800px; margin:0 auto; }
.faq-item { 
    border: 1px solid rgba(255,118,0,0.1); 
    border-radius:12px; margin-bottom:10px; 
    overflow:hidden; cursor:pointer; 
    background: rgba(255,255,255,0.7);
    backdrop-filter: blur(4px);
    transition: 0.3s;
}
.faq-item:hover {
    border-color: rgba(0,150,255,0.2);
}
.faq-item .faq-question { 
    padding:18px 24px; font-weight:600; 
    display:flex; justify-content:space-between; 
    color: #1a2a3a;
    font-size: 1rem;
}
.faq-item .faq-question::after {
    content: '+';
    font-size: 1.4rem;
    background: linear-gradient(135deg, #ff7600, #0096ff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    transition: transform 0.3s;
}
.faq-item.open .faq-question::after {
    content: '−';
    transform: rotate(180deg);
}
.faq-item .faq-answer { 
    padding:0 24px 20px; display:none; 
    opacity:0.7; line-height: 1.6;
}
.faq-item.open .faq-answer { display:block; }

/* CTA横幅 */
.cta-banner { 
    padding:64px 32px; text-align:center; 
    border-radius:20px; 
    background: linear-gradient(135deg, #ff7600, #0096ff);
    color:#fff; 
    box-shadow: 0 12px 40px rgba(255,118,0,0.25);
    position: relative;
    overflow: hidden;
}
.cta-banner::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 300px;
    height: 300px;
    background: radial-gradient(circle, rgba(255,255,255,0.1), transparent 70%);
    border-radius: 50%;
}
.cta-banner h2 { 
    color:#fff; 
    font-size: 2rem;
    margin-bottom: 12px;
}
.cta-banner p { 
    color: rgba(255,255,255,0.85); 
    margin-bottom: 28px;
    font-size: 1.1rem;
}
.cta-banner .btn-primary { 
    background:#fff; 
    color: #ff7600;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}
.cta-banner .btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

/* 页脚 */
.site-footer { 
    padding:60px 0 28px; 
    background: linear-gradient(135deg, #1a2a3a, #2a3a4a);
    color: rgba(255,255,255,0.8);
}
.site-footer .container { }
.footer-grid { display:grid; grid-template-columns:2fr 1fr 1fr 1fr; gap:40px; }
.footer-brand { }
.footer-brand .logo { 
    -webkit-text-fill-color: #fff;
    margin-bottom: 16px;
}
.footer-col { }
.footer-col h4 { 
    color: #fff; 
    margin-bottom: 16px;
    font-weight: 700;
}
.footer-col a { 
    display: block; 
    color: rgba(255,255,255,0.6); 
    text-decoration: none; 
    padding: 4px 0;
    transition: 0.3s;
}
.footer-col a:hover { 
    color: #ff7600; 
    padding-left: 4px;
}
.footer-bottom { 
    border-top: 1px solid rgba(255,255,255,0.1); 
    margin-top:40px; padding-top:20px; 
    text-align:center; font-size:0.85rem; 
    color: rgba(255,255,255,0.4);
}

/* 工具类 */
.text-accent { 
    background: linear-gradient(135deg, #ff7600, #0096ff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.text-center { text-align:center; }
.seo-description { max-width:600px; margin:0 auto 48px; opacity:0.7; }
.mt-0 { margin-top:0; }
.mb-0 { margin-bottom:0; }

/* ⚠️ 响应式 */
@media (max-width: 768px) {
    .hero h1 { font-size: 2.2rem; }
    .section-title { font-size: 1.6rem; }
    .feature-block { grid-template-columns:1fr; gap: 32px; }
    .stats-bar { grid-template-columns:repeat(2,1fr); }
    .footer-grid { grid-template-columns:1fr 1fr; }
    .main-nav { display:none; }
    .menu-toggle { display:flex; }
    .menu-toggle { 
        width: 40px; height: 40px; 
        border: none; background: none; 
        cursor: pointer; position: relative;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: 5px;
    }
    .menu-toggle span {
        display: block;
        width: 24px;
        height: 2px;
        background: #1a2a3a;
        border-radius: 2px;
        transition: 0.3s;
    }
    .main-nav.open { 
        display:flex; flex-direction:column; 
        position:absolute; top:68px; left:0; width:100%; 
        background: rgba(255,255,255,0.98);
        backdrop-filter: blur(10px);
        padding:24px; 
        gap: 16px;
        border-bottom: 1px solid rgba(255,118,0,0.1);
        box-shadow: 0 8px 30px rgba(0,0,0,0.06);
    }
}
@media (max-width: 480px) {
    .cards-grid,.content-wall,.stats-bar { grid-template-columns:1fr; }
    .footer-grid { grid-template-columns:1fr; }
    .hero-buttons { flex-direction:column; }
    .hero h1 { font-size: 1.8rem; }
    .cta-banner { padding: 40px 20px; }
}