```css
/* ============================================
   b体育网站app - B体育app下载中心
   设计系统：暖沙赤陶 × 自然运动
   Awwwards风格定制
   ============================================ */

/* === 基础重置 === */
*, *::before, *::after { margin:0; padding:0; box-sizing:border-box; }

:root {
  --bg-warm: #faf7f2;
  --bg-cream: #f5f0ea;
  --bg-card: #ffffff;
  --terracotta: #c75b39;
  --terracotta-deep: #b04a2e;
  --terracotta-light: #fdf3ed;
  --sage: #7a9a76;
  --sage-deep: #5f7d5b;
  --sage-light: #f2f7f0;
  --text-warm: #3d2c24;
  --text-soft: #6b5d55;
  --text-muted: #9b8c82;
  --border-soft: #e8ddd0;
  --border-warm: #d9cec0;
  --shadow-sm: 0 2px 12px rgba(61,44,36,0.06);
  --shadow-md: 0 6px 24px rgba(61,44,36,0.09);
  --shadow-lg: 0 12px 40px rgba(61,44,36,0.12);
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-xl: 24px;
  --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

body {
  font-family: system-ui, 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
  background: var(--bg-warm);
  color: var(--text-warm);
  overflow-x:hidden;
  line-height:1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  background-image:
    radial-gradient(ellipse at 15% 10%, rgba(199,91,57,0.03) 0%, transparent 60%),
    radial-gradient(ellipse at 85% 90%, rgba(122,154,118,0.04) 0%, transparent 60%),
    radial-gradient(ellipse at 50% 50%, rgba(61,44,36,0.015) 0%, transparent 70%);
  background-attachment: fixed;
}

/* === 核心布局 === */
.container { max-width:1200px; margin:0 auto; padding:0 24px; }

.section { padding:80px 0; position:relative; }
.section:nth-child(even) { background:var(--bg-cream); }
.section:nth-child(even)::before {
  content:'';
  position:absolute;
  top:0;left:0;right:0;
  height:1px;
  background:linear-gradient(90deg,transparent,var(--border-soft),transparent);
}

/* === 导航 === */
.site-header {
  position:fixed; top:0; left:0; width:100%; z-index:1000;
  background:rgba(250,247,242,0.92);
  backdrop-filter:blur(16px);
  -webkit-backdrop-filter:blur(16px);
  border-bottom:1px solid var(--border-soft);
  transition:var(--transition);
}
.site-header.scrolled {
  background:rgba(250,247,242,0.97);
  box-shadow:var(--shadow-sm);
}

.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:700; font-size:1.25rem; text-decoration:none;
  color:var(--text-warm); letter-spacing:-0.3px;
  transition:var(--transition);
}
.logo:hover { color:var(--terracotta); }

.logo-icon {
  width:38px; height:38px;
  border-radius:10px;
  background:linear-gradient(135deg, var(--terracotta), #d4785a);
  display:flex; align-items:center; justify-content:center;
  font-size:1rem; color:#fff; font-weight:800;
  box-shadow:0 3px 10px rgba(199,91,57,0.25);
  transition:var(--transition);
}
.logo:hover .logo-icon {
  box-shadow:0 5px 18px rgba(199,91,57,0.35);
  transform:scale(1.04);
}

.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;
  color:var(--text-warm); position:relative;
  transition:var(--transition); padding:4px 0;
}
.main-nav a::after {
  content:'';
  position:absolute; bottom:-2px; left:0;
  width:0; height:2px;
  background:var(--terracotta);
  border-radius:2px;
  transition:var(--transition);
}
.main-nav a:hover { color:var(--terracotta); }
.main-nav a:hover::after { width:100%; }

.nav-cta {
  padding:9px 22px!important; border-radius:25px!important;
  color:#fff!important; font-weight:600!important;
  background:linear-gradient(135deg, var(--terracotta), #d4785a);
  box-shadow:0 3px 12px rgba(199,91,57,0.25);
  transition:var(--transition)!important;
  letter-spacing:0.2px;
}
.nav-cta::after { display:none!important; }
.nav-cta:hover {
  transform:translateY(-2px);
  box-shadow:0 6px 20px rgba(199,91,57,0.35)!important;
  color:#fff!important;
}

.menu-toggle {
  display:none; align-items:center; justify-content:center;
  width:40px; height:40px; border-radius:var(--radius-sm);
  background:transparent; border:1.5px solid var(--border-soft);
  cursor:pointer; color:var(--text-warm); font-size:1.3rem;
  transition:var(--transition);
}
.menu-toggle:hover { border-color:var(--terracotta); color:var(--terracotta); }

/* === Hero === */
.hero {
  min-height:70vh; display:flex; align-items:center;
  padding-top:88px; position:relative;
  background:
    radial-gradient(circle at 20% 30%, rgba(199,91,57,0.04) 0%, transparent 50%),
    radial-gradient(circle at 75% 65%, rgba(122,154,118,0.05) 0%, transparent 50%);
}
.hero .container {
  display:grid; grid-template-columns:1fr 1fr; gap:48px; align-items:center;
}
.hero-content { max-width:720px; }

.hero-eyebrow {
  display:inline-block; font-size:0.82rem; font-weight:600;
  padding:5px 16px; border-radius:25px; margin-bottom:18px;
  background:var(--terracotta-light);
  color:var(--terracotta);
  letter-spacing:1.5px;
  text-transform:uppercase;
  animation:fadeInUp 0.6s ease both;
}

.hero h1 {
  font-size:3.2rem; line-height:1.15; margin-bottom:22px;
  font-weight:800; letter-spacing:-0.5px;
  color:var(--text-warm);
  animation:fadeInUp 0.6s ease 0.1s both;
}
.hero h1 .highlight {
  background:linear-gradient(135deg, var(--terracotta), #e0886a);
  -webkit-background-clip:text;
  -webkit-text-fill-color:transparent;
  background-clip:text;
}

.hero p {
  font-size:1.1rem; opacity:0.75; max-width:520px;
  margin-bottom:34px; color:var(--text-soft);
  line-height:1.7;
  animation:fadeInUp 0.6s ease 0.2s both;
}

.hero-buttons { display:flex; gap:14px; flex-wrap:wrap; animation:fadeInUp 0.6s ease 0.3s both; }

.hero-image {
  border-radius:var(--radius-xl); overflow:hidden;
  box-shadow:var(--shadow-lg);
  animation:fadeInRight 0.7s ease 0.2s both;
  position:relative;
}
.hero-image::after {
  content:'';
  position:absolute; inset:0;
  border-radius:var(--radius-xl);
  box-shadow:inset 0 0 0 1px rgba(255,255,255,0.6);
  pointer-events:none;
}
.hero-image img { width:100%; height:auto; display:block; border-radius:var(--radius-xl); }

@keyframes fadeInUp {
  from { opacity:0; transform:translateY(20px); }
  to { opacity:1; transform:translateY(0); }
}
@keyframes fadeInRight {
  from { opacity:0; transform:translateX(30px); }
  to { opacity:1; transform:translateX(0); }
}

/* === 按钮 === */
.btn {
  display:inline-flex; align-items:center; gap:8px;
  padding:13px 30px; border-radius:25px;
  font-weight:600; cursor:pointer; border:none;
  text-decoration:none; transition:var(--transition);
  font-size:0.95rem; letter-spacing:0.2px;
  position:relative; overflow:hidden;
}
.btn:active { transform:scale(0.97); }

.btn-primary {
  color:#fff;
  background:linear-gradient(135deg, var(--terracotta), #d4785a);
  box-shadow:0 4px 14px rgba(199,91,57,0.28);
}
.btn-primary:hover {
  box-shadow:0 8px 24px rgba(199,91,57,0.4);
  transform:translateY(-2px);
}

.btn-outline {
  background:transparent;
  border:1.5px solid var(--terracotta);
  color:var(--terracotta);
}
.btn-outline:hover {
  background:var(--terracotta-light);
  border-color:var(--terracotta-deep);
  color:var(--terracotta-deep);
}

.btn-secondary {
  background:var(--sage);
  color:#fff;
  box-shadow:0 4px 14px rgba(122,154,118,0.25);
}
.btn-secondary:hover {
  background:var(--sage-deep);
  box-shadow:0 8px 24px rgba(122,154,118,0.35);
  transform:translateY(-2px);
}

/* === 标签/标题 === */
.section-label {
  display:inline-block; font-size:0.8rem; font-weight:600;
  letter-spacing:2.5px; margin-bottom:12px;
  color:var(--sage); text-transform:uppercase;
}
.section-title {
  font-size:2.2rem; margin-bottom:14px;
  font-weight:800; letter-spacing:-0.3px;
  color:var(--text-warm);
}
.section-desc {
  max-width:600px; opacity:0.7; margin-bottom:40px;
  color:var(--text-soft); font-size:1.05rem; line-height:1.7;
}

/* === 卡片网格 === */
.cards-grid {
  display:grid; grid-template-columns:repeat(auto-fill,minmax(260px,1fr));
  gap:24px;
}

.category-card {
  border-radius:var(--radius-lg); padding:30px 26px;
  border:1px solid var(--border-soft);
  background:var(--bg-card);
  transition:var(--transition);
  position:relative;
  overflow:hidden;
}
.category-card::before {
  content:'';
  position:absolute; top:0; left:0; right:0;
  height:3px;
  background:linear-gradient(90deg, var(--terracotta), var(--sage));
  opacity:0; transition:var(--transition);
  border-radius:0 0 3px 3px;
}
.category-card:hover {
  transform:translateY(-4px);
  box-shadow:var(--shadow-md);
  border-color:transparent;
}
.category-card:hover::before { opacity:1; }

.card-icon {
  width:50px; height:50px; border-radius:14px;
  display:flex; align-items:center; justify-content:center;
  margin-bottom:18px; font-size:1.4rem;
  background:var(--sage-light);
  color:var(--sage);
  transition:var(--transition);
}
.category-card:hover .card-icon {
  background:var(--terracotta-light);
  color:var(--terracotta);
}

.category-card h3 {
  font-size:1.1rem; font-weight:700;
  margin-bottom:8px; color:var(--text-warm);
}
.category-card p {
  font-size:0.9rem; color:var(--text-soft);
  line-height:1.6; margin-bottom:14px;
}

.card-link {
  font-weight:600; font-size:0.85rem; text-decoration:none;
  color:var(--terracotta); display:inline-flex; align-items:center; gap:4px;
  transition:var(--transition);
}
.card-link::after { content:'→'; transition:var(--transition); }
.card-link:hover { color:var(--terracotta-deep); gap:8px; }

/* === 特性块 === */
.feature-block {
  display:grid; grid-template-columns:1fr 1fr; gap:56px; align-items:center;
}
.feature-image {
  border-radius:var(--radius-xl); overflow:hidden;
  box-shadow:var(--shadow-md);
  position:relative;
}
.feature-image::after {
  content:'';
  position:absolute; inset:0;
  border-radius:var(--radius-xl);
  box-shadow:inset 0 0 0 1px rgba(255,255,255,0.5);
  pointer-events:none;
}
.feature-image img { width:100%; height:auto; display:block; border-radius:var(--radius-xl); }

.feature-text h3 { font-size:1.6rem; font-weight:700; margin-bottom:16px; color:var(--text-warm); }
.feature-text p { color:var(--text-soft); line-height:1.7; margin-bottom:20px; }

.feature-list { list-style:none; }
.feature-list li {
  padding:8px 0; display:flex; align-items:center; gap:10px;
  color:var(--text-warm); font-weight:500; font-size:0.95rem;
}
.feature-list li::before {
  content:'✓'; font-weight:700; color:#fff;
  background:var(--sage);
  width:22px; height:22px; border-radius:50%;
  display:inline-flex; align-items:center; justify-content:center;
  font-size:0.7rem; flex-shrink:0;
}

/* === 数据条 === */
.stats-bar {
  display:grid; grid-template-columns:repeat(4,1fr); gap:24px; text-align:center;
}
.stat-item {
  padding:32px 20px; border-radius:var(--radius-lg);
  border:1px solid var(--border-soft);
  background:var(--bg-card);
  transition:var(--transition);
  position:relative;
}
.stat-item:hover {
  transform:translateY(-3px);
  box-shadow:var(--shadow-md);
  border-color:transparent;
}
.stat-number {
  font-size:2.6rem; font-weight:800;
  background:linear-gradient(135deg, var(--terracotta), #e0886a);
  -webkit-background-clip:text;
  -webkit-text-fill-color:transparent;
  background-clip:text;
  line-height:1.2;
}
.stat-label { font-size:0.9rem; color:var(--text-muted); margin-top:8px; font-weight:500; }
.stat-item .stat-suffix { font-size:1.2rem; font-weight:700; color:var(--terracotta); }

/* === 内容墙 === */
.content-wall {
  display:grid; grid-template-columns:repeat(auto-fill,minmax(280px,1fr)); gap:24px;
}
.content-wall-item {
  border-radius:var(--radius-lg); overflow:hidden;
  border:1px solid var(--border-soft);
  background:var(--bg-card);
  transition:var(--transition);
}
.content-wall-item:hover {
  transform:translateY(-4px);
  box-shadow:var(--shadow-md);
  border-color:transparent;
}
.content-wall-item img { width:100%; height:200px; object-fit:cover; display:block; }
.content-wall-body { padding:20px; }
.content-wall-body h4 { font-size:1.05rem; font-weight:700; margin-bottom:6px; color:var(--text-warm); }
.content-wall-body p { font-size:0.88rem; color:var(--text-soft); line-height:1.5; }
.content-wall-body .tag {
  display:inline-block; padding:3px 10px; border-radius:15px;
  font-size:0.75rem; font-weight:600; margin-bottom:8px;
  background:var(--sage-light); color:var(--sage);
}

/* === FAQ === */
.faq-list { max-width:800px; margin:0 auto; }
.faq-item {
  border:1px solid var(--border-soft);
  border-radius:var(--radius-md); margin-bottom:10px;
  overflow:hidden; cursor:pointer;
  background:var(--bg-card);
  transition:var(--transition);
}
.faq-item:hover { border-color:var(--border-warm); }
.faq-item .faq-question {
  padding:18px 22px; font-weight:600;
  display:flex; justify-content:space-between; align-items:center;
  color:var(--text-warm); font-size:1rem; user-select:none;
}
.faq-item .faq-question .faq-icon {
  width:28px; height:28px; border-radius:50%;
  background:var(--terracotta-light);
  display:flex; align-items:center; justify-content:center;
  font-size:0.8rem; color:var(--terracotta);
  transition:var(--transition); flex-shrink:0;
}
.faq-item .faq-answer {
  padding:0 22px 18px; display:none;
  opacity:0.8; color:var(--text-soft);
  line-height:1.7; font-size:0.95rem;
}
.faq-item.open .faq-answer { display:block; }
.faq-item.open {
  border-color:var(--terracotta);
  box-shadow:var(--shadow-sm);
}
.faq-item.open .faq-icon {
  background:var(--terracotta); color:#fff;
  transform:rotate(45deg);
}

/* === CTA横幅 === */
.cta-banner {
  padding:60px 24px; text-align:center;
  border-radius:var(--radius-xl);
  background:linear-gradient(135deg, var(--terracotta), #d4785a, #c75b39);
  color:#fff;
  position:relative;
  overflow:hidden;
  box-shadow:var(--shadow-lg);
}
.cta-banner::before {
  content:'';
  position:absolute;
  width:300px; height:300px;
  background:rgba(255,255,255,0.06);
  border-radius:50%;
  top:-80px; right:-60px;
}
.cta-banner::after {
  content:'';
  position:absolute;
  width:200px; height:200px;
  background:rgba(255,255,255,0.04);
  border-radius:50%;
  bottom:-50px; left:-40px;
}
.cta-banner h2 {
  color:#fff; font-size:2rem; font-weight:800;
  position:relative; z-index:1; margin-bottom:12px;
}
.cta-banner p {
  position:relative; z-index:1;
  opacity:0.9; margin-bottom:24px; font-size:1.05rem;
}
.cta-banner .btn-primary {
  background:#fff; color:var(--terracotta);
  box-shadow:0 4px 16px rgba(0,0,0,0.15);
  position:relative; z-index:1;
}
.cta-banner .btn-primary:hover {
  background:#fff;
  box-shadow:0 8px 28px rgba(0,0,0,0.2);
  transform:translateY(-3px);
}

/* === 页脚 === */
.site-footer {
  padding:56px 0 28px;
  background:var(--bg-cream);
  border-top:1px solid var(--border-soft);
  color:var(--text-warm);
}
.site-footer .container { }

.footer-grid {
  display:grid; grid-template-columns:2fr 1fr 1fr 1fr; gap:40px;
}

.footer-brand .logo { margin-bottom:12px; }
.footer-brand p { color:var(--text-soft); font-size:0.9rem; line-height:1.6; max-width:280px; }

.footer-col h4 { font-weight:700; font-size:0.95rem; margin-bottom:16px; color:var(--text-warm); }
.footer-col ul { list-style:none; }
.footer-col ul li { margin-bottom:8px; }
.footer-col ul li a {
  text-decoration:none; color:var(--text-soft);
  font-size:0.88rem; transition:var(--transition);
}
.footer-col ul li a:hover { color:var(--terracotta); }

.footer-bottom {
  border-top:1px solid var(--border-soft);
  margin-top:40px; padding-top:20px;
  text-align:center; font-size:0.85rem;
  color:var(--text-muted);
}

/* === 工具类 === */
.text-accent { color:var(--terracotta); }
.text-center { text-align:center; }
.seo-description {
  max-width:600px; margin:0 auto 48px;
  opacity:0.7; color:var(--text-soft);
  text-align:center; line-height:1.7;
}
.mt-0 { margin-top:0; }
.mb-0 { margin-bottom:0; }

/* === 响应式 === */
@media (max-width: 1024px) {
  .hero .container { grid-template-columns:1fr; gap:36px; }
  .hero-image { max-width:500px; margin:0 auto; }
  .hero h1 { font-size:2.4rem; }
  .feature-block { gap:36px; }
  .footer-grid { grid-template-columns:1fr 1fr; gap:28px; }
  .stats-bar { grid-template-columns:repeat(2,1fr); }
}

@media (max-width: 768px) {
  .hero { min-height:auto; padding-top:100px; padding-bottom:40px; }
  .hero h1 { font-size:2rem; }
  .hero p { font-size:1rem; }
  .hero-buttons { flex-direction:column; align-items:flex-start; }
  .hero .container { grid-template-columns:1fr; }

  .feature-block { grid-template-columns:1fr; gap:32px; }
  .feature-image { order:-1; max-width:100%; }

  .stats-bar { grid-template-columns:repeat(2,1fr); gap:16px; }
  .stat-number { font-size:2rem; }

  .footer-grid { grid-template-columns:1fr 1fr; gap:24px; }
  .footer-brand { grid-column:span 2; }

  .section-title { font-size:1.7rem; }
  .section { padding:56px 0; }

  .main-nav { display:none; }
  .menu-toggle { display:flex; }
  .main-nav.open {
    display:flex; flex-direction:column;
    position:absolute; top:68px; left:0; width:100%;
    background:rgba(250,247,242,0.98);
    backdrop-filter:blur(16px);
    padding:20px 24px;
    border-bottom:1px solid var(--border-soft);
    box-shadow:var(--shadow-md);
    gap:0;
  }
  .main-nav.open li { width:100%; }
  .main-nav.open a {
    display:block; padding:14px 0; font-size:1rem;
    border-bottom:1px solid var(--border-soft);
  }
  .main-nav.open .nav-cta {
    text-align:center; margin-top:8px;
    border-radius:25px!important;
    padding:12px 22px!important;
  }
  .main-nav.open a::after { display:none; }
}

@media (max-width: 480px) {
  .container { padding:0 16px; }
  .header-inner { padding:0 16px; }

  .hero h1 { font-size:1.7rem; }
  .hero-eyebrow { font-size:0.75rem; padding:4px 12px; }
  .hero-buttons { width:100%; }
  .hero-buttons .btn { width:100%; justify-content:center; }

  .cards-grid, .content-wall, .stats-bar { grid-template-columns:1fr; }
  .stats-bar { gap:12px; }
  .stat-item { padding:20px 16px; }
  .stat-number { font-size:1.8rem; }

  .footer-grid { grid-template-columns:1fr; gap:20px; }
  .footer-brand { grid-column:span 1; }

  .section-title { font-size:1.5rem; }
  .section { padding:40px 0; }

  .feature-block { gap:24px; }
  .cta-banner { padding:40px 16px; }
  .cta-banner h2 { font-size:1.5rem; }

  .category-card { padding:22px 18px; }
  .content-wall-item img { height:160px; }

  .btn { padding:11px 22px; font-size:0.9rem; width:100%; justify-content:center; }
}