/* ===== B体育 完整样式表 ===== */
/* 暗色主题 + 渐变 + 毛玻璃 + 响应式 + 动画 */

:root {
  --primary: #1a1a2e;
  --accent: #ffd700;
  --accent-hover: #e6c200;
  --bg: #0f0f1a;
  --card-bg: #1e1e36;
  --text: #e0e0e0;
  --text-light: #a0a0b0;
  --shadow: 0 4px 20px rgba(0,0,0,0.3);
  --radius: 12px;
  --max-width: 1200px;
  --nav-bg: rgba(26,26,46,0.95);
  --gradient-hero: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
  --glass-bg: rgba(30,30,54,0.6);
  --glass-border: rgba(255,215,0,0.1);
  --animation-speed: 0.3s;
}

/* 亮色模式变量 */
[data-theme="light"] {
  --bg: #f5f5fa;
  --primary: #ffffff;
  --card-bg: #ffffff;
  --text: #1a1a2e;
  --text-light: #4a4a5a;
  --nav-bg: rgba(255,255,255,0.95);
  --gradient-hero: linear-gradient(135deg, #e0e7ff 0%, #f0f4ff 50%, #ffffff 100%);
  --glass-bg: rgba(255,255,255,0.6);
  --glass-border: rgba(26,26,46,0.1);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  transition: background var(--animation-speed), color var(--animation-speed);
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.2s;
}

a:hover {
  color: var(--accent-hover);
}

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

/* 容器 */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

/* 标题 */
h1, h2, h3, h4 {
  line-height: 1.3;
  color: #fff;
  transition: color var(--animation-speed);
}

[data-theme="light"] h1,
[data-theme="light"] h2,
[data-theme="light"] h3,
[data-theme="light"] h4 {
  color: #1a1a2e;
}

h1 {
  font-size: clamp(2rem, 5vw, 3.2rem);
}

h2 {
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  margin-bottom: 1.5rem;
  position: relative;
  display: inline-block;
}

h2::after {
  content: '';
  display: block;
  width: 60px;
  height: 3px;
  background: var(--accent);
  margin-top: 8px;
  border-radius: 2px;
}

h3 {
  font-size: 1.3rem;
  margin-bottom: 0.8rem;
}

p {
  margin-bottom: 1rem;
}

/* 通用区域 */
.section {
  padding: 80px 0;
  transition: background var(--animation-speed);
}

.section-dark {
  background: var(--primary);
}

/* 卡片 - 圆角 + 毛玻璃效果 */
.card {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow);
  transition: transform 0.3s, box-shadow 0.3s, background var(--animation-speed);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  border: 1px solid transparent;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 30px rgba(0,0,0,0.4);
  border-color: rgba(255,215,0,0.2);
  background: var(--glass-bg);
}

/* 网格系统 */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 20px;
}

/* 按钮 */
.btn {
  display: inline-block;
  padding: 12px 28px;
  background: var(--accent);
  color: var(--primary);
  font-weight: 700;
  border-radius: 30px;
  transition: background 0.3s, transform 0.2s, box-shadow 0.3s;
  border: none;
  cursor: pointer;
  font-size: 1rem;
  box-shadow: 0 2px 12px rgba(255,215,0,0.3);
}

.btn:hover {
  background: var(--accent-hover);
  transform: scale(1.02);
  color: var(--primary);
  box-shadow: 0 4px 20px rgba(255,215,0,0.4);
}

.btn-outline {
  background: transparent;
  border: 2px solid var(--accent);
  color: var(--accent);
  box-shadow: none;
}

.btn-outline:hover {
  background: var(--accent);
  color: var(--primary);
  box-shadow: 0 4px 20px rgba(255,215,0,0.3);
}

/* 工具类 */
.text-center {
  text-align: center;
}

.mt-2 {
  margin-top: 2rem;
}

.mb-1 {
  margin-bottom: 1rem;
}

.mb-2 {
  margin-bottom: 2rem;
}

.badge {
  display: inline-block;
  background: rgba(255,215,0,0.15);
  color: var(--accent);
  padding: 4px 12px;
  border-radius: 20px;
  font-size: 0.85rem;
  margin-bottom: 12px;
  border: 1px solid rgba(255,215,0,0.2);
}

/* 导航栏 - 毛玻璃效果 */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: var(--nav-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--glass-border);
  transition: background 0.3s, border-color 0.3s;
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav-logo {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--accent);
  letter-spacing: 1px;
}

.nav-logo span {
  color: #fff;
  transition: color var(--animation-speed);
}

[data-theme="light"] .nav-logo span {
  color: #1a1a2e;
}

.nav-links {
  display: flex;
  gap: 24px;
  list-style: none;
}

.nav-links a {
  color: var(--text);
  font-size: 0.95rem;
  padding: 6px 0;
  border-bottom: 2px solid transparent;
  transition: border-color 0.2s, color 0.2s;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

.menu-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text);
  font-size: 1.8rem;
  cursor: pointer;
  padding: 4px;
  transition: color 0.2s;
}

/* Hero 区域 - 渐变Banner */
.hero {
  min-height: 100vh;
  background: var(--gradient-hero);
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 120px 20px 80px;
  position: relative;
  overflow: hidden;
  transition: background var(--animation-speed);
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle at 30% 50%, rgba(255,215,0,0.05) 0%, transparent 50%);
  animation: heroGlow 10s ease-in-out infinite alternate;
}

@keyframes heroGlow {
  0% {
    transform: translate(0, 0);
  }
  100% {
    transform: translate(10%, 10%);
  }
}

.hero h1 {
  margin-bottom: 1rem;
  position: relative;
  z-index: 1;
}

.hero p {
  font-size: 1.2rem;
  max-width: 700px;
  margin: 0 auto 2rem;
  color: var(--text-light);
  position: relative;
  z-index: 1;
}

.hero-buttons {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
  position: relative;
  z-index: 1;
}

/* 统计数字 */
.stat-number {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--accent);
  display: block;
  transition: color var(--animation-speed);
}

/* 页脚 */
.footer {
  background: #0a0a14;
  padding: 40px 0 20px;
  border-top: 1px solid rgba(255,215,0,0.05);
  transition: background var(--animation-speed);
}

[data-theme="light"] .footer {
  background: #e8e8f0;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 24px;
  margin-bottom: 30px;
}

.footer h4 {
  color: var(--accent);
  margin-bottom: 12px;
  font-size: 1rem;
}

.footer ul {
  list-style: none;
}

.footer ul li {
  margin-bottom: 6px;
}

.footer ul li a {
  color: var(--text-light);
  font-size: 0.9rem;
  transition: color 0.2s;
}

.footer ul li a:hover {
  color: var(--accent);
}

.footer-bottom {
  text-align: center;
  padding-top: 20px;
  border-top: 1px solid rgba(255,255,255,0.05);
  font-size: 0.85rem;
  color: var(--text-light);
}

[data-theme="light"] .footer-bottom {
  border-top-color: rgba(0,0,0,0.05);
}

.footer-bottom a {
  color: var(--text-light);
  margin: 0 8px;
  transition: color 0.2s;
}

.footer-bottom a:hover {
  color: var(--accent);
}

/* FAQ 手风琴 */
.faq-item {
  border-bottom: 1px solid rgba(255,255,255,0.06);
  padding: 16px 0;
  transition: border-color var(--animation-speed);
}

[data-theme="light"] .faq-item {
  border-bottom-color: rgba(0,0,0,0.06);
}

.faq-question {
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  font-weight: 600;
  font-size: 1.05rem;
  color: #fff;
  background: none;
  border: none;
  width: 100%;
  text-align: left;
  padding: 8px 0;
  transition: color var(--animation-speed);
}

[data-theme="light"] .faq-question {
  color: #1a1a2e;
}

.faq-question::after {
  content: '+';
  font-size: 1.5rem;
  transition: transform 0.3s;
  color: var(--accent);
}

.faq-item.open .faq-question::after {
  transform: rotate(45deg);
  content: '+';
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s;
  color: var(--text-light);
}

.faq-item.open .faq-answer {
  max-height: 300px;
  padding: 8px 0 16px;
}

/* HowTo 步骤 */
.howto-step {
  display: flex;
  gap: 16px;
  margin-bottom: 20px;
  align-items: flex-start;
}

.step-number {
  flex-shrink: 0;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--accent);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  transition: transform 0.2s;
}

.howto-step:hover .step-number {
  transform: scale(1.1);
}

.step-content h4 {
  margin-bottom: 4px;
}

/* 轮播 */
.carousel-container {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.carousel-track {
  display: flex;
  transition: transform 0.5s ease;
}

.carousel-slide {
  min-width: 100%;
  padding: 40px 20px;
  text-align: center;
  background: var(--card-bg);
  transition: background var(--animation-speed);
}

.carousel-slide p {
  max-width: 600px;
  margin: 0 auto;
}

.carousel-btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  background: rgba(0,0,0,0.5);
  color: #fff;
  border: none;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  cursor: pointer;
  font-size: 1.2rem;
  z-index: 2;
  transition: background 0.2s, transform 0.2s;
}

.carousel-btn:hover {
  background: rgba(255,215,0,0.7);
  transform: translateY(-50%) scale(1.1);
}

.carousel-btn.prev {
  left: 10px;
}

.carousel-btn.next {
  right: 10px;
}

/* 返回顶部 */
.scroll-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--accent);
  color: var(--primary);
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s, visibility 0.3s, transform 0.2s;
  z-index: 999;
  box-shadow: 0 2px 12px rgba(255,215,0,0.3);
}

.scroll-top.visible {
  opacity: 1;
  visibility: visible;
}

.scroll-top:hover {
  transform: scale(1.1);
  box-shadow: 0 4px 20px rgba(255,215,0,0.4);
}

/* 暗色模式切换按钮 */
.dark-toggle {
  background: none;
  border: 2px solid var(--accent);
  color: var(--accent);
  width: 40px;
  height: 40px;
  border-radius: 50%;
  cursor: pointer;
  font-size: 1.2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.2s, border-color 0.2s;
}

.dark-toggle:hover {
  background: rgba(255,215,0,0.1);
}

/* 滚动动画 - fade-in */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* 延迟动画 */
.fade-in-delay-1 { transition-delay: 0.1s; }
.fade-in-delay-2 { transition-delay: 0.2s; }
.fade-in-delay-3 { transition-delay: 0.3s; }
.fade-in-delay-4 { transition-delay: 0.4s; }

/* 卡片悬浮效果增强 */
.card-highlight {
  position: relative;
  overflow: hidden;
}

.card-highlight::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255,215,0,0.05), transparent);
  transition: left 0.5s;
}

.card-highlight:hover::before {
  left: 100%;
}

/* 毛玻璃卡片变体 */
.glass-card {
  background: var(--glass-bg);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border: 1px solid var(--glass-border);
}

.glass-card:hover {
  background: rgba(255,215,0,0.05);
  border-color: rgba(255,215,0,0.3);
}

/* 响应式 - 平板 */
@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--nav-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    flex-direction: column;
    padding: 20px;
    gap: 12px;
    border-bottom: 1px solid var(--glass-border);
  }

  .nav-links.open {
    display: flex;
  }

  .menu-toggle {
    display: block;
  }

  .hero h1 {
    font-size: 1.8rem;
  }

  .section {
    padding: 60px 0;
  }

  .grid-2,
  .grid-3,
  .grid-4 {
    gap: 16px;
  }

  .hero-buttons {
    flex-direction: column;
    align-items: center;
  }

  .stat-number {
    font-size: 2rem;
  }

  .carousel-slide {
    padding: 30px 16px;
  }
}

/* 响应式 - 手机 */
@media (max-width: 480px) {
  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }

  .section {
    padding: 40px 0;
  }

  .hero {
    padding: 100px 16px 60px;
  }

  .card {
    padding: 16px;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 16px;
  }

  .scroll-top {
    bottom: 20px;
    right: 20px;
    width: 40px;
    height: 40px;
    font-size: 1.2rem;
  }

  h2 {
    font-size: 1.4rem;
  }

  .howto-step {
    flex-direction: column;
    gap: 8px;
  }

  .step-number {
    width: 32px;
    height: 32px;
    font-size: 0.9rem;
  }
}

/* 大屏优化 */
@media (min-width: 1400px) {
  .container {
    max-width: 1320px;
  }

  .hero {
    padding: 140px 20px 100px;
  }

  .section {
    padding: 100px 0;
  }
}

/* 辅助功能 */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  border: 0;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* 自定义滚动条 */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg);
}

::-webkit-scrollbar-thumb {
  background: var(--accent);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--accent-hover);
}

/* 选中文本样式 */
::selection {
  background: rgba(255,215,0,0.3);
  color: #fff;
}

/* 打印样式 */
@media print {
  .navbar,
  .scroll-top,
  .carousel-btn,
  .dark-toggle {
    display: none;
  }

  .hero {
    min-height: auto;
    padding: 40px 20px;
  }

  .card {
    break-inside: avoid;
  }
}