/* style.css - BTi体育官网 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  background: #f8f9fa;
  color: #1a1a2e;
  line-height: 1.6;
  transition: background 0.3s, color 0.3s;
}

body.dark {
  background: #0f0f1a;
  color: #e0e0e0;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

.btn {
  display: inline-block;
  padding: 12px 32px;
  border-radius: 50px;
  text-decoration: none;
  font-weight: 600;
  transition: all 0.3s;
  cursor: pointer;
  border: none;
  font-size: 1rem;
}

.btn-primary {
  background: linear-gradient(135deg, #1a73e8, #ff6b35);
  color: #fff;
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(26, 115, 232, 0.4);
}

.btn-outline {
  border: 2px solid #1a73e8;
  color: #1a73e8;
  background: transparent;
}

.btn-outline:hover {
  background: #1a73e8;
  color: #fff;
}

.section {
  padding: 80px 0;
}

.section-title {
  text-align: center;
  font-size: 2.5rem;
  margin-bottom: 20px;
  font-weight: 800;
  background: linear-gradient(135deg, #1a73e8, #ff6b35);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-subtitle {
  text-align: center;
  font-size: 1.1rem;
  color: #666;
  margin-bottom: 50px;
  max-width: 700px;
  margin-left: auto;
  margin-right: auto;
}

body.dark .section-subtitle {
  color: #aaa;
}

.card {
  background: rgba(255, 255, 255, 0.7);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-radius: 20px;
  padding: 30px;
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.08);
  transition: all 0.4s;
  border: 1px solid rgba(255, 255, 255, 0.3);
}

.card:hover {
  transform: translateY(-8px);
  box-shadow: 0 20px 60px rgba(26, 115, 232, 0.15);
}

body.dark .card {
  background: rgba(30, 30, 60, 0.7);
  border-color: rgba(255, 255, 255, 0.1);
}

.grid-2 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 30px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 30px;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 25px;
}

.text-center {
  text-align: center;
}

.hidden {
  display: none;
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(40px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.animate-on-scroll {
  opacity: 0;
  transform: translateY(40px);
  transition: all 0.6s ease;
}

.animate-on-scroll.visible {
  opacity: 1;
  transform: translateY(0);
}

.nav {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  padding: 15px 0;
  transition: all 0.3s;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(0, 0, 0, 0.05);
}

body.dark .nav {
  background: rgba(15, 15, 26, 0.85);
  border-bottom-color: rgba(255, 255, 255, 0.05);
}

.nav .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-logo {
  font-size: 1.8rem;
  font-weight: 900;
  background: linear-gradient(135deg, #1a73e8, #ff6b35);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  text-decoration: none;
}

.nav-links {
  display: flex;
  gap: 30px;
  list-style: none;
}

.nav-links a {
  text-decoration: none;
  color: #333;
  font-weight: 500;
  transition: color 0.3s;
  position: relative;
}

body.dark .nav-links a {
  color: #ccc;
}

.nav-links a:hover,
.nav-links a.active {
  color: #1a73e8;
}

.nav-links a.active::after {
  content: '';
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 100%;
  height: 2px;
  background: #1a73e8;
  border-radius: 2px;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  cursor: pointer;
  gap: 5px;
  background: none;
  border: none;
  padding: 5px;
}

.nav-toggle span {
  width: 28px;
  height: 3px;
  background: #333;
  border-radius: 3px;
  transition: all 0.3s;
}

body.dark .nav-toggle span {
  background: #ccc;
}

.mobile-menu {
  display: none;
  position: fixed;
  top: 70px;
  left: 0;
  width: 100%;
  background: rgba(255, 255, 255, 0.98);
  backdrop-filter: blur(20px);
  padding: 20px;
  z-index: 999;
  border-bottom: 1px solid rgba(0, 0, 0, 0.05);
}

body.dark .mobile-menu {
  background: rgba(15, 15, 26, 0.98);
}

.mobile-menu.active {
  display: block;
}

.mobile-menu a {
  display: block;
  padding: 12px 0;
  text-decoration: none;
  color: #333;
  font-weight: 500;
  border-bottom: 1px solid #eee;
}

body.dark .mobile-menu a {
  color: #ccc;
  border-bottom-color: #333;
}

.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, #e8f0fe 0%, #fff3e0 100%);
}

body.dark .hero {
  background: linear-gradient(135deg, #0a0a1a 0%, #1a1a2e 100%);
}

.hero-bg {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
}

.hero-bg svg {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 800px;
}

.hero h1 {
  font-size: 4rem;
  font-weight: 900;
  line-height: 1.1;
  margin-bottom: 20px;
  background: linear-gradient(135deg, #1a73e8, #ff6b35);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: 1.3rem;
  color: #555;
  margin-bottom: 30px;
  max-width: 600px;
}

body.dark .hero p {
  color: #bbb;
}

.hero-actions {
  display: flex;
  gap: 15px;
  flex-wrap: wrap;
}

.banner-slider {
  position: relative;
  overflow: hidden;
  border-radius: 20px;
  margin-top: 40px;
}

.banner-slide {
  display: none;
  animation: fadeInUp 0.6s ease;
}

.banner-slide.active {
  display: block;
}

.banner-dots {
  display: flex;
  justify-content: center;
  gap: 10px;
  margin-top: 20px;
}

.banner-dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: #ccc;
  cursor: pointer;
  transition: all 0.3s;
  border: none;
}

.banner-dot.active {
  background: #1a73e8;
  transform: scale(1.3);
}

.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background: linear-gradient(135deg, #1a73e8, #ff6b35);
  color: #fff;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s;
  z-index: 999;
  box-shadow: 0 4px 15px rgba(26, 115, 232, 0.3);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  transform: scale(1.1);
}

.dark-toggle {
  position: fixed;
  bottom: 90px;
  right: 30px;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background: #1a1a2e;
  color: #f0c040;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  z-index: 999;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
  transition: all 0.3s;
}

body.dark .dark-toggle {
  background: #f0c040;
  color: #1a1a2e;
}

.dark-toggle:hover {
  transform: scale(1.1);
}

.faq-item {
  margin-bottom: 15px;
  border-radius: 12px;
  overflow: hidden;
  background: rgba(255, 255, 255, 0.5);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(0, 0, 0, 0.05);
}

body.dark .faq-item {
  background: rgba(30, 30, 60, 0.5);
  border-color: rgba(255, 255, 255, 0.05);
}

.faq-question {
  padding: 18px 24px;
  cursor: pointer;
  font-weight: 600;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: background 0.3s;
}

.faq-question:hover {
  background: rgba(26, 115, 232, 0.05);
}

.faq-question .icon {
  transition: transform 0.3s;
  font-size: 1.2rem;
}

.faq-item.active .faq-question .icon {
  transform: rotate(180deg);
}

.faq-answer {
  padding: 0 24px;
  max-height: 0;
  overflow: hidden;
  transition: all 0.4s ease;
}

.faq-item.active .faq-answer {
  padding: 0 24px 18px;
  max-height: 300px;
}

.search-modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(10px);
  z-index: 2000;
  display: none;
  align-items: center;
  justify-content: center;
}

.search-modal.active {
  display: flex;
}

.search-modal-content {
  background: #fff;
  padding: 40px;
  border-radius: 24px;
  width: 90%;
  max-width: 500px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.2);
}

body.dark .search-modal-content {
  background: #1a1a2e;
}

.search-modal input {
  width: 100%;
  padding: 15px 20px;
  border: 2px solid #ddd;
  border-radius: 12px;
  font-size: 1.1rem;
  outline: none;
  transition: border 0.3s;
}

body.dark .search-modal input {
  background: #2a2a4a;
  border-color: #444;
  color: #fff;
}

.search-modal input:focus {
  border-color: #1a73e8;
}

.search-modal-close {
  position: absolute;
  top: 20px;
  right: 30px;
  font-size: 2rem;
  color: #fff;
  cursor: pointer;
  background: none;
  border: none;
}

.stat-number {
  font-size: 3rem;
  font-weight: 900;
  background: linear-gradient(135deg, #1a73e8, #ff6b35);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: inline-block;
}

.footer {
  background: #1a1a2e;
  color: #ccc;
  padding: 60px 0 30px;
}

body.dark .footer {
  background: #0a0a1a;
}

.footer a {
  color: #aaa;
  text-decoration: none;
  transition: color 0.3s;
}

.footer a:hover {
  color: #fff;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 40px;
  margin-bottom: 40px;
}

.footer-bottom {
  border-top: 1px solid #333;
  padding-top: 20px;
  text-align: center;
  font-size: 0.9rem;
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
  }
  .nav-toggle {
    display: flex;
  }
  .hero h1 {
    font-size: 2.5rem;
  }
  .hero p {
    font-size: 1rem;
  }
  .section-title {
    font-size: 2rem;
  }
  .section {
    padding: 50px 0;
  }
  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }
  .stat-number {
    font-size: 2rem;
  }
  .back-to-top,
  .dark-toggle {
    width: 40px;
    height: 40px;
    font-size: 1.2rem;
    bottom: 20px;
    right: 20px;
  }
  .dark-toggle {
    bottom: 70px;
  }
}

@media (max-width: 480px) {
  .hero h1 {
    font-size: 2rem;
  }
  .container {
    padding: 0 15px;
  }
  .btn {
    padding: 10px 24px;
    font-size: 0.9rem;
  }
}