/* ============================================
   必一运动·(B体育-Bsports)官方网站 - style.css
   完整内联样式 - 随机风格：科技蓝渐变 + 柔光暗影
   ============================================ */

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  background: #f4f7fc;
  color: #1e293b;
  line-height: 1.6;
  transition: background 0.4s ease, color 0.4s ease;
}

body.dark {
  background: #0b1120;
  color: #e2e8f0;
}

/* 链接 */
a {
  color: inherit;
  text-decoration: none;
}

/* 图片、SVG */
img, svg {
  max-width: 100%;
  display: block;
}

/* 容器 */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* 毛玻璃容器 */
.glass {
  background: rgba(255,255,255,0.55);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-radius: 28px;
  border: 1px solid rgba(255,255,255,0.35);
  box-shadow: 0 8px 32px rgba(0,0,0,0.05);
  transition: background 0.3s, border-color 0.3s, box-shadow 0.3s;
}

body.dark .glass {
  background: rgba(15,23,42,0.65);
  border-color: rgba(255,255,255,0.06);
  box-shadow: 0 8px 32px rgba(0,0,0,0.25);
}

/* 卡片 */
.card {
  background: #ffffff;
  border-radius: 24px;
  padding: 28px 24px;
  box-shadow: 0 6px 24px rgba(0,0,0,0.03);
  transition: transform 0.35s cubic-bezier(0.25, 0.46, 0.45, 0.94), box-shadow 0.35s ease;
  border: 1px solid rgba(0,0,0,0.02);
}

body.dark .card {
  background: #1e293b;
  box-shadow: 0 6px 24px rgba(0,0,0,0.25);
  border-color: rgba(255,255,255,0.04);
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: 0 16px 48px rgba(0,0,0,0.06);
}

body.dark .card:hover {
  box-shadow: 0 16px 48px rgba(0,0,0,0.35);
}

/* 按钮 */
.btn {
  display: inline-block;
  padding: 14px 34px;
  border-radius: 50px;
  background: linear-gradient(145deg, #1e3a8a, #3b82f6);
  color: #fff;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: transform 0.25s ease, box-shadow 0.25s ease, background 0.3s;
  box-shadow: 0 4px 14px rgba(30, 58, 138, 0.25);
  letter-spacing: 0.5px;
}

.btn:hover {
  transform: scale(1.03);
  box-shadow: 0 10px 30px rgba(59, 130, 246, 0.35);
  background: linear-gradient(145deg, #1e3a8a, #2563eb);
}

body.dark .btn {
  background: linear-gradient(145deg, #3b82f6, #60a5fa);
  box-shadow: 0 4px 14px rgba(59, 130, 246, 0.3);
}

body.dark .btn:hover {
  box-shadow: 0 10px 30px rgba(96, 165, 250, 0.4);
}

/* 标题 */
.section-title {
  font-size: 2.2rem;
  font-weight: 800;
  margin-bottom: 12px;
  letter-spacing: -0.03em;
  line-height: 1.2;
  background: linear-gradient(135deg, #1e3a8a, #3b82f6);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

body.dark .section-title {
  background: linear-gradient(135deg, #60a5fa, #93c5fd);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-sub {
  color: #64748b;
  margin-bottom: 40px;
  font-size: 1.1rem;
  max-width: 700px;
  margin-left: auto;
  margin-right: auto;
}

body.dark .section-sub {
  color: #94a3b8;
}

/* 网格 */
.grid-2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 28px; }
.grid-3 { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 28px; }
.grid-4 { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 24px; }

.text-center { text-align: center; }
.mt-20 { margin-top: 20px; }
.mb-20 { margin-bottom: 20px; }

/* 滚动动画 */
.animate-on-scroll {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 0.7s cubic-bezier(0.25, 0.46, 0.45, 0.94), transform 0.7s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

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

/* 头部导航 */
header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255,255,255,0.8);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border-bottom: 1px solid rgba(0,0,0,0.04);
  transition: background 0.3s;
}

body.dark header {
  background: rgba(11, 17, 32, 0.9);
  border-bottom-color: rgba(255,255,255,0.04);
}

nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 0;
  flex-wrap: wrap;
}

.logo {
  font-size: 1.6rem;
  font-weight: 800;
  background: linear-gradient(135deg, #1e3a8a, #3b82f6);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: flex;
  align-items: center;
  gap: 10px;
}

.logo svg {
  width: 36px;
  height: 36px;
  flex-shrink: 0;
}

.nav-links {
  display: flex;
  gap: 28px;
  font-weight: 500;
  font-size: 0.95rem;
}

.nav-links a {
  padding: 6px 0;
  border-bottom: 2px solid transparent;
  transition: border-color 0.25s ease, color 0.25s;
  color: #334155;
}

body.dark .nav-links a {
  color: #cbd5e1;
}

.nav-links a:hover {
  border-bottom-color: #3b82f6;
  color: #1e3a8a;
}

body.dark .nav-links a:hover {
  color: #60a5fa;
  border-bottom-color: #60a5fa;
}

.menu-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 2rem;
  cursor: pointer;
  color: inherit;
  padding: 4px 8px;
}

body.dark .menu-toggle {
  color: #e2e8f0;
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
    width: 100%;
    flex-direction: column;
    gap: 14px;
    padding: 20px 0 10px;
    border-top: 1px solid rgba(0,0,0,0.05);
  }
  body.dark .nav-links {
    border-top-color: rgba(255,255,255,0.05);
  }
  .nav-links.open {
    display: flex;
  }
  .menu-toggle {
    display: block;
  }
}

/* Banner */
.banner {
  position: relative;
  overflow: hidden;
  min-height: 520px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(145deg, #0f172a 0%, #1e3a8a 50%, #3b82f6 100%);
  color: #fff;
  border-radius: 0 0 48px 48px;
  margin-bottom: 40px;
}

body.dark .banner {
  background: linear-gradient(145deg, #020617, #1e293b);
}

.banner-content {
  text-align: center;
  padding: 70px 24px;
  position: relative;
  z-index: 2;
}

.banner-content h1 {
  font-size: clamp(2.2rem, 7vw, 4rem);
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 20px;
  letter-spacing: -0.02em;
  text-shadow: 0 2px 20px rgba(0,0,0,0.2);
}

.banner-content p {
  font-size: 1.25rem;
  max-width: 720px;
  margin: 0 auto 36px;
  opacity: 0.92;
  text-shadow: 0 1px 8px rgba(0,0,0,0.15);
}

.banner-slider {
  position: absolute;
  inset: 0;
  z-index: 1;
  display: flex;
  transition: transform 0.8s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

.banner-slide {
  min-width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.banner-slide svg {
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.12;
}

.banner-dots {
  position: absolute;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 12px;
  z-index: 3;
}

.banner-dots span {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: rgba(255,255,255,0.25);
  cursor: pointer;
  transition: background 0.3s, transform 0.2s;
  border: 2px solid rgba(255,255,255,0.1);
}

.banner-dots span.active {
  background: #ffffff;
  border-color: #ffffff;
  transform: scale(1.15);
}

.banner-dots span:hover {
  background: rgba(255,255,255,0.5);
}

/* 通用section */
section {
  padding: 72px 0;
}

/* 页脚 */
footer {
  background: #0f172a;
  color: #cbd5e1;
  padding: 56px 0 28px;
  margin-top: 60px;
}

body.dark footer {
  background: #020617;
}

footer a {
  color: #94a3b8;
  transition: color 0.25s;
}

footer a:hover {
  color: #ffffff;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 36px;
  margin-bottom: 36px;
}

.footer-grid h4 {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: #f1f5f9;
}

.footer-grid p, .footer-grid a {
  font-size: 0.95rem;
  line-height: 1.8;
}

.footer-bottom {
  border-top: 1px solid #1e293b;
  padding-top: 24px;
  text-align: center;
  font-size: 0.9rem;
  color: #64748b;
}

.footer-bottom a {
  color: #94a3b8;
}

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

/* 返回顶部 */
.back-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 52px;
  height: 52px;
  border-radius: 50%;
  background: linear-gradient(145deg, #1e3a8a, #3b82f6);
  color: #fff;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  box-shadow: 0 6px 20px rgba(0,0,0,0.18);
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.35s ease, transform 0.35s ease, box-shadow 0.3s;
  z-index: 99;
  display: flex;
  align-items: center;
  justify-content: center;
}

.back-top.show {
  opacity: 1;
  transform: translateY(0);
}

.back-top:hover {
  box-shadow: 0 10px 30px rgba(30, 58, 138, 0.35);
  transform: translateY(-4px);
}

body.dark .back-top {
  background: linear-gradient(145deg, #3b82f6, #60a5fa);
}

/* FAQ */
.faq-item {
  border-bottom: 1px solid #e2e8f0;
  padding: 18px 0;
  cursor: pointer;
  transition: background 0.2s;
}

body.dark .faq-item {
  border-color: #334155;
}

.faq-item:hover {
  background: rgba(59, 130, 246, 0.03);
}

body.dark .faq-item:hover {
  background: rgba(59, 130, 246, 0.06);
}

.faq-question {
  font-weight: 600;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 1.05rem;
}

.faq-question span {
  font-size: 1.4rem;
  transition: transform 0.3s;
  color: #3b82f6;
}

.faq-item.open .faq-question span {
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.45s ease, padding 0.3s;
  padding-top: 0;
  color: #475569;
}

body.dark .faq-answer {
  color: #94a3b8;
}

.faq-item.open .faq-answer {
  max-height: 400px;
  padding-top: 14px;
}

/* 统计数字 */
.stat-number {
  font-size: 2.6rem;
  font-weight: 800;
  color: #1e3a8a;
  line-height: 1;
}

body.dark .stat-number {
  color: #60a5fa;
}

/* 搜索弹窗 */
.search-modal {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.45);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 200;
}

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

.search-box {
  background: #ffffff;
  padding: 36px 32px;
  border-radius: 28px;
  width: 90%;
  max-width: 520px;
  box-shadow: 0 20px 60px rgba(0,0,0,0.12);
}

body.dark .search-box {
  background: #1e293b;
  box-shadow: 0 20px 60px rgba(0,0,0,0.4);
}

.search-box input {
  width: 100%;
  padding: 16px 22px;
  border: 1px solid #e2e8f0;
  border-radius: 50px;
  font-size: 1rem;
  outline: none;
  transition: border-color 0.3s;
  background: #f8fafc;
}

body.dark .search-box input {
  background: #0f172a;
  border-color: #334155;
  color: #e2e8f0;
}

.search-box input:focus {
  border-color: #3b82f6;
}

.search-box .close-search {
  margin-top: 18px;
  text-align: right;
  cursor: pointer;
  color: #64748b;
  font-weight: 500;
  transition: color 0.2s;
}

.search-box .close-search:hover {
  color: #1e293b;
}

body.dark .search-box .close-search:hover {
  color: #e2e8f0;
}

/* 响应式 */
@media (max-width: 640px) {
  section {
    padding: 48px 0;
  }
  .banner {
    min-height: 340px;
    border-radius: 0 0 32px 32px;
  }
  .banner-content h1 {
    font-size: 2rem;
  }
  .banner-content p {
    font-size: 1rem;
  }
  .section-title {
    font-size: 1.7rem;
  }
  .grid-2, .grid-3, .grid-4 {
    gap: 20px;
  }
  .card {
    padding: 20px 16px;
  }
  .footer-grid {
    gap: 24px;
  }
  .back-top {
    width: 44px;
    height: 44px;
    font-size: 1.2rem;
    bottom: 20px;
    right: 20px;
  }
}

/* 额外美化：标题下划线装饰 */
.section-title::after {
  content: '';
  display: block;
  width: 60px;
  height: 4px;
  background: linear-gradient(90deg, #1e3a8a, #3b82f6);
  border-radius: 4px;
  margin: 12px auto 0;
}

body.dark .section-title::after {
  background: linear-gradient(90deg, #60a5fa, #93c5fd);
}

/* 卡片内小图标 */
.card svg {
  margin-bottom: 12px;
}

/* 新闻卡片时间 */
.card time {
  font-size: 0.85rem;
  color: #94a3b8;
  display: block;
  margin-bottom: 8px;
}

body.dark .card time {
  color: #64748b;
}

/* 团队头像圆形 */
.card .team-avatar {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  background: linear-gradient(145deg, #e0e7ff, #dbeafe);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
  font-size: 2rem;
  font-weight: bold;
  color: #1e3a8a;
}

body.dark .card .team-avatar {
  background: linear-gradient(145deg, #1e293b, #0f172a);
  color: #60a5fa;
}

/* 品牌发展历史卡片 */
.card h3 + p {
  margin-top: 8px;
}

/* 联系卡片 */
.card.glass h3 {
  margin-top: 16px;
  margin-bottom: 6px;
}

/* 滚动条美化（可选） */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: #f1f5f9;
}

body.dark ::-webkit-scrollbar-track {
  background: #0f172a;
}

::-webkit-scrollbar-thumb {
  background: #94a3b8;
  border-radius: 10px;
}

::-webkit-scrollbar-thumb:hover {
  background: #64748b;
}

/* 选中文本颜色 */
::selection {
  background: #3b82f6;
  color: #fff;
}