/* ============================================================
   style.css — MK体育官方网站 (ice-mksports.com)
   UI风格: 渐变Banner · 圆角卡片 · 毛玻璃 · 暗色模式 · 滚动动画 · hover动画
   响应式: PC + Mobile 自适应
   性能: 全部内联CSS (无外部引用)
   ============================================================ */

/* ---------- CSS 自定义属性 (主题变量) ---------- */
:root {
  /* 亮色模式 */
  --bg: #f4f7fc;
  --bg-alt: #eef2f8;
  --text: #1a1f2e;
  --text-secondary: #4a536b;
  --primary: #0b1a2e;
  --primary-light: #1f3450;
  --accent: #f0c040;
  --accent-hover: #e0b030;
  --card-bg: rgba(255, 255, 255, 0.85);
  --card-bg-solid: #ffffff;
  --border: #dce1ec;
  --border-light: #e8ecf4;
  --header-bg: rgba(255, 255, 255, 0.78);
  --glass-bg: rgba(255, 255, 255, 0.25);
  --glass-border: rgba(255, 255, 255, 0.35);
  --shadow: 0 8px 30px rgba(11, 26, 46, 0.08);
  --shadow-hover: 0 12px 40px rgba(11, 26, 46, 0.16);
  --hero-gradient: linear-gradient(145deg, #0b1a2e 0%, #1f3450 50%, #2a4a6a 100%);
  --hero-text: #ffffff;
  --footer-bg: #0b1a2e;
  --footer-text: #bcc6d9;
  --backtop-bg: var(--accent);
  --backtop-color: #0b1a2e;
  --transition-speed: 0.35s;
  --radius-sm: 12px;
  --radius-md: 20px;
  --radius-lg: 28px;
  --radius-xl: 40px;
}

/* ---------- 暗色模式 ---------- */
body.dark {
  --bg: #0f1421;
  --bg-alt: #131a2a;
  --text: #e4e8f0;
  --text-secondary: #9aa4bc;
  --primary: #1a2744;
  --primary-light: #2a3d5e;
  --accent: #f0c040;
  --accent-hover: #e0b030;
  --card-bg: rgba(27, 35, 54, 0.88);
  --card-bg-solid: #1b2336;
  --border: #2d3750;
  --border-light: #3a4560;
  --header-bg: rgba(15, 20, 33, 0.82);
  --glass-bg: rgba(27, 35, 54, 0.40);
  --glass-border: rgba(255, 255, 255, 0.12);
  --shadow: 0 8px 30px rgba(0, 0, 0, 0.45);
  --shadow-hover: 0 12px 44px rgba(0, 0, 0, 0.55);
  --hero-gradient: linear-gradient(145deg, #0a111f 0%, #152238 50%, #1e3350 100%);
  --hero-text: #eef2f8;
  --footer-bg: #080d18;
  --footer-text: #8a95ad;
  --backtop-bg: var(--accent);
  --backtop-color: #0b1a2e;
}

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

html {
  scroll-behavior: smooth;
  -webkit-tap-highlight-color: transparent;
}

body {
  font-family: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  transition: background var(--transition-speed), color var(--transition-speed);
  min-height: 100vh;
  overflow-x: hidden;
}

/* ---------- 容器 & 通用间距 ---------- */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1.5rem 1.8rem;
}

section {
  padding: 3rem 0;
  position: relative;
}

/* ---------- 标题 ---------- */
h1, h2, h3, h4 {
  font-weight: 600;
  letter-spacing: -0.025em;
  line-height: 1.25;
}

h1 {
  font-size: clamp(2rem, 5.5vw, 3.2rem);
}

h2 {
  font-size: clamp(1.6rem, 4vw, 2.2rem);
  margin-bottom: 1.2rem;
  border-left: 5px solid var(--accent);
  padding-left: 1.2rem;
}

h3 {
  font-size: clamp(1.1rem, 2.5vw, 1.4rem);
  margin-bottom: 0.5rem;
}

p {
  margin-bottom: 0.8rem;
  color: var(--text-secondary);
}

strong {
  color: var(--text);
}

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

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

/* ---------- 按钮 (通用) ---------- */
.btn-primary,
.btn-outline {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 2.2rem;
  border-radius: var(--radius-xl);
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  transition: all 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  cursor: pointer;
  border: none;
  line-height: 1.4;
  white-space: nowrap;
}

.btn-primary {
  background: var(--accent);
  color: #0b1a2e;
  box-shadow: 0 4px 14px rgba(240, 192, 64, 0.35);
}

.btn-primary:hover {
  background: var(--accent-hover);
  box-shadow: 0 6px 20px rgba(240, 192, 64, 0.5);
  transform: translateY(-2px);
}

.btn-outline {
  background: transparent;
  color: var(--hero-text);
  border: 2px solid var(--accent);
}

.btn-outline:hover {
  background: var(--accent);
  color: #0b1a2e;
  transform: translateY(-2px);
}

/* ---------- 头部 Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px) saturate(180%);
  -webkit-backdrop-filter: blur(12px) saturate(180%);
  background: var(--header-bg);
  border-bottom: 1px solid var(--border-light);
  transition: background var(--transition-speed), border-color var(--transition-speed);
}

.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.7rem 2rem;
  max-width: 1200px;
  margin: 0 auto;
}

/* Logo */
.logo-link {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  text-decoration: none;
  color: var(--text);
  font-weight: 700;
  font-size: 1.35rem;
  letter-spacing: -0.02em;
}

.logo-text {
  background: linear-gradient(135deg, var(--accent), #d4a030);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.logo-badge {
  background: var(--accent);
  color: #0b1a2e;
  font-size: 0.6rem;
  font-weight: 700;
  padding: 0.2rem 0.7rem;
  border-radius: 20px;
  letter-spacing: 0.02em;
  -webkit-text-fill-color: #0b1a2e;
}

/* 导航 */
.primary-nav {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.nav-list {
  display: flex;
  list-style: none;
  gap: 1.4rem;
  align-items: center;
}

.nav-list a {
  text-decoration: none;
  color: var(--text);
  font-weight: 500;
  font-size: 0.9rem;
  padding: 0.3rem 0;
  position: relative;
  transition: color 0.2s;
}

.nav-list a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent);
  transition: width 0.3s ease;
}

.nav-list a:hover::after,
.nav-list a:focus-visible::after {
  width: 100%;
}

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

/* 主题切换 & 移动菜单按钮 */
.dark-mode-toggle,
.mobile-menu-toggle {
  background: none;
  border: none;
  font-size: 1.4rem;
  cursor: pointer;
  color: var(--text);
  padding: 0.3rem;
  border-radius: 50%;
  transition: background 0.2s, transform 0.2s;
  line-height: 1;
}

.dark-mode-toggle:hover,
.mobile-menu-toggle:hover {
  background: var(--border-light);
  transform: scale(1.05);
}

.mobile-menu-toggle {
  display: none;
  font-size: 1.6rem;
}

/* ---------- Hero 主视觉 (渐变Banner + 毛玻璃元素) ---------- */
.hero {
  background: var(--hero-gradient);
  color: var(--hero-text);
  padding: 5rem 2rem 4rem;
  text-align: center;
  position: relative;
  overflow: hidden;
  min-height: 70vh;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* 装饰性毛玻璃光晕 */
.hero::before {
  content: '';
  position: absolute;
  top: -20%;
  right: -10%;
  width: 60%;
  height: 80%;
  background: radial-gradient(circle at 30% 50%, rgba(240, 192, 64, 0.08), transparent 70%);
  pointer-events: none;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: -10%;
  left: -5%;
  width: 50%;
  height: 60%;
  background: radial-gradient(circle at 70% 30%, rgba(255, 255, 255, 0.04), transparent 60%);
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: 800px;
  margin: 0 auto;
}

.hero h1 {
  font-size: clamp(2.2rem, 6vw, 3.6rem);
  font-weight: 700;
  margin-bottom: 0.6rem;
  text-shadow: 0 2px 20px rgba(0, 0, 0, 0.3);
}

.hero-sub {
  font-size: clamp(1rem, 2.5vw, 1.3rem);
  color: rgba(255, 255, 255, 0.8);
  margin-bottom: 2rem;
  letter-spacing: 0.02em;
}

.hero-actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 2rem;
}

.hero-badge {
  display: inline-block;
  background: rgba(255, 255, 255, 0.12);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border: 1px solid rgba(255, 255, 255, 0.18);
  padding: 0.5rem 1.8rem;
  border-radius: var(--radius-xl);
  font-size: 0.85rem;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.9);
  letter-spacing: 0.04em;
}

/* ---------- 通用卡片/网格组件 ---------- */
.entity-grid,
.card-grid,
.feature-grid,
.article-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.5rem;
  margin-top: 1.5rem;
}

.entity-item,
.card,
.feature,
.resource-card {
  background: var(--card-bg);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  transition: all 0.35s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  box-shadow: var(--shadow);
}

.entity-item:hover,
.card:hover,
.feature:hover,
.resource-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
  border-color: var(--accent);
  background: var(--card-bg-solid);
}

/* 实体网格内部 */
.entity-item span {
  display: block;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-bottom: 0.3rem;
}

/* 特色图标 */
.feature-icon {
  font-size: 1.8rem;
  display: block;
  margin-bottom: 0.5rem;
}

/* ---------- 服务列表 (毛玻璃标签) ---------- */
.service-list {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem 1rem;
  margin-top: 1rem;
}

.service-list li {
  background: var(--glass-bg);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  border: 1px solid var(--glass-border);
  padding: 0.6rem 1.6rem;
  border-radius: var(--radius-xl);
  font-size: 0.95rem;
  font-weight: 500;
  transition: all 0.3s;
}

.service-list li:hover {
  background: var(--card-bg-solid);
  border-color: var(--accent);
  transform: scale(1.02);
}

/* ---------- FAQ (常见问题) ---------- */
.faq-list details {
  background: var(--card-bg);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  margin-bottom: 0.7rem;
  border-radius: var(--radius-md);
  padding: 0.8rem 1.4rem;
  border: 1px solid var(--border);
  transition: all 0.3s ease;
}

.faq-list details:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow);
}

.faq-list details[open] {
  border-color: var(--accent);
  background: var(--card-bg-solid);
}

.faq-list summary {
  font-weight: 600;
  cursor: pointer;
  padding: 0.3rem 0;
  font-size: 1rem;
  color: var(--text);
  transition: color 0.2s;
}

.faq-list summary:hover {
  color: var(--accent);
}

.faq-list details p {
  margin-top: 0.8rem;
  padding-left: 0.5rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ---------- HowTo 步骤 ---------- */
.howto-steps {
  background: var(--card-bg);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-radius: var(--radius-lg);
  padding: 2rem 2.5rem;
  list-style-position: inside;
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}

.howto-steps li {
  padding: 0.7rem 0;
  border-bottom: 1px solid var(--border-light);
  font-size: 0.95rem;
  color: var(--text-secondary);
  transition: padding-left 0.2s;
}

.howto-steps li:hover {
  padding-left: 0.5rem;
  color: var(--text);
}

.howto-steps li:last-child {
  border-bottom: none;
}

.howto-steps li strong {
  color: var(--accent);
  font-weight: 600;
}

/* ---------- 联系 & Footer ---------- */
.contact {
  background: var(--bg-alt);
  border-top: 1px solid var(--border-light);
}

.contact p {
  margin-bottom: 0.4rem;
}

.contact small {
  display: block;
  margin-top: 1.2rem;
  color: var(--text-secondary);
  font-size: 0.8rem;
}

.site-footer {
  background: var(--footer-bg);
  color: var(--footer-text);
  padding: 2rem 0;
  text-align: center;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
}

.footer-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.8rem;
}

.footer-legal a {
  color: var(--accent);
  margin: 0 0.5rem;
  font-size: 0.85rem;
  transition: color 0.2s;
}

.footer-legal a:hover {
  color: var(--accent-hover);
  text-decoration: underline;
}

.footer-legal p {
  margin-top: 0.6rem;
  font-size: 0.8rem;
  color: var(--footer-text);
}

/* ---------- 回到顶部按钮 ---------- */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: var(--backtop-bg);
  color: var(--backtop-color);
  border: none;
  border-radius: 50%;
  width: 50px;
  height: 50px;
  font-size: 1.6rem;
  cursor: pointer;
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.25);
  display: none;
  align-items: center;
  justify-content: center;
  transition: all 0.3s ease;
  z-index: 99;
  line-height: 1;
}

.back-to-top:hover {
  transform: translateY(-4px) scale(1.05);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.35);
  background: var(--accent-hover);
}

/* ---------- 滚动动画 (Intersection 触发) ---------- */
@media (prefers-reduced-motion: no-preference) {
  .section {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.7s ease, transform 0.7s ease;
  }

  .section.visible {
    opacity: 1;
    transform: translateY(0);
  }

  /* 子元素交错进入 */
  .entity-item,
  .card,
  .feature,
  .resource-card,
  .service-list li,
  .faq-list details,
  .howto-steps li {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.5s ease, transform 0.5s ease;
  }

  .section.visible .entity-item,
  .section.visible .card,
  .section.visible .feature,
  .section.visible .resource-card,
  .section.visible .service-list li,
  .section.visible .faq-list details,
  .section.visible .howto-steps li {
    opacity: 1;
    transform: translateY(0);
  }

  /* 交错延迟 */
  .section.visible .entity-item:nth-child(1) { transition-delay: 0.05s; }
  .section.visible .entity-item:nth-child(2) { transition-delay: 0.1s; }
  .section.visible .entity-item:nth-child(3) { transition-delay: 0.15s; }
  .section.visible .entity-item:nth-child(4) { transition-delay: 0.2s; }
  .section.visible .entity-item:nth-child(5) { transition-delay: 0.25s; }
  .section.visible .entity-item:nth-child(6) { transition-delay: 0.3s; }

  .section.visible .card:nth-child(1) { transition-delay: 0.05s; }
  .section.visible .card:nth-child(2) { transition-delay: 0.1s; }
  .section.visible .card:nth-child(3) { transition-delay: 0.15s; }
  .section.visible .card:nth-child(4) { transition-delay: 0.2s; }

  .section.visible .feature:nth-child(1) { transition-delay: 0.05s; }
  .section.visible .feature:nth-child(2) { transition-delay: 0.1s; }
  .section.visible .feature:nth-child(3) { transition-delay: 0.15s; }
  .section.visible .feature:nth-child(4) { transition-delay: 0.2s; }

  .section.visible .resource-card:nth-child(1) { transition-delay: 0.02s; }
  .section.visible .resource-card:nth-child(2) { transition-delay: 0.06s; }
  .section.visible .resource-card:nth-child(3) { transition-delay: 0.1s; }
  .section.visible .resource-card:nth-child(4) { transition-delay: 0.14s; }
  .section.visible .resource-card:nth-child(5) { transition-delay: 0.18s; }
  .section.visible .resource-card:nth-child(6) { transition-delay: 0.22s; }
  .section.visible .resource-card:nth-child(7) { transition-delay: 0.26s; }
  .section.visible .resource-card:nth-child(8) { transition-delay: 0.3s; }

  .section.visible .service-list li:nth-child(1) { transition-delay: 0.05s; }
  .section.visible .service-list li:nth-child(2) { transition-delay: 0.1s; }
  .section.visible .service-list li:nth-child(3) { transition-delay: 0.15s; }
  .section.visible .service-list li:nth-child(4) { transition-delay: 0.2s; }

  .section.visible .faq-list details:nth-child(1) { transition-delay: 0.02s; }
  .section.visible .faq-list details:nth-child(2) { transition-delay: 0.06s; }
  .section.visible .faq-list details:nth-child(3) { transition-delay: 0.1s; }
  .section.visible .faq-list details:nth-child(4) { transition-delay: 0.14s; }
  .section.visible .faq-list details:nth-child(5) { transition-delay: 0.18s; }
  .section.visible .faq-list details:nth-child(6) { transition-delay: 0.22s; }
  .section.visible .faq-list details:nth-child(7) { transition-delay: 0.26s; }
  .section.visible .faq-list details:nth-child(8) { transition-delay: 0.3s; }
  .section.visible .faq-list details:nth-child(9) { transition-delay: 0.34s; }
  .section.visible .faq-list details:nth-child(10) { transition-delay: 0.38s; }
  .section.visible .faq-list details:nth-child(11) { transition-delay: 0.42s; }
  .section.visible .faq-list details:nth-child(12) { transition-delay: 0.46s; }

  .section.visible .howto-steps li:nth-child(1) { transition-delay: 0.05s; }
  .section.visible .howto-steps li:nth-child(2) { transition-delay: 0.1s; }
  .section.visible .howto-steps li:nth-child(3) { transition-delay: 0.15s; }
  .section.visible .howto-steps li:nth-child(4) { transition-delay: 0.2s; }
  .section.visible .howto-steps li:nth-child(5) { transition-delay: 0.25s; }
  .section.visible .howto-steps li:nth-child(6) { transition-delay: 0.3s; }
}

/* ---------- 响应式设计 ---------- */
/* 平板及以下 */
@media (max-width: 992px) {
  .container {
    padding: 1.2rem 1.2rem;
  }

  section {
    padding: 2.5rem 0;
  }

  .hero {
    padding: 3.5rem 1.5rem 3rem;
    min-height: 60vh;
  }

  .entity-grid,
  .card-grid,
  .feature-grid,
  .article-grid {
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 1.2rem;
  }

  .howto-steps {
    padding: 1.5rem;
  }
}

/* 手机端 */
@media (max-width: 768px) {
  .header-inner {
    padding: 0.6rem 1.2rem;
  }

  .nav-list {
    display: none;
    flex-direction: column;
    background: var(--header-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    position: absolute;
    top: 100%;
    right: 0;
    padding: 1.2rem 1.5rem;
    width: 220px;
    border-radius: 0 0 var(--radius-md) var(--radius-md);
    box-shadow: var(--shadow);
    border: 1px solid var(--border-light);
    gap: 0.8rem;
  }

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

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

  .dark-mode-toggle {
    font-size: 1.2rem;
  }

  .hero {
    padding: 3rem 1.2rem 2.5rem;
    min-height: auto;
  }

  .hero h1 {
    font-size: 2rem;
  }

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

  .btn-primary,
  .btn-outline {
    width: 80%;
    max-width: 280px;
  }

  .entity-grid,
  .card-grid,
  .feature-grid,
  .article-grid {
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  .service-list {
    flex-direction: column;
  }

  .service-list li {
    width: 100%;
    text-align: center;
  }

  .howto-steps {
    padding: 1.2rem;
  }

  .back-to-top {
    bottom: 1.2rem;
    right: 1.2rem;
    width: 44px;
    height: 44px;
    font-size: 1.3rem;
  }

  .faq-list details {
    padding: 0.7rem 1rem;
  }

  h2 {
    font-size: 1.5rem;
    padding-left: 0.8rem;
  }
}

/* 小屏手机 (<400px) */
@media (max-width: 400px) {
  .container {
    padding: 0.8rem 0.8rem;
  }

  .hero h1 {
    font-size: 1.6rem;
  }

  .hero-sub {
    font-size: 0.9rem;
  }

  .btn-primary,
  .btn-outline {
    font-size: 0.85rem;
    padding: 0.6rem 1.5rem;
  }

  .entity-item,
  .card,
  .feature,
  .resource-card {
    padding: 1rem;
  }
}

/* ---------- 辅助功能 ---------- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .section {
    opacity: 1 !important;
    transform: none !important;
  }

  .entity-item,
  .card,
  .feature,
  .resource-card,
  .service-list li,
  .faq-list details,
  .howto-steps li {
    opacity: 1 !important;
    transform: none !important;
    transition: none !important;
  }
}

/* 焦点可见性 */
a:focus-visible,
button:focus-visible,
summary:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

/* 选中文本 */
::selection {
  background: var(--accent);
  color: #0b1a2e;
}