/* ===== 基础重置与全局变量 ===== */
:root {
  /* 主色调 - 深蓝紫渐变 */
  --primary: #1a1a2e;
  --primary-light: #16213e;
  --primary-dark: #0f0f1a;
  --accent: #e94560;
  --accent-hover: #ff6b81;
  --accent-glow: rgba(233, 69, 96, 0.4);
  /* 渐变Banner */
  --gradient-bg: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
  --gradient-accent: linear-gradient(135deg, #e94560, #ff6b81, #e94560);
  --gradient-card: linear-gradient(145deg, rgba(255,255,255,0.08), rgba(255,255,255,0.02));
  /* 毛玻璃 */
  --glass-bg: rgba(255,255,255,0.06);
  --glass-border: rgba(255,255,255,0.12);
  --glass-shadow: 0 8px 32px rgba(0,0,0,0.3);
  /* 文字 */
  --text-primary: #f0f0f0;
  --text-secondary: #b0b0c0;
  --text-muted: #7a7a8a;
  /* 间距 */
  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 1.5rem;
  --space-lg: 2.5rem;
  --space-xl: 4rem;
  /* 圆角 */
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-xl: 32px;
  /* 过渡 */
  --transition-fast: 0.2s ease;
  --transition-normal: 0.35s ease;
  --transition-slow: 0.6s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  /* 字体 */
  --font-sans: 'Helvetica Neue', Arial, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-mono: 'SF Mono', 'Fira Code', monospace;
}

/* 暗色模式支持 (默认即为暗色) */
@media (prefers-color-scheme: light) {
  :root {
    --primary: #1a1a2e;
    --primary-light: #16213e;
    --primary-dark: #0f0f1a;
    --text-primary: #f0f0f0;
    --text-secondary: #b0b0c0;
    --glass-bg: rgba(255,255,255,0.06);
    --glass-border: rgba(255,255,255,0.12);
  }
}

/* 暗色模式手动切换 (由JS控制body类) */
body.dark-mode {
  --primary: #1a1a2e;
  --primary-light: #16213e;
  --primary-dark: #0f0f1a;
  --text-primary: #f0f0f0;
  --text-secondary: #b0b0c0;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background: var(--primary-dark);
  color: var(--text-primary);
  line-height: 1.7;
  min-height: 100vh;
  overflow-x: hidden;
  background-image: radial-gradient(ellipse at top right, rgba(233,69,96,0.08), transparent 60%),
                    radial-gradient(ellipse at bottom left, rgba(15,52,96,0.3), transparent 60%);
  background-attachment: fixed;
}

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

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

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

ul, ol {
  list-style: none;
}

/* ===== 滚动动画 (Intersection Observer 配合) ===== */
.fade-in-up {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

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

/* ===== 全局容器 ===== */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-md);
}

/* ===== Header & 导航 ===== */
header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background: rgba(15, 15, 26, 0.85);
  backdrop-filter: blur(16px) saturate(180%);
  -webkit-backdrop-filter: blur(16px) saturate(180%);
  border-bottom: 1px solid var(--glass-border);
  transition: background var(--transition-normal), box-shadow var(--transition-normal);
}

header.scrolled {
  background: rgba(15, 15, 26, 0.95);
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.5);
}

nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-sm) var(--space-md);
  max-width: 1200px;
  margin: 0 auto;
}

nav > a[aria-label="米兰体育首页"] {
  font-size: 1.4rem;
  font-weight: 800;
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: 1px;
  text-shadow: 0 0 20px var(--accent-glow);
  position: relative;
}

nav > a[aria-label="米兰体育首页"]::after {
  content: '⚡';
  font-size: 1rem;
  margin-left: 4px;
  -webkit-text-fill-color: initial;
  color: var(--accent);
}

nav ul {
  display: flex;
  gap: var(--space-xs);
  align-items: center;
}

nav ul li a {
  padding: 0.4rem 0.9rem;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: all var(--transition-fast);
  position: relative;
}

nav ul li a::before {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 0;
  height: 2px;
  background: var(--accent);
  transition: width var(--transition-normal);
  border-radius: 2px;
}

nav ul li a:hover {
  color: var(--text-primary);
  background: rgba(233, 69, 96, 0.1);
}

nav ul li a:hover::before {
  width: 60%;
}

/* ===== Hero 区域 (渐变Banner) ===== */
#hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--space-xl) var(--space-md);
  background: var(--gradient-bg);
  position: relative;
  overflow: hidden;
}

#hero::before {
  content: '';
  position: absolute;
  top: -30%;
  right: -20%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(233,69,96,0.15), transparent 70%);
  border-radius: 50%;
  pointer-events: none;
  animation: heroGlow 8s ease-in-out infinite alternate;
}

#hero::after {
  content: '';
  position: absolute;
  bottom: -20%;
  left: -15%;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(15,52,96,0.2), transparent 70%);
  border-radius: 50%;
  pointer-events: none;
  animation: heroGlow 10s ease-in-out infinite alternate-reverse;
}

@keyframes heroGlow {
  0% { transform: translate(0, 0) scale(1); }
  100% { transform: translate(30px, -20px) scale(1.1); }
}

#hero h1 {
  font-size: clamp(1.8rem, 6vw, 3.2rem);
  font-weight: 800;
  background: linear-gradient(135deg, #ffffff 0%, #e94560 80%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: var(--space-md);
  line-height: 1.3;
  position: relative;
  z-index: 1;
  text-shadow: 0 0 40px rgba(233,69,96,0.3);
}

#hero p {
  font-size: clamp(0.95rem, 2.5vw, 1.15rem);
  color: var(--text-secondary);
  max-width: 700px;
  margin-bottom: var(--space-lg);
  position: relative;
  z-index: 1;
  line-height: 1.8;
}

#hero a {
  display: inline-block;
  padding: 0.8rem 2.2rem;
  border-radius: var(--radius-xl);
  font-weight: 700;
  font-size: 1rem;
  letter-spacing: 0.5px;
  transition: all var(--transition-normal);
  margin: 0 var(--space-xs);
  position: relative;
  z-index: 1;
}

#hero a[aria-label="下载米兰体育APP官方正版"] {
  background: var(--gradient-accent);
  color: #fff;
  box-shadow: 0 4px 20px var(--accent-glow);
}

#hero a[aria-label="下载米兰体育APP官方正版"]:hover {
  transform: translateY(-3px) scale(1.03);
  box-shadow: 0 8px 30px var(--accent-glow);
}

#hero a[aria-label="手机网页版登录入口"] {
  background: var(--glass-bg);
  backdrop-filter: blur(8px);
  border: 1px solid var(--glass-border);
  color: var(--text-primary);
}

#hero a[aria-label="手机网页版登录入口"]:hover {
  background: rgba(233, 69, 96, 0.2);
  border-color: var(--accent);
  transform: translateY(-3px);
}

/* ===== 通用 Section 样式 (圆角卡片 + 毛玻璃) ===== */
section {
  padding: var(--space-xl) var(--space-md);
  max-width: 1200px;
  margin: 0 auto;
  scroll-margin-top: 80px;
}

section h2 {
  font-size: clamp(1.6rem, 4vw, 2.2rem);
  font-weight: 700;
  margin-bottom: var(--space-lg);
  position: relative;
  display: inline-block;
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

section h2::after {
  content: '';
  display: block;
  width: 60%;
  height: 3px;
  background: var(--gradient-accent);
  border-radius: 4px;
  margin-top: var(--space-xs);
}

section p {
  color: var(--text-secondary);
  margin-bottom: var(--space-sm);
  line-height: 1.8;
}

/* ===== About 区域 ===== */
#about {
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  margin-bottom: var(--space-lg);
  box-shadow: var(--glass-shadow);
  transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

#about:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(0,0,0,0.4);
}

#about p:last-of-type {
  font-style: italic;
  color: var(--accent);
  border-left: 3px solid var(--accent);
  padding-left: var(--space-sm);
  margin-top: var(--space-sm);
}

/* ===== Products 区域 (圆角卡片) ===== */
#products {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
}

#products h2 {
  grid-column: 1 / -1;
}

#products article {
  background: var(--glass-bg);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  box-shadow: var(--glass-shadow);
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

#products article::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: var(--gradient-accent);
  opacity: 0.6;
}

#products article:hover {
  transform: translateY(-6px);
  box-shadow: 0 16px 48px rgba(0,0,0,0.5);
  border-color: rgba(233, 69, 96, 0.3);
}

#products article h3 {
  font-size: 1.3rem;
  margin-bottom: var(--space-sm);
  color: var(--text-primary);
}

#products article ul {
  margin-top: var(--space-sm);
  padding-left: var(--space-sm);
}

#products article ul li {
  position: relative;
  padding-left: 1.5rem;
  margin-bottom: 0.4rem;
  color: var(--text-secondary);
}

#products article ul li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--accent);
  font-weight: bold;
}

/* ===== Services 区域 ===== */
#services ul {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: var(--space-md);
}

#services ul li {
  background: var(--glass-bg);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  transition: all var(--transition-normal);
}

#services ul li:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(0,0,0,0.3);
  border-color: rgba(233, 69, 96, 0.2);
}

#services ul li strong {
  display: block;
  color: var(--accent);
  margin-bottom: var(--space-xs);
  font-size: 1.05rem;
}

/* ===== FAQ 区域 (details/summary) ===== */
#faq details {
  background: var(--glass-bg);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  margin-bottom: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  transition: all var(--transition-normal);
  cursor: pointer;
}

#faq details:hover {
  border-color: rgba(233, 69, 96, 0.3);
}

#faq details[open] {
  border-color: var(--accent);
  box-shadow: 0 4px 16px rgba(233, 69, 96, 0.15);
}

#faq summary {
  font-weight: 600;
  color: var(--text-primary);
  padding: var(--space-xs) 0;
  outline: none;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

#faq summary::-webkit-details-marker {
  display: none;
}

#faq summary::after {
  content: '+';
  font-size: 1.3rem;
  font-weight: 300;
  color: var(--accent);
  transition: transform var(--transition-normal);
}

#faq details[open] summary::after {
  content: '−';
  transform: rotate(180deg);
}

#faq details p {
  padding: var(--space-sm) 0 var(--space-xs);
  color: var(--text-secondary);
  border-top: 1px solid var(--glass-border);
  margin-top: var(--space-xs);
}

/* ===== Contact 区域 ===== */
#contact address {
  background: var(--glass-bg);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  font-style: normal;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--space-sm);
}

#contact address p {
  color: var(--text-secondary);
}

#contact address a {
  color: var(--accent);
  font-weight: 500;
}

/* ===== Legal 区域 ===== */
#legal {
  background: var(--glass-bg);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  text-align: center;
}

#legal a {
  font-weight: 600;
}

/* ===== Footer ===== */
footer {
  text-align: center;
  padding: var(--space-lg) var(--space-md);
  border-top: 1px solid var(--glass-border);
  color: var(--text-muted);
  font-size: 0.85rem;
  background: rgba(15,15,26,0.6);
  backdrop-filter: blur(8px);
}

footer p {
  margin-bottom: var(--space-xs);
}

/* ===== 响应式布局 (PC + 手机自适应) ===== */
@media (max-width: 768px) {
  nav {
    flex-wrap: wrap;
    gap: var(--space-sm);
    padding: var(--space-sm);
  }

  nav ul {
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.3rem;
  }

  nav ul li a {
    font-size: 0.8rem;
    padding: 0.3rem 0.6rem;
  }

  #hero {
    padding: 6rem var(--space-sm) var(--space-xl);
  }

  #hero a {
    display: block;
    width: 80%;
    margin: var(--space-xs) auto;
  }

  section {
    padding: var(--space-lg) var(--space-sm);
  }

  #about {
    padding: var(--space-md);
  }

  #products article {
    padding: var(--space-md);
  }

  #contact address {
    grid-template-columns: 1fr;
    padding: var(--space-md);
  }

  #services ul {
    grid-template-columns: 1fr;
  }

  #faq details {
    padding: var(--space-sm);
  }
}

@media (max-width: 480px) {
  html {
    font-size: 14px;
  }

  nav > a[aria-label="米兰体育首页"] {
    font-size: 1.2rem;
  }

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

  #hero p {
    font-size: 0.9rem;
  }
}

/* ===== 滚动条美化 ===== */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

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

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

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

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

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

/* ===== 动画关键帧 ===== */
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.7; }
}

/* ===== 所有卡片通用毛玻璃效果 ===== */
.glass {
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  box-shadow: var(--glass-shadow);
}

/* ===== 暗色模式切换按钮 (预留) ===== */
.dark-toggle {
  position: fixed;
  bottom: 20px;
  right: 20px;
  z-index: 9999;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--glass-bg);
  backdrop-filter: blur(10px);
  border: 1px solid var(--glass-border);
  color: var(--text-primary);
  font-size: 1.2rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-normal);
  box-shadow: var(--glass-shadow);
}

.dark-toggle:hover {
  transform: scale(1.1);
  border-color: var(--accent);
}

/* ===== 打印样式 ===== */
@media print {
  body {
    background: #fff;
    color: #000;
  }
  header {
    position: static;
    background: #fff;
    backdrop-filter: none;
  }
  .dark-toggle {
    display: none;
  }
}