/* 
 * 谷歌浏览器 - 全新未来主义模板
 * 设计风格：深色主题，霓虹渐变，现代玻璃态，2025年设计趋势
 */

/* ===== 变量定义 ===== */
:root {
  /* 主色调 - 霓虹渐变 */
  --primary-gradient: linear-gradient(135deg, #4285F4 0%, #34A853 50%, #FBBC04 100%);
  --primary-blue: #4285F4;
  --primary-green: #34A853;
  --primary-yellow: #FBBC04;
  --primary-red: #EA4335;
  
  /* 背景色 - 深色主题 */
  --bg-dark: #0A0A0F;
  --bg-darker: #050508;
  --bg-card: rgba(20, 20, 30, 0.8);
  --bg-card-hover: rgba(30, 30, 45, 0.9);
  
  /* 文字色 */
  --text-primary: #FFFFFF;
  --text-secondary: #A0A0B0;
  --text-muted: #6C6C80;
  
  /* 边框与玻璃态效果 */
  --border-color: rgba(255, 255, 255, 0.1);
  --border-glow: 0 0 20px rgba(66, 133, 244, 0.3);
  --glass-bg: rgba(255, 255, 255, 0.05);
  --glass-border: rgba(255, 255, 255, 0.1);
  
  /* 阴影与深度 */
  --shadow-sm: 0 4px 12px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.4);
  --shadow-xl: 0 24px 64px rgba(0, 0, 0, 0.5);
  
  /* 圆角 */
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-xl: 32px;
  --radius-full: 9999px;
  
  /* 过渡效果 */
  --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);
  
  /* 间距 */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 32px;
  --space-2xl: 48px;
  --space-3xl: 64px;
  --space-4xl: 80px;
  
  /* 动画 */
  --float-animation: float 6s ease-in-out infinite;
  --pulse-animation: pulse 3s ease-in-out infinite;
  --glow-animation: glow 2s ease-in-out infinite;
}

/* ===== 浅色主题支持 ===== */
@media (prefers-color-scheme: light) {
  :root {
    --bg-dark: #F8F9FA;
    --bg-darker: #FFFFFF;
    --bg-card: rgba(255, 255, 255, 0.9);
    --bg-card-hover: rgba(255, 255, 255, 1);
    
    --text-primary: #1A1A2E;
    --text-secondary: #4A4A6A;
    --text-muted: #7A7A9A;
    
    --border-color: rgba(0, 0, 0, 0.1);
    --border-glow: 0 0 20px rgba(66, 133, 244, 0.2);
    --glass-bg: rgba(255, 255, 255, 0.7);
    --glass-border: rgba(0, 0, 0, 0.1);
    
    --shadow-sm: 0 4px 12px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.15);
    --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.2);
    --shadow-xl: 0 24px 64px rgba(0, 0, 0, 0.25);
  }
}

/* ===== 基础重置 ===== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  color: var(--text-primary);
  background: var(--bg-dark);
  min-height: 100vh;
  line-height: 1.6;
  overflow-x: hidden;
  position: relative;
}

body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: 
    radial-gradient(circle at 20% 50%, rgba(66, 133, 244, 0.08) 0%, transparent 50%),
    radial-gradient(circle at 80% 20%, rgba(52, 168, 83, 0.06) 0%, transparent 50%),
    radial-gradient(circle at 40% 80%, rgba(251, 188, 4, 0.05) 0%, transparent 50%);
  z-index: -1;
}

/* ===== 容器 ===== */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

/* ===== 卡片效果 ===== */
.card {
  background: var(--bg-card);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-color);
  transition: all var(--transition-normal);
  backdrop-filter: blur(10px);
}

.card:hover {
  box-shadow: var(--shadow-lg), var(--border-glow);
  transform: translateY(-8px);
  border-color: var(--primary-blue);
}

.elevated {
  box-shadow: var(--shadow-lg);
  border-radius: var(--radius-xl);
}

/* ===== 导航栏 ===== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  padding: var(--space-lg) 0;
  background: rgba(10, 10, 15, 0.85);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
}

.navbar.scrolled {
  box-shadow: var(--shadow-md);
}

.navbar .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.chrome-logo {
  position: relative;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  overflow: hidden;
  box-shadow: 0 0 30px rgba(66, 133, 244, 0.6);
}

.chrome-gradient {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: conic-gradient(
    from 0deg,
    #ea4335 0deg 90deg,
    #fbbc04 90deg 180deg,
    #34a853 180deg 270deg,
    #4285f4 270deg 360deg
  );
  animation: rotate 10s linear infinite;
}

@keyframes rotate {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

.brand-text {
  font-size: 1.8rem;
  font-weight: 800;
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  letter-spacing: -0.5px;
}

.nav-menu {
  display: flex;
  gap: 30px;
  align-items: center;
}

.nav-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 600;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  gap: 8px;
  position: relative;
  padding: var(--space-sm) 0;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 3px;
  background: var(--primary-gradient);
  transition: width var(--transition-normal);
  border-radius: 3px;
}

.nav-link:hover {
  color: var(--text-primary);
}

.nav-link:hover::after,
.nav-link.active::after {
  width: 100%;
}

.nav-link i {
  font-size: 1.2rem;
}

.nav-btn {
  background: var(--primary-gradient);
  color: white;
  padding: var(--space-md) var(--space-xl);
  border-radius: var(--radius-full);
  text-decoration: none;
  font-weight: 700;
  transition: all var(--transition-normal);
  box-shadow: var(--shadow-sm);
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.1rem;
  letter-spacing: 0.5px;
}

.nav-btn:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 1.8rem;
  cursor: pointer;
  width: 48px;
  height: 48px;
  border-radius: 12px;
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  transition: all var(--transition-normal);
}

.nav-toggle:hover {
  background: rgba(255, 255, 255, 0.1);
}

/* ===== 英雄区域 ===== */
.hero {
  padding: 180px 0 120px;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 800px;
  height: 800px;
  background: radial-gradient(circle, rgba(66, 133, 244, 0.1) 0%, transparent 70%);
  z-index: -1;
  filter: blur(60px);
}

.hero-content {
  text-align: center;
  max-width: 900px;
  margin: 0 auto;
  position: relative;
  z-index: 1;
}

.hero-title {
  font-size: 4.5rem;
  font-weight: 900;
  margin-bottom: var(--space-lg);
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  line-height: 1.1;
  letter-spacing: -1px;
}

.hero-subtitle {
  font-size: 1.4rem;
  color: var(--text-secondary);
  margin-bottom: var(--space-xl);
  max-width: 700px;
  margin-left: auto;
  margin-right: auto;
  font-weight: 400;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  gap: var(--space-lg);
  justify-content: center;
  margin-bottom: var(--space-2xl);
}

/* ===== 按钮样式 ===== */
.btn-primary {
  background: var(--primary-gradient);
  color: white;
  padding: var(--space-lg) var(--space-2xl);
  border-radius: var(--radius-full);
  text-decoration: none;
  font-weight: 700;
  font-size: 1.2rem;
  transition: all var(--transition-normal);
  border: none;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  box-shadow: var(--shadow-md);
  position: relative;
  overflow: hidden;
  letter-spacing: 0.5px;
}

.btn-primary::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
  transition: left 0.5s ease;
}

.btn-primary:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-xl);
}

.btn-primary:hover::before {
  left: 100%;
}

.btn-secondary {
  background: transparent;
  color: var(--text-primary);
  padding: var(--space-lg) var(--space-2xl);
  border-radius: var(--radius-full);
  text-decoration: none;
  font-weight: 700;
  font-size: 1.2rem;
  transition: all var(--transition-normal);
  border: 2px solid rgba(255, 255, 255, 0.2);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  position: relative;
  overflow: hidden;
}

.btn-secondary::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.05), transparent);
  transition: left 0.5s ease;
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.05);
  border-color: var(--primary-blue);
}

.btn-secondary:hover::before {
  left: 100%;
}

.btn-large {
  padding: var(--space-xl) var(--space-3xl);
  font-size: 1.3rem;
}

.btn-xl {
  padding: var(--space-xl) var(--space-4xl);
  font-size: 1.4rem;
}

/* ===== 统计卡片 ===== */
.hero-stats {
  display: flex;
  justify-content: center;
  gap: var(--space-2xl);
  margin-top: var(--space-4xl);
}

.stat {
  text-align: center;
  padding: var(--space-xl);
  min-width: 200px;
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  backdrop-filter: blur(10px);
  transition: all var(--transition-normal);
}

.stat:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
  border-color: var(--primary-green);
}

.stat-number {
  display: block;
  font-size: 3.5rem;
  font-weight: 900;
  margin-bottom: var(--space-sm);
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  line-height: 1;
}

.stat-label {
  color: var(--text-secondary);
  font-size: 1.1rem;
  font-weight: 500;
  letter-spacing: 0.5px;
}

/* ===== 特性区域 ===== */
.features {
  padding: var(--space-4xl) 0;
  position: relative;
}

.features::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(66, 133, 244, 0.5), transparent);
}

.section-header {
  text-align: center;
  margin-bottom: var(--space-3xl);
}

.section-header h2 {
  font-size: 3.5rem;
  font-weight: 800;
  margin-bottom: var(--space-md);
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  line-height: 1.2;
}

.section-header p {
  color: var(--text-secondary);
  font-size: 1.3rem;
  max-width: 700px;
  margin: 0 auto;
  font-weight: 400;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: var(--space-xl);
}

.feature-card {
  padding: var(--space-2xl);
  border-radius: var(--radius-xl);
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  transition: all var(--transition-normal);
  box-shadow: var(--shadow-sm);
  backdrop-filter: blur(10px);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: var(--primary-gradient);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-normal);
}

.feature-card:hover {
  transform: translateY(-10px);
  border-color: var(--primary-blue);
  box-shadow: var(--shadow-xl);
}

.feature-card:hover::before {
  transform: scaleX(1);
}

.feature-icon {
  width: 80px;
  height: 80px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-lg);
  font-size: 2.2rem;
  background: rgba(255, 255, 255, 0.1);
  color: white;
  backdrop-filter: blur(10px);
  position: relative;
  z-index: 1;
}

.feature-icon::before {
  content: '';
  position: absolute;
  top: -5px;
  left: -5px;
  right: -5px;
  bottom: -5px;
  background: var(--primary-gradient);
  border-radius: inherit;
  z-index: -1;
  opacity: 0.5;
  filter: blur(10px);
}

.feature-card h3 {
  font-size: 1.8rem;
  margin-bottom: var(--space-md);
  color: var(--text-primary);
  font-weight: 700;
}

.feature-card p {
  color: var(--text-secondary);
  line-height: 1.8;
  font-size: 1.1rem;
}

/* ===== 下载区域 ===== */
.download-section {
  padding: var(--space-4xl) 0;
  position: relative;
}

.download-section::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(52, 168, 83, 0.5), transparent);
}

.download-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3xl);
  align-items: center;
}

.download-info h2 {
  font-size: 3.5rem;
  margin-bottom: var(--space-lg);
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  font-weight: 800;
  line-height: 1.2;
}

.download-desc {
  color: var(--text-secondary);
  margin-bottom: var(--space-xl);
  font-size: 1.3rem;
  line-height: 1.7;
}

.version-card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  margin-bottom: var(--space-xl);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  backdrop-filter: blur(10px);
  transition: all var(--transition-normal);
}

.version-card:hover {
  transform: translateY(-5px);
  border-color: var(--primary-green);
  box-shadow: var(--shadow-lg);
}

.version-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-lg);
}

.version-header h3 {
  font-size: 1.5rem;
  color: var(--text-primary);
  font-weight: 700;
}

.version-badge {
  background: var(--primary-gradient);
  color: white;
  padding: var(--space-xs) var(--space-lg);
  border-radius: var(--radius-full);
  font-weight: 700;
  font-size: 1rem;
  letter-spacing: 0.5px;
}

.version-details .detail {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin-bottom: var(--space-md);
  color: var(--text-secondary);
}

.version-details .detail i {
  color: var(--primary-blue);
  font-size: 1.2rem;
}

.download-note {
  color: var(--text-muted);
  font-size: 1rem;
  margin-top: var(--space-lg);
}

.platforms {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-lg);
}

.platform {
  text-align: center;
  padding: var(--space-xl);
  border-radius: var(--radius-lg);
  background: rgba(255, 255, 255, 0.03);
  transition: all var(--transition-normal);
  border: 1px solid transparent;
  position: relative;
  overflow: hidden;
}

.platform::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--primary-gradient);
  opacity: 0;
  transition: opacity var(--transition-normal);
  z-index: -1;
}

.platform:hover {
  transform: translateY(-5px);
  border-color: var(--primary-blue);
}

.platform:hover::before {
  opacity: 0.05;
}

.platform i {
  font-size: 3.5rem;
  margin-bottom: var(--space-md);
  display: block;
  transition: all var(--transition-normal);
}

.platform:hover i {
  transform: scale(1.1);
}

.platform:nth-child(1) i { color: #4285F4; } /* Windows */
.platform:nth-child(2) i { color: #EA4335; } /* Apple */
.platform:nth-child(3) i { color: #FBBC04; } /* Linux */
.platform:nth-child(4) i { color: #34A853; } /* Android */
.platform:nth-child(5) i { color: #4285F4; } /* iOS */
.platform:nth-child(6) i { color: #FBBC04; } /* Other */

.platform span {
  display: block;
  color: var(--text-primary);
  font-weight: 600;
  font-size: 1.2rem;
  transition: color var(--transition-normal);
}

.platform:hover span {
  color: var(--primary-blue);
}

/* ===== 系统要求 ===== */
.requirements {
  padding: var(--space-4xl) 0;
  position: relative;
}

.requirements::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(251, 188, 4, 0.5), transparent);
}

.requirements-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-xl);
}

.req-card {
  padding: var(--space-2xl);
  border-radius: var(--radius-xl);
  background: var(--bg-card);
  backdrop-filter: blur(10px);
  border: 1px solid var(--border-color);
  transition: all var(--transition-normal);
  box-shadow: var(--shadow-sm);
  position: relative;
  overflow: hidden;
}

.req-card:hover {
  transform: translateY(-8px);
  border-color: var(--primary-yellow);
  box-shadow: var(--shadow-lg);
}

.req-icon {
  font-size: 3rem;
  margin-bottom: var(--space-lg);
  color: var(--primary-yellow);
  transition: transform var(--transition-normal);
}

.req-card:hover .req-icon {
  transform: scale(1.1);
}

.req-card h3 {
  font-size: 1.7rem;
  margin-bottom: var(--space-lg);
  color: var(--text-primary);
  font-weight: 700;
}

.req-card ul {
  list-style: none;
}

.req-card li {
  color: var(--text-secondary);
  margin-bottom: var(--space-sm);
  padding-left: var(--space-xl);
  position: relative;
  line-height: 1.7;
}

.req-card li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--primary-yellow);
  font-weight: 700;
  font-size: 1.1rem;
}

/* ===== 常见问题 ===== */
.faq {
  padding: var(--space-4xl) 0;
  position: relative;
}

.faq::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(234, 67, 53, 0.5), transparent);
}

.faq-grid {
  max-width: 900px;
  margin: 0 auto;
}

.faq-item {
  margin-bottom: var(--space-lg);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--bg-card);
  backdrop-filter: blur(10px);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
}

.faq-item:hover {
  border-color: var(--primary-red);
  box-shadow: var(--shadow-md);
}

.faq-question {
  padding: var(--space-xl) var(--space-2xl);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: background var(--transition-fast);
  position: relative;
}

.faq-question:hover {
  background: rgba(255, 255, 255, 0.02);
}

.faq-question h3 {
  font-size: 1.4rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.5;
}

.faq-question i {
  color: var(--primary-red);
  transition: all var(--transition-normal);
  font-size: 1.2rem;
}

.faq-answer {
  padding: 0 var(--space-2xl);
  max-height: 0;
  overflow: hidden;
  transition: all var(--transition-normal);
}

.faq-item.active .faq-answer {
  padding: 0 var(--space-2xl) var(--space-xl);
  max-height: 500px;
}

.faq-item.active .faq-question i {
  transform: rotate(180deg);
}

/* ===== 页脚 ===== */
.footer {
  padding: var(--space-4xl) 0 var(--space-2xl);
  background: var(--bg-darker);
  border-top: 1px solid var(--border-color);
  position: relative;
}

.footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(66, 133, 244, 0.5), transparent);
}

.footer-content {
  display: grid;
  grid-template-columns: 2fr 3fr;
  gap: var(--space-3xl);
  margin-bottom: var(--space-3xl);
}

.footer-brand {
  display: flex;
  gap: var(--space-lg);
  align-items: flex-start;
}

.chrome-logo.small {
  width: 64px;
  height: 64px;
  flex-shrink: 0;
}

.brand-info h3 {
  font-size: 2.2rem;
  margin-bottom: var(--space-md);
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  font-weight: 800;
  line-height: 1.2;
}

.brand-info p {
  color: var(--text-secondary);
  line-height: 1.7;
  font-size: 1.1rem;
}

.footer-links {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-2xl);
}

.link-group h4 {
  font-size: 1.4rem;
  margin-bottom: var(--space-lg);
  color: var(--text-primary);
  font-weight: 700;
  letter-spacing: 0.5px;
}

.link-group a {
  display: block;
  color: var(--text-secondary);
  text-decoration: none;
  margin-bottom: var(--space-sm);
  transition: all var(--transition-fast);
  padding: var(--space-xs) 0;
  position: relative;
  font-size: 1.1rem;
}

.link-group a:hover {
  color: var(--primary-blue);
  transform: translateX(5px);
}

.link-group a:hover::before {
  content: '→';
  position: absolute;
  left: -15px;
  color: var(--primary-blue);
}

.footer-bottom {
  text-align: center;
  padding-top: var(--space-xl);
  border-top: 1px solid var(--border-color);
  color: var(--text-muted);
  font-size: 1rem;
}

/* ===== 响应式设计 ===== */
@media (max-width: 1200px) {
  .container {
    padding: 0 var(--space-md);
  }
}

@media (max-width: 992px) {
  .hero-title {
    font-size: 3.5rem;
  }
  
  .section-header h2 {
    font-size: 2.8rem;
  }
  
  .download-content {
    grid-template-columns: 1fr;
    gap: var(--space-2xl);
  }
  
  .footer-content {
    grid-template-columns: 1fr;
    gap: var(--space-2xl);
  }
  
  .footer-links {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .navbar {
    padding: var(--space-md) 0;
  }
  
  .nav-menu {
    position: fixed;
    top: 80px;
    left: 0;
    width: 100%;
    background: rgba(10, 10, 15, 0.95);
    backdrop-filter: blur(30px);
    flex-direction: column;
    padding: var(--space-xl) var(--space-lg);
    gap: var(--space-lg);
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal);
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow-lg);
    z-index: 999;
  }
  
  .nav-menu.active {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }
  
  .nav-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
  }
  
  .hero {
    padding: 140px 0 80px;
  }
  
  .hero-title {
    font-size: 2.8rem;
  }
  
  .hero-subtitle {
    font-size: 1.2rem;
  }
  
  .hero-actions {
    flex-direction: column;
    align-items: center;
    gap: var(--space-md);
  }
  
  .hero-stats {
    flex-direction: column;
    align-items: center;
    gap: var(--space-lg);
  }
  
  .stat {
    width: 100%;
    max-width: 300px;
  }
  
  .features-grid,
  .requirements-grid {
    grid-template-columns: 1fr;
  }
  
  .platforms {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 576px) {
  .hero-title {
    font-size: 2.3rem;
  }
  
  .section-header h2 {
    font-size: 2.2rem;
  }
  
  .btn-primary,
  .btn-secondary {
    padding: var(--space-md) var(--space-xl);
    font-size: 1.1rem;
  }
  
  .btn-large {
    padding: var(--space-lg) var(--space-2xl);
  }
  
  .btn-xl {
    padding: var(--space-lg) var(--space-2xl);
  }
  
  .footer-links {
    grid-template-columns: 1fr;
  }
}

/* ===== 辅助类 ===== */
.skip-link {
  position: absolute;
  top: -100px;
  left: 0;
  background: var(--primary-blue);
  color: white;
  padding: var(--space-sm) var(--space-lg);
  text-decoration: none;
  border-radius: var(--radius-sm);
  z-index: 1001;
  font-weight: 600;
  transition: all var(--transition-fast);
}

.skip-link:focus {
  top: var(--space-md);
  outline: none;
  box-shadow: 0 0 0 3px rgba(66, 133, 244, 0.3);
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ===== 动画效果 ===== */
@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-15px); }
}

.float {
  animation: var(--float-animation);
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.8; }
}

.pulse {
  animation: var(--pulse-animation);
}

@keyframes glow {
  0%, 100% { box-shadow: 0 0 20px rgba(66, 133, 244, 0.3); }
  50% { box-shadow: 0 0 40px rgba(66, 133, 244, 0.5); }
}

.glow {
  animation: var(--glow-animation);
}

/* ===== 加载动画 ===== */
@keyframes shimmer {
  0% { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}

.shimmer {
  background: linear-gradient(90deg, 
    transparent, 
    rgba(255, 255, 255, 0.1), 
    transparent);
  background-size: 200% 100%;
  animation: shimmer 2s infinite;
}