/* ============================================
   洱语官网 - 设计系统 CSS
   ============================================ */

/* CSS Variables - 设计系统变量 */
:root {
  /* 主色调 */
  --color-primary: #4ECDC4;
  --color-primary-light: #7EDDD6;
  --color-primary-dark: #3DBDB5;
  
  /* 糖果色系 */
  --color-purple: #B39DDB;
  --color-orange: #FFB74D;
  --color-blue: #4FC3F7;
  --color-pink: #F48FB1;
  
  /* 中性色 */
  --color-white: #FFFFFF;
  --color-bg: #F5F5F5;
  --color-text: #333333;
  --color-text-light: #666666;
  --color-text-lighter: #999999;
  
  /* 间距系统 */
  --spacing-xs: 8px;
  --spacing-sm: 16px;
  --spacing-md: 24px;
  --spacing-lg: 40px;
  --spacing-xl: 64px;
  --spacing-xxl: 80px;
  
  /* 圆角系统 */
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-xl: 32px;
  --radius-full: 9999px;
  
  /* 阴影系统 */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.12);
  --shadow-3d: 0 12px 40px rgba(78, 205, 196, 0.2);
  
  /* 过渡效果 */
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s ease;
  --transition-slow: 0.5s ease;
  
  /* 字体 */
  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  --font-size-xs: 12px;
  --font-size-sm: 14px;
  --font-size-md: 16px;
  --font-size-lg: 18px;
  --font-size-xl: 24px;
  --font-size-xxl: 36px;
  --font-size-hero: 48px;
  
  /* 最大宽度 */
  --container-max: 1200px;
}

/* ============================================
   基础样式重置
   ============================================ */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-family);
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  overflow-x: hidden;
}

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

ul, ol {
  list-style: none;
}

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

/* ============================================
   容器和布局
   ============================================ */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

.section {
  padding: var(--spacing-xxl) 0;
}

.section-title {
  text-align: center;
  margin-bottom: var(--spacing-xl);
}

.section-title h2 {
  font-size: var(--font-size-xxl);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--spacing-sm);
}

.section-title p {
  font-size: var(--font-size-lg);
  color: var(--color-text-light);
}

/* ============================================
   动画关键帧
   ============================================ */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

@keyframes float {
  0%, 100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-10px);
  }
}

@keyframes pulse {
  0%, 100% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.05);
  }
}

@keyframes rotate {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}

/* 动画类 */
.animate-fade-in {
  animation: fadeIn var(--transition-slow) ease forwards;
}

.animate-fade-in-up {
  animation: fadeInUp var(--transition-slow) ease forwards;
}

.animate-float {
  animation: float 3s ease-in-out infinite;
}

/* 延迟动画 */
.delay-1 { animation-delay: 0.1s; }
.delay-2 { animation-delay: 0.2s; }
.delay-3 { animation-delay: 0.3s; }
.delay-4 { animation-delay: 0.4s; }
.delay-5 { animation-delay: 0.5s; }

/* 初始隐藏，等滚动到视口时显示 */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.active {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================
   导航栏
   ============================================ */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
}

.navbar.scrolled {
  background: rgba(255, 255, 255, 1);
  box-shadow: var(--shadow-md);
}

.navbar .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 70px;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.logo-icon {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-blue));
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-3d);
}

.logo-icon svg {
  width: 24px;
  height: 24px;
  fill: var(--color-white);
}

.logo-text {
  font-size: var(--font-size-xl);
  font-weight: 600;
  color: var(--color-primary);
}

.nav-links {
  display: flex;
  gap: var(--spacing-lg);
}

.nav-links a {
  font-size: var(--font-size-md);
  color: var(--color-text);
  font-weight: 500;
  position: relative;
  padding: var(--spacing-xs) 0;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-primary);
  transition: width var(--transition-fast);
}

.nav-links a:hover {
  color: var(--color-primary);
}

.nav-links a:hover::after {
  width: 100%;
}

.nav-cta {
  background: var(--color-primary);
  color: var(--color-white);
  padding: var(--spacing-xs) var(--spacing-md);
  border-radius: var(--radius-full);
  font-weight: 500;
  box-shadow: var(--shadow-3d);
  transition: all var(--transition-fast);
}

.nav-cta:hover {
  background: var(--color-primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(78, 205, 196, 0.4);
}

/* 移动端菜单按钮 */
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: var(--spacing-xs);
}

.menu-toggle span {
  width: 24px;
  height: 2px;
  background: var(--color-text);
  transition: all var(--transition-fast);
}

/* ============================================
   Hero 区域
   ============================================ */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 120px var(--spacing-md) var(--spacing-xxl);
  background: linear-gradient(180deg, var(--color-white) 0%, var(--color-bg) 100%);
  position: relative;
  overflow: hidden;
}

/* 装饰元素 */
.hero-decoration {
  position: absolute;
  border-radius: 50%;
  opacity: 0.5;
}

.hero-decoration-1 {
  width: 400px;
  height: 400px;
  background: linear-gradient(135deg, rgba(78, 205, 196, 0.2), rgba(79, 195, 247, 0.1));
  top: -100px;
  right: -100px;
  animation: float 6s ease-in-out infinite;
}

.hero-decoration-2 {
  width: 300px;
  height: 300px;
  background: linear-gradient(135deg, rgba(179, 157, 219, 0.2), rgba(255, 183, 77, 0.1));
  bottom: 100px;
  left: -50px;
  animation: float 8s ease-in-out infinite reverse;
}

.hero-decoration-3 {
  width: 200px;
  height: 200px;
  background: linear-gradient(135deg, rgba(244, 143, 177, 0.15), rgba(78, 205, 196, 0.1));
  bottom: 200px;
  right: 100px;
  animation: float 5s ease-in-out infinite;
}

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

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  background: var(--color-white);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-full);
  box-shadow: var(--shadow-sm);
  margin-bottom: var(--spacing-md);
  font-size: var(--font-size-sm);
  color: var(--color-primary);
  opacity: 0;
  animation: fadeInUp 0.6s ease 0.2s forwards;
}

.hero-badge-dot {
  width: 8px;
  height: 8px;
  background: var(--color-primary);
  border-radius: 50%;
  animation: pulse 2s ease infinite;
}

.hero h1 {
  font-size: var(--font-size-hero);
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.2;
  margin-bottom: var(--spacing-md);
  opacity: 0;
  animation: fadeInUp 0.6s ease 0.4s forwards;
}

.hero h1 .highlight {
  background: linear-gradient(135deg, var(--color-primary), var(--color-blue));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: var(--font-size-lg);
  color: var(--color-text-light);
  line-height: 1.8;
  margin-bottom: var(--spacing-xl);
  opacity: 0;
  animation: fadeInUp 0.6s ease 0.6s forwards;
}

.hero-cta {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  flex-wrap: wrap;
  opacity: 0;
  animation: fadeInUp 0.6s ease 0.8s forwards;
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: var(--color-white);
  padding: var(--spacing-sm) var(--spacing-lg);
  border-radius: var(--radius-full);
  font-size: var(--font-size-lg);
  font-weight: 600;
  box-shadow: var(--shadow-3d);
  transition: all var(--transition-fast);
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 30px rgba(78, 205, 196, 0.4);
}

.btn-primary svg {
  width: 20px;
  height: 20px;
}

.btn-secondary {
  background: var(--color-white);
  color: var(--color-text);
  padding: var(--spacing-sm) var(--spacing-lg);
  border-radius: var(--radius-full);
  font-size: var(--font-size-lg);
  font-weight: 500;
  box-shadow: var(--shadow-md);
  transition: all var(--transition-fast);
  border: 2px solid transparent;
}

.btn-secondary:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  transform: translateY(-3px);
}

.hero-scroll {
  position: absolute;
  bottom: 40px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-xs);
  color: var(--color-text-lighter);
  font-size: var(--font-size-sm);
  cursor: pointer;
  opacity: 0;
  animation: fadeIn 1s ease 1.2s forwards;
}

.hero-scroll-icon {
  width: 24px;
  height: 40px;
  border: 2px solid var(--color-text-lighter);
  border-radius: 12px;
  position: relative;
}

.hero-scroll-icon::before {
  content: '';
  position: absolute;
  top: 8px;
  left: 50%;
  transform: translateX(-50%);
  width: 4px;
  height: 8px;
  background: var(--color-primary);
  border-radius: 2px;
  animation: scrollDown 1.5s ease infinite;
}

@keyframes scrollDown {
  0% {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
  }
  100% {
    opacity: 0;
    transform: translateX(-50%) translateY(12px);
  }
}

/* ============================================
   产品特性
   ============================================ */
.features {
  background: var(--color-white);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-lg);
}

.feature-card {
  background: var(--color-white);
  padding: var(--spacing-lg);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-blue));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-normal);
}

.feature-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
}

.feature-card:hover::before {
  transform: scaleX(1);
}

.feature-icon {
  width: 64px;
  height: 64px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--spacing-md);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
}

.feature-card:hover .feature-icon {
  transform: scale(1.1) rotate(5deg);
  box-shadow: var(--shadow-md);
}

.feature-icon svg {
  width: 32px;
  height: 32px;
}

.feature-icon-primary {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-light));
}

.feature-icon-purple {
  background: linear-gradient(135deg, var(--color-purple), #D1C4E9);
}

.feature-icon-orange {
  background: linear-gradient(135deg, var(--color-orange), #FFCC80);
}

.feature-icon-blue {
  background: linear-gradient(135deg, var(--color-blue), #81D4FA);
}

.feature-card h3 {
  font-size: var(--font-size-xl);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--spacing-sm);
}

.feature-card p {
  font-size: var(--font-size-md);
  color: var(--color-text-light);
  line-height: 1.7;
}

/* ============================================
   品牌理念
   ============================================ */
.philosophy {
  background: linear-gradient(180deg, var(--color-bg) 0%, var(--color-white) 100%);
}

.philosophy-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-xl);
  align-items: center;
}

.philosophy-text {
  padding-right: var(--spacing-lg);
}

.philosophy-text h2 {
  font-size: var(--font-size-xxl);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--spacing-md);
}

.philosophy-text p {
  font-size: var(--font-size-lg);
  color: var(--color-text-light);
  line-height: 1.8;
  margin-bottom: var(--spacing-sm);
}

.philosophy-highlight {
  font-size: var(--font-size-xl);
  color: var(--color-primary);
  font-weight: 600;
  padding: var(--spacing-md);
  background: linear-gradient(135deg, rgba(78, 205, 196, 0.1), rgba(79, 195, 247, 0.1));
  border-radius: var(--radius-md);
  border-left: 4px solid var(--color-primary);
}

.philosophy-visual {
  display: flex;
  justify-content: center;
  align-items: center;
}

.philosophy-circles {
  position: relative;
  width: 300px;
  height: 300px;
}

.philosophy-circle {
  position: absolute;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--color-white);
  transition: transform var(--transition-normal);
}

.philosophy-circle:hover {
  transform: scale(1.1);
}

.philosophy-circle-1 {
  width: 200px;
  height: 200px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-blue));
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  box-shadow: var(--shadow-3d);
  z-index: 3;
}

.philosophy-circle-1:hover {
  transform: translate(-50%, -50%) scale(1.05);
}

.philosophy-circle-2 {
  width: 140px;
  height: 140px;
  background: linear-gradient(135deg, var(--color-purple), #D1C4E9);
  top: 10%;
  left: 50%;
  transform: translateX(-50%);
  box-shadow: var(--shadow-md);
  z-index: 2;
}

.philosophy-circle-3 {
  width: 100px;
  height: 100px;
  background: linear-gradient(135deg, var(--color-orange), #FFCC80);
  bottom: 10%;
  left: 10%;
  box-shadow: var(--shadow-md);
  z-index: 1;
}

/* ============================================
   应用场景
   ============================================ */
.scenarios {
  background: var(--color-white);
}

.scenarios-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: var(--spacing-lg);
}

.scenario-card {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  aspect-ratio: 16 / 10;
  box-shadow: var(--shadow-md);
  transition: all var(--transition-normal);
}

.scenario-card:hover {
  transform: translateY(-8px) scale(1.02);
  box-shadow: var(--shadow-lg);
}

.scenario-bg {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-size: cover;
  background-position: center;
  transition: transform var(--transition-slow);
}

.scenario-card:hover .scenario-bg {
  transform: scale(1.1);
}

.scenario-bg-1 {
  background: linear-gradient(135deg, var(--color-primary), var(--color-blue));
}

.scenario-bg-2 {
  background: linear-gradient(135deg, var(--color-purple), #9575CD);
}

.scenario-bg-3 {
  background: linear-gradient(135deg, var(--color-orange), #FFA726);
}

.scenario-content {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  padding: var(--spacing-lg);
  background: linear-gradient(transparent, rgba(0, 0, 0, 0.7));
  color: var(--color-white);
}

.scenario-content h3 {
  font-size: var(--font-size-xl);
  font-weight: 600;
  margin-bottom: var(--spacing-xs);
}

.scenario-content p {
  font-size: var(--font-size-md);
  opacity: 0.9;
}

/* ============================================
   Footer
   ============================================ */
.footer {
  background: var(--color-text);
  color: var(--color-white);
  padding: var(--spacing-xl) 0 var(--spacing-lg);
}

.footer-content {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-xl);
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.footer-brand .logo {
  margin-bottom: var(--spacing-xs);
}

.footer-brand .logo-text {
  color: var(--color-white);
}

.footer-brand p {
  color: rgba(255, 255, 255, 0.7);
  font-size: var(--font-size-md);
  line-height: 1.7;
}

.footer-social {
  display: flex;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-sm);
}

.footer-social a {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}

.footer-social a:hover {
  background: var(--color-primary);
  transform: translateY(-3px);
}

.footer-social svg {
  width: 20px;
  height: 20px;
  fill: var(--color-white);
}

.footer-links h4 {
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  color: var(--color-white);
}

.footer-links ul {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
}

.footer-links a {
  color: rgba(255, 255, 255, 0.7);
  font-size: var(--font-size-md);
  transition: color var(--transition-fast);
}

.footer-links a:hover {
  color: var(--color-primary);
}

.footer-bottom {
  padding-top: var(--spacing-lg);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.footer-bottom p {
  color: rgba(255, 255, 255, 0.5);
  font-size: var(--font-size-sm);
}

.footer-bottom-links {
  display: flex;
  gap: var(--spacing-md);
}

.footer-bottom-links a {
  color: rgba(255, 255, 255, 0.5);
  font-size: var(--font-size-sm);
}

/* APK 下载按钮样式 */
.footer-apk-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: var(--color-white);
  padding: 8px 16px;
  border-radius: var(--radius-full);
  font-size: var(--font-size-sm);
  font-weight: 500;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-fast);
}

.footer-apk-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(78, 205, 196, 0.4);
}

.footer-apk-btn svg {
  width: 16px;
  height: 16px;
}

/* Footer 操作区（包含下载按钮和链接） */
.footer-actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
  flex-wrap: wrap;
}

.footer-bottom-links a:hover {
  color: var(--color-primary);
}

/* APK 下载按钮样式 */
.apk-download-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: var(--color-white);
  padding: 12px 24px;
  border-radius: var(--radius-full);
  font-size: var(--font-size-md);
  font-weight: 600;
  box-shadow: 0 4px 16px rgba(78, 205, 196, 0.3);
  transition: all var(--transition-fast);
  text-decoration: none;
  margin-top: var(--spacing-sm);
}

.apk-download-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(78, 205, 196, 0.4);
}

.apk-download-btn svg {
  width: 20px;
  height: 20px;
}

/* 隐私协议链接样式 */
.privacy-link {
  color: rgba(255, 255, 255, 0.7);
  font-size: var(--font-size-sm);
  text-decoration: none;
  transition: color var(--transition-fast);
  position: relative;
}

.privacy-link:hover {
  color: var(--color-primary);
}

.privacy-link::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 1px;
  background: var(--color-primary);
  transition: width var(--transition-fast);
}

.privacy-link:hover::after {
  width: 100%;
}

/* Footer 底部链接区域 - 增强 */
.footer-bottom-right {
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
  flex-wrap: wrap;
}

/* 响应式 - Footer 增强 */
@media (max-width: 768px) {
  .footer-bottom-right {
    flex-direction: column;
    gap: var(--spacing-sm);
  }
  
  .apk-download-btn {
    width: 100%;
    justify-content: center;
  }
}

/* ============================================
   响应式设计
   ============================================ */

/* 平板 */
@media (max-width: 1024px) {
  :root {
    --font-size-hero: 40px;
    --font-size-xxl: 30px;
  }
  
  .philosophy-content {
    grid-template-columns: 1fr;
    text-align: center;
  }
  
  .philosophy-text {
    padding-right: 0;
  }
  
  .philosophy-visual {
    order: -1;
  }
  
  .footer-content {
    grid-template-columns: 1fr 1fr;
  }
}

/* 移动端 */
@media (max-width: 768px) {
  :root {
    --font-size-hero: 32px;
    --font-size-xxl: 26px;
    --spacing-xl: 48px;
    --spacing-xxl: 64px;
  }
  
  .nav-links {
    display: none;
    position: absolute;
    top: 70px;
    left: 0;
    right: 0;
    background: var(--color-white);
    flex-direction: column;
    padding: var(--spacing-md);
    gap: var(--spacing-sm);
    box-shadow: var(--shadow-md);
  }
  
  .nav-links.active {
    display: flex;
  }
  
  .menu-toggle {
    display: flex;
  }
  
  .menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
  }
  
  .menu-toggle.active span:nth-child(2) {
    opacity: 0;
  }
  
  .menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
  }
  
  .hero {
    padding-top: 100px;
  }
  
  .hero h1 {
    font-size: var(--font-size-hero);
  }
  
  .hero-cta {
    flex-direction: column;
    align-items: center;
  }
  
  .features-grid {
    grid-template-columns: 1fr;
  }
  
  .scenarios-grid {
    grid-template-columns: 1fr;
  }
  
  .footer-content {
    grid-template-columns: 1fr;
    text-align: center;
  }
  
  .footer-brand {
    align-items: center;
  }
  
  .footer-social {
    justify-content: center;
  }
  
  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }
}

/* ============================================
   工具类
   ============================================ */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }
.mt-xl { margin-top: var(--spacing-xl); }

.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }
.mb-xl { margin-bottom: var(--spacing-xl); }

.hidden { display: none; }
.visible { display: block; }