/* Fonts */
:root {
  --font-cn: 'Noto Sans SC', system-ui, -apple-system, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-jp: 'Noto Sans JP', system-ui, -apple-system, sans-serif;
  --font-kr: 'Noto Sans KR', system-ui, -apple-system, sans-serif;
  --font-en: 'Inter', system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
  
  --color-primary: #3b82f6;
  --color-primary-dark: #2563eb;
  --color-text: #1e293b;
  --color-text-light: #334155;
  --color-bg: #f8fafc;
}

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

html {
  scroll-behavior: smooth;
}

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

/* Language-specific fonts */
html[lang^="zh-CN"] body,
html[lang^="zh-TW"] body {
  font-family: var(--font-cn);
}

html[lang="ja"] body {
  font-family: var(--font-jp);
}

html[lang="ko"] body {
  font-family: var(--font-kr);
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Header */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(226, 232, 240, 0.8);
  padding: 1rem 0;
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text);
}

.logo-icon {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  flex-shrink: 0;
}

.lang-select {
  padding: 0.5rem 1rem;
  border: 1px solid #e2e8f0;
  border-radius: 0.5rem;
  background: white;
  font-size: 0.875rem;
  color: var(--color-text);
  cursor: pointer;
  transition: all 0.2s;
}

.lang-select:hover {
  border-color: var(--color-primary);
}

/* Hero Section */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 6rem 0 4rem;
  overflow: hidden;
}

.hero-background {
  position: absolute;
  inset: 0;
  background: radial-gradient(1200px 800px at 50% 30%, #e0f2fe 0%, #eef2ff 30%, #f8fafc 100%);
  z-index: -1;
}

.hero-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: center;
}

.hero-text {
  z-index: 1;
}

.hero-title {
  font-size: clamp(2.5rem, 5vw, 4rem);
  font-weight: 800;
  line-height: 1.1;
  margin-bottom: 1.5rem;
  color: var(--color-text);
  letter-spacing: -0.02em;
}

.hero-subtitle {
  font-size: clamp(1.25rem, 2.5vw, 1.5rem);
  color: var(--color-text-light);
  margin-bottom: 2.5rem;
  font-weight: 500;
}

.hero-buttons {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.875rem 1.5rem;
  border-radius: 0.75rem;
  font-weight: 600;
  font-size: 1rem;
  text-decoration: none;
  transition: all 0.3s ease;
  border: none;
  cursor: pointer;
}

.btn-app-store {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  box-shadow: 0 4px 14px rgba(102, 126, 234, 0.4);
}

.btn-app-store:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(102, 126, 234, 0.5);
}

.btn-google-play {
  background: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%);
  color: white;
  box-shadow: 0 4px 14px rgba(59, 130, 246, 0.4);
}

.btn-google-play:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(59, 130, 246, 0.5);
}

.btn-large {
  padding: 1.125rem 2rem;
  font-size: 1.125rem;
}

.btn svg {
  flex-shrink: 0;
}

/* Device Frame */
.device {
  position: relative;
  width: min(80%, 320px);
  aspect-ratio: 9 / 19.5;
  border-radius: 2.2rem;
  background: linear-gradient(180deg, #111827, #0f172a);
  box-shadow: 0 20px 60px rgba(15, 23, 42, 0.35), inset 0 0 0 2px rgba(255, 255, 255, 0.08);
  padding: 0.75rem;
  margin: 0 auto;
}

.device::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: 2.2rem;
  background: linear-gradient(145deg, rgba(255, 255, 255, 0.16), rgba(255, 255, 255, 0.02));
  pointer-events: none;
}

/* 图片直接放在device内，与screenshot_studio保持一致 */
.device > img {
  /* 绝对定位实现叠加切换 */
  position: absolute;
  top: 0.75rem;
  left: 0.75rem;
  width: calc(100% - 1.5rem);
  height: calc(100% - 1.5rem);
  
  /* 使用原始尺寸 */
  max-width: 1206px;
  max-height: 2622px;
  object-fit: cover;
  border-radius: 1.6rem;
  display: block;
  
  /* 动画效果 */
  opacity: 0;
  transition: opacity 1.5s ease-in-out;
  z-index: 1;
  
  /* 渲染优化 */
  image-rendering: -webkit-optimize-contrast;
  image-rendering: high-quality;
  image-rendering: auto;
  -ms-interpolation-mode: bicubic;
  transform: translateZ(0);
  backface-visibility: hidden;
}

.device > img.active {
  opacity: 1;
  z-index: 2;
}

/* Features Section */
.features {
  padding: 6rem 0;
  background: white;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
}

.feature-card {
  text-align: center;
  padding: 2rem;
  border-radius: 1rem;
  transition: transform 0.3s ease;
}

.feature-card:hover {
  transform: translateY(-4px);
}

.feature-icon {
  width: 64px;
  height: 64px;
  margin: 0 auto 1rem;
  color: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, rgba(59, 130, 246, 0.1) 0%, rgba(102, 126, 234, 0.1) 100%);
  border-radius: 16px;
  padding: 12px;
}

.feature-icon svg {
  width: 100%;
  height: 100%;
}

.feature-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  color: var(--color-text);
}

.feature-desc {
  color: var(--color-text-light);
  font-size: 0.9375rem;
  line-height: 1.6;
}

/* Screenshots Section Removed */

/* CTA Section */
.cta {
  padding: 6rem 0;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  text-align: center;
}

.cta-title {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 800;
  margin-bottom: 2rem;
}

.cta-buttons {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

.cta .btn {
  background: white;
  color: #667eea;
}

.cta .btn:hover {
  background: rgba(255, 255, 255, 0.95);
}

/* Footer */
.footer {
  padding: 3rem 0;
  background: #1e293b;
  color: rgba(255, 255, 255, 0.8);
  text-align: center;
}

.footer-content {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.footer-links {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.footer-links a {
  color: rgba(255, 255, 255, 0.9);
  text-decoration: none;
  transition: color 0.2s;
}

.footer-links a:hover {
  color: white;
}

.separator {
  color: rgba(255, 255, 255, 0.5);
}

.footer-copyright {
  font-size: 0.875rem;
  color: rgba(255, 255, 255, 0.6);
}

/* Responsive Design */
@media (max-width: 768px) {
  .hero-content {
    grid-template-columns: 1fr;
    gap: 3rem;
    text-align: center;
  }
  
  .hero-device {
    order: -1;
  }
  
  .device {
    width: min(70%, 280px);
  }
  
  .features-grid {
    grid-template-columns: 1fr;
  }
  
  .hero-buttons,
  .cta-buttons {
    flex-direction: column;
  }
  
  .btn {
    width: 100%;
    justify-content: center;
  }
}

@media (max-width: 480px) {
  .hero {
    padding: 4rem 0 3rem;
    min-height: auto;
  }
  
  .hero-title {
    font-size: 2rem;
  }
  
  .hero-subtitle {
    font-size: 1.125rem;
  }
  
  .features,
  .cta {
    padding: 4rem 0;
  }
}

/* Loading animation */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.hero-text,
.hero-device,
.feature-card {
  animation: fadeIn 0.6s ease-out;
}