/* ==================== 基础样式 ==================== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  /* 颜色系统 */
  --color-primary: #667eea;
  --color-secondary: #764ba2;
  --color-accent: linear-gradient(135deg, #667eea 0%, #764ba2 100%);

  --bg-dark: #0a0a0a;
  --bg-darker: #050505;
  --bg-card: #1a1a1a;
  --bg-elevated: #2a2a2a;

  --text-primary: #ffffff;
  --text-secondary: #b0b0b0;
  --text-tertiary: #707070;

  --border-color: rgba(255, 255, 255, 0.1);

  /* 间距 */
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-2xl: 48px;
  --spacing-3xl: 64px;

  /* 阴影 */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 20px rgba(102, 126, 234, 0.3);
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  background: var(--bg-dark);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

/* ==================== 导航栏 ==================== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(10, 10, 10, 0.9);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-color);
  padding: var(--spacing-md) 0;
}

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

.nav-brand {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: 1.25rem;
  font-weight: 700;
}

.logo-icon {
  width: 40px;
  height: 40px;
  background: var(--color-accent);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  box-shadow: var(--shadow-glow);
}

.nav-menu {
  display: flex;
  gap: var(--spacing-xl);
  list-style: none;
}

.nav-menu a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.3s;
  font-weight: 500;
}

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

/* ==================== 英雄区 ==================== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: 80px;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  top: -50%;
  right: -20%;
  width: 100%;
  height: 200%;
  background: radial-gradient(circle, rgba(102, 126, 234, 0.15) 0%, transparent 70%);
  animation: float 20s ease-in-out infinite;
}

@keyframes float {
  0%, 100% {
    transform: translate(0, 0) rotate(0deg);
  }
  50% {
    transform: translate(-50px, -50px) rotate(5deg);
  }
}

.hero-content {
  position: relative;
  z-index: 1;
  text-align: center;
  max-width: 800px;
  margin: 0 auto;
}

.hero-title {
  font-size: 3.5rem;
  font-weight: 800;
  margin-bottom: var(--spacing-lg);
  line-height: 1.2;
}

.gradient-text {
  background: var(--color-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-2xl);
  line-height: 1.8;
}

.hero-actions {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  margin-bottom: var(--spacing-3xl);
}

.hero-stats {
  display: flex;
  gap: var(--spacing-3xl);
  justify-content: center;
  padding-top: var(--spacing-2xl);
  border-top: 1px solid var(--border-color);
}

.stat-item {
  text-align: center;
}

.stat-value {
  font-size: 2rem;
  font-weight: 700;
  background: var(--color-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.stat-label {
  color: var(--text-tertiary);
  font-size: 0.9rem;
  margin-top: var(--spacing-xs);
}

/* ==================== 按钮 ==================== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: 14px 32px;
  border-radius: 12px;
  font-weight: 600;
  text-decoration: none;
  transition: all 0.3s;
  cursor: pointer;
  border: none;
  font-size: 1rem;
}

.btn-primary {
  background: var(--color-accent);
  color: white;
  box-shadow: var(--shadow-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 30px rgba(102, 126, 234, 0.5);
}

.btn-secondary {
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background: var(--bg-elevated);
  border-color: var(--color-primary);
}

.btn-icon {
  width: 20px;
  height: 20px;
}

/* ==================== 功能区 ==================== */
.features {
  padding: var(--spacing-3xl) 0;
  background: var(--bg-darker);
}

.section-title {
  text-align: center;
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: var(--spacing-md);
}

.section-subtitle {
  text-align: center;
  color: var(--text-secondary);
  font-size: 1.1rem;
  margin-bottom: var(--spacing-3xl);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-lg);
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: var(--spacing-xl);
  transition: all 0.3s;
}

.feature-card:hover {
  transform: translateY(-5px);
  border-color: var(--color-primary);
  box-shadow: var(--shadow-md);
}

.feature-icon {
  font-size: 3rem;
  margin-bottom: var(--spacing-md);
}

.feature-title {
  font-size: 1.3rem;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
}

.feature-desc {
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ==================== 下载区 ==================== */
.download {
  padding: var(--spacing-3xl) 0;
}

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

.download-card {
  position: relative;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: var(--spacing-xl);
  text-align: center;
  transition: all 0.3s;
}

.download-card.featured {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-glow);
}

.download-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}

.download-card .badge {
  position: absolute;
  top: -12px;
  right: 20px;
  background: var(--color-accent);
  color: white;
  padding: 4px 12px;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
}

.download-icon {
  font-size: 3.5rem;
  margin-bottom: var(--spacing-md);
}

.download-title {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
}

.download-desc {
  color: var(--text-secondary);
  margin-bottom: var(--spacing-md);
  min-height: 48px;
}

.download-size {
  color: var(--text-tertiary);
  font-size: 0.9rem;
  margin-bottom: var(--spacing-lg);
}

.system-req {
  margin-top: var(--spacing-2xl);
  padding: var(--spacing-lg);
  background: var(--bg-card);
  border-radius: 12px;
  text-align: center;
  color: var(--text-secondary);
}

/* ==================== 使用说明 ==================== */
.usage {
  padding: var(--spacing-3xl) 0;
  background: var(--bg-darker);
}

.steps {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xl);
}

.step {
  display: flex;
  gap: var(--spacing-lg);
  align-items: flex-start;
}

.step-number {
  width: 60px;
  height: 60px;
  background: var(--color-accent);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  font-weight: 700;
  flex-shrink: 0;
  box-shadow: var(--shadow-glow);
}

.step-content {
  flex: 1;
  padding-top: var(--spacing-sm);
}

.step-title {
  font-size: 1.3rem;
  font-weight: 600;
  margin-bottom: var(--spacing-xs);
}

.step-desc {
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ==================== 价格 ==================== */
.pricing {
  padding: var(--spacing-3xl) 0;
}

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

.pricing-card {
  position: relative;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: var(--spacing-xl);
  text-align: center;
  transition: all 0.3s;
}

.pricing-card.featured {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-glow);
  transform: scale(1.05);
}

.pricing-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}

.pricing-card.featured:hover {
  transform: translateY(-5px) scale(1.05);
}

.pricing-title {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: var(--spacing-lg);
}

.pricing-price {
  margin-bottom: var(--spacing-lg);
}

.price {
  font-size: 3rem;
  font-weight: 700;
  background: var(--color-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.pricing-features {
  list-style: none;
  margin-bottom: var(--spacing-xl);
  text-align: left;
}

.pricing-features li {
  padding: var(--spacing-sm) 0;
  color: var(--text-secondary);
}

/* ==================== 页脚 ==================== */
.footer {
  background: var(--bg-darker);
  border-top: 1px solid var(--border-color);
  padding: var(--spacing-3xl) 0 var(--spacing-lg);
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-xl);
}

.footer-section h4 {
  margin-bottom: var(--spacing-md);
  font-size: 1.1rem;
}

.footer-section ul {
  list-style: none;
}

.footer-section li {
  margin-bottom: var(--spacing-sm);
}

.footer-section a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.3s;
}

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

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

.social-link {
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--bg-card);
  border-radius: 8px;
  transition: all 0.3s;
}

.social-link:hover {
  background: var(--color-primary);
  color: white !important;
}

.footer-bottom {
  text-align: center;
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--border-color);
  color: var(--text-tertiary);
}

/* ==================== 响应式 ==================== */
@media (max-width: 768px) {
  .hero-title {
    font-size: 2.5rem;
  }

  .nav-menu {
    display: none;
  }

  .hero-stats {
    flex-direction: column;
    gap: var(--spacing-lg);
  }

  .hero-actions {
    flex-direction: column;
  }

  .section-title {
    font-size: 2rem;
  }

  .pricing-card.featured {
    transform: none;
  }

  .pricing-card.featured:hover {
    transform: translateY(-5px);
  }
}