/* ========================================
   七亿测试中心 - 样式文件
   ======================================== */

:root {
  /* 主色调 */
  --primary: #6366f1;
  --primary-dark: #4f46e5;
  --primary-light: #818cf8;
  
  /* 辅助色 */
  --accent-orange: #f97316;
  --accent-pink: #ec4899;
  --accent-green: #10b981;
  --accent-blue: #3b82f6;
  
  /* 中性色 */
  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-300: #d1d5db;
  --gray-400: #9ca3af;
  --gray-500: #6b7280;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-800: #1f2937;
  --gray-900: #111827;
  
  /* 背景 */
  --bg: #fafafa;
  --bg-card: #ffffff;
  
  /* 字体 */
  --font-sans: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  
  /* 圆角 */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  
  /* 阴影 */
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
}

/* ========================================
   基础样式
   ======================================== */

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--gray-800);
  line-height: 1.6;
  min-height: 100vh;
}

a {
  color: inherit;
  text-decoration: none;
}

/* ========================================
   导航
   ======================================== */

.nav {
  position: sticky;
  top: 0;
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--gray-100);
  z-index: 100;
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--gray-900);
}

.logo-icon {
  font-size: 1.5rem;
}

.nav-links {
  display: flex;
  gap: 32px;
}

.nav-link {
  font-size: 0.9375rem;
  color: var(--gray-600);
  transition: color 0.2s;
}

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

/* ========================================
   Hero 区域
   ======================================== */

.hero {
  position: relative;
  max-width: 1200px;
  margin: 0 auto;
  padding: 80px 24px 120px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  overflow: hidden;
}

.hero-content {
  max-width: 600px;
}

.hero-title {
  font-size: 3.5rem;
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 24px;
}

.gradient-text {
  background: linear-gradient(135deg, var(--primary) 0%, var(--accent-pink) 50%, var(--accent-orange) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.highlight {
  color: var(--gray-900);
}

.hero-desc {
  font-size: 1.25rem;
  color: var(--gray-600);
  margin-bottom: 40px;
}

.hero-stats {
  display: flex;
  gap: 48px;
}

.stat {
  text-align: center;
}

.stat-number {
  display: block;
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--primary);
}

.stat-label {
  font-size: 0.875rem;
  color: var(--gray-500);
}

/* 浮动卡片装饰 */
.hero-decoration {
  position: absolute;
  right: 100px;
  top: 50%;
  transform: translateY(-50%);
}

.floating-card {
  position: absolute;
  font-size: 4rem;
  animation: float 6s ease-in-out infinite;
  filter: drop-shadow(0 20px 40px rgba(0, 0, 0, 0.1));
}

.card-1 {
  animation-delay: 0s;
}

.card-2 {
  top: 60px;
  left: 40px;
  animation-delay: 2s;
}

.card-3 {
  top: -40px;
  left: 80px;
  animation-delay: 4s;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-20px); }
}

/* ========================================
   主内容区
   ======================================== */

.main {
  background: var(--bg);
}

.section {
  max-width: 1200px;
  margin: 0 auto;
  padding: 80px 24px;
}

.section-header {
  text-align: center;
  margin-bottom: 48px;
}

.section-title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--gray-900);
  margin-bottom: 12px;
}

.section-desc {
  font-size: 1rem;
  color: var(--gray-500);
}

/* ========================================
   测试卡片网格
   ======================================== */

.tests-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
}

.test-card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: 28px;
  border: 1px solid var(--gray-100);
  transition: all 0.3s ease;
  position: relative;
}

.test-card:hover:not(.coming-soon) {
  border-color: var(--primary-light);
  box-shadow: var(--shadow-xl);
}

.test-card.featured {
  border: 2px solid var(--primary);
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.02) 0%, rgba(236, 72, 153, 0.02) 100%);
}

.test-card.coming-soon {
  opacity: 0.7;
}

.test-badge {
  position: absolute;
  top: 20px;
  right: 20px;
  background: var(--accent-orange);
  color: white;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 4px 10px;
  border-radius: 20px;
}

.test-badge.coming {
  background: var(--gray-400);
}

.test-icon {
  font-size: 3rem;
  margin-bottom: 16px;
}

.test-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--gray-900);
  margin-bottom: 4px;
}

.test-name-en {
  font-size: 0.75rem;
  color: var(--gray-400);
  font-family: monospace;
  margin-bottom: 12px;
}

.test-desc {
  font-size: 0.9375rem;
  color: var(--gray-600);
  margin-bottom: 20px;
  line-height: 1.6;
}

.test-meta {
  display: flex;
  gap: 16px;
  margin-bottom: 24px;
}

.meta-item {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.8125rem;
  color: var(--gray-500);
}

.meta-item .icon {
  width: 16px;
  height: 16px;
}

.test-button {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  width: 100%;
  padding: 14px 24px;
  background: var(--primary);
  color: white;
  font-size: 0.9375rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: all 0.2s;
}

.test-button:hover:not(.disabled) {
  background: var(--primary-dark);
  transform: translateY(-2px);
}

.test-button.disabled {
  background: var(--gray-300);
  cursor: not-allowed;
}

.test-button .arrow {
  width: 18px;
  height: 18px;
  transition: transform 0.2s;
}

.test-button:hover:not(.disabled) .arrow {
  transform: translateX(4px);
}

/* ========================================
   特点区域
   ======================================== */

.features {
  background: var(--gray-50);
  border-radius: var(--radius-xl);
  padding: 60px 40px;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 40px;
}

.feature {
  text-align: center;
}

.feature-icon {
  font-size: 2.5rem;
  margin-bottom: 16px;
}

.feature-title {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--gray-900);
  margin-bottom: 8px;
}

.feature-desc {
  font-size: 0.875rem;
  color: var(--gray-500);
}

/* ========================================
   页脚
   ======================================== */

.footer {
  background: var(--gray-900);
  color: var(--gray-400);
  padding: 48px 24px;
}

.footer-content {
  max-width: 1200px;
  margin: 0 auto;
  text-align: center;
}

.footer-brand {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  font-size: 1.25rem;
  font-weight: 600;
  color: white;
  margin-bottom: 24px;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 32px;
  margin-bottom: 24px;
}

.footer-links a {
  color: var(--gray-400);
  transition: color 0.2s;
}

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

.footer-copyright {
  font-size: 0.875rem;
  color: var(--gray-500);
}

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

@media (max-width: 768px) {
  .hero {
    flex-direction: column;
    text-align: center;
    padding: 60px 24px 80px;
  }

  .hero-decoration {
    display: none;
  }

  .hero-title {
    font-size: 2.25rem;
  }

  .hero-desc {
    font-size: 1rem;
  }

  .hero-stats {
    justify-content: center;
    gap: 32px;
  }

  .stat-number {
    font-size: 2rem;
  }

  .tests-grid {
    grid-template-columns: 1fr;
  }

  .section {
    padding: 60px 16px;
  }

  .features-grid {
    grid-template-columns: 1fr 1fr;
    gap: 32px;
  }

  .footer-links {
    flex-direction: column;
    gap: 16px;
  }
}

@media (max-width: 480px) {
  .nav-links {
    gap: 16px;
  }

  .hero-title {
    font-size: 1.875rem;
  }

  .hero-stats {
    flex-direction: column;
    gap: 16px;
  }

  .features-grid {
    grid-template-columns: 1fr;
  }
}