/* ============================================
   注意力工程 SaaS - 样式表 v2
   清爽风格（参考 diaolong.mangofolio.com）
   ============================================ */

/* 基础重置 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Noto Sans SC', sans-serif;
  color: #333;
  line-height: 1.8;
  background: #faf9f8;
}

/* 导航栏 */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(250, 249, 248, 0.95);
  backdrop-filter: blur(10px);
  padding: 20px 0;
  border-bottom: 1px solid rgba(0,0,0,0.05);
}

.nav-container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 40px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-emoji {
  font-size: 20px;
}

.nav-title {
  font-family: 'Noto Serif SC', serif;
  font-size: 16px;
  font-weight: 600;
  color: #1a1a1a;
  letter-spacing: 2px;
}

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

.nav-link {
  font-size: 14px;
  color: #666;
  text-decoration: none;
  transition: color 0.3s;
  letter-spacing: 1px;
}

.nav-link:hover {
  color: #c45a3d;
}

.nav-cta {
  font-size: 14px;
  color: #fff;
  background: #c45a3d;
  padding: 10px 24px;
  border-radius: 4px;
  text-decoration: none;
  transition: all 0.3s;
  font-weight: 500;
}

.nav-cta:hover {
  background: #a84a32;
  transform: translateY(-1px);
}

/* Hero */
.hero {
  min-height: 90vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 140px 40px 80px;
  background: #faf9f8;
  color: #1a1a1a;
}

.hero-content {
  max-width: 800px;
}

.hero-tagline {
  font-size: 13px;
  letter-spacing: 4px;
  color: #c45a3d;
  text-transform: uppercase;
  margin-bottom: 32px;
  font-weight: 500;
}

.hero h1 {
  font-family: 'Noto Serif SC', serif;
  font-size: clamp(36px, 6vw, 56px);
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 20px;
  color: #1a1a1a;
}

.hero h1 em {
  font-style: normal;
  color: #c45a3d;
}

.hero-subtitle {
  font-size: clamp(16px, 2.5vw, 18px);
  color: #666;
  line-height: 1.8;
  margin-bottom: 40px;
  font-weight: 300;
}

.hero-divider {
  width: 40px;
  height: 2px;
  background: #c45a3d;
  margin: 32px auto;
}

/* 双引擎卡片 */
.dual-engines {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
  margin-top: 48px;
}

.engine-card {
  background: #fff;
  border: 1px solid rgba(0,0,0,0.06);
  border-radius: 8px;
  padding: 40px 32px;
  text-decoration: none;
  color: #1a1a1a;
  transition: all 0.3s;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
}

.engine-card:hover {
  border-color: #c45a3d;
  box-shadow: 0 8px 24px rgba(0,0,0,0.08);
  transform: translateY(-4px);
}

.engine-icon {
  font-size: 40px;
  margin-bottom: 8px;
}

.engine-title {
  font-family: 'Noto Serif SC', serif;
  font-size: 22px;
  font-weight: 600;
  margin-bottom: 4px;
  color: #1a1a1a;
}

.engine-subtitle {
  font-size: 13px;
  color: #999;
  letter-spacing: 2px;
  text-transform: uppercase;
}

.engine-desc {
  font-size: 14px;
  color: #666;
  line-height: 1.6;
  margin-top: 8px;
  text-align: center;
}

.engine-cta {
  font-size: 13px;
  color: #c45a3d;
  margin-top: 20px;
  font-weight: 500;
}

.engine-cta-card {
  padding: 32px;
}

.engine-cta-card .engine-title {
  font-size: 18px;
}

/* 滚动提示 */
.scroll-hint {
  position: absolute;
  bottom: 40px;
  font-size: 12px;
  color: #999;
  letter-spacing: 2px;
  animation: bounce 2s infinite;
}

@keyframes bounce {
  0%, 20%, 50%, 80%, 100% { transform: translateY(0); }
  40% { transform: translateY(-10px); }
  60% { transform: translateY(-5px); }
}

/* Section 通用 */
.section {
  padding: 100px 40px;
  background: #faf9f8;
}

.section-content {
  max-width: 900px;
  margin: 0 auto;
}

.section-title {
  font-family: 'Noto Serif SC', serif;
  font-size: clamp(26px, 4vw, 34px);
  font-weight: 700;
  margin-bottom: 20px;
  line-height: 1.4;
  color: #1a1a1a;
}

.section-title em {
  font-style: normal;
  color: #c45a3d;
}

.section-subtitle {
  font-size: 16px;
  color: #666;
  line-height: 1.8;
  margin-bottom: 48px;
  font-weight: 300;
}

/* 亮色区 */
.section-light {
  background: #fff;
}

.section-light .body-text {
  font-size: 16px;
  color: #555;
  line-height: 2;
  font-weight: 300;
}

.section-light .body-text strong {
  font-weight: 500;
  color: #1a1a1a;
}

/* 书籍区 */
.section-books {
  background: #faf9f8;
}

.books-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
  margin-top: 32px;
}

.book-card {
  padding: 24px;
  background: #fff;
  border-radius: 8px;
  border: 1px solid rgba(0,0,0,0.06);
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
  transition: all 0.3s;
}

.book-card:hover {
  border-color: rgba(0,0,0,0.12);
  box-shadow: 0 4px 16px rgba(0,0,0,0.08);
}

.book-card .book-title {
  font-size: 14px;
  font-weight: 600;
  color: #1a1a1a;
  margin-bottom: 8px;
}

.book-card .book-method {
  font-size: 13px;
  color: #666;
  line-height: 1.6;
}

/* 暗色区（方法论） */
.section-dark {
  background: #1a1a1a;
  color: #fff;
}

.section-dark .section-title {
  color: #fff;
}

.section-dark .section-subtitle {
  color: #999;
}

.section-alt {
  background: #222;
}

/* 方法论流程 */
.framework-flow {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  margin-top: 40px;
  flex-wrap: wrap;
}

.flow-step {
  text-align: center;
  padding: 28px 24px;
  background: rgba(255,255,255,0.08);
  border-radius: 8px;
  border: 1px solid rgba(255,255,255,0.12);
  min-width: 160px;
  transition: all 0.3s;
}

.flow-step:hover {
  background: rgba(255,255,255,0.12);
  border-color: rgba(255,255,255,0.2);
}

.flow-num {
  font-family: 'Noto Serif SC', serif;
  font-size: 13px;
  color: #c45a3d;
  margin-bottom: 10px;
  font-weight: 600;
  letter-spacing: 1px;
}

.flow-title {
  font-size: 16px;
  font-weight: 500;
  color: #fff;
  margin-bottom: 6px;
}

.flow-desc {
  font-size: 13px;
  color: #999;
}

.flow-arrow {
  font-size: 20px;
  color: #c45a3d;
  opacity: 0.6;
}

/* 组合拳 */
.combo-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
  margin-top: 40px;
}

.combo-card {
  padding: 32px;
  background: #fff;
  border-radius: 8px;
  border: 1px solid rgba(0,0,0,0.06);
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
}

.combo-label {
  font-size: 12px;
  color: #999;
  margin-bottom: 10px;
  letter-spacing: 1px;
  text-transform: uppercase;
}

.combo-title {
  font-size: 20px;
  font-weight: 600;
  color: #1a1a1a;
  margin-bottom: 10px;
}

.combo-desc {
  font-size: 14px;
  color: #666;
  line-height: 1.7;
  font-weight: 300;
}

/* CTA 区 */
.section-hero {
  background: #1a1a1a;
  color: #fff;
  text-align: center;
  padding: 120px 40px;
}

.section-hero h2 {
  font-family: 'Noto Serif SC', serif;
  font-size: clamp(28px, 4vw, 40px);
  font-weight: 700;
  line-height: 1.5;
  margin-bottom: 24px;
  color: #fff;
}

.cta-divider {
  width: 40px;
  height: 2px;
  background: #c45a3d;
  margin: 32px auto;
}

/* 页面底部 */
.footer {
  background: #1a1a1a;
  color: #fff;
  padding: 80px 40px 40px;
  border-top: 1px solid rgba(255,255,255,0.08);
}

.footer-container {
  max-width: 900px;
  margin: 0 auto;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  margin-bottom: 48px;
}

.footer-col-title {
  font-family: 'Noto Serif SC', serif;
  font-size: 15px;
  font-weight: 600;
  color: #fff;
  margin-bottom: 20px;
  letter-spacing: 1px;
}

.footer-item {
  font-size: 14px;
  color: #999;
  line-height: 1.8;
}

.footer-link {
  font-size: 14px;
  color: #c45a3d;
  text-decoration: none;
  display: block;
  margin-bottom: 10px;
  transition: color 0.3s;
}

.footer-link:hover {
  color: #D4920B;
}

.footer-divider {
  width: 100%;
  height: 1px;
  background: rgba(255,255,255,0.08);
  margin-bottom: 24px;
}

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

.footer-copyright {
  font-size: 13px;
  color: #666;
  letter-spacing: 1px;
}

.footer-disclaimer {
  font-size: 13px;
  color: #666;
}

/* 响应式 */
@media (max-width: 768px) {
  .nav-container {
    padding: 0 20px;
  }
  
  .nav-links {
    gap: 16px;
  }
  
  .nav-link {
    font-size: 13px;
  }
  
  .hero {
    padding: 120px 20px 60px;
  }
  
  .dual-engines {
    grid-template-columns: 1fr;
    gap: 20px;
  }
  
  .section {
    padding: 80px 20px;
  }
  
  .framework-flow {
    flex-direction: column;
    gap: 16px;
  }
  
  .flow-arrow {
    transform: rotate(90deg);
  }
  
  .combo-grid {
    grid-template-columns: 1fr;
  }
  
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }
  
  .footer-bottom {
    flex-direction: column;
    gap: 16px;
    text-align: center;
  }
  
  .books-grid {
    grid-template-columns: 1fr;
  }
}