/* ==========================================================================
   项目名称：中国八海通国际贸易有限公司 - 官方网站样式表
   设计风格：国际化 B2B 跨境贸易 | 极简、稳重、高转化
   SEO & 视觉优化：包含防累赘设计、平滑滚动、微交互与响应式布局
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. 基础重置与全局变量 (Variables & Reset)
   -------------------------------------------------------------------------- */
:root {
  /* 色彩系统 */
  --primary-color: #0B2545;       /* 深海蓝：主色，象征国际航运与稳重 */
  --primary-light: #133966;       /* 深海蓝浅色变体 */
  --secondary-color: #D4AF37;     /* 琥珀金：辅助色，象征品质贸易 */
  --secondary-hover: #C59F28;     /* 琥珀金悬停态 */
  
  --bg-main: #FFFFFF;             /* 主背景色 */
  --bg-alt: #F8F9FA;              /* 区块交替背景色 */
  --bg-dark: #071930;             /* 深色暗纹背景 */
  
  --text-main: #1D2A44;           /* 主文本色（深邃炭灰） */
  --text-muted: #5C6B73;          /* 次级文本色 */
  --text-light: #F4F6F8;          /* 深色背景上的浅色文本 */
  
  --border-color: #E2E8F0;        /* 边框分割线颜色 */
  --shadow-sm: 0 2px 8px rgba(11, 37, 69, 0.06);
  --shadow-md: 0 8px 24px rgba(11, 37, 69, 0.1);
  --shadow-lg: 0 16px 40px rgba(11, 37, 69, 0.15);
  --shadow-gold: 0 6px 20px rgba(212, 175, 55, 0.25);
  
  /* 布局与字体 */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, 'Noto Sans SC', sans-serif;
  --max-width: 1280px;
  --header-height: 80px;
  --transition-fast: all 0.2s ease;
  --transition-normal: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

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

/* 锚点偏移预留（防止固定导航栏遮挡内容） */
section[id] {
  scroll-margin-top: calc(var(--header-height) + 20px);
}

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

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

ul {
  list-style: none;
}

button, input, textarea, select {
  font: inherit;
  border: none;
  outline: none;
}

/* --------------------------------------------------------------------------
   2. 通用组件与排版 (Typography & Components)
   -------------------------------------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.section-padding {
  padding: 100px 0; /* 严格保持 80px-120px 呼吸感留白 */
}

.section-padding-alt {
  padding: 100px 0;
  background-color: var(--bg-alt);
}

.section-header {
  text-align: center;
  max-width: 760px;
  margin: 0 auto 60px auto;
}

.section-subtitle {
  display: inline-block;
  color: var(--secondary-color);
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: 2px;
  text-transform: uppercase;
  margin-bottom: 12px;
}

.section-title {
  font-size: 2.375rem; /* ~38px */
  font-weight: 800;
  color: var(--primary-color);
  line-height: 1.25;
  margin-bottom: 16px;
  letter-spacing: -0.5px;
}

.section-description {
  font-size: 1.125rem;
  color: var(--text-muted);
  line-height: 1.7;
}

/* 按钮规范 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 32px;
  font-size: 1rem;
  font-weight: 600;
  border-radius: 6px;
  cursor: pointer;
  white-space: nowrap;
  transition: var(--transition-normal);
  text-align: center;
}

.btn-primary {
  background: linear-gradient(135deg, var(--secondary-color) 0%, #B89628 100%);
  color: #FFFFFF;
  box-shadow: var(--shadow-gold);
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 25px rgba(212, 175, 55, 0.4);
  background: linear-gradient(135deg, #E2BD44 0%, var(--secondary-color) 100%);
}

.btn-secondary {
  background-color: transparent;
  color: #FFFFFF;
  border: 2px solid rgba(255, 255, 255, 0.4);
  margin-left: 16px;
}

.btn-secondary:hover {
  background-color: rgba(255, 255, 255, 0.1);
  border-color: #FFFFFF;
  transform: translateY(-3px);
}

.btn-outline-dark {
  background-color: transparent;
  color: var(--primary-color);
  border: 2px solid var(--primary-color);
}

.btn-outline-dark:hover {
  background-color: var(--primary-color);
  color: #FFFFFF;
  transform: translateY(-3px);
}

/* --------------------------------------------------------------------------
   3. 区块1：吸顶导览列 (Sticky Header)
   -------------------------------------------------------------------------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--header-height);
  background-color: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  z-index: 1000;
  border-bottom: 1px solid rgba(226, 232, 240, 0.8);
  transition: var(--transition-normal);
}

.site-header.scrolled {
  height: 70px;
  box-shadow: var(--shadow-sm);
  background-color: #FFFFFF;
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

/* 纯 CSS / 现代文本 Logo */
.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 900;
  text-decoration: none;
}

.logo-icon-box {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--primary-color) 0%, #174276 100%);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--secondary-color);
  font-size: 1.25rem;
  box-shadow: 0 4px 10px rgba(11, 37, 69, 0.15);
  position: relative;
  overflow: hidden;
}

.logo-icon-box::after {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: linear-gradient(45deg, transparent, rgba(255,255,255,0.15), transparent);
  transform: rotate(45deg);
}

.logo-text-group {
  display: flex;
  flex-direction: column;
}

.logo-cn {
  font-size: 1.25rem;
  color: var(--primary-color);
  letter-spacing: 1px;
  line-height: 1.1;
  font-weight: 800;
}

.logo-en {
  font-size: 0.625rem;
  color: var(--secondary-color);
  letter-spacing: 1.5px;
  font-weight: 700;
  margin-top: 2px;
}

/* 导航菜单 */
.nav-menu {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-link {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-main);
  position: relative;
  padding: 6px 0;
}

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

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

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

.header-cta {
  padding: 10px 24px;
  font-size: 0.875rem;
}

/* 移动端汉堡菜单按钮 */
.mobile-toggle {
  display: none;
  background: none;
  cursor: pointer;
  padding: 8px;
  flex-direction: column;
  gap: 5px;
}

.hamburger-bar {
  width: 24px;
  height: 2px;
  background-color: var(--primary-color);
  transition: var(--transition-fast);
}

/* --------------------------------------------------------------------------
   4. 区块2：英雄区 (Hero Section)
   -------------------------------------------------------------------------- */
.hero-section {
  position: relative;
  padding-top: calc(var(--header-height) + 80px);
  padding-bottom: 120px;
  background-color: var(--primary-color);
  color: #FFFFFF;
  background-image: linear-gradient(135deg, rgba(11, 37, 69, 0.92) 0%, rgba(7, 25, 48, 0.95) 100%), 
                    url('/images/hero-bg.jpg');
  background-size: cover;
  background-position: center center;
  background-attachment: fixed;
  overflow: hidden;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 60px;
  align-items: center;
}

.hero-content {
  max-width: 680px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  background: rgba(212, 175, 55, 0.15);
  border: 1px solid rgba(212, 175, 55, 0.4);
  border-radius: 50px;
  color: var(--secondary-color);
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 24px;
}

.hero-title {
  font-size: 3.25rem; /* ~52px */
  font-weight: 900;
  line-height: 1.18;
  margin-bottom: 24px;
  letter-spacing: -1px;
}

.hero-title span {
  color: var(--secondary-color);
  background: linear-gradient(135deg, #F9E29C 0%, #D4AF37 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: rgba(255, 255, 255, 0.85);
  line-height: 1.6;
  margin-bottom: 40px;
  font-weight: 400;
}

.hero-actions {
  display: flex;
  align-items: center;
}

.hero-card-preview {
  position: relative;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  border: 1px solid rgba(255, 255, 255, 0.1);
}

.hero-card-preview img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* --------------------------------------------------------------------------
   5. 区块3：客户痛点与行业情境 (Pain Points)
   -------------------------------------------------------------------------- */
.pain-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.pain-card {
  background-color: var(--bg-main);
  padding: 36px 28px;
  border-radius: 10px;
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  transition: var(--transition-normal);
  position: relative;
  top: 0;
}

.pain-card:hover {
  top: -8px;
  box-shadow: var(--shadow-md);
  border-color: rgba(212, 175, 55, 0.4);
}

.pain-icon {
  width: 56px;
  height: 56px;
  border-radius: 10px;
  background-color: #FFF9E6;
  color: var(--secondary-color);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 20px;
}

.pain-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--primary-color);
  margin-bottom: 12px;
}

.pain-desc {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* --------------------------------------------------------------------------
   6. 区块4：核心解决方案与服务 (Solutions)
   -------------------------------------------------------------------------- */
.solutions-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

.solution-card {
  background: #FFFFFF;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  transition: var(--transition-normal);
}

.solution-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
}

.solution-img-wrapper {
  height: 220px;
  overflow: hidden;
  position: relative;
}

.solution-img-wrapper img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.solution-card:hover .solution-img-wrapper img {
  transform: scale(1.05);
}

.solution-body {
  padding: 32px;
  flex-grow: 1;
  display: flex;
  flex-direction: column;
}

.solution-title {
  font-size: 1.375rem;
  font-weight: 700;
  color: var(--primary-color);
  margin-bottom: 12px;
}

.solution-desc {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 20px;
}

.solution-features {
  margin-top: auto;
  border-top: 1px solid var(--border-color);
  padding-top: 16px;
}

.solution-features li {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.9rem;
  color: var(--text-main);
  margin-bottom: 8px;
}

.solution-features li::before {
  content: "✓";
  color: var(--secondary-color);
  font-weight: bold;
}

/* --------------------------------------------------------------------------
   7. 区块5：信任背书与数据 (Social Proof)
   -------------------------------------------------------------------------- */
.stats-banner {
  background: linear-gradient(135deg, var(--primary-color) 0%, var(--bg-dark) 100%);
  color: #FFFFFF;
  border-radius: 16px;
  padding: 60px 40px;
  margin-bottom: 80px;
  box-shadow: var(--shadow-lg);
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 30px;
  text-align: center;
}

.stat-number {
  font-size: 3rem;
  font-weight: 900;
  color: var(--secondary-color);
  line-height: 1;
  margin-bottom: 8px;
}

.stat-label {
  font-size: 0.95rem;
  color: rgba(255, 255, 255, 0.8);
}

.case-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 30px;
}

.case-card {
  background: #FFFFFF;
  border-radius: 10px;
  padding: 28px;
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  transition: var(--transition-normal);
}

.case-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.case-tag {
  display: inline-block;
  padding: 4px 12px;
  background-color: var(--bg-alt);
  color: var(--primary-color);
  font-size: 0.8rem;
  font-weight: 600;
  border-radius: 4px;
  margin-bottom: 16px;
}

.case-title {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--primary-color);
  margin-bottom: 10px;
}

.case-result {
  font-size: 0.9rem;
  color: var(--text-muted);
}

/* --------------------------------------------------------------------------
   8. 区块6：关于八海通 (About Us)
   -------------------------------------------------------------------------- */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

.about-img-box {
  position: relative;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: var(--shadow-md);
}

.about-img-box img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.about-info-list {
  margin-top: 24px;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.about-info-item {
  border-left: 3px solid var(--secondary-color);
  padding-left: 12px;
}

.about-info-item h4 {
  font-size: 1rem;
  color: var(--primary-color);
  font-weight: 700;
}

.about-info-item p {
  font-size: 0.875rem;
  color: var(--text-muted);
}

/* --------------------------------------------------------------------------
   9. 区块7：常见问题 (FAQ Accordion)
   -------------------------------------------------------------------------- */
.faq-container {
  max-width: 840px;
  margin: 0 auto;
}

.faq-item {
  background-color: #FFFFFF;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  margin-bottom: 16px;
  overflow: hidden;
  transition: var(--transition-fast);
}

.faq-item.active {
  border-color: var(--secondary-color);
  box-shadow: var(--shadow-sm);
}

.faq-question {
  width: 100%;
  padding: 20px 24px;
  text-align: left;
  background: none;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--primary-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
}

.faq-icon {
  font-size: 1.25rem;
  transition: transform 0.3s ease;
  color: var(--secondary-color);
}

.faq-item.active .faq-icon {
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s cubic-bezier(0, 1, 0, 1);
  padding: 0 24px;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.7;
}

.faq-item.active .faq-answer {
  max-height: 500px;
  padding: 0 24px 20px 24px;
  transition: max-height 0.3s cubic-bezier(1, 0, 1, 0);
}

/* --------------------------------------------------------------------------
   10. 区块8：终极呼吁 (Final CTA & Form)
   -------------------------------------------------------------------------- */
.cta-section {
  background: linear-gradient(135deg, var(--primary-color) 0%, var(--bg-dark) 100%);
  color: #FFFFFF;
  position: relative;
}

.cta-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

.cta-text h2 {
  font-size: 2.5rem;
  font-weight: 800;
  margin-bottom: 20px;
  line-height: 1.2;
}

.cta-text p {
  color: rgba(255, 255, 255, 0.8);
  font-size: 1.1rem;
  margin-bottom: 32px;
}

.contact-direct {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.contact-item {
  display: flex;
  align-items: center;
  gap: 16px;
  font-size: 1rem;
}

.contact-icon {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: rgba(212, 175, 55, 0.2);
  color: var(--secondary-color);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
}

.cta-form-wrapper {
  background: #FFFFFF;
  border-radius: 12px;
  padding: 40px;
  color: var(--text-main);
  box-shadow: var(--shadow-lg);
}

.form-group {
  margin-bottom: 20px;
}

.form-label {
  display: block;
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--primary-color);
}

.form-input, .form-textarea {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  background-color: #F8F9FA;
  transition: var(--transition-fast);
}

.form-input:focus, .form-textarea:focus {
  border-color: var(--secondary-color);
  background-color: #FFFFFF;
  box-shadow: 0 0 0 3px rgba(212, 175, 55, 0.2);
}

.form-textarea {
  resize: vertical;
  min-height: 100px;
}

.form-submit {
  width: 100%;
  padding: 16px;
  font-size: 1.05rem;
}

/* --------------------------------------------------------------------------
   11. 区块9：页尾 (Footer)
   -------------------------------------------------------------------------- */
.site-footer {
  background-color: #051326;
  color: rgba(255, 255, 255, 0.6);
  padding: 60px 0 30px 0;
  font-size: 0.875rem;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.5fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-col h4 {
  color: #FFFFFF;
  font-size: 1rem;
  margin-bottom: 20px;
  font-weight: 700;
}

.footer-links li {
  margin-bottom: 10px;
}

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

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: 30px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}

.footer-beian a {
  color: rgba(255, 255, 255, 0.6);
  transition: var(--transition-fast);
}

.footer-beian a:hover {
  color: var(--secondary-color);
}

/* --------------------------------------------------------------------------
   12. 响应式适配 (Responsive Design)
   -------------------------------------------------------------------------- */
@media (max-width: 1024px) {
  .hero-grid, .solutions-grid, .about-grid, .cta-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }
  
  .pain-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 40px;
  }
  
  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .section-padding, .section-padding-alt {
    padding: 60px 0;
  }
  
  .hero-title {
    font-size: 2.25rem;
  }
  
  .nav-menu {
    position: fixed;
    top: var(--header-height);
    left: 0;
    width: 100%;
    background-color: #FFFFFF;
    flex-direction: column;
    padding: 30px;
    gap: 20px;
    box-shadow: var(--shadow-md);
    transform: translateY(-150%);
    transition: transform 0.3s ease;
    z-index: 999;
  }
  
  .nav-menu.active {
    transform: translateY(0);
  }
  
  .mobile-toggle {
    display: flex;
  }
  
  .header-cta {
    display: none;
  }
  
  .pain-grid, .case-grid {
    grid-template-columns: 1fr;
  }
  
  .footer-grid {
    grid-template-columns: 1fr;
  }
  
  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }
}