/* ========================================================================
   全局样式
   ======================================================================== */
   * {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
  
  html {
    /* 平滑滚动效果 */
    scroll-behavior: smooth;
  }
  
  body {
    width: 100%;
    font-family: "Helvetica Neue", Arial, sans-serif;
    color: #333;
    background-color: #ffffff; /* 默认白色背景 */
  }
  
  a {
    text-decoration: none;
    color: inherit;
  }
  
  ul {
    list-style: none;
  }
  
  /* 统一容器宽度 */
  .container {
    width: 1200px;
    max-width: 95%;
    margin: 0 auto;
  }
  
  /* ========================================================================
     头部导航 .site-header
     ======================================================================== */
  .site-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: transparent; /* 默认透明 */
    z-index: 100;
    padding: 20px 0;
    transition: background-color 0.3s ease, padding 0.3s ease;
  }
  
  /* 当添加 .header-scrolled 时，导航栏背景变为纯白，padding 变小 */
  .site-header.header-scrolled {
    background-color: #ffffff;
    padding: 10px 0;
  }
  
  .header-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
  }
  
  /* Logo 区域 */
  .logo img {
    height: 40px;
    transition: filter 0.3s;
  }
  
  /* 如果需要滚动后替换 Logo，可以使用类似： */
  /* .site-header.header-scrolled .logo img { content: url(img/ic_logo_dark.png); } */
  
  /* 导航菜单 */
  .main-nav ul {
    display: flex;
    gap: 30px;
  }
  
  /* 默认状态（透明背景），文字白色 */
  .main-nav ul li a {
    font-size: 16px;
    font-weight: 500;
    color: #ffffff;
    transition: color 0.3s;
  }
  
  /* 滚动后（白底），文字变成深色 */
  .site-header.header-scrolled .main-nav ul li a {
    color: #333333;
  }
  
  .main-nav ul li a:hover {
    color: #ff70a6;
  }
  
  /* 右侧 Download 按钮 */
  .header-cta .btn-download {
    display: inline-block;
    padding: 10px 25px;
    background-color: #ff2e63;
    border-radius: 50px;
    font-size: 16px;
    font-weight: 600;
    color: #fff;
    transition: background-color 0.3s, color 0.3s;
  }
  
  /* ========================================================================
     模块 1：英雄版块 Hero
     ======================================================================== */
  .hero {
    position: relative;
    /* 背景贴近底部曲线 */
    background: url("img/img_bg1.png") no-repeat center bottom;
    background-size: cover;
    padding-top: 80px;    /* 留出给固定导航的空间 */
    padding-bottom: 0;    /* 底部留白设为 0，显示曲线 */
    min-height: 100vh;    /* 让 Hero 至少撑满一屏 */
    overflow: hidden;     /* 保证底部曲线完整可见 */
  }
  
  /* 如需半透明遮罩，可解除注释 */
  // .hero-overlay {
  //   position: absolute;
  //   top: 0;
  //   left: 0;
  //   right: 0;
  //   bottom: 0;
  //   background-color: rgba(0, 0, 0, 0.5);
  //   z-index: 1;
  // }
  
  .hero-container {
    position: relative;
    z-index: 2;
    display: flex;
    align-items: center;
    justify-content: space-between;
  }
  
  .hero-text {
    max-width: 550px;
  }
  
  .hero-title {
    font-size: 48px;
    color: #ffffff;
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 20px;
  }
  
  .hero-subtitle {
    font-size: 18px;
    color: rgba(255, 255, 255, 0.8);
    margin-bottom: 30px;
    line-height: 1.6;
  }
  
  #download {
    height: 0;
  }
  
  .download-buttons {
    display: flex;
    gap: 20px;
  }
  
  .download-buttons a img {
    height: 60px;
  }
  
  .hero-phone img {
    max-width: 500px;
    width: 100%;
    height: auto;
  }
  
  /* ========================================================================
     模块 2：功能区 1 — .section-two（图片在左、文字在右）
     ======================================================================== */
  .section-two {
    padding: 60px 0;       /* 从原来的 100px 缩小到 60px */
    background-color: #ffffff;
  }
  
  .feature-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 50px;
  }
  
  .feature-phone img {
    width: 100%;
    max-width: 500px;
    height: auto;
  }
  
  .feature-text {
    max-width: 550px;
  }
  
  .feature-text h2 {
    font-size: 32px;
    font-weight: 700;
    color: #1e1e1e;
    margin-bottom: 20px;
  }
  
  .feature-text p {
    font-size: 16px;
    color: #555;
    line-height: 1.7;
  }
  
  /* ========================================================================
     模块 3：功能区 2 — .section-three（文字在左、图片在右）
     ======================================================================== */
  .section-three {
    padding: 60px 0;       /* 从原来的 100px 缩小到 60px */
    background-color: #ffffff;
  }
  
  .section-three .feature-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 50px;
  }
  
  .section-three .feature-text {
    max-width: 550px;
  }
  
  .section-three .feature-text h2 {
    font-size: 32px;
    font-weight: 700;
    color: #1e1e1e;
    margin-bottom: 20px;
  }
  
  .section-three .feature-text p {
    font-size: 16px;
    color: #555;
    line-height: 1.7;
  }
  
  .section-three .feature-phone img {
    width: 100%;
    max-width: 500px;
    height: auto;
  }
  
  /* ========================================================================
     模块 4+5：Wave 背景 — .wave-bg
     ======================================================================== */
  .wave-bg {
    position: relative;
    /* 上下预留曲线空间，从 200px 缩小到 150px */
    padding-top: 150px;
    padding-bottom: 150px;
    background-color: transparent;
  }
  
  .wave-bg-img {
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 100%;
    height: auto;
    z-index: 1;
  }
  
  /* 模块 4：Every connection deserves to be protected. */
  .section-four {
    position: relative;
    z-index: 2;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 50px;
    /* 从原来的 padding: 100px 0 60px 缩小到 60px 0 40px */
    padding: 60px 0 40px;
    background-color: transparent;
  }
  
  /* 模块 5：Add warmth to sincerity（图片在左、文字在右） */
  .section-five {
    position: relative;
    z-index: 2;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 50px;
    /* 从原来的 padding: 60px 0 0 缩小到 40px 0 0 */
    padding: 40px 0 0;
    background-color: transparent;
  }
  
  /* ========================================================================
     模块 6：关于我们 — .about（取消蒙层，左对齐，增高上下间距）
     ======================================================================== */
  .about {
    position: relative;
    /* 将 padding-top 从 150px 提升到 200px，padding-bottom 从 60px 提升到 100px */
    padding-top: 200px;
    padding-bottom: 100px;
    background: url("img/img_bg3.png") no-repeat center top;
    background-size: cover;
    color: #ffffff;
    overflow: hidden;    /* 保证曲线完整可见 */
  }
  
  /* .about-overlay { ... } 已移除灰色蒙层 */
  // .about-overlay {
  //   position: absolute;
  //   top: 0;
  //   left: 0;
  //   right: 0;
  //   bottom: 0;
  //   background-color: rgba(0, 0, 0, 0.6);
  //   z-index: 1;
  // }
  
  .about-container {
    position: relative;
    z-index: 2;
    max-width: 800px;
    margin: 0 auto;
    text-align: left;     /* 由 center 改为 left，文字左对齐 */
  }
  
  .about-container h2 {
    font-size: 36px;
    font-weight: 700;
    margin-bottom: 25px;
  }
  
  .about-container p {
    font-size: 16px;
    line-height: 1.8;
    margin-bottom: 20px;
    opacity: 0.9;
  }
  
  .contact-info {
    margin-top: 30px;
    display: flex;
    flex-direction: column;
    align-items: flex-start; /* 由 center 改为 flex-start，让图标文字左对齐 */
    gap: 15px;
  }
  
  .contact-info li {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 16px;
    opacity: 0.9;
  }
  
  .contact-info li img {
    width: 24px;
    height: 24px;
  }
  
  /* ========================================================================
     页脚 Footer — .site-footer
     ======================================================================== */
  .site-footer {
    background-color: #0e0e0e;
    color: #ccc;
    font-size: 14px;
    line-height: 1.8;
    padding: 60px 0 20px;
  }
  
  .footer-container {
    display: flex;
    gap: 50px;
    flex-wrap: wrap;
    justify-content: space-between;
  }
  
  .footer-col-about {
    flex: 1 1 300px;
  }
  
  .footer-logo img {
    height: 40px;
    margin-bottom: 20px;
  }
  
  .footer-desc {
    margin-bottom: 20px;
    color: #999;
  }
  
  .social-icons a {
    display: inline-block;
    margin-right: 12px;
  }
  
  .social-icons a img {
    width: 28px;
    height: 28px;
    filter: invert(1);
  }
  
  .footer-col {
    flex: 1 1 180px;
  }
  
  .footer-col h3 {
    color: #fff;
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 15px;
  }
  
  .footer-col ul li {
    margin-bottom: 10px;
  }
  
  .footer-col ul li a {
    color: #ccc;
    transition: color 0.3s;
  }
  
  .footer-col ul li a:hover {
    color: #fff;
  }
  
  .footer-bottom {
    margin-top: 40px;
    text-align: center;
    color: #555;
    font-size: 13px;
  }
  
  /* ========================================================================
     响应式（可选，根据设计稿宽度自行调整）
     ======================================================================== */
  @media screen and (max-width: 1024px) {
    .header-container,
    .hero-container,
    .feature-container,
    .section-three .feature-container,
    .section-four,
    .section-five {
      flex-direction: column;
      text-align: center;
    }
  
    .main-nav {
      margin-top: 15px;
    }
  
    .main-nav ul {
      flex-direction: column;
      gap: 15px;
    }
  
    .hero-text,
    .feature-text {
      max-width: 100%;
    }
  
    .hero-phone,
    .feature-phone {
      margin-top: 40px;
    }
  
    .footer-container {
      flex-direction: column;
      align-items: center;
    }
  
    .footer-col {
      margin-top: 40px;
    }
  }
  
  @media screen and (max-width: 600px) {
    .hero-title {
      font-size: 32px;
    }
  
    .hero-subtitle {
      font-size: 16px;
    }
  
    .feature-text h2 {
      font-size: 24px;
    }
  
    .feature-text p {
      font-size: 14px;
    }
  }