body {
      margin: 0;
      padding: 0;
      height: 100vh;
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      font-family: "Segoe UI", "Microsoft YaHei", sans-serif;
      overflow: hidden;
      background: linear-gradient(135deg, #a8edea, #fed6e3);
      position: relative;
    }

    /* 水泡背景 */
    .bubbles {
      position: absolute;
      width: 100%;
      height: 100%;
      top: 0; left: 0;
      overflow: hidden;
      z-index: 0;
      pointer-events: none;
    }
    .bubble {
      position: absolute;
      bottom: -60px;
      border-radius: 50%;
      background: radial-gradient(circle at 30% 30%, rgba(255,255,255,0.7), rgba(255,255,255,0.2));
      box-shadow: 0 0 10px rgba(255,255,255,0.4);
      animation: rise linear infinite;
    }
    @keyframes rise {
      0%   { transform: translateY(0) scale(1); opacity: 0.8; }
      50%  { opacity: 0.4; }
      100% { transform: translateY(-120vh) scale(1.3); opacity: 0; }
    }

    /* 头像 */
    .avatar {
      width: 140px;
      height: 140px;
      border-radius: 50%;
      overflow: hidden;
      border: 4px solid rgba(255,255,255,0.7);
      box-shadow: 0 4px 15px rgba(0,0,0,0.15);
      /* 调整头像与下方内容的间距 */
      margin-bottom: 40px;
      z-index: 1;
      position: relative;
    }
    .avatar img {
      width: 100%;
      height: 100%;
      object-fit: cover;
    }

    /* 按钮容器 - 使用 Grid 实现两行两列布局 */
    .nav {
      display: grid;
      grid-template-columns: repeat(2, auto); /* 改为 auto，让列宽适应内容 */
      grid-auto-rows: auto;
      gap: 25px; /* 按钮之间的间距（上下和左右） */
      /* 不设置固定宽度，让其自然收缩 */
      /* width: 90%; max-width: 800px; */
      justify-content: center; /* 将整个按钮网格在容器中水平居中 */
      
      /* 调整按钮区域与上下元素的间距 */
      margin-bottom: 25px;
      opacity: 0;
      transform: translateY(40px);
      animation: fadeUp 1s ease forwards;
      z-index: 1;
      position: relative;
      /* 移除或注释掉 justify-items: center; */
      /* justify-items: center; */
    }
    @keyframes fadeUp {
      to { opacity: 1; transform: translateY(0); }
    }

    /* 按钮通用样式 - 更贴近内容宽度，非拉伸 */
    .btn {
      flex: 1 1 auto;
      min-width: 180px;
      padding: 14px 36px;
      font-size: 16px;
      font-weight: bold;
      color: #fff;
      text-decoration: none;
      position: relative;
      overflow: hidden;
      border-radius: 50px;
      box-shadow: 0 4px 20px rgba(0,0,0,0.15);
      transition: transform 0.3s ease;
      text-align: center;
    }
    .btn.left  { background: rgba(0, 172, 193, 0.85); border: 2px solid rgba(255,255,255,0.6); }
    .btn.right { background: rgba(255, 140, 0, 0.85); border: 2px solid rgba(255,255,255,0.6); }
    .btn::before {
      content: "";
      position: absolute;
      top: -50%; left: -50%;
      width: 200%; height: 200%;
      background: linear-gradient(120deg, rgba(255,255,255,0.1), rgba(255,255,255,0.4), rgba(255,255,255,0.1));
      transform: rotate(25deg);
      opacity: 0;
      transition: all 0.6s ease;
    }
    .btn:hover {
      transform: translateY(-4px) scale(1.05);
    }
    .btn:hover::before {
      left: -30%;
      opacity: 1;
      animation: shimmer 1.2s linear forwards;
    }
    @keyframes shimmer {
      0%   { transform: translateX(-100%) rotate(25deg); }
      100% { transform: translateX(100%) rotate(25deg); }
    }

    /* 按钮配色 - 柔和渐变护眼系 */
    .btn1 { background: linear-gradient(135deg, #89f7fe, #66a6ff); }  /* 青蓝渐变 */
    .btn2 { background: linear-gradient(135deg, #f6d365, #fda085); }  /* 暖橙渐变 */
    .btn3 { background: linear-gradient(135deg, #c3cfe2, #cfd9df); }  /* 灰蓝渐变 */
    .btn4 { background: linear-gradient(135deg, #a1c4fd, #c2e9fb); }  /* 浅蓝渐变 */


    /* 按钮下方文字 */
    .worktime {
      font-size: 16px;
      text-align: center;
      max-width: 90%;
      line-height: 1.8em;
      margin-top: 15px;
      z-index: 1;
      position: relative;
    }
    .worktime span {
      display: block;
      margin: 6px 0; /* 调整每行文字的上下间距 */
      opacity: 0;
      animation: textFade 0.8s forwards;
    }
    @keyframes textFade {
      0%   { opacity: 0; transform: translateY(10px); }
      100% { opacity: 1; transform: translateY(0); }
    }
    /* 设置动画延迟 */
    .worktime span:nth-child(1){ animation-delay:0.3s; }
    .worktime span:nth-child(2){ animation-delay:0.8s; }
    .worktime span:nth-child(3){ animation-delay:1.3s; }
    .worktime span:nth-child(4){ animation-delay:1.8s; }

    /* 文字颜色 */
    .line1 { color: #4A90E2; animation: glow 4s ease-in-out infinite alternate; }
    .line2 { color: #50C878; animation: glow 4s ease-in-out infinite alternate; }
    .line3 { color: #F5A623; animation: glow 4s ease-in-out infinite alternate; }
    .line4 { color: #D65DB1; font-weight: bold; animation: glow 4s ease-in-out infinite alternate; }

    @keyframes glow {
      0%   { text-shadow: 0 0 4px rgba(255,255,255,0.2); transform: scale(1); }
      100% { text-shadow: 0 0 12px rgba(255,255,255,0.5); transform: scale(1.02); }
    }

    /* 页脚版权 */
    .copyright {
      font-size: 12px;
      color: rgba(0,0,0,0.6);
      text-align: center;
      position: fixed;   /* 改为固定定位 */
      bottom: 10px;
      width: 100%;
      z-index: 99;       /* 提高层级，避免被泡泡覆盖 */
      background: transparent;
    }

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

    /* 自定义光标 */
    .cursor {
      width: 12px;
      height: 12px;
      position: fixed;
      border-radius: 50%;
      background: rgba(255,255,255,0.8);
      pointer-events: none;
      transform: translate(-50%, -50%);
      transition: transform 0.15s ease;
      z-index: 9999;
    }

    /* 移动端适配 */
    @media (max-width: 600px) {
      .avatar {
        width: 100px;
        height: 100px;
        margin-bottom: 30px; /* 移动端调整头像间距 */
      }
      .btn {
        padding: 12px 20px; /* 移动端调整按钮内边距 */
        font-size: 15px;
        min-width: 130px; /* 移动端调整最小宽度 */
      }
      .nav {
        gap: 18px; /* 移动端调整按钮间距 */
        margin-bottom: 20px; /* 移动端调整按钮区域间距 */
      }
      .worktime {
        font-size: 14px;
        padding-top: 15px; /* 移动端调整文字区域顶部间距 */
        margin-bottom: 20px; /* 移动端调整文字区域底部间距 */
      }
      .worktime span {
        margin: 5px 0; /* 移动端调整文字行间距 */
      }
    }