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

    body {
      min-height: 100vh;
      display: flex;
      flex-direction: column;
      font-family: "Microsoft YaHei", Arial, sans-serif;
      background: #f5f7fa;
      color: #333;
    }

    a {
      text-decoration: none;
    }

    .container {
      width: 100%;
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 2rem;
    }

    .top-bar {
      background: #fff;
      border-bottom: 1px solid #e8edf5;
      color: #6b7280;
      font-size: 13px;
    }

    .top-bar .container {
      min-height: 42px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 16px;
    }

    .top-links {
      display: flex;
      align-items: center;
      gap: 18px;
    }

    .top-links a {
      color: #6b7280;
      transition: color 0.2s ease;
    }

    .top-links a:hover {
      color: #3557ff;
    }

    .main-nav {
      background: #fff;
      box-shadow: 0 10px 30px rgba(17, 24, 39, 0.08);
    }

    .main-nav .container {
      min-height: 78px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 24px;
    }

    .logo {
      display: inline-flex;
      align-items: center;
      gap: 12px;
      color: #111827;
      font-size: 22px;
      font-weight: 700;
    }

    .logo img {
      width: 50px;
      height: 50px;
      object-fit: contain;
      border-radius: 12px;
      background: #fff;
    }

    .logo-icon {
      width: 50px;
      height: 50px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      border-radius: 12px;
      background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
      color: #fff;
      font-size: 24px;
      font-weight: 700;
    }

    .nav-links {
      list-style: none;
      display: flex;
      align-items: center;
      gap: 24px;
      color: #374151;
      font-size: 15px;
    }

    .nav-links a {
      color: #374151;
      transition: color 0.2s ease;
    }

    .nav-links a:hover {
      color: #3557ff;
    }

    .login-wrapper {
      flex: 1;
      display: flex;
      align-items: center;
      justify-content: center;
      padding: 48px 20px;
      background:
        radial-gradient(circle at top left, rgba(255, 255, 255, 0.22), transparent 24%),
        radial-gradient(circle at bottom right, rgba(255, 255, 255, 0.16), transparent 20%),
        linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    }

    .login-container {
      width: 100%;
      max-width: 430px;
      overflow: hidden;
      border-radius: 10px;
      background: #fff;
      box-shadow: 0 18px 48px rgba(31, 41, 55, 0.24);
    }

    .login-header {
      padding: 32px 30px 26px;
      text-align: center;
      color: #fff;
      background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    }

    .login-header h1 {
      margin-bottom: 8px;
      font-size: 28px;
      font-weight: 700;
    }

    .login-header p {
      font-size: 14px;
      opacity: 0.92;
    }

    .login-form {
      padding: 34px 30px 28px;
    }

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

    .form-label {
      display: block;
      margin-bottom: 8px;
      color: #374151;
      font-size: 14px;
      font-weight: 600;
    }

    .form-input {
      width: 100%;
      height: 44px;
      padding: 0 14px;
      border: 1px solid #d8dee9;
      border-radius: 6px;
      font-size: 14px;
      color: #111827;
      transition: border-color 0.2s ease, box-shadow 0.2s ease;
    }

    .form-input:focus {
      border-color: #667eea;
      box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.12);
      outline: none;
    }

    .captcha-row {
      display: flex;
      align-items: stretch;
      gap: 10px;
    }

    .captcha-input {
      flex: 1;
    }

    .captcha-image-wrap {
      display: flex;
      align-items: stretch;
      gap: 8px;
    }

    .captcha-image {
      width: 112px;
      height: 44px;
      border: 1px solid #d8dee9;
      border-radius: 6px;
      background: linear-gradient(45deg, #f8fafc, #eef2ff);
      cursor: pointer;
      object-fit: cover;
    }

    .captcha-refresh-btn {
      height: 44px;
      padding: 0 14px;
      border-radius: 6px;
    }

    .error-box {
      margin-bottom: 18px;
      padding: 10px 12px;
      border: 1px solid #fecaca;
      border-radius: 6px;
      background: #fef2f2;
      color: #dc2626;
      font-size: 13px;
      line-height: 1.6;
    }

    .form-options {
      margin-bottom: 20px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 12px;
      color: #6b7280;
      font-size: 13px;
    }

    .remember-me {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      cursor: pointer;
    }

    .remember-me input {
      margin: 0;
    }

    .forgot-password {
      color: #0066cc;
      text-decoration: none;
      transition: color 0.3s;
    }

    .btn-submit {
      width: 100%;
      height: 46px;
      border: none;
      border-radius: 6px;
      background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
      box-shadow: 0 10px 24px rgba(102, 126, 234, 0.24);
      font-size: 16px;
      font-weight: 700;
    }

    .btn-submit:hover,
    .btn-submit:focus {
      background: linear-gradient(135deg, #5b72ea 0%, #6f42c1 100%);
    }

    .login-footer-text {
      margin-top: 20px;
      color: #6b7280;
      font-size: 14px;
      text-align: center;
      line-height: 1.8;
    }

    .login-footer-text a {
      color: #3557ff;
      font-weight: 600;
    }

    .app-download {
      margin-top: 24px;
      padding-top: 20px;
      border-top: 1px solid #e8edf5;
      color: #9ca3af;
      font-size: 13px;
      text-align: center;
    }

    .download-links {
      margin-top: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 24px;
      color: #6b7280;
    }

    .download-links span {
      display: inline-flex;
      align-items: center;
      gap: 6px;
    }

    .footer {
      color: rgba(255, 255, 255, 0.92);
      background: rgba(20, 26, 54, 0.9);
      backdrop-filter: blur(8px);
    }

    .footer .container {
      padding-top: 28px;
      padding-bottom: 28px;
      font-size: 13px;
      line-height: 1.9;
      text-align: center;
    }

    .footer a {
      color: rgba(255, 255, 255, 0.96);
    }

    @media (max-width: 768px) {
      .container {
        padding: 0 16px;
      }

      .nav-links {
        display: none;
      }

      .main-nav .container {
        min-height: 68px;
      }

      .logo {
        font-size: 18px;
      }

      .logo img,
      .logo-icon {
        width: 42px;
        height: 42px;
      }

      .login-wrapper {
        padding: 28px 16px;
      }

      .login-header {
        padding: 28px 22px 24px;
      }

      .login-header h1 {
        font-size: 24px;
      }

      .login-form {
        padding: 28px 22px 24px;
      }

      .captcha-row {
        flex-direction: column;
      }

      .captcha-image-wrap {
        width: 100%;
      }

      .captcha-image,
      .captcha-refresh-btn {
        width: 100%;
      }

      .form-options {
        flex-direction: column;
        align-items: flex-start;
      }
    }