* { margin: 0; padding: 0; box-sizing: border-box; }
        body { font-family: 'Microsoft YaHei', Arial, sans-serif; background: #f5f7fa; min-height: 100vh; display: flex; align-items: center; justify-content: center; }
        .container { width: 400px; background: #fff; border-radius: 8px; box-shadow: 0 2px 12px rgba(0,0,0,0.1); padding: 40px; }
        .logo { text-align: center; margin-bottom: 30px; }
        .logo img { height: 50px; }
        .logo h2 { font-size: 20px; color: #1e3a5f; margin-top: 10px; }
        .form-group { margin-bottom: 20px; }
        .form-group label { display: block; margin-bottom: 6px; color: #333; font-size: 14px; }
        .form-group input { width: 100%; padding: 10px 12px; border: 1px solid #dcdfe6; border-radius: 4px; font-size: 14px; transition: border-color 0.2s; }
        .form-group input:focus { outline: none; border-color: #1e3a5f; }
        .btn { width: 100%; padding: 12px; background: #1e3a5f; color: #fff; border: none; border-radius: 4px; font-size: 16px; cursor: pointer; transition: background 0.2s; }
        .btn:hover { background: #2a5298; }
        .error { background: #fef0f0; color: #f56c6c; padding: 10px; border-radius: 4px; margin-bottom: 20px; font-size: 14px; }
        .security-tip { background: #f0f7ff; border: 1px solid #d6e8ff; color: #4a7db3; padding: 10px 12px; border-radius: 4px; margin-top: 16px; font-size: 13px; line-height: 1.8; }
        .security-tip b { color: #2a5298; }
        .security-tip .tip-red { color: #f5222d; font-weight: 600; }
        .links { display: flex; justify-content: space-between; margin-top: 20px; font-size: 14px; }
        .links a { color: #1e3a5f; text-decoration: none; }
        .links a:hover { text-decoration: underline; }