* {
     margin: 0;
     padding: 0;
     box-sizing: border-box;
     font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
 }
 
 body {
     display: flex;
     justify-content: center;
     align-items: center;
     min-height: 100vh;
     background: linear-gradient(135deg, #6e8efb, #a777e3);
     padding: 20px;
 }
 
 .container {
     width: 100%;
     max-width: 420px;
 }
 
 .login-card {
     background: #fff;
     border-radius: 16px;
     box-shadow: 0 15px 30px rgba(0, 0, 0, 0.15);
     padding: 35px 30px;
     text-align: center;
     transition: transform 0.3s ease;
 }
 
 .login-card:hover {
     transform: translateY(-5px);
 }
 
 .logo {
     width: 80px;
     height: 80px;
     margin: 0 auto 15px;
     background: linear-gradient(135deg, #6e8efb, #a777e3);
     border-radius: 50%;
     display: flex;
     align-items: center;
     justify-content: center;
 }
 
 .logo i {
     font-size: 40px;
     color: white;
 }
 
 h2 {
     color: #333;
     margin-bottom: 25px;
     font-weight: 600;
 }
 
 .input-group {
     margin-bottom: 20px;
     text-align: left;
 }
 
 label {
     display: block;
     margin-bottom: 8px;
     color: #555;
     font-weight: 500;
 }
 
 .input-field {
     width: 100%;
     padding: 14px 15px;
     border: 2px solid #ddd;
     border-radius: 10px;
     font-size: 16px;
     transition: border-color 0.3s;
 }
 
 .input-field:focus {
     border-color: #6e8efb;
     outline: none;
 }
 
 .captcha-container {
     display: flex;
     gap: 10px;
     margin-bottom: 20px;
 }
 
 .captcha-code {
     flex: 1;
     background: #f0f4ff;
     border-radius: 10px;
     display: flex;
     align-items: center;
     justify-content: center;
     font-size: 22px;
     font-weight: bold;
     letter-spacing: 3px;
     color: #333;
     user-select: none;
     height: 55px;
     cursor: pointer;
     transition: background 0.3s;
 }
 
 .captcha-code:hover {
     background: #e1e9ff;
 }
 
 .captcha-input {
     flex: 1;
 }
 
 .refresh-btn {
     background: #f0f4ff;
     border: none;
     border-radius: 10px;
     width: 55px;
     cursor: pointer;
     transition: background 0.3s;
 }
 
 .refresh-btn:hover {
     background: #e1e9ff;
 }
 
 .refresh-btn i {
     font-size: 22px;
     color: #6e8efb;
 }
 
 .login-btn {
     width: 100%;
     padding: 14px;
     background: linear-gradient(135deg, #6e8efb, #a777e3);
     border: none;
     border-radius: 10px;
     color: white;
     font-size: 16px;
     font-weight: 600;
     cursor: pointer;
     transition: opacity 0.3s;
 }
 
 .login-btn:hover {
     opacity: 0.9;
 }
 
 .options {
     display: flex;
     justify-content: space-between;
     margin-top: 20px;
     font-size: 14px;
 }
 
 .remember {
     display: flex;
     align-items: center;
     color: #666;
 }
 
 .remember input {
     margin-right: 6px;
 }
 
 .forgot {
     color: #6e8efb;
     text-decoration: none;
 }
 
 .forgot:hover {
     text-decoration: underline;
 }
 
 .footer {
     margin-top: 25px;
     color: #777;
     font-size: 13px;
 }
 
 .error-message {
     color: #ff4757;
     font-size: 14px;
     margin-top: 5px;
     text-align: left;
     display: none;
 }
 
 @media (max-width: 480px) {
     .login-card {
         padding: 25px 20px;
     }
     
     .captcha-container {
         flex-direction: column;
     }
     
     .refresh-btn {
         width: 100%;
         height: 45px;
     }
 }