body {
     margin: 0;
     padding: 0;
     background: #f7f9fb;
     min-height: 100vh;
     font-family: 'Kanit', 'Segoe UI', Arial, sans-serif;
 }

 .navbar {
     width: 100%;
     background: #fff;
     box-shadow: 0 2px 8px 0 rgba(0, 0, 0, 0.04);
     height: 60px;
     display: flex;
     align-items: center;
     justify-content: space-between;
     padding: 0 48px;
     position: fixed;
     top: 0;
     left: 0;
     z-index: 10;
 }

 .navbar .brand {
     font-size: 1.35rem;
     font-weight: 500;
     color: #2d3a4a;
     letter-spacing: 0.5px;
 }

 .navbar .nav-link {
     color: #2d3a4a;
     font-size: 1rem;
     text-decoration: none;
     font-weight: 400;
     transition: color 0.2s;
 }

 .navbar .nav-link:hover {
     color: #1976d2;
 }

 .center-container {
     min-height: 100vh;
     display: flex;
     align-items: center;
     justify-content: center;
 }

 .login-card {
     background: #fff;
     border-radius: 12px;
     box-shadow: 0 8px 32px 0 rgba(60, 72, 88, 0.10);
     padding: 40px 32px 32px 32px;
     width: 100%;
     max-width: 400px;
     margin-top: 60px;
     display: flex;
     flex-direction: column;
     align-items: center;
 }

 .login-card .logo {
     width: 80px;
 }

 .login-card .title {
     font-size: 1.5rem;
     font-weight: 500;
     color: #2d3a4a;
     margin-bottom: 4px;
     text-align: center;
 }

 .login-card .subtitle {
     font-size: 1rem;
     color: #6c757d;
     margin-bottom: 16px;
     text-align: center;
 }

 .login-card form {
     width: 100%;
 }

 .login-card label {
     font-size: 0.85rem;
     color: #6c757d;
     margin-bottom: 4px;
     margin-top: 12px;
     display: block;
     font-weight: 500;
 }

 .login-card .input-group {
     position: relative;
     margin-bottom: 18px;
     display: flex;
     align-items: center;
 }

 .login-card .input-group input[type="password"] {
     width: 100%;
     padding: 10px 38px 10px 38px;
     border: 1px solid #dbe2ea;
     border-radius: 5px;
     font-size: 1rem;
     background: #f7f9fb;
     color: #2d3a4a;
     transition: border 0.2s;
     outline: none;
     font-family: 'Kanit', 'Segoe UI', Arial, sans-serif;
 }

 .login-card .input-group input[type="text"] {
     width: 100%;
     padding: 10px 12px 10px 38px;
     border: 1px solid #dbe2ea;
     border-radius: 5px;
     font-size: 1rem;
     background: #f7f9fb;
     color: #2d3a4a;
     transition: border 0.2s;
     font-size: 15px;
     outline: none;
     font-family: 'Kanit', 'Segoe UI', Arial, sans-serif;
 }

 .login-card .input-group i.fas.fa-user,
 .login-card .input-group i.fas.fa-lock {
     position: absolute;
     left: 12px;
     top: 50%;
     transform: translateY(-50%);
     color: #b0b8c1;
     font-size: 1rem;
     pointer-events: none;
 }

 .login-card .input-group .password-toggle {
     position: absolute;
     right: 12px;
     top: 50%;
     transform: translateY(-50%);
     color: #b0b8c1;
     font-size: 1rem;
     cursor: pointer;
     z-index: 2;
 }

 .login-card .login-btn {
     width: auto;
     min-width: 100px;
     float: right;
     display: block;
     margin-left: auto;
     margin-top: 8px;
     background: #4285f4;
     color: #fff;
     border: none;
     border-radius: 5px;
     padding: 10px 28px;
     font-size: 1rem;
     font-weight: 500;
     cursor: pointer;
     transition: background 0.2s;
 }

 .login-card .login-btn:hover {
     background: #1976d2;
 }

 .login-card .error,
 .login-card .success {
     width: 100%;
     margin-bottom: 12px;
     padding: 10px;
     border-radius: 5px;
     text-align: center;
     font-size: 0.95rem;
 }

 .login-card .error {
     background: #fdeaea;
     color: #d32f2f;
 }

 .login-card .success {
     background: #eafaf1;
     color: #388e3c;

 }

 @media (max-width: 600px) {
     .navbar {
         padding: 0 16px;
     }

     .login-card {
         padding: 28px 8px 24px 8px;
     }
 }