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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.login-container {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.login-card {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    padding: 40px;
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
    width: 100%;
    max-width: 450px;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.login-header {
    text-align: center;
    margin-bottom: 30px;
}

.login-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, #667eea, #764ba2);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 8px;
}

.login-header p {
    color: #666;
    font-size: 1.1rem;
}

.login-form {
    margin-bottom: 25px;
}

.login-footer {
    text-align: center;
    color: #666;
}

.login-footer p {
    margin-bottom: 15px;
}

.register-links {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    flex-wrap: wrap;
}

.register-link {
    color: #667eea;
    text-decoration: none;
    font-weight: 500;
    padding: 5px 10px;
    border-radius: 5px;
    transition: all 0.3s ease;
}

.register-link:hover {
    background: #667eea;
    color: white;
}

.register-link.student {
    border: 1px solid #667eea;
}

.register-link.lecturer {
    border: 1px solid #764ba2;
    color: #764ba2;
}

.register-link.lecturer:hover {
    background: #764ba2;
}

.form-container {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    padding: 40px;
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
    width: 100%;
    max-width: 900px;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.form-container h2 {
    text-align: center;
    margin-bottom: 30px;
    font-size: 2.2rem;
    font-weight: 700;
    background: linear-gradient(135deg, #667eea, #764ba2);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.tab-buttons {
    display: flex;
    margin-bottom: 30px;
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.tab-btn {
    flex: 1;
    padding: 15px 20px;
    border: none;
    background: #f8f9fa;
    color: #666;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
}

.tab-btn.active {
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
    transform: translateY(-2px);
    z-index: 2;
}

.tab-btn:hover:not(.active) {
    background: #e9ecef;
    transform: translateY(-1px);
}

.tab-content {
    display: none;
    animation: fadeIn 0.5s ease;
}

.tab-content.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin-bottom: 20px;
}

.form-group {
    display: flex;
    flex-direction: column;
}

.form-group label {
    margin-bottom: 8px;
    font-weight: 600;
    color: #333;
    font-size: 0.95rem;
}

.form-group input,
.form-group select {
    padding: 12px 15px;
    border: 2px solid #e1e5e9;
    border-radius: 10px;
    font-size: 1rem;
    transition: all 0.3s ease;
    background: white;
}

.form-group input:focus,
.form-group select:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
    transform: translateY(-1px);
}

.form-group select {
    cursor: pointer;
}

.form-group input::placeholder {
    color: #999;
}

.btn {
    padding: 12px 25px;
    border: none;
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-block;
    text-align: center;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.btn-primary {
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(102, 126, 234, 0.3);
}

.btn-secondary {
    background: #6c757d;
    color: white;
}

.btn-secondary:hover {
    background: #5a6268;
    transform: translateY(-2px);
}

.btn-full {
    width: 100%;
}

.form-actions {
    display: flex;
    gap: 15px;
    justify-content: center;
    margin-top: 30px;
    flex-wrap: wrap;
}

.alert {
    padding: 15px 20px;
    border-radius: 10px;
    margin-bottom: 20px;
    font-weight: 500;
    animation: slideDown 0.3s ease;
}

.alert.error {
    background: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.alert.success {
    background: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.error-message {
    color: #dc3545;
    font-size: 0.85rem;
    margin-top: 5px;
    display: block;
    min-height: 1.2rem;
    font-weight: 500;
}

.error-message:empty {
    display: none;
}

@keyframes slideDown {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}

.footer {
    text-align: center;
    padding: 20px;
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.9rem;
}

@media (max-width: 768px) {
    .container, .login-container {
        padding: 10px;
    }
    
    .form-container, .login-card {
        padding: 20px;
        margin: 10px;
    }
    
    .form-container h2, .login-header h1 {
        font-size: 1.8rem;
    }
    
    .form-row {
        grid-template-columns: 1fr;
        gap: 15px;
    }
    
    .tab-buttons {
        flex-direction: column;
    }
    
    .tab-btn {
        border-radius: 0;
    }
    
    .tab-btn:first-child {
        border-radius: 10px 10px 0 0;
    }
    
    .tab-btn:last-child {
        border-radius: 0 0 10px 10px;
    }
    
    .form-actions {
        flex-direction: column;
    }
    
    .register-links {
        flex-direction: column;
        gap: 5px;
    }
}

@media (max-width: 480px) {
    .form-container, .login-card {
        padding: 15px;
    }
    
    .form-group input,
    .form-group select {
        padding: 10px 12px;
        font-size: 0.95rem;
    }
    
    .btn {
        padding: 10px 20px;
        font-size: 0.95rem;
    }
}

.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: #fff;
    animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.form-group input.invalid,
.form-group select.invalid {
    border-color: #dc3545;
    box-shadow: 0 0 0 3px rgba(220, 53, 69, 0.1);
}

.form-group input.valid,
.form-group select.valid {
    border-color: #28a745;
    box-shadow: 0 0 0 3px rgba(40, 167, 69, 0.1);
}

.form-group input:hover,
.form-group select:hover {
    border-color: #b8c4d0;
}

.form-group {
    position: relative;
}

.form-group input:focus + label,
.form-group select:focus + label {
    color: #667eea;
}

* {
    transition: all 0.3s ease;
}

::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: #f1f1f1;
    border-radius: 10px;
}

::-webkit-scrollbar-thumb {
    background: linear-gradient(135deg, #667eea, #764ba2);
    border-radius: 10px;
}

::-webkit-scrollbar-thumb:hover {
    background: linear-gradient(135deg, #5a6fd8, #6a4190);
}