@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+TC:wght@300;400;500;700&display=swap');
        
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Noto Sans TC', 'Microsoft JhengHei', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #8b5cf6 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    position: relative;
    overflow: hidden;
}

body::before {
    content: '';
    position: absolute;
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(139, 92, 246, 0.3) 0%, transparent 70%);
    top: -250px;
    right: -250px;
    border-radius: 50%;
    animation: float 8s ease-in-out infinite;
}

body::after {
    content: '';
    position: absolute;
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(102, 126, 234, 0.3) 0%, transparent 70%);
    bottom: -200px;
    left: -200px;
    border-radius: 50%;
    animation: float 10s ease-in-out infinite reverse;
}

@keyframes float {
    0%, 100% { transform: translateY(0) rotate(0deg); }
    50% { transform: translateY(-30px) rotate(5deg); }
}

.auth-container {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    border-radius: 24px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    overflow: hidden;
    width: 100%;
    max-width: 900px;
    min-height: 600px;
    display: flex;
    position: relative;
    z-index: 1;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.auth-sidebar {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 60px 40px;
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.auth-sidebar::before {
    content: '囍';
    position: absolute;
    font-size: 22em;
    color: rgba(255, 255, 255, 0.06);
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) rotate(-12deg);
    font-family: 'DFKai-SB', 'BiauKai', serif;
    pointer-events: none;
}

.auth-sidebar h1 {
    font-family: 'DFKai-SB', 'BiauKai', '標楷體', 'Noto Sans TC', serif;
    font-size: 4.2em;
    margin-bottom: 25px;
    font-weight: 400;
    letter-spacing: 12px;
    position: relative;
    z-index: 1;
    text-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
}

.auth-sidebar .subtitle {
    font-size: 1.15em;
    color: rgba(255, 255, 255, 0.95);
    line-height: 2;
    position: relative;
    z-index: 1;
    font-weight: 300;
    margin-top: 20px;
}

.auth-sidebar .feature-list {
    margin-top: 30px;
    text-align: left;
    position: relative;
    z-index: 1;
}

.auth-sidebar .feature-item {
    display: flex;
    align-items: center;
    margin: 15px 0;
    font-size: 1em;
    color: rgba(255, 255, 255, 0.9);
}

.auth-sidebar .feature-item::before {
    content: '✓';
    display: inline-block;
    width: 24px;
    height: 24px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    margin-right: 12px;
    text-align: center;
    line-height: 24px;
    font-weight: bold;
}

.auth-forms {
    flex: 1;
    padding: 60px 40px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    background: white;
}

.tab-buttons {
    display: flex;
    margin-bottom: 35px;
    border-radius: 12px;
    background: #f1f3f9;
    padding: 6px;
    gap: 6px;
}

.tab-btn {
    flex: 1;
    background: none;
    border: none;
    padding: 14px;
    border-radius: 10px;
    font-size: 1.05em;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    color: #64748b;
    font-family: 'Noto Sans TC', sans-serif;
}

.tab-btn.active {
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.3);
    transform: translateY(-1px);
}

.tab-btn:hover:not(.active) {
    background: rgba(102, 126, 234, 0.1);
    color: #667eea;
}

.form-container {
    display: none;
    animation: fadeIn 0.4s ease-out;
}

.form-container.active {
    display: block;
}

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

.form-group {
    margin-bottom: 22px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: #334155;
    font-size: 0.95em;
}

.form-control {
    width: 100%;
    padding: 14px 16px;
    border: 2px solid #e2e8f0;
    border-radius: 10px;
    font-size: 15px;
    transition: all 0.3s ease;
    font-family: inherit;
    background: #f8fafc;
}

.form-control:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 4px rgba(102, 126, 234, 0.1);
    background: white;
}

.form-row {
    display: flex;
    gap: 15px;
}

.form-row .form-group {
    flex: 1;
}

.btn {
    width: 100%;
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
    border: none;
    padding: 15px;
    border-radius: 10px;
    font-size: 1.05em;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    margin-top: 10px;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
    font-family: 'Noto Sans TC', sans-serif;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(102, 126, 234, 0.4);
}

.btn:active {
    transform: translateY(0);
}

.alert {
    padding: 14px 16px;
    border-radius: 10px;
    margin-bottom: 25px;
    font-weight: 500;
    font-size: 0.95em;
    border-left: 4px solid;
}

.alert-success {
    background: #d1fae5;
    color: #065f46;
    border-color: #10b981;
}

.alert-error {
    background: #fee2e2;
    color: #991b1b;
    border-color: #ef4444;
}

.forgot-password {
    text-align: center;
    margin-top: 20px;
}

.forgot-password a {
    color: #667eea;
    text-decoration: none;
    font-size: 0.9em;
    font-weight: 500;
    transition: color 0.3s ease;
}

.forgot-password a:hover {
    color: #764ba2;
    text-decoration: underline;
}

@media (max-width: 768px) {
    .auth-container {
        flex-direction: column;
        max-width: 500px;
    }
    
    .auth-sidebar {
        padding: 40px 30px;
    }
    
    .auth-sidebar h1 {
        font-size: 3em;
        letter-spacing: 8px;
    }
    
    .auth-forms {
        padding: 40px 30px;
    }
    
    .form-row {
        flex-direction: column;
        gap: 0;
    }
}