:root {
    --primary-color: #4f46e5;
    --primary-hover: #4338ca;
    --secondary-color: #e5e7eb;
    --success-color: #10b981;
    --error-color: #ef4444;
    --text-color: #1f2937;
    --text-muted: #6b7280;
    --border-color: #d1d5db;
    --background-color: #f9fafb;
    --white: #ffffff;
    --google-color: #db4437;
    --google-hover: #c23321;
}

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

body {
    font-family: 'Poppins', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.login-container {
    width: 100%;
    max-width: 450px;
    position: relative;
}

.login-box {
    background: var(--white);
    border-radius: 16px;
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    padding: 40px;
    width: 100%;
}

.logo-section {
    text-align: center;
    margin-bottom: 30px;
}

.logo-image {
    width: 80px;
    height: 80px;
    margin-bottom: 10px;
    border-radius: 12px;
}

.logo-section h1 {
    font-size: 2rem;
    font-weight: 600;
    color: var(--text-color);
    margin-bottom: 5px;
}

.logo-section p {
    color: var(--text-muted);
    font-size: 0.9rem;
}

.login-tabs {
    display: flex;
    margin-bottom: 30px;
    border-radius: 8px;
    background: var(--background-color);
    padding: 4px;
}

.tab-button {
    flex: 1;
    background: transparent;
    border: none;
    padding: 12px 16px;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 500;
    color: var(--text-muted);
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.tab-button.active {
    background: var(--white);
    color: var(--primary-color);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.tab-content {
    display: none;
}

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

/* 기본적으로 소셜 탭은 숨김 */
#social-tab {
    display: none;
}

/* 이메일 탭은 기본적으로 보임 */
#email-tab {
    display: block;
}

/* 소셜 탭이 활성화되었을 때만 보임 */
#social-tab.active {
    display: block !important;
}

/* 이메일 탭이 비활성화되었을 때 숨김 */
#email-tab:not(.active) {
    display: none !important;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: var(--text-color);
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 8px;
}

.form-group input {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    transition: all 0.3s ease;
    font-family: inherit;
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.login-btn {
    width: 100%;
    background: var(--primary-color);
    color: var(--white);
    border: none;
    padding: 14px 20px;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    margin-bottom: 20px;
}

.login-btn:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
}

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

.divider {
    text-align: center;
    margin: 25px 0;
    position: relative;
}

.divider::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 0;
    right: 0;
    height: 1px;
    background: var(--border-color);
}

.divider span {
    background: var(--white);
    padding: 0 15px;
    color: var(--text-muted);
    font-size: 0.9rem;
}

.auth-links {
    text-align: center;
}

.auth-links p {
    color: var(--text-muted);
    font-size: 0.9rem;
}

.auth-links a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
}

.auth-links a:hover {
    text-decoration: underline;
}

.social-login-buttons {
    margin-bottom: 20px;
}

.social-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    width: 100%;
    padding: 14px 20px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    font-size: 1rem;
    transition: all 0.3s ease;
    margin-bottom: 10px;
}

.google-btn {
    background: var(--google-color);
    color: var(--white);
}

.google-btn:hover {
    background: var(--google-hover);
    transform: translateY(-1px);
}

.social-info {
    text-align: center;
    background: var(--background-color);
    padding: 15px;
    border-radius: 8px;
}

.social-info p {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin: 0;
}

.register-section {
    border-top: 1px solid var(--border-color);
    padding-top: 30px;
    margin-top: 30px;
}

.register-section h3 {
    text-align: center;
    color: var(--text-color);
    margin-bottom: 25px;
    font-weight: 600;
}

.message {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 12px 20px;
    border-radius: 8px;
    font-weight: 500;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    z-index: 1000;
    max-width: 400px;
}

.message.success {
    background: var(--success-color);
    color: var(--white);
}

.message.error {
    background: var(--error-color);
    color: var(--white);
}

/* 반응형 디자인 */
@media (max-width: 480px) {
    body {
        padding: 10px;
    }
    
    .login-box {
        padding: 30px 20px;
    }
    
    .logo-section h1 {
        font-size: 1.5rem;
    }
    
    .tab-button {
        padding: 10px 12px;
        font-size: 0.9rem;
    }
}