:root {
    --primary-color: #0d6efd;
    --primary-light: #e6f0ff;
    --primary-dark: #0056b3;
    --secondary-color: #6c757d;
    --success-color: #198754;
    --danger-color: #dc3545;
    --warning-color: #ffc107;
    --info-color: #17a2b8;
    --light-color: #f8f9fa;
    --dark-color: #212529;
    --white-color: #ffffff;
    --text-dark: #212529;
    --text-medium: #495057;
    --text-light: #6c757d;
    --border-color: #dee2e6;
    --border-radius: 12px;
    --box-shadow: 0 8px 30px rgba(0, 0, 0, 0.12);
    --transition-base: all 0.3s ease;
}

/* 基本樣式 */
body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: rgb(240, 244, 250);
    color: var(--text-dark);
    min-height: 100vh;
    margin: 0;
    padding: 0;
    overflow-x: hidden;
}

.login-page {
    width: 100%;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    background: linear-gradient(135deg, rgba(13, 110, 253, 0.05) 0%, rgba(66, 134, 244, 0.08) 100%);
}

/* 品牌樣式 */
.brand-link {
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 10px;
}

.brand-icon {
    font-size: 2rem;
    color: var(--primary-color);
    margin-right: 10px;
}

.brand-name {
    font-size: 1.8rem;
    font-weight: 700;
    background: linear-gradient(90deg, var(--primary-color), #4286f4);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin: 0;
    letter-spacing: -0.5px;
}

.welcome-text {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 5px;
}

/* 登入容器 */
.login-container {
    background-color: var(--white-color);
    border-radius: var(--border-radius);
    padding: 2.5rem;
    width: 100%;
    box-shadow: var(--box-shadow);
    position: relative;
    z-index: 1;
    overflow: hidden;
    animation: slideUp 0.5s ease-out forwards;
}

.login-container::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 5px;
    background: linear-gradient(90deg, var(--primary-color), #4286f4);
    z-index: 2;
}

/* 表單樣式 */
.form-floating {
    position: relative;
}

.form-control {
    height: 58px;
    font-size: 1rem;
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 1rem 1rem 1rem 2.5rem;
    transition: var(--transition-base);
}

.form-control:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 0.25rem rgba(0, 120, 255, 0.25);
}

.form-floating > label {
    padding-left: 2.5rem;
    font-size: 0.9rem;
}

.form-floating > .form-control:focus ~ label,
.form-floating > .form-control:not(:placeholder-shown) ~ label {
    padding-left: 1rem;
    color: var(--primary-color);
    font-weight: 500;
}

.form-check-label {
    font-size: 0.9rem;
    color: var(--text-medium);
}

.form-check-input:checked {
    background-color: var(--primary-color);
    border-color: var(--primary-color);
}

/* 密碼欄位樣式 */
.password-field {
    position: relative;
}

.toggle-password {
    position: absolute;
    right: 10px;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    color: var(--text-medium);
    font-size: 1.1rem;
    padding: 0;
    z-index: 10;
}

.toggle-password:hover {
    color: var(--primary-color);
}

/* 按鈕樣式 */
.login-btn {
    width: 100%;
    padding: 0.8rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    border-radius: 30px;
    background-color: var(--primary-color);
    border: none;
    color: white;
    transition: var(--transition-base);
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
}

.login-btn:before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(
        90deg, 
        transparent, 
        rgba(255, 255, 255, 0.2), 
        transparent
    );
    transition: all 0.6s;
}

.login-btn:hover:before {
    left: 100%;
}

.login-btn:hover, .login-btn:focus {
    background-color: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(13, 110, 253, 0.35);
}

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

/* 分隔線樣式 */
.separator {
    display: flex;
    align-items: center;
    text-align: center;
    color: var(--text-medium);
    font-size: 0.9rem;
}

.separator::before,
.separator::after {
    content: '';
    flex: 1;
    border-bottom: 1px solid var(--border-color);
}

.separator::before {
    margin-right: 1rem;
}

.separator::after {
    margin-left: 1rem;
}

/* 社交登入按鈕 */
.social-login {
    display: flex;
    justify-content: center;
    gap: 15px;
}

.social-btn {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    transition: var(--transition-base);
    border: 1px solid var(--border-color);
}

.social-btn:hover {
    background-color: var(--light-color);
    transform: translateY(-3px);
}

/* 連結樣式 */
.forgot-link, .signup-link {
    color: var(--primary-color);
    font-weight: 500;
    text-decoration: none;
    transition: var(--transition-base);
}

.forgot-link:hover, .signup-link:hover {
    color: var(--primary-dark);
    text-decoration: underline;
}

/* 錯誤訊息樣式 */
.alert-danger {
    border-radius: 8px;
    border-left: 4px solid var(--danger-color);
    background-color: rgba(220, 53, 69, 0.1);
    color: var(--danger-color);
    padding: 0.75rem 1rem;
    font-size: 0.9rem;
}

/* 載入中遮罩 */
#loadingOverlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.6);
    backdrop-filter: blur(5px);
    z-index: 9999;
    display: none;
    justify-content: center;
    align-items: center;
}

.loading-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.spinner {
    width: 60px;
    height: 60px;
    border: 5px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: var(--primary-color);
    animation: spin 1s ease-in-out infinite;
}

.loading-text {
    color: white;
    font-size: 1.1rem;
    font-weight: 500;
}

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

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* 響應式樣式 */
@media (max-width: 768px) {
    .login-container {
        padding: 2rem 1.5rem;
    }
    
    .brand-icon {
        font-size: 1.8rem;
    }
    
    .brand-name {
        font-size: 1.5rem;
    }
    
    .welcome-text {
        font-size: 1.3rem;
    }
}

@media (max-width: 576px) {
    .login-container {
        padding: 1.5rem;
    }
    
    .brand-icon {
        font-size: 1.5rem;
    }
    
    .brand-name {
        font-size: 1.3rem;
    }
    
    .welcome-text {
        font-size: 1.2rem;
    }
}