/* CSS Variables */
:root {
    --primary-color: #0088cc;
    --primary-hover: #006ba3;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --danger-color: #dc3545;
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-gradient-start: #0088cc;
    --bg-gradient-end: #00c6ff;
    --text-primary: #212529;
    --text-secondary: #6c757d;
    --border-color: #dee2e6;
    --border-radius: 12px;
    --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --box-shadow-hover: 0 8px 16px rgba(0, 0, 0, 0.15);
}

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

body {
    font-family: 'Noto Sans', sans-serif;
    background: linear-gradient(135deg, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

body.lang-cn {
    font-family: 'Noto Sans SC', sans-serif;
}

/* Login Container */
.login-container {
    width: 100%;
    max-width: 450px;
    animation: fadeIn 0.5s ease-in-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Login Card */
.login-card {
    background: var(--bg-primary);
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 40px;
    transition: box-shadow 0.3s ease;
}

.login-card:hover {
    box-shadow: var(--box-shadow-hover);
}

/* Login Header */
.login-header {
    text-align: center;
    margin-bottom: 30px;
}

.logo-container {
    margin-bottom: 20px;
}

.logo-icon {
    font-size: 64px;
    color: var(--primary-color);
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
}

.app-title {
    font-size: 32px;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 10px;
}

.app-subtitle {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 0;
}

/* Form Styles */
.login-form {
    margin-bottom: 30px;
}

.form-label {
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 8px;
    font-size: 14px;
}

.form-control {
    border: 2px solid var(--border-color);
    border-radius: 8px;
    padding: 12px 16px;
    font-size: 15px;
    transition: all 0.3s ease;
}

.form-control:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 0.2rem rgba(0, 136, 204, 0.25);
    outline: none;
}

/* Password Input Wrapper */
.password-input-wrapper {
    position: relative;
}

.password-input-wrapper .form-control {
    padding-right: 45px;
}

.btn-toggle-password {
    position: absolute;
    right: 12px;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 5px 10px;
    transition: color 0.3s ease;
}

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

.btn-toggle-password:focus {
    outline: none;
}

/* Login Button */
.btn-login {
    background: var(--primary-color);
    border: none;
    border-radius: 8px;
    padding: 14px;
    font-size: 16px;
    font-weight: 600;
    color: white;
    transition: all 0.3s ease;
    margin-top: 10px;
}

.btn-login:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 136, 204, 0.4);
}

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

/* Language Selector */
.language-selector {
    border-top: 1px solid var(--border-color);
    padding-top: 20px;
    margin-bottom: 20px;
}

.language-selector .form-label {
    text-align: center;
    display: block;
    margin-bottom: 12px;
}

.language-options {
    display: flex;
    gap: 10px;
    justify-content: center;
}

.language-option {
    padding: 8px 20px;
    border: 2px solid var(--border-color);
    border-radius: 20px;
    text-decoration: none;
    color: var(--text-primary);
    font-size: 14px;
    font-weight: 500;
    transition: all 0.3s ease;
    background: var(--bg-primary);
}

.language-option:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    transform: translateY(-2px);
}

.language-option.active {
    background: var(--primary-color);
    border-color: var(--primary-color);
    color: white;
}

/* Login Footer */
.login-footer {
    text-align: center;
    padding-top: 15px;
    border-top: 1px solid var(--border-color);
}

.login-footer p {
    margin: 0;
    font-size: 13px;
}

/* Alert Styles */
.alert {
    border-radius: 8px;
    margin-bottom: 20px;
    font-size: 14px;
}

/* Responsive Design */
@media (max-width: 576px) {
    .login-card {
        padding: 30px 20px;
    }
    
    .app-title {
        font-size: 28px;
    }
    
    .logo-icon {
        font-size: 48px;
    }
    
    .language-options {
        flex-direction: column;
    }
    
    .language-option {
        text-align: center;
    }
}

/* Loading State */
.btn-login.loading {
    position: relative;
    color: transparent;
    pointer-events: none;
}

.btn-login.loading::after {
    content: "";
    position: absolute;
    width: 20px;
    height: 20px;
    top: 50%;
    left: 50%;
    margin-left: -10px;
    margin-top: -10px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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