:root {
    --primary-color: #6B46C1;
    --primary-light: #F3E8FF;
    --primary-dark: #553C9A;
    --secondary-color: #4ECDC4;
    --success-color: #7ED687;
    --warning-color: #FFA500;
    --error-color: #FF6B6B;
    --info-color: #4A90D9;
    
    --text-color: #2D3436;
    --text-secondary: #666666;
    --text-light: #999999;
    --text-lighter: #CCCCCC;
    
    --border-color: #E5E5EA;
    --border-color-soft: #EEEEEE;
    --bg-color: #F5F5F7;
    --bg-white: #FFFFFF;
    
    --border-radius: 16px;
    --border-radius-sm: 8px;
    --border-radius-lg: 24px;
    
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -2px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -4px rgba(0,0,0,0.1);
    
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    
    --font-size-xs: 12px;
    --font-size-sm: 13px;
    --font-size-md: 15px;
    --font-size-lg: 22px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    background-color: var(--bg-color);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-lg);
}

.login-card {
    width: 100%;
    max-width: 400px;
    background-color: var(--bg-white);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-lg);
    padding: var(--spacing-xl) var(--spacing-lg);
    animation: cardIn 0.5s ease-out;
}

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

.logo-area {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.logo-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto var(--spacing-lg);
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: var(--border-radius);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    color: var(--bg-white);
    box-shadow: 0 4px 12px rgba(107, 70, 193, 0.3);
}

.logo-title {
    font-size: var(--font-size-lg);
    font-weight: 700;
    color: var(--text-color);
    letter-spacing: -0.3px;
}

.logo-subtitle {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    margin-top: var(--spacing-xs);
}

.alert-error {
    background-color: rgba(255, 107, 107, 0.08);
    border: 1px solid rgba(255, 107, 107, 0.2);
    color: var(--error-color);
    padding: var(--spacing-md);
    border-radius: var(--border-radius-sm);
    margin-bottom: var(--spacing-lg);
    font-size: var(--font-size-sm);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    animation: alertIn 0.3s ease-out;
}

@keyframes alertIn {
    from { opacity: 0; transform: translateY(-8px); }
    to { opacity: 1; transform: translateY(0); }
}

.form-group { margin-bottom: var(--spacing-lg); }

.form-label {
    display: block;
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--text-color);
    margin-bottom: var(--spacing-sm);
}

.input-field {
    position: relative;
}

.input-field input {
    width: 100%;
    padding: 12px var(--spacing-md) 12px 42px;
    border: 1.5px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    font-size: var(--font-size-md);
    color: var(--text-color);
    background-color: var(--bg-color);
    transition: all 0.2s ease;
    outline: none;
}

.input-field input::placeholder {
    color: var(--text-lighter);
}

.input-field input:focus {
    border-color: var(--primary-color);
    background-color: var(--bg-white);
    box-shadow: 0 0 0 3px rgba(107, 70, 193, 0.1);
}

.input-field .icon {
    position: absolute;
    left: 14px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-light);
    font-size: 17px;
    pointer-events: none;
    transition: color 0.2s;
}

.input-field input:focus + .icon,
.input-field input:focus ~ .icon {
    color: var(--primary-color);
}

.toggle-pwd {
    position: absolute;
    right: 12px;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    cursor: pointer;
    font-size: 18px;
    color: var(--text-light);
    padding: 4px;
    line-height: 1;
    transition: color 0.2s;
}

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

.form-options {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-lg);
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    cursor: pointer;
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    user-select: none;
}

.checkbox-label input[type="checkbox"] {
    width: 16px;
    height: 16px;
    accent-color: var(--primary-color);
    cursor: pointer;
}

.btn-login {
    width: 100%;
    padding: 13px;
    background-color: var(--primary-color);
    color: var(--bg-white);
    border: none;
    border-radius: var(--border-radius-sm);
    font-size: var(--font-size-md);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    letter-spacing: 0.5px;
}

.btn-login:hover {
    background-color: var(--primary-dark);
    box-shadow: 0 4px 12px rgba(107, 70, 193, 0.35);
}

.btn-login:active { transform: scale(0.98); }

.btn-login.loading {
    opacity: 0.7;
    cursor: wait;
    pointer-events: none;
}

.btn-login.loading .btn-text { visibility: hidden; }

.btn-login .spinner {
    display: none;
    position: absolute;
    width: 20px;
    height: 20px;
    border: 2.5px solid rgba(255,255,255,0.3);
    border-top-color: #fff;
    border-radius: 50%;
    animation: spin 0.7s linear infinite;
}

.btn-login.loading .spinner { display: block; }

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

.login-footer {
    text-align: center;
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--border-color);
    font-size: var(--font-size-xs);
    color: var(--text-light);
}

@media (max-width: 480px) {
    .login-card {
        padding: var(--spacing-lg) var(--spacing-md);
        border-radius: var(--border-radius-sm);
    }
    .logo-title { font-size: 20px; }
}

input:-webkit-autofill,
input:-webkit-autofill:hover,
input:-webkit-autofill:focus {
    box-shadow: 0 0 0 30px var(--bg-color) inset, 0 0 0 2px transparent;
    -webkit-text-fill-color: var(--text-color);
    transition: background-color 5000s ease-in-out 0s;
}

input:-webkit-autofill:focus {
    box-shadow: 0 0 0 30px var(--bg-white) inset, 0 0 0 3px rgba(107, 70, 193, 0.1);
}