/* ==================== CSS Variables ==================== */
:root {
    /* Primary Colors */
    --primary-color: #4F46E5;
    --primary-hover: #4338CA;
    --primary-light: #EEF2FF;
    --primary-border: #C7D2FE;

    /* Secondary Colors */
    --secondary-color: #7C3AED;
    --secondary-hover: #6D28D9;

    /* Accent Colors */
    --success-color: #10B981;
    --success-light: #D1FAE5;
    --warning-color: #F59E0B;
    --warning-light: #FEF3C7;
    --error-color: #EF4444;
    --error-light: #FEE2E2;

    /* Neutral Colors */
    --bg-primary: #F8FAFC;
    --bg-secondary: #FFFFFF;
    --bg-tertiary: #F1F5F9;

    --text-primary: #1E293B;
    --text-secondary: #64748B;
    --text-tertiary: #94A3B8;
    --text-inverse: #FFFFFF;

    --border-color: #E2E8F0;
    --border-light: #F1F5F9;

    /* Spacing */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    --spacing-2xl: 48px;

    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;

    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);

    /* Transitions */
    --transition-fast: 150ms ease-out;
    --transition-normal: 200ms ease-out;
}

/* ==================== Reset & Base Styles ==================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* ==================== Login Container ==================== */
.login-container {
    width: 100%;
    max-width: 420px;
    padding: var(--spacing-lg);
}

.login-card {
    background: var(--bg-secondary);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    box-shadow: var(--shadow-lg);
}

/* ==================== Login Header ==================== */
.login-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.logo-icon {
    width: 48px;
    height: 48px;
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
}

.login-title {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
}

.login-subtitle {
    font-size: 0.9375rem;
    color: var(--text-secondary);
}

/* ==================== Form Styles ==================== */
.login-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.form-label {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-primary);
}

.form-input {
    padding: var(--spacing-md);
    font-family: inherit;
    font-size: 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    background: var(--bg-secondary);
}

.form-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px var(--primary-light);
}

.form-input::placeholder {
    color: var(--text-tertiary);
}

/* ==================== Error Message ==================== */
.form-error {
    padding: var(--spacing-md);
    background: var(--error-light);
    color: var(--error-color);
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    border-left: 4px solid var(--error-color);
}

.form-error:empty {
    display: none;
}

/* ==================== Login Button ==================== */
.btn-login {
    width: 100%;
    padding: var(--spacing-md) var(--spacing-lg);
    font-family: inherit;
    font-size: 1rem;
    font-weight: 600;
    background: var(--primary-color);
    color: var(--text-inverse);
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-normal);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
}

.btn-login:hover:not(:disabled) {
    background: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-login:disabled {
    opacity: 0.7;
    cursor: not-allowed;
}

.btn-login.btn-loading .btn-text {
    display: none;
}

.btn-login.btn-loading .btn-loading {
    display: flex !important;
}

.spinner {
    width: 20px;
    height: 20px;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    from {
        transform: rotate(0deg);
    }
    to {
        transform: rotate(360deg);
    }
}

/* ==================== Login Footer ==================== */
.login-footer {
    margin-top: var(--spacing-xl);
    text-align: center;
}

.login-info {
    font-size: 0.8125rem;
    color: var(--text-tertiary);
}

/* ==================== Responsive ==================== */
@media (max-width: 480px) {
    .login-container {
        padding: var(--spacing-md);
    }

    .login-card {
        padding: var(--spacing-xl);
    }

    .login-title {
        font-size: 1.5rem;
    }
}