/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Color scheme */
    --primary-color: #0d6efd;
    --primary-hover: #0b5ed7;
    --error-color: #dc3545;
    --success-color: #198754;
    --text-primary: #212529;
    --text-secondary: #6c757d;
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --border-color: #dee2e6;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 40px rgba(0, 0, 0, 0.1);
    
    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-size-base: 16px;
    --line-height-base: 1.5;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    
    /* Border radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 1rem;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: var(--line-height-base);
    color: var(--text-primary);
    background-color: var(--bg-secondary);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Login container */
.login-container {
    width: 100%;
    max-width: 400px;
    padding: var(--spacing-md);
}

/* Login card */
.login-card {
    background: var(--bg-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-lg);
}

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

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: var(--spacing-lg);
}

.login-title {
    font-size: 1.75rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.login-subtitle {
    color: var(--text-secondary);
    font-size: 1rem;
}

/* Form styles */
.login-form {
    margin-bottom: var(--spacing-lg);
}

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

.form-label {
    display: block;
    font-weight: 500;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.form-input {
    width: 100%;
    padding: 0.75rem 1rem;
    font-size: 1rem;
    line-height: 1.5;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    transition: border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
    font-family: inherit;
}

.form-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 0.2rem rgba(13, 110, 253, 0.25);
}

.form-input::placeholder {
    color: #adb5bd;
}

/* Error states */
.form-input.error {
    border-color: var(--error-color);
}

.form-input.error:focus {
    box-shadow: 0 0 0 0.2rem rgba(220, 53, 69, 0.25);
}

.error-message {
    display: block;
    margin-top: var(--spacing-xs);
    font-size: 0.875rem;
    color: var(--error-color);
    min-height: 1.2em;
}

/* Submit button */
.submit-button {
    width: 100%;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 500;
    line-height: 1.5;
    color: white;
    background-color: var(--primary-color);
    border: 1px solid var(--primary-color);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all 0.15s ease-in-out;
    position: relative;
    overflow: hidden;
    font-family: inherit;
}

.submit-button:hover:not(:disabled) {
    background-color: var(--primary-hover);
    border-color: var(--primary-hover);
}

.submit-button:focus {
    outline: none;
    box-shadow: 0 0 0 0.2rem rgba(13, 110, 253, 0.25);
}

.submit-button:disabled {
    opacity: 0.65;
    cursor: not-allowed;
}

.button-text,
.button-loading {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
}

/* Loading spinner */
.spinner {
    display: inline-block;
    width: 1rem;
    height: 1rem;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 0.8s linear infinite;
}

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

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

.footer-text {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.footer-link {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
}

.footer-link:hover {
    text-decoration: underline;
}

/* Login info */
.login-info {
    text-align: center;
}

.info-text {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* Responsive design */
@media (max-width: 480px) {
    .login-container {
        padding: var(--spacing-sm);
    }
    
    .login-card {
        padding: var(--spacing-lg);
    }
    
    .login-title {
        font-size: 1.5rem;
    }
    
    .login-subtitle {
        font-size: 0.875rem;
    }
}

/* Accessibility improvements */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    .form-input {
        border-width: 2px;
    }
    
    .submit-button {
        border-width: 2px;
    }
}

/* Dark mode support (optional, for future) */
@media (prefers-color-scheme: dark) {
    :root {
        --text-primary: #f8f9fa;
        --text-secondary: #adb5bd;
        --bg-primary: #212529;
        --bg-secondary: #343a40;
        --border-color: #495057;
    }
    
    .form-input {
        background-color: var(--bg-secondary);
        color: var(--text-primary);
    }
    
    .login-card {
        box-shadow: 0 10px 40px rgba(0, 0, 0, 0.5);
    }
}