/**
 * Button Component - PPL Questions v2
 *
 * Unified button system with consistent styling across the application.
 * Replaces duplicated button styles from multiple files.
 *
 * Usage:
 *   <button class="btn btn--primary">Primary</button>
 *   <button class="btn btn--secondary">Secondary</button>
 *   <button class="btn btn--danger">Danger</button>
 *   <a href="#" class="btn btn--outline">Link Button</a>
 *
 * Size variants:
 *   <button class="btn btn--primary btn--sm">Small</button>
 *   <button class="btn btn--primary btn--lg">Large</button>
 *
 * With icons:
 *   <button class="btn btn--primary">
 *       <svg>...</svg>
 *       <span>With Icon</span>
 *   </button>
 */

/* =========================================================================
   BASE BUTTON
   ========================================================================= */

.btn {
    /* Display */
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm, 0.5rem);

    /* Sizing */
    padding: 0.5rem 1.5rem;
    height: var(--btn-height, 34px);
    min-height: var(--btn-min-height, 34px);

    /* Typography */
    font-family: var(--font-family-base, 'Public Sans', sans-serif);
    font-size: var(--btn-font-size, 1rem);
    font-weight: var(--btn-font-weight, 600);
    line-height: 1;
    text-align: center;
    text-decoration: none;
    white-space: nowrap;

    /* Appearance */
    background: var(--color-gray-200, #e9ecef);
    color: var(--color-text-primary, #212529);
    border: none;
    border-radius: var(--btn-border-radius, 6px);
    cursor: pointer;

    /* Transitions */
    transition: all var(--transition-fast, 150ms ease);

    /* Prevent text selection */
    user-select: none;
    -webkit-user-select: none;

    /* Remove default button styles */
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
}

/* Hover state */
.btn:hover:not(:disabled) {
    transform: translateY(-2px);
}

/* Active/pressed state */
.btn:active:not(:disabled) {
    transform: translateY(0);
}

/* Focus state */
.btn:focus {
    outline: none;
}

.btn:focus-visible {
    outline: 2px solid var(--color-primary, #368BC1);
    outline-offset: 2px;
}

/* Disabled state */
.btn:disabled,
.btn.disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none !important;
    box-shadow: none !important;
}

/* =========================================================================
   BUTTON VARIANTS
   ========================================================================= */

/* Primary - Main action button */
.btn--primary {
    background: var(--color-primary, #368BC1);
    color: var(--color-white, #ffffff);
    box-shadow: var(--shadow-primary, 0 4px 12px rgba(54, 139, 193, 0.3));
}

.btn--primary:hover:not(:disabled) {
    background: var(--color-primary-dark, #2a6d96);
    box-shadow: var(--shadow-primary-hover, 0 6px 16px rgba(54, 139, 193, 0.4));
}

.btn--primary:active:not(:disabled) {
    box-shadow: var(--shadow-primary, 0 4px 12px rgba(54, 139, 193, 0.3));
}

/* Secondary - Alternative/cancel actions */
.btn--secondary {
    background: var(--color-gray-600, #6c757d);
    color: var(--color-white, #ffffff);
    box-shadow: 0 4px 12px rgba(108, 117, 125, 0.3);
}

.btn--secondary:hover:not(:disabled) {
    background: var(--color-gray-700, #5a6268);
    box-shadow: 0 6px 16px rgba(108, 117, 125, 0.4);
}

.btn--secondary:active:not(:disabled) {
    box-shadow: 0 4px 12px rgba(108, 117, 125, 0.3);
}

/* Danger - Destructive actions */
.btn--danger {
    background: var(--color-danger, #dc3545);
    color: var(--color-white, #ffffff);
    box-shadow: var(--shadow-danger, 0 4px 12px rgba(220, 53, 69, 0.3));
}

.btn--danger:hover:not(:disabled) {
    background: var(--color-danger-hover, #c82333);
    box-shadow: 0 6px 16px rgba(220, 53, 69, 0.4);
}

/* Success - Positive actions */
.btn--success {
    background: var(--color-success, #28a745);
    color: var(--color-white, #ffffff);
    box-shadow: var(--shadow-success, 0 4px 12px rgba(40, 167, 69, 0.3));
}

.btn--success:hover:not(:disabled) {
    background: var(--color-success-hover, #218838);
    box-shadow: 0 6px 16px rgba(40, 167, 69, 0.4);
}

/* Warning */
.btn--warning {
    background: var(--color-warning, #ffc107);
    color: var(--color-warning-dark, #856404);
    box-shadow: 0 4px 12px rgba(255, 193, 7, 0.3);
}

.btn--warning:hover:not(:disabled) {
    background: var(--color-warning-hover, #e0a800);
    box-shadow: 0 6px 16px rgba(255, 193, 7, 0.4);
}

/* Info */
.btn--info {
    background: var(--color-info, #17a2b8);
    color: var(--color-white, #ffffff);
    box-shadow: 0 4px 12px rgba(23, 162, 184, 0.3);
}

.btn--info:hover:not(:disabled) {
    background: var(--color-info-hover, #138496);
    box-shadow: 0 6px 16px rgba(23, 162, 184, 0.4);
}

/* Light - Subtle button */
.btn--light {
    background: var(--color-gray-50, #f8f9fa);
    color: var(--color-text-primary, #212529);
    border: 1px solid var(--color-border, #dee2e6);
}

.btn--light:hover:not(:disabled) {
    background: var(--color-gray-100, #e9ecef);
    border-color: var(--color-gray-400, #ced4da);
}

/* =========================================================================
   OUTLINE VARIANTS
   ========================================================================= */

.btn--outline {
    background: transparent;
    color: var(--color-primary, #368BC1);
    border: 2px solid var(--color-primary, #368BC1);
    box-shadow: none;
}

.btn--outline:hover:not(:disabled) {
    background: var(--color-primary, #368BC1);
    color: var(--color-white, #ffffff);
    box-shadow: var(--shadow-primary, 0 4px 12px rgba(54, 139, 193, 0.3));
}

.btn--outline-secondary {
    background: transparent;
    color: var(--color-gray-600, #6c757d);
    border: 2px solid var(--color-gray-400, #ced4da);
}

.btn--outline-secondary:hover:not(:disabled) {
    background: var(--color-gray-600, #6c757d);
    color: var(--color-white, #ffffff);
    border-color: var(--color-gray-600, #6c757d);
}

.btn--outline-danger {
    background: transparent;
    color: var(--color-danger, #dc3545);
    border: 2px solid var(--color-danger, #dc3545);
}

.btn--outline-danger:hover:not(:disabled) {
    background: var(--color-danger, #dc3545);
    color: var(--color-white, #ffffff);
}

.btn--outline-success {
    background: transparent;
    color: var(--color-success, #28a745);
    border: 2px solid var(--color-success, #28a745);
}

.btn--outline-success:hover:not(:disabled) {
    background: var(--color-success, #28a745);
    color: var(--color-white, #ffffff);
}

.btn--outline-white {
    background: transparent;
    color: var(--color-white, #ffffff);
    border: 2px solid var(--color-white, #ffffff);
}

.btn--outline-white:hover:not(:disabled) {
    background: var(--color-white, #ffffff);
    color: var(--color-primary, #368BC1);
}

/* =========================================================================
   GHOST BUTTONS (no background, no border)
   ========================================================================= */

.btn--ghost {
    background: transparent;
    color: var(--color-primary, #368BC1);
    border: none;
    box-shadow: none;
}

.btn--ghost:hover:not(:disabled) {
    background: var(--color-primary-light, #e8f4fc);
    transform: none;
}

.btn--ghost-danger {
    background: transparent;
    color: var(--color-danger, #dc3545);
}

.btn--ghost-danger:hover:not(:disabled) {
    background: var(--color-danger-light, #f8d7da);
    transform: none;
}

/* =========================================================================
   SIZE VARIANTS
   ========================================================================= */

/* Small */
.btn--sm {
    padding: 0.25rem 0.75rem;
    font-size: var(--font-size-sm, 0.875rem);
    height: 28px;
    min-height: 28px;
}

/* Large */
.btn--lg {
    padding: 0.5rem 1.5rem;
    font-size: var(--font-size-lg, 1.125rem);
    height: 42px;
    min-height: 42px;
}

/* Extra large */
.btn--xl {
    padding: 0.75rem 2rem;
    font-size: var(--font-size-xl, 1.25rem);
    height: 48px;
    min-height: 48px;
}

/* =========================================================================
   SHAPE VARIANTS
   ========================================================================= */

/* Rounded/Pill shape */
.btn--rounded {
    border-radius: var(--radius-full, 9999px);
}

/* Square (equal padding) */
.btn--square {
    padding: var(--btn-padding-y, 0.75rem);
    aspect-ratio: 1;
}

/* Block button (full width) */
.btn--block {
    display: flex;
    width: 100%;
}

/* =========================================================================
   ICON BUTTONS
   ========================================================================= */

/* Button with icon */
.btn svg,
.btn .btn__icon {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
}

/* Icon-only button */
.btn--icon {
    padding: var(--btn-padding-y, 0.75rem);
    min-width: var(--btn-min-height, 44px);
}

.btn--icon.btn--sm {
    padding: 0.5rem;
    min-width: 36px;
    min-height: 36px;
}

.btn--icon.btn--lg {
    padding: 1rem;
    min-width: 52px;
}

.btn--icon svg {
    width: 24px;
    height: 24px;
}

/* Icon on left (default) - already handled by flex gap */
/* Icon on right */
.btn--icon-right {
    flex-direction: row-reverse;
}

/* =========================================================================
   LOADING STATE
   ========================================================================= */

.btn--loading {
    position: relative;
    color: transparent !important;
    pointer-events: none;
}

.btn--loading::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 20px;
    height: 20px;
    margin: -10px 0 0 -10px;
    border: 2px solid currentColor;
    border-right-color: transparent;
    border-radius: 50%;
    animation: btn-spin 0.75s linear infinite;
}

/* Restore color for spinner */
.btn--primary.btn--loading::after,
.btn--danger.btn--loading::after,
.btn--success.btn--loading::after,
.btn--info.btn--loading::after,
.btn--secondary.btn--loading::after {
    border-color: var(--color-white, #ffffff);
    border-right-color: transparent;
}

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

/* =========================================================================
   BUTTON GROUPS
   ========================================================================= */

.btn-group {
    display: inline-flex;
    gap: 0;
}

.btn-group .btn {
    border-radius: 0;
}

.btn-group .btn:first-child {
    border-radius: var(--btn-border-radius, 6px) 0 0 var(--btn-border-radius, 6px);
}

.btn-group .btn:last-child {
    border-radius: 0 var(--btn-border-radius, 6px) var(--btn-border-radius, 6px) 0;
}

.btn-group .btn:not(:last-child) {
    border-right: 1px solid rgba(0, 0, 0, 0.1);
}

/* Vertical button group */
.btn-group--vertical {
    flex-direction: column;
}

.btn-group--vertical .btn:first-child {
    border-radius: var(--btn-border-radius, 6px) var(--btn-border-radius, 6px) 0 0;
}

.btn-group--vertical .btn:last-child {
    border-radius: 0 0 var(--btn-border-radius, 6px) var(--btn-border-radius, 6px);
}

.btn-group--vertical .btn:not(:last-child) {
    border-right: none;
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
}

/* =========================================================================
   RESPONSIVE ADJUSTMENTS
   ========================================================================= */

@media (max-width: 768px) {
    .btn {
        /* Ensure touch-friendly size on mobile */
        height: 36px;
        min-height: 36px;
        padding: 0.375rem 1rem;
    }

    .btn--sm {
        height: 32px;
        min-height: 32px;
        padding: 0.25rem 0.75rem;
    }

    /* Full width buttons on mobile when needed */
    .btn--mobile-block {
        display: flex;
        width: 100%;
    }
}

@media (max-width: 480px) {
    /* Stack button groups on very small screens */
    .btn-group--mobile-stack {
        flex-direction: column;
        width: 100%;
    }

    .btn-group--mobile-stack .btn {
        width: 100%;
        border-radius: 0;
    }

    .btn-group--mobile-stack .btn:first-child {
        border-radius: var(--btn-border-radius, 6px) var(--btn-border-radius, 6px) 0 0;
    }

    .btn-group--mobile-stack .btn:last-child {
        border-radius: 0 0 var(--btn-border-radius, 6px) var(--btn-border-radius, 6px);
    }

    .btn-group--mobile-stack .btn:not(:last-child) {
        border-right: none;
        border-bottom: 1px solid rgba(0, 0, 0, 0.1);
    }
}

/* =========================================================================
   ACCESSIBILITY
   ========================================================================= */

/* Reduce motion */
@media (prefers-reduced-motion: reduce) {
    .btn {
        transition: none;
    }

    .btn:hover:not(:disabled) {
        transform: none;
    }

    .btn--loading::after {
        animation: none;
    }
}

/* High contrast mode support */
@media (forced-colors: active) {
    .btn {
        border: 2px solid currentColor;
    }
}

/* =========================================================================
   LEGACY CLASS SUPPORT
   Keep old class names working during migration
   ========================================================================= */

/* Map old button classes */
.btn-primary {
    background: var(--color-primary, #368BC1);
    color: var(--color-white, #ffffff);
    box-shadow: var(--shadow-primary, 0 4px 12px rgba(54, 139, 193, 0.3));
}

.btn-secondary {
    background: var(--color-gray-600, #6c757d);
    color: var(--color-white, #ffffff);
    box-shadow: 0 4px 12px rgba(108, 117, 125, 0.3);
}

.btn-danger {
    background: var(--color-danger, #dc3545);
    color: var(--color-white, #ffffff);
}

.btn-success {
    background: var(--color-success, #28a745);
    color: var(--color-white, #ffffff);
}