/**
 * Accessibility Styles for EAA/BFSG Compliance
 * WCAG 2.1 Level AA
 *
 * These styles are backward compatible and do not change visual appearance
 * except for keyboard focus indicators and skip links.
 */

/* ==========================================================================
   Screen Reader Only Content
   ========================================================================== */

/**
 * Hide content visually but keep it accessible to screen readers
 * Used for skip links, form labels, and other assistive content
 */
.sr-only {
    position: absolute !important;
    width: 1px !important;
    height: 1px !important;
    padding: 0 !important;
    margin: -1px !important;
    overflow: hidden !important;
    clip: rect(0, 0, 0, 0) !important;
    white-space: nowrap !important;
    border: 0 !important;
}

/**
 * Allow the element to be focusable when navigated to via keyboard
 * Used for skip links that become visible on focus
 */
.sr-only-focusable:focus,
.sr-only-focusable:active {
    position: fixed !important;
    top: 10px !important;
    left: 10px !important;
    z-index: 100000 !important;
    width: auto !important;
    height: auto !important;
    margin: 0 !important;
    overflow: visible !important;
    clip: auto !important;
    white-space: normal !important;
    background-color: #fff !important;
    color: #333 !important;
    padding: 12px 24px !important;
    font-size: 16px !important;
    font-weight: 600 !important;
    text-decoration: none !important;
    border: 2px solid #333 !important;
    border-radius: 4px !important;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3) !important;
}

/* ==========================================================================
   Focus Indicators (WCAG 2.4.7)
   ========================================================================== */

/**
 * Enhanced focus styles for keyboard navigation
 * Uses :focus-visible to only show on keyboard focus, not mouse clicks
 */

/* Default focus outline for all focusable elements */
a:focus-visible,
button:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible,
[tabindex]:focus-visible,
[role="button"]:focus-visible,
[role="link"]:focus-visible,
[role="menuitem"]:focus-visible {
    outline: 2px solid currentColor !important;
    outline-offset: 2px !important;
}

/* High contrast focus for elements where currentColor might not be visible */
.burger-button:focus-visible,
.nav__item:focus-visible a,
.burger-menu__item:focus-visible a {
    outline: 2px solid #005fcc !important;
    outline-offset: 2px !important;
}

/* Fallback for browsers that don't support :focus-visible */
@supports not selector(:focus-visible) {
    a:focus,
    button:focus,
    input:focus,
    select:focus,
    textarea:focus,
    [tabindex]:focus,
    [role="button"]:focus {
        outline: 2px solid currentColor;
        outline-offset: 2px;
    }
}

/* ==========================================================================
   Skip Link Styles
   ========================================================================== */

.skip-link {
    position: absolute;
    top: -100%;
    left: 50%;
    transform: translateX(-50%);
    z-index: 100001;
    background-color: #fff;
    color: #333;
    padding: 12px 24px;
    font-size: 16px;
    font-weight: 600;
    text-decoration: none;
    border: 2px solid #333;
    border-radius: 4px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    transition: top 0.2s ease;
}

.skip-link:focus {
    top: 10px;
    outline: none;
}

/* ==========================================================================
   Reduced Motion
   ========================================================================== */

/**
 * Respect user preference for reduced motion (WCAG 2.3.3)
 */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }

    .skip-link {
        transition: none;
    }
}

/* ==========================================================================
   High Contrast Mode Support
   ========================================================================== */

@media (forced-colors: active) {
    .skip-link:focus,
    a:focus-visible,
    button:focus-visible,
    [tabindex]:focus-visible {
        outline: 3px solid CanvasText !important;
    }
}

/* ==========================================================================
   Form Error Styles (WCAG 3.3.1, 3.3.3)
   ========================================================================== */

/**
 * Form field error messages
 * These are linked to inputs via aria-describedby
 */
.form-field-error {
    display: block;
    color: #d32f2f;
    font-size: 0.875em;
    margin-top: 4px;
    min-height: 1.2em;
}

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

/**
 * Error summary for screen readers
 * Hidden visually but announced by screen readers
 */
.form-error-summary {
    /* Uses .sr-only styles, additional styling for when shown visually */
}

.form-error-summary:not(.sr-only) {
    background-color: #ffebee;
    border: 1px solid #d32f2f;
    border-radius: 4px;
    padding: 12px;
    margin-bottom: 16px;
    color: #d32f2f;
}

/**
 * Invalid input styling
 */
input[aria-invalid="true"],
textarea[aria-invalid="true"],
select[aria-invalid="true"] {
    border-color: #d32f2f !important;
}

input[aria-invalid="true"]:focus,
textarea[aria-invalid="true"]:focus,
select[aria-invalid="true"]:focus {
    outline-color: #d32f2f !important;
    box-shadow: 0 0 0 1px #d32f2f;
}