/**
 * ============================================
 * ACCESSIBILITY (WCAG 2.1 AA)
 * Focus indicators, screen reader support, keyboard navigation
 * ============================================
 */

/* ===== FOCUS INDICATORS ===== */

*:focus {
    outline: 2px solid var(--color-accent-blue);
    outline-offset: 2px;
}

*:focus:not(:focus-visible) {
    outline: none;
}

*:focus-visible {
    outline: 2px solid var(--color-accent-blue);
    outline-offset: 2px;
}

/* High contrast focus for interactive elements */
a:focus-visible,
button:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible,
[tabindex]:focus-visible {
    outline: 3px solid var(--color-accent-blue);
    outline-offset: 3px;
}

/* ===== SKIP LINKS ===== */

.skip-link {
    position: absolute;
    top: -100px;
    left: 0;
    background: var(--color-accent-blue);
    color: white;
    padding: var(--spacing-3) var(--spacing-6);
    text-decoration: none;
    font-weight: var(--font-weight-semibold);
    border-radius: var(--radius-base);
    z-index: var(--z-tooltip);
    transition: top var(--duration-fast);
}

.skip-link:focus {
    top: var(--spacing-md);
    left: var(--spacing-md);
}

/* ===== SCREEN READER ONLY ===== */

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

.sr-only-focusable:active,
.sr-only-focusable:focus {
    position: static;
    width: auto;
    height: auto;
    overflow: visible;
    clip: auto;
    white-space: normal;
}

/* ===== KEYBOARD NAVIGATION HINTS ===== */

[data-keyboard-hint]::after {
    content: attr(data-keyboard-hint);
    position: absolute;
    bottom: calc(100% + 8px);
    left: 50%;
    transform: translateX(-50%);
    background: var(--color-bg-elevated);
    color: var(--color-text-primary);
    padding: var(--spacing-2) var(--spacing-3);
    border-radius: var(--radius-base);
    font-size: var(--font-size-xs);
    white-space: nowrap;
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--duration-fast);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--color-border-primary);
}

[data-keyboard-hint]:focus::after {
    opacity: 1;
}

/* ===== REDUCED MOTION ===== */

@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;
    }

    .toast,
    .modal,
    .sidebar {
        transition: none !important;
    }
}

/* ===== HIGH CONTRAST MODE ===== */

@media (prefers-contrast: high) {
    :root {
        --color-border-primary: rgba(255, 255, 255, 0.3);
        --color-border-secondary: rgba(255, 255, 255, 0.2);
    }

    .card,
    .provider-card,
    .table-container {
        border-width: 2px;
    }

    .btn {
        border-width: 2px;
    }
}

/* ===== ARIA LIVE REGIONS ===== */

.aria-live-polite {
    position: absolute;
    left: -10000px;
    width: 1px;
    height: 1px;
    overflow: hidden;
}

[aria-live="polite"],
[aria-live="assertive"] {
    position: absolute;
    left: -10000px;
    width: 1px;
    height: 1px;
    overflow: hidden;
}

/* ===== LOADING STATES (for screen readers) ===== */

[aria-busy="true"] {
    cursor: wait;
}

[aria-busy="true"]::after {
    content: " (Loading...)";
    position: absolute;
    left: -10000px;
}

/* ===== DISABLED STATES ===== */

[aria-disabled="true"],
[disabled] {
    cursor: not-allowed;
    opacity: 0.6;
    pointer-events: none;
}

/* ===== TOOLTIPS (Accessible) ===== */

[role="tooltip"] {
    position: absolute;
    background: var(--color-bg-elevated);
    color: var(--color-text-primary);
    padding: var(--spacing-2) var(--spacing-3);
    border-radius: var(--radius-base);
    font-size: var(--font-size-sm);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--color-border-primary);
    z-index: var(--z-tooltip);
    max-width: 300px;
}

/* ===== COLOR CONTRAST HELPERS ===== */

.text-high-contrast {
    color: var(--color-text-primary);
    font-weight: var(--font-weight-medium);
}

.bg-high-contrast {
    background: var(--color-bg-primary);
    color: var(--color-text-primary);
}

/* ===== KEYBOARD NAVIGATION INDICATORS ===== */

body:not(.using-mouse) *:focus {
    outline: 3px solid var(--color-accent-blue);
    outline-offset: 3px;
}

/* Detect mouse usage */
body.using-mouse *:focus {
    outline: none;
}

body.using-mouse *:focus-visible {
    outline: 2px solid var(--color-accent-blue);
    outline-offset: 2px;
}