/**
 * BAV Mega Menu — Desktop dropdown panel styles (deferred, non-critical).
 *
 * Mobile-first: panels hidden by default, shown at >= 992px.
 * All values use design tokens from bav-components.css.
 * BEM naming: bav-mega-menu__{element}--{modifier}
 *
 * @since BAV 2.0 — Story 14.2
 */

/* ===== Base / Mobile (panels + overlay hidden) ===== */

.bav-mega-menu {
    display: none !important;
}

.bav-header-overlay {
    display: none;
}

/* ===== Desktop (>= 992px) ===== */

@media (min-width: 992px) {

    /* --- Panel (opacity transition for smooth appearance) --- */

    .bav-mega-menu {
        display: block !important;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--bav-bg);
        border-top: 3px solid var(--bav-accent);
        box-shadow: 0 12px 32px rgba(26, 33, 80, 0.12);
        z-index: 99;
        padding: var(--bav-space-xl) 0;
        visibility: hidden;
        opacity: 0;
        pointer-events: none;
        transition: opacity var(--bav-transition-normal), visibility 0s var(--bav-transition-normal);
    }

    .bav-mega-menu--open {
        visibility: visible;
        opacity: 1;
        pointer-events: auto;
        transition: opacity var(--bav-transition-normal), visibility 0s;
    }

    /* Instant swap when switching between panels (no fade) */
    .bav-mega-menu--instant {
        transition: none !important;
    }

    /* --- Page overlay (navy tint behind mega menu) --- */

    .bav-header-overlay {
        display: block;
        position: fixed;
        top: var(--_header-height, 80px);
        left: 0;
        right: 0;
        bottom: 0;
        background: var(--bav-bg-overlay);
        opacity: 0;
        pointer-events: none;
        transition: opacity var(--bav-transition-normal);
        z-index: -1;
    }

    .bav-header-overlay--visible {
        opacity: 1;
        pointer-events: auto;
    }

    /* --- Grid layout (3 columns) --- */

    .bav-mega-menu__grid {
        display: grid;
        grid-template-columns: repeat(3, 1fr);
        gap: var(--bav-space-lg);
        max-width: 1200px;
        margin: 0 auto;
        padding: 0 var(--bav-space-xl);
    }

    /* --- Column (subcategory group) --- */

    .bav-mega-menu__column {
        display: flex;
        flex-direction: column;
        gap: var(--bav-space-sm);
    }

    /* --- Subcategory heading --- */

    .bav-mega-menu__heading {
        display: block;
        font-family: var(--bav-font-family);
        font-size: var(--bav-font-size-sm);
        font-weight: var(--bav-font-weight-semibold);
        color: var(--bav-primary);
        text-transform: uppercase;
        letter-spacing: 0.05em;
        padding-bottom: var(--bav-space-xs);
        border-bottom: 2px solid var(--bav-accent);
        margin-bottom: var(--bav-space-xs);
    }

    /* --- Links --- */

    .bav-mega-menu__link {
        font-size: var(--bav-font-size-sm);
        color: var(--bav-text-secondary);
        text-decoration: none;
        padding: var(--bav-space-xs) 0;
        transition: color var(--bav-transition-fast);
    }

    .bav-mega-menu__link:hover {
        color: var(--bav-primary);
        text-decoration: none;
    }

    /* --- CTA link (button appearance) --- */

    .bav-mega-menu__link--cta {
        display: inline-block;
        background: var(--bav-primary);
        color: var(--bav-text-inverse);
        font-weight: var(--bav-font-weight-semibold);
        font-size: var(--bav-font-size-xs);
        padding: var(--bav-space-xs) var(--bav-space-md);
        margin-top: var(--bav-space-xs);
        border-radius: var(--bav-radius-none);
        transition: background var(--bav-transition-fast);
        text-decoration: none;
    }

    .bav-mega-menu__link--cta:hover {
        background: var(--bav-accent);
        color: var(--bav-primary);
        text-decoration: none;
    }

    /* --- Separator (bottom section) --- */

    .bav-mega-menu__separator {
        grid-column: 1 / -1;
        border-top: 1px solid var(--bav-border);
        margin: var(--bav-space-sm) 0;
    }

    /* --- Semantic list reset (proper <ul>/<li> inside columns) --- */

    .bav-mega-menu__list {
        list-style: none;
        margin: 0;
        padding: 0;
        display: flex;
        flex-direction: column;
        gap: 0;
    }

    /* --- Focus-visible indicators on mega menu elements --- */

    .bav-mega-menu__link:focus-visible {
        outline: none;
        box-shadow: var(--bav-focus-ring);
    }

    .bav-mega-menu__link--cta:focus-visible {
        outline: none;
        box-shadow: var(--bav-focus-ring);
    }
}

/* ===== Reduced motion ===== */

@media (prefers-reduced-motion: reduce) {
    .bav-mega-menu,
    .bav-mega-menu__link,
    .bav-mega-menu__link--cta,
    .bav-header-overlay {
        transition: none;
    }
}