/**
 * BAV Drawer — Mobile slide-out navigation with drill-down panels.
 *
 * Deferred (non-render-blocking). Critical burger CSS lives in bav-header-critical.css.
 * All values via design tokens from bav-components.css.
 *
 * @since BAV 2.0 — Story 14.3
 */

/* ===== Container (fixed overlay wrapper) ===== */

.bav-drawer-container {
    --_header-height: 80px;

    position: fixed;
    top: var(--_header-height);
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 999;
    pointer-events: none;
    visibility: hidden;
}

.bav-drawer-container--open {
    pointer-events: auto;
    visibility: visible;
}

/* ===== Overlay (remaining 20%) ===== */

.bav-drawer__overlay {
    position: absolute;
    inset: 0;
    background: var(--bav-bg-overlay);
    opacity: 0;
    transition: opacity var(--bav-transition-normal);
}

.bav-drawer-container--open .bav-drawer__overlay {
    opacity: 1;
}

/* ===== Drawer panel (80% width, slides from left) ===== */

.bav-drawer {
    --_drawer-width: 80%;
    --_drawer-max-width: 320px;

    position: relative;
    width: var(--_drawer-width);
    max-width: var(--_drawer-max-width);
    height: 100%;
    background: var(--bav-bg);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    transform: translateX(-100%);
    transition: transform var(--bav-transition-normal);
    z-index: 1;
    pointer-events: auto;
    font-family: var(--bav-font-family);
}

.bav-drawer-container--open .bav-drawer {
    transform: translateX(0);
}

/* ===== Top-level view & drill-down transitions ===== */

.bav-drawer__top-level,
.bav-drawer__drill-content {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    overflow-y: auto;
}

.bav-drawer__top-level {
    transform: translateX(0);
    transition: transform var(--bav-transition-fast);
}

.bav-drawer--drilled .bav-drawer__top-level {
    transform: translateX(-100%);
}

.bav-drawer__drill-content {
    transform: translateX(100%);
    transition: transform var(--bav-transition-fast), visibility 0s var(--bav-transition-fast);
    pointer-events: none;
    visibility: hidden;
    background: var(--bav-bg);
    padding-bottom: var(--bav-space-lg);
}

/* Active drill panel: visible immediately, slides in after short delay */
.bav-drill--active {
    visibility: visible;
    transition: transform var(--bav-transition-fast) 80ms, visibility 0s 0s;
}

.bav-drawer--drilled .bav-drill--active {
    transform: translateX(0);
    pointer-events: auto;
}

/* Staggered timing: top-level waits on return, exits immediately on drill */
.bav-drawer--drilled .bav-drawer__top-level {
    transition-delay: 0ms;
}

.bav-drawer:not(.bav-drawer--drilled) .bav-drawer__top-level {
    transition-delay: 80ms;
}

/* ===== Top-level list ===== */

.bav-drawer__list {
    list-style: none;
    margin: 0;
    padding: 0;
}

.bav-drawer__item {
    border-bottom: var(--bav-border-width) solid var(--bav-border);
}

/* ===== Item link (top-level) ===== */

.bav-drawer__item-link {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--bav-space-md) var(--bav-space-lg);
    font-size: var(--bav-font-size-base);
    font-weight: var(--bav-font-weight-semibold);
    color: var(--bav-text);
    text-decoration: none;
    cursor: pointer;
}

.bav-drawer__item-link:hover {
    background: var(--bav-bg-surface);
    text-decoration: none;
}

/* ===== Drill arrow ===== */

.bav-drawer__arrow {
    flex-shrink: 0;
    color: var(--bav-text-secondary);
    font-size: var(--bav-font-size-sm);
}

/* ===== Back button (inside drill panel) ===== */

.bav-drawer__back {
    display: flex;
    align-items: center;
    gap: var(--bav-space-sm);
    width: 100%;
    padding: var(--bav-space-md) var(--bav-space-xl);
    font-weight: var(--bav-font-weight-semibold);
    color: var(--bav-primary);
    background: var(--bav-bg-surface);
    border: none;
    border-bottom: var(--bav-border-width) solid var(--bav-border);
    cursor: pointer;
    min-height: 44px;
    font-size: var(--bav-font-size-base);
}

/* ===== Sub-heading (level 1 — non-clickable) ===== */

.bav-drawer__sub-heading {
    display: block;
    font-size: var(--bav-font-size-sm);
    font-weight: var(--bav-font-weight-bold);
    color: var(--bav-text);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    padding: var(--bav-space-md) var(--bav-space-lg) var(--bav-space-xs);
}

/* ===== Sub-link (level 2 — clickable) ===== */

.bav-drawer__sub-link {
    display: block;
    padding: var(--bav-space-sm) var(--bav-space-lg) var(--bav-space-sm) var(--bav-space-2xl);
    font-size: var(--bav-font-size-sm);
    color: var(--bav-text-secondary);
    text-decoration: none;
}

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

/* ===== CTA link (level 2 with menu-cta class) ===== */

.bav-drawer__sub-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: var(--bav-space-xs) 0 var(--bav-space-sm) var(--bav-space-2xl);
    text-decoration: none;
    transition: background var(--bav-transition-fast), color var(--bav-transition-fast);
}

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

/* ===== Separator (before menu-bottom-section headings) ===== */

.bav-drawer__sub-separator {
    border: none;
    border-top: var(--bav-border-width) solid var(--bav-border);
    margin: var(--bav-space-sm) var(--bav-space-lg);
}

/* ===== Focus indicators ===== */

.bav-drawer__item-link:focus-visible,
.bav-drawer__back:focus-visible,
.bav-drawer__sub-link:focus-visible,
.bav-drawer__sub-cta:focus-visible {
    outline: none;
    box-shadow: var(--bav-focus-ring);
}

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

@media (prefers-reduced-motion: reduce) {
    .bav-drawer-container *,
    .bav-drawer-container *::before,
    .bav-drawer-container *::after {
        transition-duration: 0s !important;
    }
}

/* ===== Desktop: hide drawer completely ===== */

@media (min-width: 992px) {
    .bav-drawer-container {
        display: none !important;
    }
}