/**
 * Smart Nav Styles
 * 
 * Desktop: Flyout submenus with collision detection (via JS)
 * Mobile: Drill-down panel stack
 * RTL: Automatic via [dir="rtl"] selectors
 */

/* ==========================================================================
   CSS Custom Properties
   ========================================================================== */

.smart-nav {
    --smart-nav-bg: #fff;
    --smart-nav-text: #222;
    --smart-nav-border: #e0e0e0;
    --smart-nav-hover-bg: #f5f5f5;
    --smart-nav-submenu-width: 220px;
    --smart-nav-item-padding: 0.75rem 1rem;
    --smart-nav-mobile-breakpoint: 768px;
    --smart-nav-transition: 200ms ease;
}

/* ==========================================================================
   Container
   ========================================================================== */

.smart-nav-container {
    position: relative;
}

/* ==========================================================================
   Base / Reset
   ========================================================================== */

.smart-nav,
.smart-nav *,
.smart-nav *::before,
.smart-nav *::after {
    box-sizing: border-box;
}

.smart-nav__menu,
.smart-nav__submenu {
    list-style: none;
    margin: 0;
    padding: 0;
}

.smart-nav__link {
    text-decoration: none;
    color: inherit;
}

/* ==========================================================================
   Toggle Button (Mobile)
   ========================================================================== */

.smart-nav__toggle {
    display: none;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    padding: 0;
    background: transparent;
    border: 1px solid var(--smart-nav-border);
    cursor: pointer;
}

.smart-nav__toggle-icon {
    display: block;
    position: relative;
    width: 24px;
    height: 3px;
    background: var(--smart-nav-text);
}

.smart-nav__toggle-icon::before,
.smart-nav__toggle-icon::after {
    content: '';
    position: absolute;
    left: 0;
    width: 100%;
    height: 3px;
    background: inherit;
    transition: transform var(--smart-nav-transition);
}

.smart-nav__toggle-icon::before {
    top: -8px;
}

.smart-nav__toggle-icon::after {
    top: 8px;
}

/* Toggle open state */
.smart-nav__toggle[aria-expanded="true"] .smart-nav__toggle-icon {
    background: transparent;
}

.smart-nav__toggle[aria-expanded="true"] .smart-nav__toggle-icon::before {
    top: 0;
    transform: rotate(45deg);
}

.smart-nav__toggle[aria-expanded="true"] .smart-nav__toggle-icon::after {
    top: 0;
    transform: rotate(-45deg);
}

/* ==========================================================================
   Desktop Styles
   ========================================================================== */

@media (min-width: 769px) {
    
    /* Hide mobile-only elements on desktop */
    .smart-nav__close,
    .smart-nav__back,
    .smart-nav__expand {
        display: none !important;
    }
    
    /* Remove active class effects on desktop */
    .smart-nav__submenu--active {
        transform: none;
    }
    
    .smart-nav__menu {
        display: flex;
        flex-wrap: wrap;
        gap: 0;
    }
    
    .smart-nav__item {
        position: relative;
    }
    
    .smart-nav__link {
        display: flex;
        align-items: center;
        padding: var(--smart-nav-item-padding);
        white-space: nowrap;
        transition: background-color var(--smart-nav-transition);
    }
    
    .smart-nav__link:hover,
    .smart-nav__link:focus {
        background-color: var(--smart-nav-hover-bg);
    }
    
    .smart-nav__item--current > .smart-nav__link {
        font-weight: 600;
    }
    
    /* Expand button on desktop - inline indicator */
    .smart-nav__expand {
        display: none;
    }
    
    /* Arrow indicator for items with children */
    .smart-nav__item--has-children > .smart-nav__link::after {
        content: '';
        display: inline-block;
        width: 0;
        height: 0;
        margin-inline-start: 0.5rem;
        border-style: solid;
        border-width: 4px 4px 0 4px;
        border-color: currentColor transparent transparent transparent;
    }
    
    /* Nested items have side arrow */
    .smart-nav__submenu .smart-nav__item--has-children > .smart-nav__link::after {
        border-width: 4px 0 4px 4px;
        border-color: transparent transparent transparent currentColor;
    }
    
    /* RTL: flip the nested arrow */
    [dir="rtl"] .smart-nav__submenu .smart-nav__item--has-children > .smart-nav__link::after {
        border-width: 4px 4px 4px 0;
        border-color: transparent currentColor transparent transparent;
    }
    
    /* Submenus - Desktop Flyout */
    .smart-nav__submenu {
        position: absolute;
        top: 100%;
        left: 0;
        z-index: 1000;
        min-width: var(--smart-nav-submenu-width);
        background: var(--smart-nav-bg);
        border: 1px solid var(--smart-nav-border);
        opacity: 0;
        visibility: hidden;
        transform: translateY(-8px);
        transition: 
            opacity var(--smart-nav-transition),
            visibility var(--smart-nav-transition),
            transform var(--smart-nav-transition);
    }
    
    /* RTL: flip submenu alignment */
    [dir="rtl"] .smart-nav__submenu {
        left: auto;
        right: 0;
    }
    
    /* Nested submenus appear to the side */
    .smart-nav__submenu .smart-nav__submenu {
        top: 0;
        left: 100%;
    }
    
    [dir="rtl"] .smart-nav__submenu .smart-nav__submenu {
        left: auto;
        right: 100%;
    }
    
    /* Show submenu on hover/focus */
    .smart-nav__item:hover > .smart-nav__submenu,
    .smart-nav__item:focus-within > .smart-nav__submenu {
        opacity: 1;
        visibility: visible;
        transform: translateY(0);
    }
    
    /* ==========================================================================
       Collision Classes (Applied by JS)
       ========================================================================== */
    
    /* Flip horizontal: submenu opens to the left instead of right */
    .smart-nav__submenu--flip-x {
        left: auto;
        right: 100%;
    }
    
    [dir="rtl"] .smart-nav__submenu--flip-x {
        left: 100%;
        right: auto;
    }
    
    /* Flip vertical: submenu opens upward */
    .smart-nav__submenu--flip-y {
        top: auto;
        bottom: 100%;
        transform: translateY(8px);
    }
    
    .smart-nav__item:hover > .smart-nav__submenu--flip-y,
    .smart-nav__item:focus-within > .smart-nav__submenu--flip-y {
        transform: translateY(0);
    }
    
    /* Top-level flip-y needs different positioning */
    .smart-nav__menu > .smart-nav__item > .smart-nav__submenu--flip-y {
        top: auto;
        bottom: 100%;
    }
    
    /* Constrain height if submenu is too tall */
    .smart-nav__submenu--constrain-y {
        max-height: calc(100vh - 2rem);
        overflow-y: auto;
    }
}

/* ==========================================================================
   Mobile Styles - Drill Down
   ========================================================================== */

@media (max-width: 768px) {
    .smart-nav__toggle {
        display: flex;
    }
    
    .smart-nav {
        position: relative;
    }
    
    /* Panel container */
    .smart-nav__menu {
        position: fixed;
        top: 0;
        left: 0;
        z-index: 9999;
        width: 100%;
        height: 100%;
        background: var(--smart-nav-bg);
        transform: translateX(-100%);
        transition: transform var(--smart-nav-transition);
        overflow: hidden;
    }
    
    [dir="rtl"] .smart-nav__menu {
        left: auto;
        right: 0;
        transform: translateX(100%);
    }
    
    /* Open state */
    .smart-nav--open .smart-nav__menu {
        transform: translateX(0);
    }
    
    /* All menu levels are stacked panels */
    .smart-nav__menu,
    .smart-nav__submenu {
        display: flex;
        flex-direction: column;
    }
    
    .smart-nav__submenu {
        position: absolute;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        background: var(--smart-nav-bg);
        transform: translateX(100%);
        transition: transform var(--smart-nav-transition);
    }
    
    [dir="rtl"] .smart-nav__submenu {
        left: auto;
        right: 0;
        transform: translateX(-100%);
    }
    
    /* Active submenu slides in */
    .smart-nav__submenu--active {
        transform: translateX(0);
    }
    
    .smart-nav__item {
        border-bottom: 1px solid var(--smart-nav-border);
    }
    
    .smart-nav__item--has-children {
        display: flex;
        flex-wrap: wrap;
    }
    
    .smart-nav__item--has-children > .smart-nav__link {
        flex: 1;
    }
    
    .smart-nav__link {
        display: block;
        padding: 1rem;
    }
    
    /* Expand button visible on mobile */
    .smart-nav__expand {
        display: flex;
        align-items: center;
        justify-content: center;
        width: 60px;
        padding: 0;
        background: transparent;
        border: none;
        border-inline-start: 1px solid var(--smart-nav-border);
        cursor: pointer;
    }
    
    .smart-nav__expand-icon {
        display: block;
        width: 0;
        height: 0;
        border-style: solid;
        border-width: 10px 0 10px 12px;
        border-color: transparent transparent transparent var(--smart-nav-text);
    }
    
    [dir="rtl"] .smart-nav__expand-icon {
        border-width: 10px 12px 10px 0;
        border-color: transparent var(--smart-nav-text) transparent transparent;
    }
    
    /* Back button (injected by JS) */
    .smart-nav__back {
        display: flex;
        align-items: center;
        gap: 0.75rem;
        width: 100%;
        padding: 1rem;
        background: var(--smart-nav-hover-bg);
        border: none;
        border-bottom: 1px solid var(--smart-nav-border);
        font-size: inherit;
        cursor: pointer;
        text-align: start;
    }
    
    .smart-nav__back-icon {
        display: block;
        width: 0;
        height: 0;
        border-style: solid;
        border-width: 10px 12px 10px 0;
        border-color: transparent var(--smart-nav-text) transparent transparent;
    }
    
    [dir="rtl"] .smart-nav__back-icon {
        border-width: 10px 0 10px 12px;
        border-color: transparent transparent transparent var(--smart-nav-text);
    }
    
    /* Close button */
    .smart-nav__close {
        display: flex;
        align-items: center;
        justify-content: flex-end;
        padding: 1rem;
        background: transparent;
        border: none;
        border-bottom: 1px solid var(--smart-nav-border);
        cursor: pointer;
    }
    
    .smart-nav__close-icon {
        position: relative;
        width: 24px;
        height: 24px;
    }
    
    .smart-nav__close-icon::before,
    .smart-nav__close-icon::after {
        content: '';
        position: absolute;
        top: 50%;
        left: 0;
        width: 100%;
        height: 3px;
        background: var(--smart-nav-text);
    }
    
    .smart-nav__close-icon::before {
        transform: rotate(45deg);
    }
    
    .smart-nav__close-icon::after {
        transform: rotate(-45deg);
    }
}

/* ==========================================================================
   Accessibility
   ========================================================================== */

.smart-nav__link:focus,
.smart-nav__expand:focus,
.smart-nav__toggle:focus,
.smart-nav__back:focus,
.smart-nav__close:focus {
    outline: 2px solid currentColor;
    outline-offset: -2px;
}

/* Visually hidden but accessible */
.smart-nav__sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}