/**
 * APG Photo Gallery - Frontend Styles
 *
 * @package APG_Photo_Gallery
 */

/* ==========================================================================
   CSS Custom Properties (Variables)
   ========================================================================== */
:root {
    --apg-cols-desktop: 4;
    --apg-cols-tablet: 3;
    --apg-cols-mobile: 2;
    --apg-gap: 12px;
    --apg-border-radius: 8px;
    --apg-transition: 0.3s ease;
    --apg-overlay-bg: rgba(0, 0, 0, 0.92);
    --apg-accent-color: #3b82f6;
}

/* ==========================================================================
   Gallery Grid Layout
   ========================================================================== */
.apg-gallery {
    width: 100%;
    margin: 1.5em 0;
}

.apg-gallery--grid {
    display: grid;
    grid-template-columns: repeat(var(--apg-cols-desktop), 1fr);
    gap: var(--apg-gap);
}

.apg-gallery__item {
    position: relative;
    overflow: hidden;
    border-radius: var(--apg-border-radius);
    background: #f3f4f6;
    aspect-ratio: 1 / 1;
}

.apg-gallery__link {
    display: block;
    width: 100%;
    height: 100%;
    cursor: pointer;
    text-decoration: none;
}

.apg-gallery__image {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--apg-transition), opacity var(--apg-transition);
}

.apg-gallery__item:hover .apg-gallery__image {
    transform: scale(1.05);
    opacity: 0.9;
}

/* Image loading state */
.apg-gallery__image[loading] {
    background: linear-gradient(90deg, #f3f4f6 25%, #e5e7eb 50%, #f3f4f6 75%);
    background-size: 200% 100%;
    animation: apg-shimmer 1.5s infinite;
}

@keyframes apg-shimmer {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

/* ==========================================================================
   Carousel Layout
   ========================================================================== */
.apg-gallery--carousel {
    position: relative;
}

.apg-gallery__carousel-wrapper {
    position: relative;
    overflow: hidden;
    border-radius: var(--apg-border-radius);
}

.apg-gallery__carousel-track {
    display: flex;
    transition: transform 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    touch-action: pan-y;
}

.apg-gallery--carousel .apg-gallery__item {
    flex: 0 0 calc(100% / var(--apg-cols-desktop));
    min-width: calc(100% / var(--apg-cols-desktop));
    padding: 0 calc(var(--apg-gap) / 2);
    box-sizing: border-box;
    aspect-ratio: 4 / 3;
}

.apg-gallery--carousel .apg-gallery__item:first-child {
    padding-left: 0;
}

.apg-gallery--carousel .apg-gallery__item:last-child {
    padding-right: 0;
}

/* Carousel Navigation Buttons */
.apg-gallery__carousel-prev,
.apg-gallery__carousel-next {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    z-index: 10;
    width: 44px;
    height: 44px;
    border: none;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.95);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--apg-transition);
    color: #1f2937;
}

.apg-gallery__carousel-prev:hover,
.apg-gallery__carousel-next:hover {
    background: #fff;
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.2);
    transform: translateY(-50%) scale(1.05);
}

.apg-gallery__carousel-prev:focus,
.apg-gallery__carousel-next:focus {
    outline: 2px solid var(--apg-accent-color);
    outline-offset: 2px;
}

.apg-gallery__carousel-prev {
    left: 12px;
}

.apg-gallery__carousel-next {
    right: 12px;
}

.apg-gallery__carousel-prev:disabled,
.apg-gallery__carousel-next:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

/* ==========================================================================
   Lightbox Styles
   ========================================================================== */
.apg-lightbox {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 999999;
    background: var(--apg-overlay-bg);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
    padding: 60px 20px 20px;
    box-sizing: border-box;
}

.apg-lightbox.is-active {
    opacity: 1;
    visibility: visible;
}

.apg-lightbox__content {
    position: relative;
    max-width: 100%;
    max-height: calc(100vh - 200px);
    display: flex;
    align-items: center;
    justify-content: center;
    flex: 1;
    min-height: 0;
}

.apg-lightbox__image {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
    border-radius: 4px;
    opacity: 0;
    transform: scale(0.95);
    transition: opacity 0.3s ease, transform 0.3s ease;
    user-select: none;
    -webkit-user-drag: none;
}

.apg-lightbox.is-active .apg-lightbox__image {
    opacity: 1;
    transform: scale(1);
}

.apg-lightbox__close {
    position: absolute;
    top: 20px;
    right: 20px;
    width: 48px;
    height: 48px;
    border: none;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.1);
    color: #fff;
    font-size: 28px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--apg-transition);
    z-index: 10;
}

.apg-lightbox__close:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: scale(1.1);
}

.apg-lightbox__close:focus {
    outline: 2px solid #fff;
    outline-offset: 2px;
}

/* Navigation wrapper - below image */
.apg-lightbox__nav {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 20px;
    padding: 20px 0;
    flex-shrink: 0;
}

.apg-lightbox__prev,
.apg-lightbox__next {
    position: relative;
    width: 56px;
    height: 56px;
    border: none;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.15);
    color: #fff;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--apg-transition);
}

.apg-lightbox__prev:hover,
.apg-lightbox__next:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: scale(1.1);
}

.apg-lightbox__prev:focus,
.apg-lightbox__next:focus {
    outline: 2px solid #fff;
    outline-offset: 2px;
}

.apg-lightbox__prev:disabled,
.apg-lightbox__next:disabled {
    opacity: 0.3;
    cursor: not-allowed;
}

.apg-lightbox__prev:disabled:hover,
.apg-lightbox__next:disabled:hover {
    transform: none;
    background: rgba(255, 255, 255, 0.15);
}

.apg-lightbox__caption {
    position: absolute;
    bottom: 100px;
    left: 50%;
    transform: translateX(-50%);
    max-width: 80%;
    padding: 12px 24px;
    background: rgba(0, 0, 0, 0.6);
    color: #fff;
    font-size: 14px;
    text-align: center;
    border-radius: 8px;
    backdrop-filter: blur(10px);
    pointer-events: none;
}

.apg-lightbox__counter {
    position: absolute;
    top: 20px;
    left: 20px;
    padding: 8px 16px;
    background: rgba(0, 0, 0, 0.5);
    color: #fff;
    font-size: 14px;
    border-radius: 20px;
    backdrop-filter: blur(10px);
}

/* Loading indicator */
.apg-lightbox__loader {
    position: absolute;
    width: 40px;
    height: 40px;
    border: 3px solid rgba(255, 255, 255, 0.2);
    border-top-color: #fff;
    border-radius: 50%;
    animation: apg-spin 0.8s linear infinite;
}

@keyframes apg-spin {
    to { transform: rotate(360deg); }
}

/* ==========================================================================
   Responsive Styles
   ========================================================================== */

/* Tablet */
@media (max-width: 1024px) {
    .apg-gallery--grid {
        grid-template-columns: repeat(var(--apg-cols-tablet), 1fr);
    }

    .apg-gallery--carousel .apg-gallery__item {
        flex: 0 0 calc(100% / var(--apg-cols-tablet));
        min-width: calc(100% / var(--apg-cols-tablet));
    }
}

/* Mobile */
@media (max-width: 640px) {
    .apg-gallery--grid {
        grid-template-columns: repeat(var(--apg-cols-mobile), 1fr);
    }

    .apg-gallery--carousel .apg-gallery__item {
        flex: 0 0 calc(100% / var(--apg-cols-mobile));
        min-width: calc(100% / var(--apg-cols-mobile));
    }

    .apg-gallery__carousel-prev,
    .apg-gallery__carousel-next {
        width: 36px;
        height: 36px;
    }

    .apg-gallery__carousel-prev {
        left: 8px;
    }

    .apg-gallery__carousel-next {
        right: 8px;
    }

    /* Lightbox mobile adjustments */
    .apg-lightbox {
        padding: 50px 10px 10px;
    }

    .apg-lightbox__content {
        max-height: calc(100vh - 160px);
    }

    .apg-lightbox__nav {
        gap: 30px;
        padding: 15px 0;
    }

    .apg-lightbox__prev,
    .apg-lightbox__next {
        width: 48px;
        height: 48px;
    }

    .apg-lightbox__close {
        top: 10px;
        right: 10px;
        width: 40px;
        height: 40px;
        font-size: 24px;
    }

    .apg-lightbox__counter {
        top: 10px;
        left: 10px;
        font-size: 12px;
        padding: 6px 12px;
    }

    .apg-lightbox__caption {
        bottom: 80px;
        font-size: 12px;
        padding: 8px 16px;
    }
}

/* ==========================================================================
   Accessibility
   ========================================================================== */
@media (prefers-reduced-motion: reduce) {
    .apg-gallery__image,
    .apg-gallery__carousel-track,
    .apg-lightbox,
    .apg-lightbox__image,
    .apg-gallery__carousel-prev,
    .apg-gallery__carousel-next {
        transition: none;
    }

    .apg-gallery__image[loading] {
        animation: none;
    }
}

/* High contrast mode */
@media (prefers-contrast: high) {
    .apg-gallery__item {
        border: 2px solid #000;
    }

    .apg-gallery__carousel-prev,
    .apg-gallery__carousel-next {
        border: 2px solid #000;
    }
}

/* Focus visible */
.apg-gallery__link:focus-visible {
    outline: 3px solid var(--apg-accent-color);
    outline-offset: 2px;
}