/* ===================================
   GRID-BASED PAGE TRANSITION V2
   Double-flip approach: Exit → Navigate → Reveal
   =================================== */

/* Transition overlay container */
.page-transition-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 9999;
    pointer-events: none;
    display: none;
}

.page-transition-overlay.active {
    display: block;
    pointer-events: all;
}

/* Grid container for transition cells */
.transition-grid {
    position: relative;
    width: 100%;
    height: 100%;
    display: grid;
    grid-template-columns: repeat(12, 1fr);
    grid-template-rows: repeat(8, 1fr);
    gap: 0;
}

/* Individual transition cell */
.transition-cell {
    position: relative;
    overflow: hidden;
    perspective: 1000px;
}

/* Flip card container */
.transition-flip-card {
    position: relative;
    width: 100%;
    height: 100%;
    transform-style: preserve-3d;
    transition: transform 0.5s cubic-bezier(0.215, 0.61, 0.355, 1);
}

/* Trigger flip */
.transition-cell.flipped .transition-flip-card {
    transform: rotateY(180deg);
}

/* Card faces */
.transition-card-front,
.transition-card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
}

/* Front face: Shows current page (transparent to see through) */
.transition-card-front {
    background-color: transparent;
}

/* Back face: Opposite color for contrast (black on white theme, white on dark theme) */
.transition-card-back {
    background-color: var(--color-primary);
    transform: rotateY(180deg);
}

/* ===================================
   RESPONSIVE GRID
   =================================== */
@media (max-width: 1024px) {
    .transition-grid {
        grid-template-columns: repeat(10, 1fr);
        grid-template-rows: repeat(8, 1fr);
    }
}

@media (max-width: 768px) {
    .transition-grid {
        grid-template-columns: repeat(6, 1fr);
        grid-template-rows: repeat(8, 1fr);
    }
}

@media (max-width: 480px) {
    .transition-grid {
        grid-template-columns: repeat(6, 1fr);
        grid-template-rows: repeat(8, 1fr);
    }
}

/* ===================================
   ACCESSIBILITY
   =================================== */
@media (prefers-reduced-motion: reduce) {
    .transition-flip-card {
        transition: none;
    }

    .transition-cell.flipped .transition-flip-card {
        transform: none;
    }

    .transition-card-back {
        transform: none;
    }
}