/* ==========================================================================
   SUBSECTION OVERVIEW GRID
   Full-screen overlay showing scaled previews of sibling pages
   Triggered by O key or pill button
   ========================================================================== */

/* Overlay */
.overview-overlay {
    position: fixed;
    inset: 0;
    z-index: 100006;
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: opacity 0.25s ease, visibility 0.25s ease;
}

.overview-overlay.open {
    opacity: 1;
    visibility: visible;
    pointer-events: all;
}

/* Backdrop */
.overview-backdrop {
    position: absolute;
    inset: 0;
    background: rgba(15, 23, 42, 0.7);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
}

/* Container */
.overview-container {
    position: relative;
    z-index: 1;
    display: flex;
    flex-direction: column;
    max-width: 1100px;
    max-height: 85vh;
    margin: 5vh auto 0;
    background: var(--surface-white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
    transform: translateY(-12px) scale(0.97);
    transition: transform 0.25s ease;
}

.overview-overlay.open .overview-container {
    transform: translateY(0) scale(1);
}

/* Header */
.overview-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.5rem;
    border-bottom: 1px solid var(--border-subtle);
    flex-shrink: 0;
}

.overview-title {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    min-width: 0;
}

.overview-title i {
    color: var(--accent-gold);
    font-size: 1.1rem;
    flex-shrink: 0;
}

.overview-title h2 {
    font-size: 1.1rem;
    font-weight: 600;
    margin: 0;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.overview-controls {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    flex-shrink: 0;
}

.overview-close {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-sm);
    background: transparent;
    color: var(--text-muted);
    cursor: pointer;
    transition: all 0.15s;
}

.overview-close:hover {
    background: var(--bg-off-white);
    color: var(--text-main);
    border-color: var(--text-muted);
}

/* Grid */
.overview-grid {
    flex: 1;
    overflow-y: auto;
    padding: 1.25rem;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: 1rem;
}

/* Card */
.overview-card {
    display: flex;
    flex-direction: column;
    border: 2px solid var(--border-subtle);
    border-radius: var(--radius-md);
    overflow: hidden;
    cursor: pointer;
    transition: border-color 0.2s, box-shadow 0.2s, transform 0.2s;
    text-decoration: none;
    color: var(--text-main);
    position: relative;
    background: var(--surface-white);
}

.overview-card:hover,
.overview-card.keyboard-focus {
    border-color: var(--primary-blue);
    box-shadow: 0 0 0 3px rgba(30, 64, 175, 0.12);
    transform: translateY(-2px);
}

.overview-card.is-current {
    border-color: var(--accent-gold);
    box-shadow: 0 0 0 3px rgba(217, 119, 6, 0.12);
}

/* Preview area */
.overview-card-preview {
    height: 160px;
    overflow: hidden;
    background: var(--bg-off-white);
    position: relative;
}

.overview-card-preview iframe {
    width: 400%;
    height: 400%;
    transform: scale(0.25);
    transform-origin: top left;
    pointer-events: none;
    border: none;
}

.overview-card-preview .preview-placeholder {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100%;
    color: var(--border-subtle);
    font-size: 2rem;
}

/* Card info */
.overview-card-info {
    padding: 0.75rem;
    border-top: 1px solid var(--border-subtle);
}

.overview-card-title {
    font-weight: 600;
    font-size: 0.9rem;
    display: block;
    margin-bottom: 0.25rem;
    line-height: 1.3;
}

.overview-card-desc {
    font-size: 0.8rem;
    color: var(--text-muted);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
    line-height: 1.4;
}

/* Current page badge */
.overview-card-badge {
    position: absolute;
    top: 0.5rem;
    right: 0.5rem;
    background: var(--accent-gold);
    color: white;
    width: 26px;
    height: 26px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.7rem;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
}

/* Footer */
.overview-footer {
    border-top: 1px solid var(--border-subtle);
    padding: 0.6rem 1.25rem;
    display: flex;
    gap: 1.5rem;
    font-size: 0.75rem;
    color: var(--text-muted);
    background: var(--bg-off-white);
    flex-shrink: 0;
}

.overview-footer kbd {
    display: inline-block;
    background: var(--surface-white);
    border: 1px solid var(--border-subtle);
    border-radius: 3px;
    padding: 0.1rem 0.35rem;
    font-size: 0.7rem;
    font-family: inherit;
    margin-right: 0.25rem;
    line-height: 1.4;
}

/* Trigger button — eyebrow above breadcrumbs */
.overview-trigger {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.2rem 0.65rem;
    background: rgba(255, 255, 255, 0.12);
    border: 1px solid rgba(255, 255, 255, 0.25);
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.02em;
    color: rgba(255, 255, 255, 0.8);
    cursor: pointer;
    transition: all 0.15s;
    margin-top: -1rem;
    margin-bottom: 0.75rem;
}

.overview-trigger:hover {
    background: rgba(255, 255, 255, 0.22);
    border-color: rgba(255, 255, 255, 0.45);
    color: white;
}

.overview-trigger kbd {
    display: inline-block;
    background: rgba(255, 255, 255, 0.12);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 3px;
    padding: 0.05rem 0.25rem;
    font-size: 0.65rem;
    font-family: inherit;
    line-height: 1.3;
}

/* View transition morph — app-like zoom from card → full page */
::view-transition-group(overview-target) {
    animation-duration: 0.55s;
    animation-timing-function: cubic-bezier(0.2, 0, 0, 1);
    overflow: hidden;
}

/* Old image (the card thumbnail) scales up and fades out */
::view-transition-old(overview-target) {
    animation: overview-zoom-out 0.55s cubic-bezier(0.2, 0, 0, 1) forwards;
    object-fit: cover;
}

/* New image (the full page) fades in as it settles */
::view-transition-new(overview-target) {
    animation: overview-zoom-in 0.55s cubic-bezier(0.2, 0, 0, 1) forwards;
    object-fit: cover;
}

@keyframes overview-zoom-out {
    0%   { opacity: 1; transform: scale(1); }
    40%  { opacity: 1; }
    100% { opacity: 0; transform: scale(1.08); }
}

@keyframes overview-zoom-in {
    0%   { opacity: 0; transform: scale(0.92); }
    40%  { opacity: 0.5; }
    100% { opacity: 1; transform: scale(1); }
}

/* Responsive */
@media (max-width: 768px) {
    .overview-container {
        margin: 2vh 0.5rem 0;
        max-height: 92vh;
        border-radius: var(--radius-md);
    }

    .overview-header {
        padding: 0.75rem 1rem;
    }

    .overview-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 0.75rem;
        padding: 0.75rem;
    }

    .overview-card-preview {
        height: 120px;
    }

    .overview-footer {
        display: none;
    }
}

@media (max-width: 480px) {
    .overview-grid {
        grid-template-columns: 1fr;
    }
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
    .overview-overlay,
    .overview-container,
    .overview-card {
        transition: none;
    }

    ::view-transition-group(overview-target),
    ::view-transition-old(overview-target),
    ::view-transition-new(overview-target) {
        animation-duration: 0s;
    }
}