/* ============================================
   KOBYGEN — SMOOTH UX LAYER 2026
   Motion utilities, transitions, CLS guards
   Load after design-system.css / tokens.css
   ============================================ */

@media (prefers-reduced-motion: no-preference) {
    html {
        scroll-behavior: smooth;
    }
}

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }
}

/* ---- Page enter / exit (nav + tab switches) ---- */
body.smooth-page-enter {
    animation: smoothPageEnter var(--duration-normal, 0.38s) var(--ease-out-expo, cubic-bezier(0.16, 1, 0.3, 1));
}

body.smooth-page-exit {
    opacity: 0;
    transition: opacity var(--duration-fast, 0.18s) ease;
}

@keyframes smoothPageEnter {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* View Transitions API (progressive enhancement) */
@supports (view-transition-name: none) {
  ::view-transition-old(root),
  ::view-transition-new(root) {
    animation-duration: var(--duration-normal, 0.38s);
    animation-timing-function: var(--ease-out-expo, cubic-bezier(0.16, 1, 0.3, 1));
  }
}

/* ---- Tab crossfade (admin + auth) ---- */
[data-tab-content-group].smooth-tab-panel {
    transition:
        opacity var(--duration-fast, 0.18s) var(--ease-out-expo),
        transform var(--duration-fast, 0.18s) var(--ease-out-expo);
}

[data-tab-content-group].smooth-tab-panel.is-hiding {
    opacity: 0;
    transform: translateY(8px);
    pointer-events: none;
}

[data-tab-content-group].smooth-tab-panel.is-showing {
    animation: smoothTabIn var(--duration-normal, 0.38s) var(--ease-out-expo);
}

.form.smooth-auth-form {
    transition:
        opacity var(--duration-fast, 0.18s) var(--ease-out-expo),
        transform var(--duration-fast, 0.18s) var(--ease-out-expo);
}

.form.smooth-auth-form.is-hiding {
    opacity: 0;
    transform: translateY(10px);
    pointer-events: none;
    position: absolute;
    width: 100%;
    visibility: hidden;
}

.form.smooth-auth-form.is-showing {
    animation: smoothTabIn var(--duration-normal, 0.38s) var(--ease-out-expo);
}

@keyframes smoothTabIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ---- Dynamic content fade-in ---- */
.smooth-content-pending {
    opacity: 0;
    min-height: 2rem;
}

.smooth-content-ready {
    animation: smoothContentIn var(--duration-normal, 0.38s) var(--ease-out-expo) forwards;
}

@keyframes smoothContentIn {
    from {
        opacity: 0;
        transform: translateY(6px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ---- Skeleton placeholder ---- */
.smooth-skeleton {
    position: relative;
    overflow: hidden;
    background: rgba(255, 255, 255, 0.04);
    border-radius: var(--radius-sm, 10px);
    min-height: 1.25rem;
}

.smooth-skeleton::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(
        90deg,
        transparent 0%,
        rgba(255, 255, 255, 0.07) 50%,
        transparent 100%
    );
    background-size: 200% 100%;
    animation: smoothSkeletonShimmer 1.4s ease-in-out infinite;
}

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

/* ---- Sticky header: GPU-friendly transitions ---- */
.site-header {
    transition:
        background-color var(--transition-smooth, 0.38s cubic-bezier(0.16, 1, 0.3, 1)),
        border-color var(--transition-smooth),
        box-shadow var(--transition-smooth),
        transform var(--duration-fast, 0.18s) var(--ease-out-expo);
}

.site-header.scrolled {
    transform: translateZ(0);
}

@media (min-width: 769px) {
    .site-header {
        transition:
            background-color var(--transition-smooth, 0.38s cubic-bezier(0.16, 1, 0.3, 1)),
            border-color var(--transition-smooth),
            box-shadow var(--transition-smooth);
    }

    .site-header.scrolled {
        transform: none;
    }
}

/* ---- Modal overlay (site + admin) ---- */
.modal-overlay.is-closing,
.upload-modal.is-closing,
.gallery-lightbox.is-closing {
    animation: smoothOverlayOut var(--duration-fast, 0.18s) ease forwards;
}

.modal-overlay.is-closing .modal,
.upload-modal.is-closing .modal-content,
.gallery-lightbox.is-closing .lightbox-content {
    animation: smoothModalOut var(--duration-fast, 0.18s) ease forwards;
}

@keyframes smoothOverlayOut {
    from { opacity: 1; }
    to { opacity: 0; }
}

@keyframes smoothModalOut {
    from {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
    to {
        opacity: 0;
        transform: translateY(12px) scale(0.97);
    }
}

/* ---- Flash alerts (account + site) ---- */
.alert.smooth-flash-in,
.site-flash.smooth-flash-in {
    animation: smoothFlashIn var(--duration-normal, 0.38s) var(--ease-out-expo);
}

@keyframes smoothFlashIn {
    from {
        opacity: 0;
        transform: translateY(-8px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ---- Gallery filter (no instant hide jank) ---- */
.gallery-item.smooth-filter-out {
    opacity: 0;
    transform: scale(0.96);
    pointer-events: none;
    transition:
        opacity var(--duration-fast, 0.18s) ease,
        transform var(--duration-fast, 0.18s) ease;
}

.gallery-item.smooth-filter-in {
    animation: smoothFilterIn var(--duration-normal, 0.38s) var(--ease-out-expo);
}

@keyframes smoothFilterIn {
    from {
        opacity: 0;
        transform: scale(0.96);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

/* ---- CLS: images without explicit dimensions ---- */
img.smooth-img-guard:not([width]):not([height]) {
    aspect-ratio: 16 / 9;
    object-fit: cover;
    background: rgba(255, 255, 255, 0.04);
}

img.smooth-img-guard[data-smooth-ratio="1"] { aspect-ratio: 1; }
img.smooth-img-guard[data-smooth-ratio="4/3"] { aspect-ratio: 4 / 3; }
img.smooth-img-guard[data-smooth-ratio="3/4"] { aspect-ratio: 3 / 4; }

/* ---- Deferred sections (perf without layout jump) ---- */
[data-smooth-defer] {
    content-visibility: auto;
    contain-intrinsic-size: auto 420px;
}

/* ---- Admin save feedback ---- */
.smooth-save-pending {
    opacity: 0.72;
    pointer-events: none;
    transition: opacity var(--duration-fast, 0.18s) ease;
}

.smooth-save-pending::after {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--gradient-cyan);
    z-index: calc(var(--z-toast, 10001) + 1);
    animation: smoothSaveBar 1.2s ease-in-out infinite;
}

@keyframes smoothSaveBar {
    0% { transform: translateX(-100%); }
    100% { transform: translateX(100%); }
}

/* ---- Stat / score bump (game + live counters) ---- */
.smooth-stat-bump {
    animation: smoothStatBump var(--duration-normal, 0.38s) var(--ease-out-expo);
}

@keyframes smoothStatBump {
    0% { transform: scale(1); }
    35% { transform: scale(1.08); color: var(--neon-cyan, #00f0ff); }
    100% { transform: scale(1); }
}

/* ---- Gallery lightbox image swap ---- */
#lightboxImg.smooth-lightbox-out {
    opacity: 0;
    transform: scale(0.96);
    transition: opacity var(--duration-fast, 0.18s) ease, transform var(--duration-fast, 0.18s) ease;
}

#lightboxImg.smooth-lightbox-in {
    animation: smoothLightboxIn var(--duration-normal, 0.38s) var(--ease-out-expo);
}

@keyframes smoothLightboxIn {
    from { opacity: 0; transform: scale(0.94); }
    to { opacity: 1; transform: scale(1); }
}

/* ---- Comic chapter body reveal ---- */
.comic-chapter-body.smooth-content-pending {
    opacity: 0;
    transform: translateY(12px);
}

.comic-chapter-body.smooth-content-ready {
    animation: smoothContentIn var(--duration-normal, 0.38s) var(--ease-out-expo) forwards;
}

/* ---- Admin mobile sidebar ---- */
@media (max-width: 768px) {
    .admin-app .sidebar {
        transition: transform var(--duration-normal, 0.38s) var(--ease-out-expo);
    }
}

/* ---- Maintenance page card ---- */
.maintenance-card.smooth-content-pending {
    opacity: 0;
    transform: translateY(16px);
}

.maintenance-card.smooth-content-ready {
    animation: smoothContentIn var(--duration-normal, 0.38s) var(--ease-out-expo) forwards;
}

/* ---- Admin dynamic toast (JS-created) ---- */
.admin-toast {
    transform: translateX(calc(100% + var(--space-8, 2rem)));
    transition: transform var(--duration-normal, 0.38s) var(--ease-spring, cubic-bezier(0.34, 1.56, 0.64, 1));
    animation: none;
}

.admin-toast.show {
    transform: translateX(0);
}

@media (max-width: 768px) {
    .site-header {
        isolation: isolate;
    }

    .admin-toast {
        transform: translateY(calc(100% + var(--space-8, 2rem)));
    }

    .admin-toast.show {
        transform: translateY(0);
    }
}

@media (prefers-reduced-motion: reduce) {
    body.smooth-page-enter,
    body.smooth-page-exit,
    [data-tab-content-group].smooth-tab-panel.is-showing,
    .form.smooth-auth-form.is-showing,
    .smooth-content-ready,
    .gallery-item.smooth-filter-in,
    .alert.smooth-flash-in,
    .site-flash.smooth-flash-in,
    .smooth-stat-bump,
    .smooth-lightbox-in,
    .smooth-lightbox-out,
    .maintenance-card.smooth-content-ready,
    .comic-chapter-body.smooth-content-ready {
        animation: none !important;
        transition: none !important;
    }

    [data-tab-content-group].smooth-tab-panel.is-hiding,
    .form.smooth-auth-form.is-hiding {
        opacity: 1;
        transform: none;
    }

    .smooth-skeleton::after {
        animation: none;
    }

    .gallery-item.smooth-filter-out {
        display: none;
    }

    .nav-links,
    .nav-mobile-backdrop {
        transition: none !important;
    }

    .admin-app .sidebar,
    .admin-app .admin-nav-backdrop {
        transition: none !important;
    }
}