/* ==========================================================================
   Design tokens
   ========================================================================== */
:root {
    --color-bg: #f4f5f7;
    --color-surface: #ffffff;
    --color-surface-alt: #eceef2;
    --color-border: #dde1e7;
    --color-text: #1b1d22;
    --color-text-muted: #5a6072;
    --color-primary: #3a6df0;
    --color-primary-hover: #2c56c9;
    --color-danger: #e0453d;
    --color-danger-hover: #c23830;
    --color-success: #21a366;

    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 18px;

    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.5rem;
    --space-6: 2rem;
    --space-7: 3rem;

    --shadow-sm: 0 1px 3px rgba(20, 20, 30, 0.08);
    --shadow-md: 0 6px 20px rgba(20, 20, 30, 0.12);
    --shadow-lg: 0 20px 50px rgba(10, 10, 20, 0.35);

    --header-height: 64px;
    --font-sans: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
    --transition-fast: 150ms ease;
    --transition-base: 220ms ease;
}

[data-theme="dark"] {
    --color-bg: #101116;
    --color-surface: #181a21;
    --color-surface-alt: #21232c;
    --color-border: #2d3039;
    --color-text: #eef0f4;
    --color-text-muted: #9aa0b0;
    --color-primary: #5b8bff;
    --color-primary-hover: #7ba0ff;
    --color-danger: #f16a63;
    --color-danger-hover: #f68b85;
    --color-success: #3ecb8a;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.4);
    --shadow-md: 0 6px 20px rgba(0, 0, 0, 0.45);
    --shadow-lg: 0 20px 60px rgba(0, 0, 0, 0.6);
}

* {
    box-sizing: border-box;
}

html {
    color-scheme: light dark;
}

body {
    margin: 0;
    font-family: var(--font-sans);
    background: var(--color-bg);
    color: var(--color-text);
    font-size: 16px;
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

img {
    max-width: 100%;
    display: block;
}

.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;
}

:focus-visible {
    outline: 3px solid var(--color-primary);
    outline-offset: 2px;
    border-radius: var(--radius-sm);
}

/* ==========================================================================
   Buttons & fields
   ========================================================================== */
.btn {
    font: inherit;
    border: none;
    border-radius: var(--radius-md);
    padding: 0.65rem 1.1rem;
    cursor: pointer;
    transition: background-color var(--transition-fast), transform var(--transition-fast), opacity var(--transition-fast);
    min-height: 44px;
}

.btn:disabled {
    opacity: 0.55;
    cursor: not-allowed;
}

.btn-primary {
    background: var(--color-primary);
    color: #fff;
}

.btn-primary:hover:not(:disabled) {
    background: var(--color-primary-hover);
}

.btn-secondary {
    background: var(--color-surface-alt);
    color: var(--color-text);
    border: 1px solid var(--color-border);
}

.btn-secondary:hover:not(:disabled) {
    background: var(--color-border);
}

.btn-ghost {
    background: transparent;
    color: var(--color-text-muted);
}

.btn-ghost:hover:not(:disabled) {
    color: var(--color-text);
    background: var(--color-surface-alt);
}

.btn-danger {
    background: var(--color-danger);
    color: #fff;
}

.btn-danger:hover:not(:disabled) {
    background: var(--color-danger-hover);
}

.btn-block {
    width: 100%;
}

.icon-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    border-radius: var(--radius-md);
    border: 1px solid transparent;
    background: transparent;
    color: var(--color-text);
    font-size: 1.1rem;
    cursor: pointer;
    transition: background-color var(--transition-fast), color var(--transition-fast);
}

.icon-btn:hover {
    background: var(--color-surface-alt);
}

.icon-btn.danger {
    color: var(--color-danger);
}

.field {
    display: flex;
    flex-direction: column;
    gap: var(--space-1);
    margin-bottom: var(--space-4);
}

.field label {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--color-text-muted);
}

.field input,
.field select {
    font: inherit;
    padding: 0.65rem 0.8rem;
    border-radius: var(--radius-sm);
    border: 1px solid var(--color-border);
    background: var(--color-surface);
    color: var(--color-text);
    min-height: 44px;
}

.field input:focus,
.field select:focus {
    border-color: var(--color-primary);
}

.form-error {
    color: var(--color-danger);
    font-size: 0.9rem;
    margin: 0 0 var(--space-3);
}

/* ==========================================================================
   Login screen
   ========================================================================== */
.login-screen {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-5);
    background:
        radial-gradient(circle at 20% 20%, rgba(58, 109, 240, 0.15), transparent 40%),
        var(--color-bg);
}

.login-card {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    padding: var(--space-6);
    width: 100%;
    max-width: 380px;
    border: 1px solid var(--color-border);
}

.login-card h1 {
    margin: 0 0 var(--space-2);
    font-size: 1.5rem;
}

.login-subtitle {
    color: var(--color-text-muted);
    margin: 0 0 var(--space-5);
    font-size: 0.95rem;
}

/* ==========================================================================
   Header / navigation
   ========================================================================== */
.site-header {
    position: sticky;
    top: 0;
    z-index: 40;
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-sm);
}

.header-bar {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    padding: var(--space-2) var(--space-4);
    height: var(--header-height);
    max-width: 1400px;
    margin: 0 auto;
}

.site-logo {
    font-weight: 700;
    font-size: 1.15rem;
    color: var(--color-text);
    text-decoration: none;
    margin-right: auto;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.nav-toggle {
    display: none;
}

.hamburger,
.hamburger::before,
.hamburger::after {
    content: "";
    display: block;
    width: 22px;
    height: 2px;
    background: currentColor;
    position: relative;
    transition: transform var(--transition-fast);
}

.hamburger::before {
    position: absolute;
    top: -7px;
}

.hamburger::after {
    position: absolute;
    top: 7px;
}

.main-nav {
    display: flex;
    align-items: center;
    gap: var(--space-3);
}

.group-nav {
    display: flex;
    align-items: center;
    gap: var(--space-1);
}

.group-select {
    font: inherit;
    padding: 0.5rem 0.7rem;
    border-radius: var(--radius-sm);
    border: 1px solid var(--color-border);
    background: var(--color-surface);
    color: var(--color-text);
    /* max-width: 220px; */
    min-height: 44px;
}

/* ==========================================================================
   Gallery
   ========================================================================== */
.gallery-main {
    max-width: 1400px;
    margin: 0 auto;
    padding: var(--space-5) var(--space-4) var(--space-7);
}

.group-heading {
    display: block;
}

.group-heading h1 {
    margin: 0;
    font-size: clamp(1.3rem, 2.5vw, 1.8rem);
}

.group-title-row {
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.group-meta {
    color: var(--color-text-muted);
    margin: var(--space-1) 0 var(--space-5);
}

.gallery-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-2);
}

@media (min-width: 600px) {
    .gallery-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

@media (min-width: 900px) {
    .gallery-grid {
        grid-template-columns: repeat(6, 1fr);
    }
}

@media (min-width: 1200px) {
    .gallery-grid {
        grid-template-columns: repeat(8, 1fr);
        gap: var(--space-3);
    }
}

.thumb {
    position: relative;
    aspect-ratio: 1 / 1;
    border-radius: var(--radius-md);
    overflow: hidden;
    background: var(--color-surface-alt);
    border: 1px solid var(--color-border);
    cursor: pointer;
    padding: 0;
    display: block;
    width: 100%;
}

.thumb img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition-base);
}

.thumb:hover img,
.thumb:focus-visible img {
    transform: scale(1.05);
}

.thumb.is-loading {
    background: linear-gradient(100deg, var(--color-surface-alt) 30%, var(--color-border) 50%, var(--color-surface-alt) 70%);
    background-size: 200% 100%;
    animation: shimmer 1.4s infinite;
}

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

.thumb-index {
    position: absolute;
    bottom: var(--space-1);
    right: var(--space-1);
    background: rgba(0, 0, 0, 0.55);
    color: #fff;
    font-size: 0.7rem;
    padding: 0.1rem 0.4rem;
    border-radius: var(--radius-sm);
    pointer-events: none;
}

.thumb-admin-menu {
    position: absolute;
    top: var(--space-1);
    right: var(--space-1);
    width: 32px;
    height: 32px;
    border-radius: var(--radius-sm);
    border: none;
    background: rgba(0, 0, 0, 0.55);
    color: #fff;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
}

.thumb-admin-menu:hover {
    background: var(--color-danger);
}

.empty-state {
    text-align: center;
    color: var(--color-text-muted);
    padding: var(--space-7) var(--space-4);
}

.load-more-wrap {
    display: flex;
    justify-content: center;
    margin-top: var(--space-6);
}

.load-more-wrap[hidden] {
    display: none;
}

/* ==========================================================================
   Back to top
   ========================================================================== */
.back-to-top {
    position: fixed;
    right: var(--space-4);
    bottom: var(--space-4);
    width: 48px;
    height: 48px;
    border-radius: 50%;
    border: none;
    background: var(--color-primary);
    color: #fff;
    box-shadow: var(--shadow-md);
    cursor: pointer;
    z-index: 30;
    font-size: 1.2rem;
    transition: opacity var(--transition-fast), transform var(--transition-fast);
}

.back-to-top:hover {
    transform: translateY(-2px);
}

/* ==========================================================================
   Lightbox
   ========================================================================== */
.lightbox {
    position: fixed;
    inset: 0;
    z-index: 100;
    display: flex;
}

.lightbox[hidden] {
    display: none;
}

.lightbox-backdrop {
    position: absolute;
    inset: 0;
    background: rgba(5, 5, 10, 0.9);
}

.lightbox-content {
    position: relative;
    z-index: 1;
    display: flex;
    flex-direction: column;
    width: 100%;
    height: 100%;
}

.lightbox-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-3) var(--space-4);
    color: #fff;
    gap: var(--space-3);
    flex-wrap: wrap;
}

.lightbox-info {
    display: flex;
    flex-direction: column;
    font-size: 0.85rem;
    color: rgba(255, 255, 255, 0.75);
}

.lightbox-actions {
    display: flex;
    gap: var(--space-1);
}

.lightbox-actions .icon-btn,
.lightbox-header .icon-btn {
    color: #fff;
}

.lightbox-actions .icon-btn:hover,
.lightbox-header .icon-btn:hover {
    background: rgba(255, 255, 255, 0.12);
}

.lightbox-stage {
    position: relative;
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    touch-action: none;
}

.lightbox-image-wrap {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.lightbox-image-wrap img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
    user-select: none;
    -webkit-user-drag: none;
    transition: transform var(--transition-fast);
}

.lightbox-nav {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 48px;
    height: 48px;
    border-radius: 50%;
    border: none;
    background: rgba(0, 0, 0, 0.45);
    color: #fff;
    font-size: 1.5rem;
    cursor: pointer;
    z-index: 2;
}

.lightbox-nav:hover {
    background: rgba(0, 0, 0, 0.7);
}

.lightbox-prev {
    left: var(--space-3);
}

.lightbox-next {
    right: var(--space-3);
}

.lightbox-thumbstrip {
    padding: var(--space-3) var(--space-4);
    overflow-x: auto;
    scrollbar-width: thin;
}

/* width: max-content + margin: auto centers the row when it fits, but auto
   margins collapse to 0 once content overflows - so it stays scrollable to
   both ends instead of clipping the first/last thumbnails. */
.lightbox-thumbstrip-inner {
    display: flex;
    gap: var(--space-2);
    width: max-content;
    margin: 0 auto;
}

.lightbox-thumbstrip img {
    width: 64px;
    height: 64px;
    object-fit: cover;
    border-radius: var(--radius-sm);
    opacity: 0.55;
    cursor: pointer;
    border: 2px solid transparent;
    flex-shrink: 0;
}

.lightbox-thumbstrip img.is-active {
    opacity: 1;
    border-color: var(--color-primary);
}

/* ==========================================================================
   Admin panel
   ========================================================================== */
.admin-panel {
    position: fixed;
    inset: 0;
    z-index: 90;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-4);
}

.admin-panel[hidden] {
    display: none;
}

.admin-panel-backdrop {
    position: absolute;
    inset: 0;
    background: rgba(5, 5, 10, 0.6);
}

.admin-panel-content {
    position: relative;
    z-index: 1;
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    width: 100%;
    max-width: 640px;
    max-height: 90vh;
    overflow-y: auto;
    padding: var(--space-5);
}

.admin-panel-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-4);
}

.admin-tabs {
    display: flex;
    gap: var(--space-2);
    border-bottom: 1px solid var(--color-border);
    margin-bottom: var(--space-4);
}

.admin-tab {
    font: inherit;
    background: none;
    border: none;
    padding: var(--space-2) var(--space-3);
    cursor: pointer;
    color: var(--color-text-muted);
    border-bottom: 2px solid transparent;
}

.admin-tab.is-active {
    color: var(--color-text);
    border-color: var(--color-primary);
}

.admin-tab-panel {
    display: none;
}

.admin-tab-panel.is-active {
    display: block;
}

.admin-inline-form {
    display: flex;
    gap: var(--space-3);
    align-items: flex-end;
    flex-wrap: wrap;
    margin-bottom: var(--space-5);
}

.admin-inline-form .field {
    margin-bottom: 0;
    flex: 1;
    min-width: 160px;
}

.admin-group-list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.admin-group-item {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-2);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    flex-wrap: wrap;
}

.admin-group-item strong {
    flex: 1;
}

.admin-group-meta {
    color: var(--color-text-muted);
    font-size: 0.85rem;
}

.upload-dropzone {
    border: 2px dashed var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--space-6);
    text-align: center;
    cursor: pointer;
    color: var(--color-text-muted);
    margin-bottom: var(--space-4);
    transition: border-color var(--transition-fast), background-color var(--transition-fast);
}

.upload-dropzone.is-dragover {
    border-color: var(--color-primary);
    background: var(--color-surface-alt);
}

.link-like {
    color: var(--color-primary);
    text-decoration: underline;
}

.upload-list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.upload-item {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    padding: var(--space-2);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
}

.upload-item img {
    width: 48px;
    height: 48px;
    object-fit: cover;
    border-radius: var(--radius-sm);
    flex-shrink: 0;
}

.upload-item-info {
    flex: 1;
    min-width: 0;
}

.upload-item-name {
    font-size: 0.9rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.upload-progress {
    height: 4px;
    background: var(--color-border);
    border-radius: 2px;
    overflow: hidden;
    margin-top: var(--space-1);
}

.upload-progress-bar {
    height: 100%;
    background: var(--color-primary);
    width: 0%;
    transition: width var(--transition-base);
}

.upload-item.is-success .upload-progress-bar {
    background: var(--color-success);
}

.upload-item.is-error .upload-progress-bar {
    background: var(--color-danger);
}

.upload-item-status {
    font-size: 0.8rem;
    color: var(--color-text-muted);
}

/* ==========================================================================
   Toasts
   ========================================================================== */
.toast-container {
    position: fixed;
    bottom: var(--space-4);
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
    z-index: 200;
    width: min(90vw, 400px);
}

.toast {
    background: var(--color-surface);
    color: var(--color-text);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--space-3) var(--space-4);
    box-shadow: var(--shadow-md);
    font-size: 0.9rem;
}

.toast.success {
    border-left: 4px solid var(--color-success);
}

.toast.error {
    border-left: 4px solid var(--color-danger);
}

/* ==========================================================================
   Mobile navigation
   ========================================================================== */
@media (max-width: 780px) {
    .nav-toggle {
        display: inline-flex;
    }

    .main-nav {
        position: fixed;
        top: var(--header-height);
        left: 0;
        right: 0;
        background: var(--color-surface);
        border-bottom: 1px solid var(--color-border);
        flex-direction: column;
        align-items: stretch;
        padding: var(--space-4);
        transform: translateY(-10px);
        opacity: 0;
        pointer-events: none;
        transition: transform var(--transition-base), opacity var(--transition-base);
    }

    .main-nav.is-open {
        transform: translateY(0);
        opacity: 1;
        pointer-events: auto;
    }

    .group-select {
        max-width: none;
        flex: 1;
    }
}

/* ==========================================================================
   Reduced motion
   ========================================================================== */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.001ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.001ms !important;
        scroll-behavior: auto !important;
    }
}