:root {
    --bg: #fff;
    --bg-secondary: #f5f5f5;
    --text: #1a1a1a;
    --text-secondary: #666;
    --border: #e0e0e0;
    --accent: #2563eb;
    --accent-hover: #1d4ed8;
    --danger: #dc2626;
    --success: #16a34a;
    --shadow: 0 1px 3px rgba(0,0,0,0.1);
    --radius: 8px;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #121212;
        --bg-secondary: #1e1e1e;
        --text: #e0e0e0;
        --text-secondary: #999;
        --border: #333;
        --shadow: 0 1px 3px rgba(0,0,0,0.3);
    }
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.5;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.container { max-width: 1400px; margin: 0 auto; padding: 20px; }

.header { margin-bottom: 30px; }
.header h1 { font-size: 2rem; font-weight: 600; }

.breadcrumbs {
    display: flex;
    gap: 8px;
    align-items: center;
    margin-bottom: 10px;
    font-size: 0.9rem;
    flex-wrap: wrap;
}
.breadcrumbs .separator { color: var(--text-secondary); }

.folders-section, .photos-section { margin-bottom: 40px; }
.folders-section h2, .photos-section h2 {
    font-size: 1.2rem;
    margin-bottom: 15px;
    color: var(--text-secondary);
}

.folders-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 320px));
    gap: 24px;
    justify-content: start;
    align-items: start;
}

.folder-card {
    display: flex;
    flex-direction: column;
    border-radius: var(--radius);
    overflow: hidden;
    background: var(--bg-secondary);
    color: var(--text);
    text-decoration: none;
    border: 1px solid var(--border);
    box-shadow: var(--shadow);
    transition: transform 0.2s, box-shadow 0.2s;
    width: 100%;
    max-width: 320px;
}

.folder-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 30px rgba(0,0,0,0.25);
    text-decoration: none;
}

.folder-card:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

.folder-cover {
    aspect-ratio: 16 / 10;
    background: var(--bg-secondary);
    position: relative;
    overflow: hidden;
    display: grid;
    gap: 2px;
}

.folder-cover > img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
    min-width: 0;
    min-height: 0;
    background: var(--bg);
    transition: opacity 0.3s;
}

.folder-cover > img.lazy { opacity: 0; }
.folder-cover > img.loaded { opacity: 1; }

.folder-cover.empty {
    display: flex;
    align-items: center;
    justify-content: center;
}

.folder-cover.empty .folder-icon {
    width: 64px;
    height: 64px;
    color: var(--text-secondary);
    opacity: 0.55;
}

.folder-cover.count-1 { grid-template-columns: 1fr; grid-template-rows: 1fr; }
.folder-cover.count-2 { grid-template-columns: 1fr 1fr; grid-template-rows: 1fr; }
.folder-cover.count-3 { grid-template-columns: 1fr 1fr; grid-template-rows: 1fr 1fr; }
.folder-cover.count-3 > img:first-child { grid-row: 1 / 3; }
.folder-cover.count-4 { grid-template-columns: 1fr 1fr; grid-template-rows: 1fr 1fr; }

.folder-info {
    padding: 16px;
    display: flex;
    flex-direction: column;
    gap: 6px;
    min-height: 84px;
}

.folder-name {
    font-weight: 600;
    font-size: 1.2rem;
    line-height: 1.25;
    word-break: break-word;
    display: -webkit-box;
    -webkit-box-orient: vertical;
    -webkit-line-clamp: 2;
    overflow: hidden;
}

.folder-count {
    margin-top: auto;
    color: var(--text-secondary);
    font-size: 1rem;
}

.folder-icon {
    width: 48px;
    height: 48px;
    color: var(--text-secondary);
}

/* Masonry using CSS columns */
.masonry {
    column-count: 4;
    column-gap: 15px;
}

.photo-item {
    display: block;
    break-inside: avoid;
    margin-bottom: 15px;
    text-decoration: none;
    color: inherit;
}

.photo-item:hover .progressive-image {
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
    transform: translateY(-2px);
}

.progressive-image {
    position: relative;
    background: var(--bg-secondary);
    overflow: hidden;
    border-radius: var(--radius);
    transition: box-shadow 0.2s, transform 0.2s;
}

.progressive-image .skeleton-shimmer {
    position: absolute;
    inset: 0;
    background: linear-gradient(90deg, var(--bg-secondary) 25%, var(--border) 50%, var(--bg-secondary) 75%);
    background-size: 400% 100%;
    animation: shimmer 1.5s infinite;
    z-index: 1;
}

.progressive-image .placeholder {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    filter: blur(20px);
    transform: scale(1.1);
    transition: opacity 0.3s ease-out;
    z-index: 2;
    opacity: 0;
}

.progressive-image .placeholder.ready {
    opacity: 1;
}

.progressive-image .full-image {
    display: block;
    width: 100%;
    height: 100%;
    object-fit: cover;
    opacity: 0;
    transition: opacity 0.3s ease-out;
    position: relative;
    z-index: 3;
}

.progressive-image.loaded .skeleton-shimmer {
    opacity: 0;
}

.progressive-image.loaded .placeholder {
    opacity: 0;
    pointer-events: none;
}

.progressive-image.loaded .full-image {
    opacity: 1;
}

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

.load-more-trigger {
    height: 100px;
    display: flex;
    align-items: center;
    justify-content: center;
    column-span: all;
}

.load-more-spinner {
    width: 32px;
    height: 32px;
    border: 3px solid var(--border);
    border-top-color: var(--accent);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

.load-more-end {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Responsive masonry columns */
@media (max-width: 1400px) {
    .masonry { column-count: 4; }
}

@media (max-width: 1100px) {
    .masonry { column-count: 3; }
}

@media (max-width: 768px) {
    .masonry { column-count: 2; }
    .folders-grid { grid-template-columns: repeat(auto-fill, minmax(180px, 1fr)); gap: 16px; }
    .folder-card { max-width: none; }
    .folder-info { padding: 12px; min-height: 76px; }
    .folder-name { font-size: 1rem; }
}

@media (max-width: 480px) {
    .masonry { column-count: 2; column-gap: 10px; }
    .photo-item { margin-bottom: 10px; }
    .container { padding: 15px; }
    .header h1 { font-size: 1.5rem; }
}

@media (max-width: 360px) {
    .folders-grid { grid-template-columns: 1fr; }
}

/* Photo viewer */
.viewer-container {
    min-height: 100vh;
    max-height: 100vh;
    display: flex;
    flex-direction: column;
    background: #0a0a0a;
    overflow: hidden;
}

.viewer-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 20px;
    background: rgba(0,0,0,0.9);
    color: #fff;
    gap: 15px;
    flex-shrink: 0;
    z-index: 20;
    height: 60px;
    box-sizing: border-box;
}

.viewer-header .breadcrumbs { margin-bottom: 0; }
.viewer-header .breadcrumbs a { color: rgba(255,255,255,0.8); }
.viewer-header .breadcrumbs a:hover { color: #fff; }

.viewer-header-left {
    display: flex;
    align-items: center;
    gap: 15px;
    flex: 1;
    min-width: 0;
}

.viewer-header-right {
    display: flex;
    align-items: center;
    gap: 5px;
    flex-shrink: 0;
}

.viewer-header-right .btn-icon {
    color: rgba(255,255,255,0.7);
    padding: 8px;
    border-radius: var(--radius);
}

.viewer-header-right .btn-icon:hover {
    color: #fff;
    background: rgba(255,255,255,0.1);
}

.viewer-header-right .btn-icon svg { width: 20px; height: 20px; }

.photo-counter {
    color: rgba(255,255,255,0.7);
    font-size: 0.9rem;
    white-space: nowrap;
}

.viewer-body {
    flex: 1;
    display: flex;
    min-height: 0;
    overflow: hidden;
}

.viewer-main {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    min-width: 0;
    padding: 20px;
    overflow: hidden;
}

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

.viewer-image img {
    max-width: 100%;
    max-height: calc(100vh - 100px);
    object-fit: contain;
    cursor: zoom-in;
    transition: transform 0.1s ease-out;
    transform-origin: center center;
}

.viewer-image img.zoomed {
    max-width: none;
    max-height: none;
    cursor: grab;
}

.viewer-nav {
    position: absolute;
    inset: 0;
    display: flex;
    justify-content: space-between;
    align-items: stretch;
    pointer-events: none;
    z-index: 10;
    transition: opacity 0.2s;
}

.nav-btn {
    width: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: rgba(255,255,255,0.6);
    background: transparent;
    opacity: 0;
    transition: opacity 0.2s, background 0.2s, color 0.2s;
    text-decoration: none;
    pointer-events: none;
}

a.nav-btn { pointer-events: auto; }

a.nav-btn:hover {
    background: rgba(0,0,0,0.5);
    color: #fff;
    opacity: 1;
    text-decoration: none;
}

.viewer-body:hover a.nav-btn { opacity: 1; }

.nav-btn svg { width: 40px; height: 40px; }

.viewer-sidebar {
    width: 360px;
    background: var(--bg);
    overflow-y: auto;
    flex-shrink: 0;
    border-left: 1px solid var(--border);
    max-height: calc(100vh - 60px);
}

.sidebar-toggle {
    display: none;
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: var(--accent);
    border: none;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    cursor: pointer;
    z-index: 101;
    align-items: center;
    justify-content: center;
    color: #fff;
    box-shadow: 0 4px 12px rgba(0,0,0,0.3);
}

.sidebar-toggle svg { width: 24px; height: 24px; }

.sidebar-content { padding: 20px; padding-bottom: 30px; }
.sidebar-content h2 {
    margin-bottom: 15px;
    font-size: 1.2rem;
    word-break: break-word;
    line-height: 1.4;
}

.description { color: var(--text-secondary); margin-bottom: 15px; }

.note {
    background: var(--bg-secondary);
    padding: 12px;
    border-radius: var(--radius);
    margin-bottom: 15px;
}

.quick-exif {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    padding: 12px;
    background: var(--bg-secondary);
    border-radius: var(--radius);
    margin-bottom: 15px;
}

.quick-exif-item {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 0.9rem;
}

.quick-exif-item svg {
    width: 16px;
    height: 16px;
    min-width: 16px;
    min-height: 16px;
    max-width: 16px;
    max-height: 16px;
    flex-shrink: 0;
    color: var(--text-secondary);
}

.quick-exif-item span {
    font-weight: 500;
}

.sidebar-content h3 {
    margin: 20px 0 10px;
    font-size: 0.85rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    font-weight: 600;
}

.sidebar-content h3:first-of-type { margin-top: 0; }

.exif-list { display: grid; grid-template-columns: auto 1fr; gap: 4px 12px; }
.exif-list dt { color: var(--text-secondary); font-size: 0.85rem; }
.exif-list dd { font-size: 0.85rem; word-break: break-word; }

.more-exif {
    margin-top: 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
}

.more-exif summary {
    cursor: pointer;
    padding: 10px 12px;
    background: var(--bg-secondary);
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text);
    list-style: none;
    display: flex;
    align-items: center;
    gap: 8px;
}

.more-exif summary::-webkit-details-marker { display: none; }

.more-exif summary::before {
    content: '';
    width: 0;
    height: 0;
    border-left: 5px solid var(--text-secondary);
    border-top: 4px solid transparent;
    border-bottom: 4px solid transparent;
    transition: transform 0.2s;
}

.more-exif[open] summary::before {
    transform: rotate(90deg);
}

.more-exif .exif-list {
    padding: 12px;
}

.btn-icon {
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    opacity: 0.7;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius);
    transition: opacity 0.2s, background 0.2s;
}

.btn-icon:hover { opacity: 1; background: rgba(255,255,255,0.1); }
.btn-icon svg { width: 20px; height: 20px; }
.close-btn { color: #fff; }
.close-btn svg { width: 24px; height: 24px; }

.sidebar-actions {
    margin-top: 20px;
    padding-top: 15px;
    border-top: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.sidebar-actions .btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 16px;
    width: 100%;
    box-sizing: border-box;
}

.sidebar-actions .btn svg {
    width: 16px;
    height: 16px;
    flex-shrink: 0;
}

.header-nav-btn svg { width: 20px; height: 20px; }

/* Index page styles */
.index-page { background: var(--bg); }

.index-container {
    max-width: 1400px;
    margin: 0 auto;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.index-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
    border-bottom: 1px solid var(--border);
    background: var(--bg-secondary);
    position: sticky;
    top: 0;
    z-index: 10;
    gap: 15px;
    flex-wrap: wrap;
}

.index-header h1 {
    font-size: 1.3rem;
    font-weight: 600;
    margin: 0;
}

.index-header .breadcrumbs { margin: 0; font-size: 1rem; }

.index-header-controls {
    display: flex;
    align-items: center;
    gap: 15px;
}

.sort-control {
    display: flex;
    align-items: center;
    gap: 8px;
}

.sort-control label { font-size: 0.9rem; color: var(--text-secondary); }

.sort-control select {
    padding: 6px 10px;
    border-radius: var(--radius);
    border: 1px solid var(--border);
    background: var(--bg);
    color: var(--text);
    font-size: 0.9rem;
}

.view-toggle {
    display: flex;
    gap: 5px;
    background: var(--bg);
    padding: 3px;
    border-radius: var(--radius);
}

.view-btn {
    background: none;
    border: none;
    padding: 6px 10px;
    cursor: pointer;
    border-radius: calc(var(--radius) - 2px);
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.15s;
}

.view-btn svg { width: 18px; height: 18px; }
.view-btn:hover { color: var(--text); }
.view-btn.active { background: var(--accent); color: #fff; }

.index-content { flex: 1; padding: 0; }

.index-footer {
    padding: 15px 20px;
    border-top: 1px solid var(--border);
    background: var(--bg-secondary);
    display: flex;
    justify-content: space-between;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

/* File list table */
.file-list {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
}

.file-list th {
    text-align: left;
    padding: 12px 15px;
    background: var(--bg-secondary);
    font-weight: 500;
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 54px;
    z-index: 5;
    user-select: none;
}

.file-list th.sortable { cursor: pointer; }
.file-list th.sortable:hover { background: var(--border); }
.file-list th.sortable::after { content: ''; display: inline-block; margin-left: 5px; opacity: 0.3; }
.file-list th.sort-asc::after { content: '▲'; opacity: 1; }
.file-list th.sort-desc::after { content: '▼'; opacity: 1; }

.file-list td {
    padding: 8px 15px;
    border-bottom: 1px solid var(--border);
    vertical-align: middle;
}

.file-list tr:hover { background: var(--bg-secondary); }

.file-list .col-icon { width: 50px; text-align: center; padding: 5px 10px; }
.file-list .col-icon svg { width: 20px; height: 20px; color: var(--text-secondary); }
.file-list .col-name { min-width: 200px; }
.file-list .col-name a { color: var(--text); font-weight: 500; }
.file-list .col-name a:hover { color: var(--accent); }
.file-list .col-size { width: 100px; text-align: right; color: var(--text-secondary); font-family: monospace; }
.file-list .col-date { width: 150px; color: var(--text-secondary); font-family: monospace; font-size: 0.85rem; }

.list-thumb { width: 36px; height: 36px; object-fit: cover; border-radius: 4px; display: block; }

.item-meta { display: block; font-size: 0.8rem; color: var(--text-secondary); font-weight: normal; }

.folder-row .col-icon svg { color: #f0c36d; }
.parent-row { background: var(--bg-secondary); }

.grid-section { padding: 20px; }
.grid-section h2 { font-size: 1rem; color: var(--text-secondary); margin-bottom: 15px; }

.empty-state { padding: 60px 20px; text-align: center; color: var(--text-secondary); }
.empty-state a { color: var(--accent); }

.path-value { font-family: monospace; font-size: 0.85rem; word-break: break-all; }

.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 20px;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    cursor: pointer;
    font-size: 0.95rem;
    color: var(--text);
    text-decoration: none;
    transition: background 0.2s;
    white-space: nowrap;
}

.btn svg { width: 16px; height: 16px; }
.btn:hover { background: var(--border); text-decoration: none; }
.btn-primary { background: var(--accent); color: #fff; border-color: var(--accent); }
.btn-primary:hover { background: var(--accent-hover); }
.btn-secondary { background: transparent; }

@media (max-width: 1000px) {
    .viewer-sidebar {
        position: fixed;
        right: 0;
        top: 0;
        bottom: 0;
        transform: translateX(100%);
        z-index: 100;
        box-shadow: -5px 0 20px rgba(0,0,0,0.3);
        width: 300px;
        max-width: calc(100% - 60px);
        max-height: 100vh;
        border-left: none;
    }
    .viewer-sidebar.open { transform: translateX(0); }
    .sidebar-toggle { display: flex; }
    .viewer-image img { max-height: calc(100vh - 80px); }
}

@media (max-width: 768px) {
    .viewer-header { padding: 10px 15px; }
    .nav-btn { width: 50px; }
    .nav-btn svg { width: 24px; height: 24px; }
    .file-list .col-date { display: none; }
    .file-list th { top: 50px; }
    .index-header { padding: 10px 15px; }
    .index-header-controls { width: 100%; justify-content: space-between; }
}

@media (max-width: 480px) {
    .file-list .col-size { display: none; }
    .item-meta { display: none; }
    .sort-control label { display: none; }
}