:root {
    --bg: #f4f6f8;
    --surface: #ffffff;
    --surface-soft: #f9fbfd;
    --text: #1f2937;
    --muted: #6b7280;
    --primary: #1f6feb;
    --primary-soft: #dbe9ff;
    --border: #e5e7eb;
    --shadow: 0 8px 28px rgba(15, 23, 42, 0.08);
    --radius: 14px;
}

* {
    box-sizing: border-box;
}

html, body {
    margin: 0;
    padding: 0;
    background: var(--bg);
    color: var(--text);
    font-family: Inter, Roboto, "Segoe UI", Arial, sans-serif;
}

.app {
    max-width: 1200px;
    margin: 0 auto;
    padding: 24px;
}

.topbar {
    margin-bottom: 20px;
}

.topbar h1 {
    margin: 0;
    font-size: 30px;
    font-weight: 700;
    letter-spacing: 0.2px;
}

.subtitle {
    margin-top: 8px;
    color: var(--muted);
    font-size: 14px;
}

.panel {
    background: var(--surface);
    border-radius: var(--radius);
    border: 1px solid var(--border);
    box-shadow: var(--shadow);
    padding: 20px;
}

.panel-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
    margin-bottom: 16px;
}

h2 {
    margin: 0;
    font-size: 22px;
}

.btn {
    background: var(--primary-soft);
    color: var(--primary);
    text-decoration: none;
    border-radius: 10px;
    padding: 10px 14px;
    font-size: 14px;
    font-weight: 600;
}

.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 14px;
}

.category-card {
    display: block;
    background: var(--surface-soft);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 12px;
    text-decoration: none;
    color: var(--text);
    transition: transform .15s ease, box-shadow .15s ease, border-color .15s ease;
}

.category-cover {
    width: 100%;
    aspect-ratio: 16 / 9;
    object-fit: cover;
    border-radius: 10px;
    border: 1px solid var(--border);
    display: block;
    margin-bottom: 10px;
}

.category-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 22px rgba(31, 111, 235, 0.12);
    border-color: #c5d8fb;
}

.category-title {
    display: block;
    font-weight: 650;
    margin-bottom: 4px;
}

.category-count {
    color: var(--muted);
    font-size: 14px;
}

.gallery-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 12px;
}

.thumb-card {
    border: 1px solid var(--border);
    border-radius: 10px;
    overflow: hidden;
    background: #fff;
    padding: 0;
    cursor: pointer;
    text-align: left;
    transition: transform .15s ease, box-shadow .15s ease;
}

.thumb-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 18px rgba(2, 6, 23, 0.12);
}

.thumb-card img {
    width: 100%;
    display: block;
    aspect-ratio: 3 / 2;
    object-fit: cover;
}

.thumb-title {
    display: block;
    padding: 10px 10px 12px;
    font-size: 13px;
    line-height: 1.35;
    color: var(--text);
    border-top: 1px solid var(--border);
    background: #fff;
}

.empty {
    color: var(--muted);
}

.footer {
    margin-top: 14px;
    color: var(--muted);
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
}

.footer-author {
    opacity: .72;
    font-size: 12px;
}

.footer-author a {
    color: inherit;
    text-decoration: none;
    border-bottom: 1px dotted rgba(107, 114, 128, .5);
}

.footer-author a:hover {
    opacity: 1;
}

.lightbox {
    position: fixed;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 999;
}

.lightbox[hidden] {
    display: none !important;
}

.lightbox-backdrop {
    position: absolute;
    inset: 0;
    background: rgba(17, 24, 39, 0.75);
}

.lightbox-content {
    position: relative;
    z-index: 1;
    width: min(92vw, 1100px);
    max-height: 90vh;
    background: #0f172a;
    border-radius: 14px;
    padding: 14px;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.lightbox-content img {
    width: 100%;
    max-height: 78vh;
    object-fit: contain;
    border-radius: 10px;
    background: #020617;
}

.lightbox-title {
    color: #e5e7eb;
    font-size: 14px;
    line-height: 1.4;
    padding: 2px 4px 6px;
    word-break: break-word;
}

.lightbox-link {
    align-self: flex-end;
    color: #dbeafe;
    text-decoration: none;
    font-size: 14px;
}

.lightbox-close {
    position: absolute;
    top: 10px;
    right: 10px;
    width: 34px;
    height: 34px;
    border: 0;
    border-radius: 50%;
    background: rgba(255,255,255,0.22);
    color: #fff;
    font-size: 22px;
    cursor: pointer;
}

@media (max-width: 720px) {
    .app {
        padding: 14px;
    }

    .topbar h1 {
        font-size: 24px;
    }
}