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

:root {
    --bg: #0a0a0f;
    --surface: #13131a;
    --surface-hover: #1a1a24;
    --border: rgba(255,255,255,0.06);
    --text: #f1f1f3;
    --text-muted: rgba(255,255,255,0.45);
    --accent: #7c5cfc;
    --accent-soft: rgba(124,92,252,0.12);
    --success: #22c55e;
    --error: #ef4444;
    --radius: 12px;
    --overlay-bg: rgba(10,10,15,0.85);
    --overlay-blur: blur(10px);
}

body {
    font-family: 'Inter', -apple-system, sans-serif;
    background: var(--bg);
    color: var(--text);
    -webkit-font-smoothing: antialiased;
}

/* ===== NAV ===== */
.navbar {
    position: sticky;
    top: 0;
    z-index: 100;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.7rem 2rem;
    background: rgba(10,10,15,0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
}

.nav-left { display: flex; align-items: center; gap: 0.85rem; min-width: 0; }
.nav-logo { height: 56px; width: 56px; object-fit: contain; flex-shrink: 0; }
.nav-brand-block { display: flex; flex-direction: column; gap: 0.2rem; min-width: 0; }
.nav-brand { font-size: 1.42rem; font-weight: 700; letter-spacing: -0.02em; }
.nav-brand span { color: inherit; }
.nav-tagline {
    font-size: 0.9rem; color: var(--text-muted); font-weight: 500;
    white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}

.nav-actions { display: flex; align-items: center; gap: 0.5rem; flex-shrink: 0; }

.nav-btn {
    display: inline-flex; align-items: center; gap: 0.4rem; flex-shrink: 0;
    padding: 0.5rem 0.9rem; border-radius: 10px;
    background: var(--surface); border: 1px solid var(--border);
    color: var(--text-muted); font-size: 0.8rem; font-weight: 500; font-family: inherit;
    cursor: pointer; transition: all 0.2s;
}
.nav-btn:hover { color: var(--text); border-color: rgba(255,255,255,0.15); background: rgba(255,255,255,0.04); }
.nav-btn svg { flex-shrink: 0; }

/* Reset = nav-btn with destructive hover */
.reset-btn:hover { color: var(--error); border-color: rgba(239,68,68,0.4); background: rgba(239,68,68,0.08); }

/* ===== FILTERS + PROGRESS ===== */
.filters {
    max-width: 1280px; margin: 0 auto; padding: 1.5rem 2rem;
    display: flex; align-items: flex-start; justify-content: space-between;
    gap: 1.5rem; flex-wrap: nowrap;
}
.block-label {
    display: block; margin-bottom: 0.6rem;
    font-size: 0.72rem; font-weight: 600; letter-spacing: 0.06em;
    text-transform: uppercase; color: var(--text-muted);
}
.filter-group { display: flex; align-items: center; gap: 0.5rem; flex-wrap: wrap; }

.filter-tag {
    padding: 0.4rem 0.95rem; font-size: 0.78rem; font-weight: 500;
    font-family: inherit; color: var(--text-muted);
    background: var(--surface); border: 1px solid var(--border);
    border-radius: 100px; cursor: pointer; transition: all 0.2s;
    white-space: nowrap;
}
.filter-tag:hover {
    color: var(--text); background: var(--surface-hover);
    border-color: rgba(255,255,255,0.12);
}
.filter-tag.active {
    color: #fff; background: var(--accent); border-color: var(--accent);
}

.progress-block { flex-shrink: 0; }
.progress-text {
    display: flex; align-items: center; gap: 0.55rem;
    font-size: 0.82rem; color: var(--text-muted); white-space: nowrap;
}
.progress-text b { color: var(--text); font-weight: 600; }
.seg-bar { display: flex; gap: 3px; }
.seg { width: 7px; height: 13px; background: rgba(34,197,94,0.22); }
.seg.on { background: var(--success); }

/* ===== GRID ===== */
.grid-container { max-width: 1280px; margin: 0 auto; padding: 0 2rem 4rem; scroll-margin-top: 90px; }
.masonry {
    display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px;
}
.card {
    border-radius: var(--radius); overflow: hidden; position: relative;
    cursor: pointer; background: var(--surface); aspect-ratio: 1 / 1;
}
.card img {
    position: absolute; inset: 0; width: 100%; height: 100%;
    object-fit: contain; display: block;
    transition: transform 0.4s ease;
    padding: 6px; border-radius: var(--radius);
}
.card.loading {
    background: linear-gradient(90deg, #15151d, #1c1c26, #15151d);
    background-size: 200% 100%;
    animation: skeleton-shine 1.4s ease-in-out infinite;
}
.card.loading img { visibility: hidden; }
.card:hover img { transform: scale(1.04); }

.card-overlay {
    position: absolute; inset: 0;
    background: linear-gradient(180deg, transparent 40%, rgba(0,0,0,0.75) 100%);
    opacity: 0; transition: opacity 0.3s ease;
    display: flex; flex-direction: column; justify-content: flex-end;
    padding: 1rem;
}
.card:hover .card-overlay { opacity: 1; }
.card-title { font-size: 0.82rem; font-weight: 600; color: #fff; margin-bottom: 0.3rem; line-height: 1.3; }
.card-author { font-size: 0.72rem; color: rgba(255,255,255,0.55); }

.card-badge {
    position: absolute; top: 0.7rem; left: 0.7rem;
    padding: 0.25rem 0.6rem; font-size: 0.65rem; font-weight: 600;
    letter-spacing: 0.04em; text-transform: uppercase;
    background: var(--accent); color: #fff; border-radius: 6px;
    opacity: 0; transition: opacity 0.3s ease;
}
.card:hover .card-badge { opacity: 1; }

.card.solved img { opacity: 0.20; }
.card.solved::after {
    content: '✓';
    position: absolute;
    top: 16px; right: 16px;
    width: 24px; height: 24px;
    background: var(--success);
    color: #fff;
    border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
    font-size: 0.85rem; font-weight: 700;
    box-shadow: 0 2px 8px rgba(0,0,0,0.4);
}

.empty-state {
    text-align: center; padding: 3rem 1rem;
    color: var(--text-muted); font-size: 0.9rem;
}

.pager-info {
    text-align: center; color: var(--text-muted); font-size: 0.82rem;
    margin-top: 2rem;
}
.pager-info:empty { display: none; }
.pager {
    display: flex; flex-wrap: wrap; align-items: center; justify-content: center;
    gap: 0.4rem; margin-top: 0.8rem;
}
.pager:empty { display: none; }
.pager-btn {
    min-width: 35px; height: 35px; padding: 0 0.62rem;
    font-family: inherit; font-size: 0.77rem; font-weight: 500;
    color: var(--text); background: var(--surface); border: 1px solid var(--border);
    border-radius: 3px; cursor: pointer; transition: all 0.15s;
}
.pager-btn:hover:not(:disabled):not(.active) { border-color: rgba(255,255,255,0.15); background: var(--surface-hover); }
.pager-btn.active { background: var(--accent); border-color: var(--accent); color: #fff; }
.pager-btn.active:hover { background: color-mix(in srgb, var(--accent) 70%, white); border-color: color-mix(in srgb, var(--accent) 70%, white); }
.pager-btn:disabled { opacity: 0.35; cursor: default; }
.pager-gap { color: var(--text-muted); padding: 0 0.2rem; }

/* Skeleton (placeholder during fetch) */
.card.skeleton {
    background: linear-gradient(
        90deg,
        #15151d 0%, #1c1c26 50%, #15151d 100%
    );
    background-size: 200% 100%;
    animation: skeleton-shine 1.4s ease-in-out infinite;
    cursor: default;
}
@keyframes skeleton-shine {
    0%   { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

@media (max-width: 1100px) { .masonry { grid-template-columns: repeat(3, 1fr); } }
@media (max-width: 768px) {
    .masonry { grid-template-columns: repeat(2, 1fr); gap: 10px; }
    .navbar { padding: 0.7rem 1rem; }
    .filters { padding: 1.25rem 1rem; }
    .grid-container { padding: 0 1rem 3rem; }
}
@media (max-width: 640px) {
    .filters { flex-wrap: wrap; }
    .progress-block { width: 100%; }
}
@media (max-width: 600px) {
    .nav-tagline { display: none; }
    .nav-label { display: none; }
    .nav-btn { padding: 0.5rem; }
}
@media (max-width: 480px) {
    .masonry { grid-template-columns: repeat(2, 1fr); gap: 8px; }
    .card { border-radius: 8px; }
}

/* ===== BOARD MODAL ===== */
.board-modal-overlay {
    position: fixed; inset: 0; z-index: 1000;
    background: var(--overlay-bg);
    backdrop-filter: var(--overlay-blur); -webkit-backdrop-filter: var(--overlay-blur);
    display: flex; align-items: center; justify-content: center;
    padding: 1rem; opacity: 0; transition: opacity 0.25s ease;
}
.board-modal-overlay.visible { opacity: 1; }

.board-modal {
    --surface: #1f1f29;
    --surface-hover: #2a2a35;
    background: var(--surface); border: 1px solid rgba(255,255,255,0.1);
    border-radius: 18px; padding: 1.5rem;
    width: 100%; max-width: 500px;
    box-shadow: 0 32px 100px rgba(0,0,0,0.7);
    transform: scale(0.94) translateY(8px);
    transition: transform 0.25s ease;
}
.board-modal-overlay.visible .board-modal { transform: scale(1) translateY(0); }

.board-modal-header {
    display: flex; align-items: center; justify-content: space-between;
    margin-bottom: 0.75rem;
}
.board-modal-info { display: flex; align-items: center; gap: 0.6rem; }
.board-modal-title { font-size: 1rem; font-weight: 600; color: var(--text); }
.board-modal-badge {
    padding: 0.2rem 0.55rem; font-size: 0.64rem; font-weight: 600;
    letter-spacing: 0.05em; text-transform: uppercase;
    background: var(--accent); color: #fff; border-radius: 6px;
}
.board-modal-close {
    width: 32px; height: 32px; border-radius: 8px;
    background: rgba(255,255,255,0.06); border: 1px solid var(--border);
    color: var(--text-muted); font-size: 1.3rem; line-height: 1;
    cursor: pointer; display: flex; align-items: center; justify-content: center;
    transition: all 0.2s; font-family: inherit; flex-shrink: 0;
}
.board-modal-close:hover { background: rgba(255,255,255,0.12); color: var(--text); }

.board-status {
    font-size: 0.8rem; color: var(--text-muted);
    margin-bottom: 0.75rem; min-height: 1.2em;
    transition: color 0.2s;
}
.board-status.success { color: var(--success); }
.board-status.error   { color: var(--error); }
.board-status.solved  { color: var(--success); font-weight: 600; }

#modalBoard { width: 100%; }

#modalBoard .white-1e1d7 { background-color: #dee8f6 !important; }
#modalBoard .black-3c85d { background-color: #6ba3d6 !important; }
#modalBoard .board-b72b1 { border-color: #6ba3d6 !important; }

#modalBoard .notation-322f9 { font-size: 12px !important; }
#modalBoard .white-1e1d7 .notation-322f9 { color: #6ba3d6 !important; font-weight: 700; }
#modalBoard .black-3c85d .notation-322f9 { color: #dee8f6 !important; font-weight: 700; }

body > img { z-index: 9999 !important; }

.board-actions {
    display: flex; gap: 0.5rem; margin-top: 1rem;
}
.board-btn {
    flex: 1; padding: 0.55rem 1rem; font-size: 0.8rem; font-weight: 500;
    font-family: inherit; color: var(--text);
    background: var(--surface-hover); border: 1px solid var(--border);
    border-radius: 8px; cursor: pointer; transition: all 0.2s;
    display: inline-flex; align-items: center; justify-content: center; gap: 0.4rem;
}
.board-btn:hover { background: rgba(255,255,255,0.08); }
.board-btn svg { flex-shrink: 0; color: var(--text); }

/* ===== VIDEO MODAL (About) ===== */
.video-modal { max-width: 760px; }
.video-frame {
    position: relative;
    width: 100%;
    aspect-ratio: 16 / 9;
    background: #0a0a0f;
    border: 1px solid var(--border);
    border-radius: 8px;
    overflow: hidden;
    display: flex; align-items: center; justify-content: center;
}
.video-frame video {
    position: absolute; inset: 0;
    width: 100%; height: 100%; object-fit: contain; background: #000;
}
.play-btn { position: relative; z-index: 1; }   /* above the video */
.video-frame.playing .play-btn { display: none; }
.play-btn {
    width: 76px; height: 76px; border-radius: 50%;
    background: rgba(255,255,255,0.12);
    -webkit-backdrop-filter: blur(8px); backdrop-filter: blur(8px);
    border: 2px solid rgba(255,255,255,0.85);
    color: #fff; cursor: pointer;
    display: flex; align-items: center; justify-content: center;
    padding: 0;
    transition: transform 0.2s, background 0.2s;
    box-shadow: 0 8px 32px rgba(0,0,0,0.5);
}
.play-btn:hover {
    background: rgba(255,255,255,0.22);
    transform: scale(1.06);
}

.about-footer {
    margin-top: 1rem;
    font-size: 0.78rem; color: var(--text-muted);
    display: flex; align-items: center; justify-content: center; flex-wrap: wrap;
}
.about-footer a { color: var(--text-muted); text-decoration: none; }
.about-footer a:hover { color: var(--text); }
.about-footer .sep { margin: 0 0.4rem; opacity: 0.4; }
.about-footer .ver { color: rgba(255,255,255,0.35); font-variant-numeric: tabular-nums; }