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

:root {
  --bg:            #0d1117;
  --surface:       #161b22;
  --border:        #30363d;
  --muted:         #8b949e;
  --text:          #e6edf3;
  --accent:        #58a6ff;
  --hover:         #1c2128;
  --active:        #1f6feb22;
  --active-border: #58a6ff;
  --tile-bg:       #0d1117;
}

html, body { height: 100%; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  display: flex;
  flex-direction: column;
  height: 100%;
  overflow: hidden;
}

/* ── Top bar ── */
#topbar {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 10px 20px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
  z-index: 10;
}

#topbar h1 {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text);
  white-space: nowrap;
  letter-spacing: 0.02em;
}

#topbar h1 span { color: var(--accent); }

#search {
  flex: 1;
  max-width: 280px;
  padding: 5px 10px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text);
  font-size: 0.85rem;
  outline: none;
  transition: border-color 0.15s;
}
#search:focus { border-color: var(--accent); }
#search::placeholder { color: var(--muted); }

#topbar-meta {
  margin-left: auto;
  font-size: 0.75rem;
  color: var(--muted);
  white-space: nowrap;
}

/* ── Layout ── */
#layout {
  display: flex;
  flex: 1;
  min-height: 0;
}

/* ── Sidebar ── */
#sidebar {
  width: 210px;
  flex-shrink: 0;
  background: var(--surface);
  border-right: 1px solid var(--border);
  overflow-y: auto;
  padding: 8px 0;
}

.group-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 6px 16px 6px 14px;
  cursor: pointer;
  user-select: none;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  transition: color 0.1s;
  gap: 6px;
}
.group-header:hover { color: var(--text); }

.group-header .g-arrow {
  margin-right: auto;
  font-size: 0.55rem;
  transition: transform 0.15s;
  opacity: 0.6;
}
.group.open .group-header .g-arrow { transform: rotate(90deg); }

.group-header .g-count {
  font-size: 0.65rem;
  font-weight: 400;
  color: var(--muted);
  opacity: 0.7;
}

.group-items { display: none; }
.group.open .group-items { display: block; }

.nav-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 5px 16px 5px 26px;
  cursor: pointer;
  font-size: 0.82rem;
  color: var(--muted);
  border-left: 2px solid transparent;
  transition: background 0.1s, color 0.1s;
  gap: 6px;
}
.nav-item:hover { background: var(--hover); color: var(--text); }
.nav-item.active {
  background: var(--active);
  color: var(--accent);
  border-left-color: var(--active-border);
  font-weight: 500;
}

.nav-item .ni-count {
  font-size: 0.7rem;
  color: var(--muted);
  margin-left: auto;
}
.nav-item.active .ni-count { color: var(--accent); opacity: 0.7; }

/* ── Main panel ── */
#main {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-width: 0;
  overflow: hidden;
}

#main-header {
  padding: 12px 20px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: baseline;
  gap: 12px;
  flex-shrink: 0;
}

#main-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text);
}

#main-sub {
  font-size: 0.78rem;
  color: var(--muted);
}

#grid-wrap {
  flex: 1;
  overflow-y: auto;
  padding: 20px;
}

#grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
  gap: 12px;
}

.tile {
  background: var(--tile-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px 8px 8px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  transition: border-color 0.15s, transform 0.1s;
}
.tile:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.tile img {
  width: 64px;
  height: 64px;
  object-fit: contain;
  image-rendering: pixelated;
  image-rendering: crisp-edges;
}

.tile-label {
  font-size: 0.65rem;
  color: var(--muted);
  text-align: center;
  line-height: 1.3;
}

#empty {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100%;
  color: var(--muted);
  font-size: 0.9rem;
  flex-direction: column;
  gap: 8px;
}

#empty svg { opacity: 0.3; }

/* ── Lightbox ── */
#lb {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 100;
  align-items: center;
  justify-content: center;
}
#lb.open { display: flex; }

#lb-bg {
  position: absolute;
  inset: 0;
  background: rgba(0,0,0,0.82);
  backdrop-filter: blur(4px);
}

#lb-box {
  position: relative;
  z-index: 1;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 28px 28px 20px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
  max-width: 90vw;
}

#lb-img {
  image-rendering: pixelated;
  image-rendering: crisp-edges;
  max-width: min(480px, 80vw);
  max-height: 60vh;
  object-fit: contain;
}

#lb-name {
  font-size: 0.8rem;
  color: var(--muted);
  font-family: monospace;
}

#lb-close {
  position: absolute;
  top: 10px;
  right: 12px;
  background: none;
  border: none;
  color: var(--muted);
  font-size: 1.1rem;
  cursor: pointer;
  padding: 2px 6px;
  border-radius: 4px;
  line-height: 1;
}
#lb-close:hover { color: var(--text); background: var(--hover); }

#lb-nav {
  display: flex;
  gap: 10px;
}

#lb-nav button {
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 5px 14px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.8rem;
}
#lb-nav button:hover { border-color: var(--accent); color: var(--accent); }
#lb-nav button:disabled { opacity: 0.3; cursor: default; }

/* ── Scrollbar ── */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--muted); }