/* ══ PAGE 2: CATEGORY — Sub-group List ══ */
#p-cat {
  overflow-y: auto; overflow-x: hidden; -webkit-overflow-scrolling: touch;
  background-color: transparent;
}

#p-cat::-webkit-scrollbar { width: 3px; }
#p-cat::-webkit-scrollbar-track { background: transparent; }
#p-cat::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.06); border-radius: 3px; }

/* 背景已迁移到共享 #space-bg 层 */
/* ── Topbar ── */
#cat-topbar {
  position: sticky; top: 0; z-index: 20;
  padding: max(env(safe-area-inset-top), 14px) 24px 0;
  background: linear-gradient(to bottom, #050810ee 60%, transparent);
  pointer-events: none;
}
#cat-topbar-row {
  display: flex; align-items: center; gap: 12px;
  padding-bottom: 12px;
  max-width: 980px; margin: 0 auto;
  pointer-events: auto;
}
#btn-cat-back {
  width: 44px; height: 44px; border-radius: 50%;
  background: rgba(255, 255, 255, .06);
  border: 1px solid var(--border);
  color: var(--text-primary); font-size: 17px;
  line-height: 1;
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  padding: 0 0 1px 1px;
  transition: background .15s; flex-shrink: 0;
  position: relative;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
}
#btn-cat-back::before {
  content: ''; position: absolute;
  top: -8px; left: -8px; right: -8px; bottom: -8px;
}
#btn-cat-back:active { background: rgba(255, 255, 255, .12); }

#cat-info { flex: 1; min-width: 0; }
#cat-title {
  font-family: var(--serif); font-size: 18px; font-weight: 600;
  color: var(--text-primary);
}
#cat-stat {
  font-family: var(--mono); font-size: 10px; letter-spacing: .12em;
  text-transform: uppercase; color: var(--text-muted); margin-top: 2px;
}

/* ── Search ── */
#cat-search {
  position: relative; z-index: 1;
  max-width: 980px; margin: 8px auto 0; padding: 0 24px;
}
#cat-search-inner {
  display: flex; align-items: center; gap: 10px;
  background: rgba(255, 255, 255, 0.025);
  border: 1px solid var(--border); border-radius: 14px;
  padding: 0 16px; height: 42px;
  transition: border-color 0.25s, background 0.25s;
}
#cat-search-inner:focus-within {
  border-color: rgba(255,255,255,0.15);
  background: rgba(255,255,255,0.045);
}
#cat-search-inner svg { flex-shrink: 0; color: var(--text-muted); transition: color 0.25s; }
#cat-search-inner:focus-within svg { color: var(--text-tertiary); }
#cat-search-input {
  flex: 1; background: none; border: none; outline: none;
  font-family: var(--mono); font-size: 13px; font-weight: 300;
  color: var(--text-primary); letter-spacing: 0.03em;
}
#cat-search-input::placeholder { color: var(--text-muted); }

/* ── Sub-group Grid (reuses .tc theme card styles from sheet.css) ── */
#cat-grid {
  position: relative; z-index: 1;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
  padding: 18px 24px max(env(safe-area-inset-bottom), 48px);
  max-width: 980px; margin: 0 auto;
}
@media (min-width: 600px) { #cat-grid { grid-template-columns: repeat(3, 1fr); gap: 16px; } }
@media (min-width: 960px) { #cat-grid { grid-template-columns: repeat(4, 1fr); gap: 18px; } }

.cat-empty {
  grid-column: 1 / -1; text-align: center; padding: 48px 20px;
  font-family: var(--mono); font-size: 13px; color: var(--text-muted);
  letter-spacing: 0.05em;
}

/* ── Theme Card (shared between category page and potentially other views) ── */
.tc {
  position: relative; overflow: hidden;
  background: rgba(255, 255, 255, 0.025);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 22px 18px 18px;
  cursor: pointer;
  display: flex; flex-direction: column;
  transition: transform 0.28s cubic-bezier(.34, 1.56, .64, 1), border-color 0.25s, background 0.25s, opacity 0.3s;
  -webkit-user-select: none; user-select: none;
  opacity: 0; animation: cardIn 0.45s ease forwards;
}
.tc.featured { grid-column: span 2; }
@media (max-width: 599px) { .tc:first-child { grid-column: span 2; } }
.tc:active { transform: scale(0.96); }
.tc:hover {
  border-color: rgba(255, 255, 255, .15);
  background: rgba(255, 255, 255, 0.04);
  transform: translateY(-3px);
}
.tc-aurora {
  position: absolute; top: -40px; right: -40px;
  width: 120px; height: 120px;
  border-radius: 50%; filter: blur(42px);
  opacity: 0.16; pointer-events: none;
  transition: opacity .3s;
}
.tc:hover .tc-aurora { opacity: .26; }
.tc-icon { font-size: 28px; display: block; margin-bottom: 12px; filter: saturate(0.85); }
.tc-name {
  font-family: var(--serif); font-size: 17px; font-weight: 600;
  line-height: 1.25; margin-bottom: 4px;
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden;
}
.tc-hint {
  font-family: var(--mono); font-size: 10px; font-weight: 300;
  letter-spacing: .08em; color: var(--text-muted); margin-bottom: 14px;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.tc-footer { margin-top: auto; }
.tc-progress {
  position: relative; height: 3px;
  background: rgba(255, 255, 255, 0.05);
  border-radius: 2px; overflow: hidden; margin-bottom: 10px;
}
.tc-progress-fill {
  position: absolute; top: 0; left: 0; height: 100%;
  border-radius: 2px;
  transition: width 0.9s cubic-bezier(.16, 1, .3, 1);
  width: 0;
}
.tc-bottom { display: flex; align-items: center; justify-content: space-between; }
.tc-count {
  font-family: var(--mono); font-size: 10px; font-weight: 300;
  letter-spacing: .05em; color: var(--text-tertiary);
}
.tc-arrow {
  font-size: 14px; color: var(--text-muted);
  transition: color 0.25s, transform 0.25s;
}
.tc:hover .tc-arrow { color: var(--text-tertiary); transform: translateX(3px); }