/* Bảng tuần hoàn — responsive + scrollbar */

.bth-table-wrap::-webkit-scrollbar { height: 8px; }
.bth-table-wrap::-webkit-scrollbar-track { background: var(--bg); border-radius: 4px; }
.bth-table-wrap::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }
.bth-table-wrap::-webkit-scrollbar-thumb:hover { background: var(--accent); }

@media (max-width: 768px) {
  .bth-info { padding: 12px; }
  .bth-info-cell { width: 70px; height: 70px; }
  .bth-info-cell-sym { font-size: 1.4rem; }
  .bth-grid { grid-template-columns: repeat(18, 40px); min-width: 720px; }
  .bth-cell-sym { font-size: 14px; }
  .bth-cell-num { font-size: 8px; }
  .bth-cell-mass { font-size: 7px; }
}

@media (max-width: 540px) {
  .bth-info-content { flex-direction: column; align-items: center; text-align: center; }
  .bth-info-grid { font-size: 0.78rem; }
}