.shellbar { display: flex; justify-content: space-between; align-items: center; gap: 12px;
  padding: 10px 16px; font: 13px/1.4 "IBM Plex Sans", system-ui, sans-serif;
  border-bottom: 1px solid rgba(127,127,127,.25); }
.shellbar-actions { display: flex; gap: 8px; }
.shellbar button { font: inherit; padding: 4px 10px; border-radius: 6px; cursor: pointer;
  border: 1px solid rgba(127,127,127,.4); background: transparent; color: inherit; }
#board:empty { display: none; }