.pad-rack {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  grid-template-rows: 1fr 1fr;
  gap: 0.45rem;
  align-content: stretch;
  height: 100%;
  touch-action: none;
}
.pad {
  min-height: 2.4rem;
  height: 100%;
  border: 0;
  border-radius: 0.5rem;
  background: var(--pad);
  color: var(--on-ink);
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
}
.pad.is-down, .key.is-down, .note-name.is-down { filter: brightness(1.25); }
.pad:hover, .step:hover, .cell:hover, .key:hover, .note-name:hover { filter: brightness(1.1); }

.step-grid {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  min-width: 0;
  overflow-x: auto;
  flex: 1 1 0;
}
.step-row {
  display: grid;
  grid-template-columns: 5.6rem repeat(16, minmax(1.05rem, 1fr));
  gap: 0.2rem;
  align-items: center;
  flex: 1;
  min-height: 0;
}
.step-label {
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}
.step, .cell {
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 0.2rem;
  background: var(--panel-light);
}
.step { height: 100%; min-height: 1.05rem; }
.step.is-on, .cell.is-on { background: var(--pad); border-color: transparent; }
.step.is-beat, .cell.is-beat:not(.is-on) { box-shadow: inset 2px 0 0 rgba(244, 239, 230, 0.2); }
.step.is-bar, .cell.is-bar {
  box-shadow: -2px 0 0 0 #c4543a;
  position: relative;
  z-index: 1;
}
.step.is-playhead, .cell.is-playhead { outline: 2px solid var(--ink); outline-offset: -2px; }
.cell.is-on { border-radius: 0; }
.cell.is-on.is-head { border-radius: 0.2rem 0 0 0.2rem; }
.cell.is-on.is-tail { border-radius: 0 0.2rem 0.2rem 0; }
.cell.is-on.is-head.is-tail { border-radius: 0.2rem; }
.cell.is-on:not(.is-tail) { margin-right: -2px; position: relative; z-index: 1; }