.mail-layout {
  display: grid;
  grid-template-columns: minmax(250px, 330px) minmax(0, 1fr);
  gap: 18px;
  max-width: 1180px;
  margin: 0 auto;
}

.mail-panel,
.mail-stage {
  padding: 18px;
}

.mail-panel {
  display: grid;
  align-content: start;
  gap: 16px;
}

.mail-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.hint {
  margin: 0;
  color: #405363;
  font-size: 1.05rem;
  font-weight: 850;
  line-height: 1.55;
}

.mail-stage {
  display: grid;
  place-items: center;
  min-height: 620px;
  background: linear-gradient(160deg, rgba(188, 232, 214, 0.88), rgba(255, 253, 245, 0.94));
}

.mail-board {
  --size: 5;
  display: grid;
  grid-template-columns: repeat(var(--size), minmax(0, 1fr));
  gap: 9px;
  width: min(100%, 660px);
}

.mail-cell {
  position: relative;
  display: grid;
  place-items: center;
  aspect-ratio: 1;
  min-width: 0;
  border: 3px solid rgba(255, 255, 255, 0.78);
  border-radius: 20px;
  background: rgba(255, 253, 245, 0.82);
  color: #263238;
  cursor: pointer;
  font-size: clamp(1.3rem, 4vw, 2.3rem);
  font-weight: 950;
  box-shadow: 0 12px 22px rgba(71, 85, 105, 0.12);
}

.mail-cell.is-path {
  background: #dff6ff;
}

.mail-cell.is-current {
  outline: 6px solid rgba(77, 163, 199, 0.5);
}

.mail-cell.is-house {
  background: #fff4c9;
}

.mail-cell.is-delivered {
  background: #c8ef9e;
}

.mail-cell.is-end {
  background: #ffd1b8;
}

.mail-cell.is-next {
  border-color: rgba(77, 163, 199, 0.78);
}

.mail-cell::after {
  position: absolute;
  right: 7px;
  bottom: 5px;
  color: #607282;
  font-size: 0.82rem;
  content: attr(data-step);
}

@media (max-width: 820px) {
  .mail-layout {
    grid-template-columns: 1fr;
  }

  .mail-stage {
    min-height: auto;
  }

  .mail-board {
    gap: 6px;
  }

  .mail-cell {
    border-radius: 15px;
  }
}