#diagram {
  position: relative;
  display: flex;
  align-items: flex-start;
  margin: 20px;
}

#arrows {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  overflow: visible;
  z-index: 10;
}

#diagram-labels {
  display: flex;
  margin: 20px 20px 4px 20px;
  font-size: 13px;
  font-weight: bold;
}

#stack-label {
  margin-left: 140px;
  width: 308px; /* stack container width + borders */
  text-align: center;
}

#heap-label {
  margin-left: 80px;
  padding-left: 10px;
}

#stack-container {
  width: 300px;
  min-height: 200px;
  border-left: 4px solid black;
  border-right: 4px solid black;
  border-bottom: 4px solid black;
  padding: 0;
  margin-left: 140px;
  overflow: visible;
  display: flex;
  flex-direction: column-reverse;
  align-items: stretch;
  gap: 0;
}

.stack-row {
  position: relative;
}

.side-text {
  position: absolute;
  right: 100%;
  top: 50%;
  transform: translateY(-50%);
  padding-right: 10px;
  font-size: 14px;
  font-weight: bold;
  white-space: nowrap;
  text-align: right;
}

#heap-container {
  display: flex;
  flex-direction: column;
  gap: 16px;
  padding: 10px;
  min-width: 120px;
  margin-left: 80px;
}

.heap-entry {
  display: flex;
  flex-direction: column;
  gap: 4px;
  align-items: center;
}

.heap-type {
  font-size: 12px;
  font-weight: bold;
  text-align: center;
}

.heap-object {
  border: 2px solid black;
  padding: 6px 10px;
  font-size: 13px;
  min-width: 80px;
  min-height: 40px;
  border-radius: 10px;
}

.array-row {
  display: flex;
  flex-direction: row;
  border: 2px solid black;
  width: fit-content;
}

.array-cell {
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
  border-right: 2px solid black;
  flex-shrink: 0;
}

.array-cell:last-child {
  border-right: none;
}

.array-empty {
  padding: 4px 8px;
  font-size: 11px;
  color: #888;
  font-style: italic;
}

.inner-box {
  flex: 1;
  border: 2px solid black;
  padding: 6px 8px;
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-height: 40px;
}

.var-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  font-size: 13px;
}

.var-label {
  font-weight: bold;
  white-space: nowrap;
}

.var-value-box {
  border: 2px solid black;
  background: white;
  width: 50px;
  height: 24px;
  text-align: center;
  font-size: 13px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}

#stdout-container {
  margin: 0 20px 10px 20px;
  border: 2px solid black;
  padding: 8px;
  max-width: 660px;
}

#stdout-label {
  font-size: 12px;
  font-weight: bold;
  margin-bottom: 4px;
}

#stdout-output {
  margin: 0;
  font-family: monospace;
  font-size: 13px;
  white-space: pre-wrap;
  min-height: 20px;
}

#controls {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin: 20px;
}

#code-input {
  width: 600px;
  font-family: monospace;
  font-size: 13px;
  padding: 8px;
  border: 2px solid black;
  resize: vertical;
}

#buttons {
  display: flex;
  align-items: center;
  gap: 8px;
}

button {
  padding: 4px 12px;
  font-size: 13px;
  cursor: pointer;
}

#step-counter {
  font-size: 13px;
}