body {
  display: flex;
  gap: 24px;
  justify-content: center;
  align-items: flex-start;
  margin: 0;
  padding: 40px 16px;
  background: pink;
  font-family: system-ui, sans-serif;
}

/* Calculator */

#calc {
  width: 600px;
  padding: 16px;
  border-radius: 16px;
  background: black;
}

#display {
  display: flex;
  align-items: flex-end;
  justify-content: flex-end;
  height: 100px;
  margin-bottom: 12px;
  padding: 8px 12px;
  overflow: hidden;
  border-radius: 8px;
  background: palegreen;
  font: 700 2.2rem monospace;
}

#keys {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
}

#keys button {
  height: 60px;
  border: 0;
  border-radius: 8px;
  background: gainsboro;
  font-size: 1.2rem;
  cursor: pointer;
}

#keys .operator {
  background: royalblue;
  color: white;
}

#keys [value="="] {
  grid-column: span 3;
  background: darkviolet;
  color: white;
}

/* History */

#history {
  width: 220px;
  padding: 16px;
  border-radius: 16px;
  background: white;
}

#history-list {
  height: 200px;
  margin: 0 0 12px;
  padding: 0;
  overflow-y: auto;
  list-style: none;
  border: 1px solid black;
  background: white;
}

#history-list li {
  padding: 8px 10px;
  cursor: pointer;
}

#history-list li:nth-child(even) {
  background: white;
}

#clear-history {
  padding: 8px 12px;
  cursor: pointer;
}