style.css

body,
button {
  font-family: "Kode Mono", monospace;
  font-optical-sizing: auto;
}

h1 {
  color: #fafafa;
  margin: 0;

  font-size: 12px;
}

.container {
  height: 95vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

.calculator {
  width: 320px;
  padding: 24px;

  display: flex;
  flex-direction: column;
  gap: 16px;

  background-color: #27272a;
  border-radius: 20px;
  border-style: outset;
}

.display {
  height: 64px;
  background-color: #f0fdf4;

  border-radius: 5px;
  border-style: inset;

  display: flex;
  flex-direction: column;
  justify-content: space-between;

  padding: 4px 8px;
}

#current-operand {
  text-align: right;
  font-size: 36px;
}

#last-operand {
  height: 16px;

  text-align: left;
  font-size: 16px;
}

.buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 3px;
  justify-content: space-between;
}

.buttons button {
  flex: auto;
  width: 24%;
  height: 64px;
}

.buttons button[value="0"] {
  width: 49.3%;
}

.operand {
  background-color: #a1a1aa;

  font-size: 16px;
}

.operator {
  background-color: #71717a;
  color: #fafafa;

  font-size: 28px;
}

.misc {
  background-color: #3f3f46;
  color: #fafafa;
}

#operate {
  background-color: #dc2626;
  color: #fafafa;

  font-size: 28px;
}