:root {
  --lightBG: #ffffff;
  --lightColor: #000000;
  --darkBG: #000000;
  --darkColor: #ffffff;
  --modeBG: var(--lightBG);
  --modeColor: var(--lightColor);
}
* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
  font-family: "Roboto Mono", monospace;
}
body {
  height: 100vh;
  background: #f9544c;
}
.calculator {
  width: 400px;
  background-color: var(--modeBG);
  padding: 10px 30px;
  position: absolute;
  transform: translate(-50%, -50%);
  top: 50%;
  left: 50%;
  border-radius: 8px;
}
.display {
  width: 100%;
}
.display input {
  width: 100%;
  padding: 5px 10px;
  text-align: right;
  border: none;
  background-color: transparent;
  color: var(--modeColor);
  font-size: 35px;
}
.display input::placeholder {
  color: #9490ac;
}
.buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-gap: 20px;
  margin-top: 40px;
}
.buttons input[type="button"] {
  font-size: 20px;
  padding: 17px;
  border: none;
  background-color: transparent;
  color: var(--modeColor);
  cursor: pointer;
  border-radius: 5px;
}
.buttons input[type="button"]:hover {
  box-shadow: 0 8px 25px var(--modeColor);
}
input[type="button"]#equal {
  grid-row: span 2;
  background-color: #f9544c;
}
input[type="button"][value="0"] {
  grid-column: span 2;
}
#dark-switch {
  margin-top: 20px;
  appearance: none;
  position: relative;
  height: 30px;
  width: 50px;
  background-color: #f9544c;
  border-radius: 20px;
}
#dark-switch::before {
  content: "";
  position: absolute;
  background-color: #ffffff;
  height: 20px;
  width: 20px;
  border-radius: 50%;
  top: 5px;
  left: 5px;
}
#dark-switch:checked:before {
  background-color: var(--darkBG);
  left: 25px;
}