body {
  background-color: hsl(0, 0%, 17%);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100vh;
  font-family: 'Megrim', cursive;
}

h1 {
  color: hsla(0, 0%, 100%, 0.78);
  text-shadow: 2px 2px hsla(0, 0%, 55%, 0.78);
  text-align: center;
  font-size: 27px;
  font-family: 'Russo One', sans-serif;
}

#calculator {
  padding: 0px;
  position: relative;
  margin-top: 3em;
  width: 370px;
}

#number-display {
  outline: 0.01px solid hsla(0, 0%, 55%, 0.78);
  text-align: right;
  padding-right: 10px;
  margin: 0px;
  vertical-align: text-top;
  line-height: 50px;
  color: hsla(0, 0%, 100%, 0.473);
}

#buttons {
  display: grid;
  width: 372px;
  position: relative;
  right: 1px;
  margin: 0px;
  grid-template-columns: 1fr 1fr 1fr 1fr;
  grid-template-rows: 5em 5em 5em 5em 5em;
}

button {
  background-color: hsla(272, 0%, 11%, 0.64);
  border: 0.01px solid hsla(0, 0%, 55%, 0.78);
  padding: 0px;
  margin: 0px;
  font-weight: lighter;
}

.number-btn {
  color: hsla(0, 0%, 100%, 0.64);
  font-size: 30px;
}

.number-btn:hover {
  font-size: 38px;
  border: 2px solid white;
}

.operation-btn {
  color: hsla(34, 81%, 55%, 0.849);
  font-size: 30px;
}

.operation-btn:hover {
  font-size: 38px;
  border: 2px solid hsla(34, 81%, 55%, 0.849);
}

#equal {
  color: hsla(219, 43%, 50%, 0.78);
  font-size: 30px;
  grid-row: 4 / 6;
  grid-column: 4;
}

#equal:hover {
  font-size: 38px;
  border: 2px solid hsla(219, 43%, 50%, 0.78);
}

#clear {
  color: hsla(0, 90%, 61%, 0.78);
  font-size: 30px;
  grid-row: 1 / 2;
  grid-column: 1 / 2;
}

#clear:hover {
  font-size: 38px;
  border: 2px solid hsla(0, 90%, 61%, 0.78);
}

#negative {
  color: hsla(147, 90%, 61%, 0.78);
  font-size: 30px;
  grid-row: 1 / 2;
  grid-column: 2 / 3;
}

#negative:hover {
  font-size: 38px;
  border: 2px solid hsla(147, 90%, 61%, 0.78);
}

#zero {
  grid-row: 5 / 6;
  grid-column: 1 / 3;
}

#plus {
  grid-row: 1 / 2;
  grid-column: 3 / 4;
}

#minus {
  grid-row: 1 / 2;
  grid-column: 4 / 5;
}

#multiply {
  grid-row: 2 / 3;
  grid-column: 4 / 5;
}

#divide {
  grid-row: 3 / 4;
  grid-column: 4 / 5;
}

.footer {
  color: hsla(0, 0%, 74%, 0.219);
  font-family: 'Russo One', sans-serif;
}