.container {
  display: grid;
  justify-content: center;
  align-items: center;
}
.calculator {
  border-radius: 10px;
  box-shadow: 0px 3px 6px 0px rgba(0, 0, 0, 0.15),
    0px 2px 4px 0px rgba(0, 0, 0, 0.12);
  margin-inline-start: auto;
  margin-inline-end: auto;
  margin-block-start: 2em;
  max-inline-size: 22rem;
  overflow: hidden;
  color: hsl(202, 11%, 29%);
}
.calculator__output {
  background: hsl(255, 100%, 100%);
  font-size: 4.2rem;
  padding-block-start: 3rem;
  padding-block-end: 0.5rem;
  padding-inline-end: 1.25rem;
  text-align: end;
}
.calculator__keys {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-gap: 1px;
  background: hsl(255, 100%, 100%);
  padding: 0.5rem;
}
.calculator__key {
  background: hsl(210, 25%, 95%);
  border: none;
  padding-block-start: 1rem;
  padding-block-end: 1rem;
  padding-inline-end: 1.25rem;
  padding-inline-start: 1.25rem;
  font-size: 1.5rem;
  inline-size: 70px;
  block-size: 70px;
  margin: 0.25rem;
  border-radius: 40px;
}

.calculator__output__dark {
  background: hsl(207, 19%, 61%);
  font-size: 4.2rem;
  padding-block-start: 3rem;
  padding-block-end: 0.5rem;
  padding-inline-end: 1.25rem;
  text-align: end;
}
.calculator__keys__dark {
  background: hsl(207, 19%, 61%);
}
.calculator__key__dark {
  background: hsl(206, 14%, 41%);
  color: hsl(255, 100%, 100%);
}

.calculator__key:active {
  box-shadow: 0 0 8px 0 rgba(0, 0, 0, 0.3) inset;
  outline: none;
}
.calculator__key--operator {
  background: hsl(208, 25%, 86%);
}
.calculator__key--operator:active {
  background: hsl(208, 24%, 80%);
}
.calculator__key--enter {
  grid-column: 4 / 5;
  grid-row: 2 / span 4;
  background: hsl(357, 100%, 72%);
  height: auto;
}

.footer {
  display: flex;
  flex-direction: row;
  justify-content: end;
  padding: 10px;
}

.switch {
  position: relative;
  display: inline-block;
  width: 60px;
  height: 34px;
}

.switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: #ccc;
  -webkit-transition: 0.4s;
  transition: 0.4s;
}

.slider:before {
  position: absolute;
  content: "";
  height: 26px;
  width: 26px;
  left: 4px;
  bottom: 4px;
  background-color: white;
  -webkit-transition: 0.4s;
  transition: 0.4s;
}

input:checked + .slider {
  background-color: hsl(357, 100%, 72%);
}

input:focus + .slider {
  box-shadow: 0 0 1px hsl(357, 100%, 72%);
}

input:checked + .slider:before {
  -webkit-transform: translateX(26px);
  -ms-transform: translateX(26px);
  transform: translateX(26px);
}

.slider.round {
  border-radius: 34px;
}

.slider.round:before {
  border-radius: 50%;
}