style.css

h1 {
  text-align: center;
  background-color: plum;
}

p {
  text-align: center;
  background-color: lavender;
}

.contain {
  display: grid;
  grid-template-columns: auto auto auto auto;
  background-color: #dadada;
  margin: 30px auto !important;
  height: 450px;
  width: 400px;
  border: 5px solid #d3d2d2;
  border-radius: 3px;
}

.input {
  border: 1px solid #dcdddf;
  text-align: center;
  padding: 20px;
  font-size: large;
}

#result {
  text-align: center;
  background-color: #b9b9b9;
  color: #919191;
  grid-column-start: 1;
  grid-column-end: 5;
  text-align: left;
  padding: 5px;
  align-items: center;
  font-size: xx-large;
  margin: 8px;
  margin-top: 15px;
  /* margin-left: 1rem; */
  /* margin-right: 1em; */
}

#equal {
  grid-column-start: 3;
  grid-column-end: 5;
  background-color: #0d6efd;
}

#divide,
#multiply,
#add,
#subtract,
#dot {
  color: blue;
}

#clear {
  color: red;
  
}

.input:hover {
  background-color: lightseagreen;
}