basicCalculator.css

* {
  box-sizing: border-box;
  margin: 0;
}
.simpleCalculator {
  max-width: 400px;
  border-radius: 7px;
  background-color: #f2f2f2;
  padding: 20px;
  margin: 40px auto;
  border: 1px solid #ccc;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.3);
}
#enteryEquation {
  width: 100%;
  border: none;
  outline: none;
  box-shadow: 0px 2px 5px rgba(0, 0, 0, 0.3);
  padding: 10px;
  font-size: 18px;
  font-weight: bold;
}
.equation {
  display: inline-block;
  margin-bottom: 5px;
  text-indent: 5px;
}
.error {
  font-size: 14px;
  font-weight: initial;
  color: red;
}
.buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-gap: 15px;
  margin-top: 20px;
}
.buttons button {
  text-align: center;
  font-size: 24px;
  border: none;
  box-shadow: 0px 2px 5px rgba(0, 0, 0, 0.3);
  padding: 10px;
  border-radius: 5px;
  cursor: pointer;
  transition: background-color 0.5s ease-in-out;
  line-height: 25px;
}
.buttons button:hover {
  background-color: #ddd;
  color: black;
}

.clear {
  background-color: #ff4136;
  color: #fff;
}
.number {
  background-color: #fff;
}
.operator {
  background-color: #007ad9;
  color: #fff;
}
.equal {
  background-color: #01ff70;
  grid-row: span 3;
  color: #fff;
}