.main-container {
  max-width: 400px;
  margin: 10vh auto 0 auto;
  box-shadow: 0px 0px 43px 17px rgba(0, 0, 0, 0.414);
}
body {
  height: 100vh;
  background-color: #85ffbd;
  background-image: linear-gradient(45deg, #85ffbd 0%, #fffb7d 100%);
}
.header {
  text-align: center;
  margin-top: 5%;
  font-size: 40px;
  font-weight: 600;
}
.disp {
  text-align: right;
  height: 60px;
  line-height: 60px;
  padding: 20px 20px;
  font-size: 25px;
  border: 0.5px solid gray;
  color: black;
  font-weight: bold;
}
.buttons {
  grid-template-columns: 1fr 1fr 1fr 1fr;
  display: grid;
  border-bottom: 1px solid gray;
  border-left: 1px solid gray;
}
.btn {
  border: 0.5px solid gray;
  height: 60px;
  line-height: 60px;
  text-align: center;
  margin: 0.3%;
  font-size: 25px;
  cursor: pointer;
  transition: 0.5s;
  font-weight: bold;
}
.btn:hover {
  background: #000;
  color: white;
  transform: rotate(-5deg);
}
#equal-btn {
  background: rgb(128, 0, 128);
  color: white;
}