body {
  margin: 0;
  padding: 0;
  text-align: center;
}

.calculator {
  margin: 20px auto;
  width: 400px;
  height: 400px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-auto-rows: minmax(50px, auto);
  user-select: none;
  box-shadow: 1px 1px gray;
}

.display {
  text-align: right;
  padding-right: 20px;
  grid-column: 1/5;
  background: rgb(58, 58, 58);
  color: white;
  font-size: 36px;
  line-height: 66px;
}

.zero {
  grid-column: 1/3;
}

.btn {
  font-size: 28px;
  line-height: 66px;
  background-color: rgb(240, 240, 240);
  border: 1px solid gray;
  cursor: pointer;
}

.opretor {
  background-color: orange;
  color: white;
}

.text {
  width: 400px;
  margin: 0 auto;
  padding: 0;
  display: flex;
}

h2 {
  margin-bottom: 0;
}
ul {
  margin: 0;
}

ul li {
  margin: 0;
  padding: 0;
  width: 150px;
  text-align: left;
}
@media screen and (max-width: 650px) {
  .text {
    display: none;
  }
  p {
    display: none;
  }
}