* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100vh;
  background-color: bisque;
}
.calculator {
  width: 350px;
  height: 525px;
  background-color: #eee;
  border-radius: 5px;
  padding: 30px;
  box-shadow: -9px 8px 4px -1px rgba(0, 0, 0, 0.18);
  -webkit-box-shadow: -9px 8px 4px -1px rgba(0, 0, 0, 0.18);
  -moz-box-shadow: -9px 8px 4px -1px rgba(0, 0, 0, 0.18);
}
.calculator .screen {
  width: 100%;
  height: 100px;
  background-color: rgb(22, 22, 22);
  position: relative;
  overflow-x: scroll;
}
.calculator .screen p {
  color: white;
  position: absolute;
  bottom: 15px;
  left: 15px;
  font-size: 20px;
}
.calculator hr {
  margin: 15px 0;
}
.calculator .buttons {
  width: 100%;
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 5px;
}
.calculator .buttons button {
  width: 55px;
  height: 55px;
}
.calculator .buttons button:active {
  -webkit-box-shadow: inset 1px 1px 10px rgb(100, 100, 100);
  -moz-box-shadow: inset 1px 1px 10px rgb(100, 100, 100);
  box-shadow: inset 1px 1px 10px rgb(100, 100, 100);
}