body {
    overflow: hidden;
}
#app {
  height: 100vh;
  min-height: 550px;
  width: 100%;
  border: 10px solid black;
  padding-top: 5%;
  padding-bottom: 10%;
}
h1 {
  color: white;
  text-align: center;
  padding-bottom: 5%;
}

#calculator {
  max-width: 180px;
  min-width: 180px;
  max-height: 400px;
  min-height: 350px;
  height: 75%;
  width: 50%;
  margin: auto;
  border: 5px solid black;
  border-radius: 25px;
}

#display {
  margin: 2%;
}
#screen {
  margin: 5% auto;
  font-size: 20px;
  resize: none;
  text-align: right;
  color: black;
  background-color: white;
  width: 85%;
  height: 10%;
}

.bt {
  margin: 2.5%;
  width: 20%;
}

.btClear {
  margin: 2.5%;
  width: 95%;
}