body{
  overflow: hidden;
  background: linear-gradient(#f4f4ed, white);
}

.container{
  width: 95%;
  height: 100vh;
  margin: auto;
  display: flex;
  align-items: center;
  justify-content: center;
}

.calculator{
  width: 370px;
  margin: auto;
  border-radius: 2px;
  background:  #f2f2f2;
  padding: 15px 15px 20px 20px;
  box-shadow: 0px 2px 4px 0px rgba(0, 0, 0, 0.5);
}

#user_input{
  box-sizing: border-box;
  width: 100%;
  padding: 40px 5px;
  background: whitesmoke;
  text-align: right;
  direction: ltr;
  outline: none;
  border: none;
  font-size: 2rem;
}

.btn{
  width: 23%;
  height: 45px;
  border-radius: 1px;
  border: none;
  outline: none;
  margin-top: 3px;
  background: whitesmoke;
}

.btnEqual{
  width: 99.2%;
  height: 45px;
  border-radius: 1px;
  border: none;
  outline: none;
  margin-top: 3px;
  background: whitesmoke;
}

.btn:hover, .btnEqual:hover{background-color: rgba(128, 128, 128, 0.1);}

@media(max-width:480px){
  .btn{width: 23.4%;}
}

@media(max-width:320px){
  .btn{width: 23%;}
}
