.calculator-float {
    width: 220px;
    border: 2px solid teal;
    border-radius: 10px;
    padding: 10px;
    float: left;
  }
  
  .calculator-float .header {
    background: teal;
    color: white;
    text-align: right;
    padding: 5px;
    font-weight: bold;
  }
  
  .calculator-float .screen {
    border: 2px solid teal;
    margin: 10px 0;
    padding: 10px;
    text-align: right;
    font-size: 18px;
  }
  
  .calculator-float .sub-screen {
    background: teal;
    width: 80px;
    height: 30px;
    float: right;
    margin-bottom: 10px;
  }
  
  .calculator-float .buttons {
    clear: both;
  }
  
  .calculator-float .btn {
    width: 40px;
    height: 40px;
    border: 2px solid teal;
    border-radius: 8px;
    float: left;
    margin: 5px;
    text-align: center;
    line-height: 40px;
    font-weight: bold;
  }