@import url('https://fonts.googleapis.com/css2?family=Bitter&display=swap');

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

.container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

button:hover {
    cursor: pointer;
}
  
body {
    padding: 10px 20px;
    background-color: #2a799e;
    color: #fff3b0;
    font-family: 'Bitter', serif;
}
  
.calculator {
    width: 400px;
    margin: 40px auto;
    background: #2a799e;
    border-radius: 10px;
    box-shadow: 0px 0px 10px #000000;
}
  
.button-key {
    display: flex;
    flex-wrap: wrap;
}
  
.display {
    font-size: 2rem;
    padding: 20px 20px;
    background: #858694;
    color: #e0e0e0;
    overflow: auto;
}
  
.btn {
    width: 25%;
    height: 4.5rem;
    border-radius: 0;
    border: solid 1px #e0e0e0;
    background-color: #858694;
    color: #e0e0e0;
    font-size: 2rem;
}
  
.btn-key {
    width: 50%;
    border: solid 1px #e0e0e0;
}
  
.btn-operator {
    background-color: #f5913e;
    border: solid 1px #e0e0e0;
    width: 25%;
    font-size: 2rem;
}
  
.displayNumber {
    display: flex;
    justify-content: flex-end;
    padding: 15px;
    color: white;
    font-size: 2rem;
}