index.css

.container{
    height: 630px;
    width: 420px;
    background-color: black;
    margin: auto;
    border-radius: 20px;
}
p{
    color: white;
    margin-left: 20px;
    padding: 20px;
    font-size: 1.5rem;
    font-weight: bold;

}

#screen{
    height: 80px;
    width: 380px;
    margin: 15px;
    border-radius: 15px;
    font-size: 4rem;
    background-color: rgb(142, 157, 157);
    text-align: right;
}

.button{
    height: 50px;
    width: 60px;
    margin-left: 35px;
    margin-top: 10px;
    margin-bottom: 0px;
    border-radius: 10px;
    font-size: 1.7rem;
}

.button:hover{
    border: 5px solid greenyellow;
}
.number{
    background-color: rgb(144, 147, 144);
    color: white;
   
}

.operator{
    background-color: rgb(186, 183, 183);
    color: white;
}

.clear{
    background-color: red;
    font-weight: bold;
    font-size: 2rem;
    color: white;
}