body{
    margin: 0;
    padding: 0;
    height: 100vh;
    justify-self: center;
    align-items: center;
    text-align: center;
    display: flex;
}
.input input{
    padding: 10px;
    width: 18rem ;
    height: 3.5rem;
    font-size: 3rem;
    text-align: right;
    border: 2px solid transparent;
    color: white;
    background-color: rgb(105, 105, 105);
    border-radius: 2rem;
    margin-bottom: 10px;
}   
.buttons{
    width: 18rem;
    margin: auto;
}
.buttons div{
    margin: 5px 0;
}
.buttons button{
    width: 4rem;
    height: 3.5rem;
    margin: 2px;
    font-size: 1.5rem;
    border: 1px solid rgb(168, 168, 168);
    border-radius: 2rem;
    background-color: black;
    color: white;
    cursor: pointer;
}
.buttons button:hover{
    opacity: 0.5;
    transition: 0.5s;
}
.buttons .operators{
    background-color: blue;
}
.buttons .ac{
    background-color: red;
}