style.css

/* body{
    background-color: black;
    color: white;
    margin: 2rem;
} */

.app_title{
    margin-left: 8rem;
    font-size: 2rem;
    font-weight: bold;
}

.container{
    border: 0.1rem solid black;
    border-radius: 1.5rem;
    margin: 2rem;
    padding: 1rem;
    max-width: 18rem;
    background-color: rgb(186, 244, 186);
}

.row{
    display: flex;
    flex-wrap: wrap;
    /* justify-content: space-between; */
}

.key{
    border: 0.2rem solid blcak;
    border-radius: 2rem;
    /* color: white; */
    width: 3.5rem;
    height: 3.5rem;
    font-size: 1.5rem;
    cursor: pointer;
    margin: 0.3rem;
}

.key:hover{
    background-color: rgb(43, 239, 17);
    color: white;
}

.expression{
    font-size: 2rem;
    padding-bottom: 0.4rem;
}

.exp_result{
    font-size: 2rem;
    padding-bottom: 1.411123rem;
}