style.css

button,
input[type="button"]{
    background-color: #00004b;
    padding: 0.5rem;
    width: 3.5rem;
    height: 3.5rem;
    margin: 0.1rem;
    font-size: 1.5rem;
    border-radius: 1rem;
    border-width: 0.25rem;
    cursor: pointer;
}
.input-box {
    text-align: right;
    font-size: 1.75rem;
    width: 15rem;
    height: 3rem;
    margin: 1rem 0.5rem 1rem 0.2rem;
    border-radius: 1rem;
    background-color: #607060;
    color: white;
    opacity: 85%;
    font-family: 'Exo 2', sans-serif;
}
.calc{
    display: flex;
    align-items: center;
    justify-content: center;
    width: fit-content;
    background-color: #4f4f4f;
    padding: 1rem;
    border-radius: 2rem;
    border: 0.2rem solid lightslategray;
}
.num{
    color: #e0ffff;
    border-color: #e0ffff;
}
.op,
.eq{
    color: peachpuff;
    border-color: peachpuff;
}
.ac,
.del{
    color: red;
    border-color: red;
}
h1{
    font-size: 3rem;
    font-family: 'Bebas Neue', cursive;
    color: #4fcfa4;
}
#zero{
    width: 8rem;
}
*{
    background-color: #202020
}
td,
tbody{
    background-color: #4f4f4f;
}
sup,
.fa-solid{
    background-color: #00004b;
}
::placeholder{
    color: white;
    opacity: 40%;
}