js-calculator/main.css

body {
    background-color: #e5e5e5;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.calculator {
    margin-bottom: auto;
    background-color: #84848452;
    border: 2px solid #4d4d4d52;
    border-radius: 5px;
}

.screen {
    padding: 5px;
    text-align: right;
    font-weight: bold;
}

.display_sml {
    height: 50px;
    font-size: 1.5rem;
}

.display_big {
    min-height: 40px;
    font-size: 1.9rem;
    line-height: 2.25rem;
    word-break: break-all;
}

.buttons {
    display: grid;
    grid-template-columns: repeat (4, 100px);
}

.buttons>button {
    width: 100px;
    height: 100px;
    font-size: larger;
    font-weight: bold;
}

.buttons>.eq {
    grid-column-start: 3;
    grid-column-end: 5;
    width: 200px;
    background-color: #94ff94;
}

.buttons>.ac {
    background-color: #ffaabb;
}