style.css

*{
    box-sizing: border-box;
    font-weight: normal;
    font-family:'Lucida Sans', 'Lucida Sans Regular', 'Lucida Grande', 'Lucida Sans Unicode', Geneva, Verdana, sans-serif
}

body{
    background: linear-gradient(to right, rgb(38, 192, 77), rgb(72, 117, 212));
    margin: 0;
    padding: 0;
}

.calculator-grid{
    display: grid;
    justify-content: center;
    align-content: center;
    min-height: 100vh;
    grid-template-columns: repeat(4, 100px);
    grid-template-rows: minmax(120px, auto) repeat(5, 100px);
}

.calculator-grid button{
    border-radius: 5px;
    border: 1px solid white;
    background-color: rgba(255, 255, 255, .75);
    font-size: 2rem;
}


.calculator-grid button:hover{
    background-color: rgba(255, 255, 255, .9);
}

.calculator-grid button:active{
    transform: scale(0.95);
}

.span-two{
    grid-column: span 2;
}

.display{
    border-radius: 5px;
    grid-column: 1 / -1; 
    display: flex;
    flex-direction: column;
    justify-content: space-around;
    align-items: flex-end;
    padding: 10px;
    background-color: rgba(0, 0, 0, .75);
}

.current-operand{
    color: white;
    font-size: 2.5rem;
    display: flex;
    word-wrap: break-word;
    word-break: break-all;
}

.previous-operand{
    color: rgba(255, 255, 255, .75);
    font-size: 1.5rem;
    display: flex;
    word-wrap: break-word;
    word-break: break-all;
}