body {

    font-family: -apple-system, BlinkMacSystemFont, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
    margin: 0;
    align-items: center;
    justify-content: center;
    display: flex;
    background: #FFFDD0;
}

.Calculator{

    overflow: hidden;
    border: 2px solid #6f0000;
    border-radius: 12px;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.1);
}

button{
    background: #FFFDD0;
    cursor: pointer;
    transition: background 0.4s;
    font-size: 1.8em;
    padding: 20px;
    border: 1px solid #6f0000;
}

button :hover{
    background: #f0f0f0;
}

button :active{
    background: #ddd;
}

.buttons{
    gap: 2px;
    background: #FFFDD0;
    display: grid;
    grid-template-columns: repeat(4, 1fr);
}

.interface{
    background:  #333;
    color:#FFFDD0;
    font-size: 2em;
    padding: 20px;
    text-align: center;
}

.interface input {
    outline: none;
    width: 100%;
    border: none;
    text-align: inherit;
    font-size: inherit;
    background: transparent;
    color: inherit;
}

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