*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: monospace;
}

body{
    width: 100vw;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

.calculator{
    width: 90%;
    max-width: 600px;
    background-color: #f5f5f5;
    padding: 10px;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.screen{
    width: 100%;
    height: 25%;
    margin: 0 auto;
    padding: 0 10px;
    background-color: #e6e6e6;
    flex-shrink: 0;
    
    font-size: 4rem;
    
    display: flex;
    align-items: flex-end;
    justify-content: flex-end;

}

.keyboard{
    width: 100%;
    background-color: #e6e6e6;

    display: flex;
    flex-flow: column nowrap;
    justify-content: center;
    align-items: stretch;
    gap: 5px;

    padding: 5px;
    
}

.keyrow{
    display: flex;
    flex-flow: row nowrap;
    gap: 5px;
}

.key{
    width: 19%;
    flex: 1;
    aspect-ratio: 5/3;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 2rem;
    border-radius: 5px;
}

.key.number{
    background-color: red;
}

.key.operator{
    background-color: lime;
}

.key.modifier{
    background-color: cyan;
}

.key.control{
    background-color: gray;
}

.key:hover{
    background-color: orange;
    cursor: pointer;
}