* {
    box-sizing: border-box;
}

body {
    margin: 0;
}

h1 {
    text-align: center;
}

#piano {
    display: flex;
    flex-wrap: wrap;
    width: 90vw;
    margin: auto;
}

.key-holder {
    display: flex;
}

.white-key {
    width: 60px;
    height: 200px;
    background-color: white;
    border: 1px solid black;
    text-align: center;

}

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

.black-key {
    width: 40px;
    height: 120px;
    background-color: black;
    color: white;
    position: absolute;
    margin-left: 40px;
    z-index: 1;
    text-align: center;
}

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

main {
    margin-bottom: 40px;
}

footer {
    bottom: 0;
    width: 100%;
    height: 30px;
    position: fixed;
    background-color: lightgray;
    padding: 10px;
    display: flex;
    align-items: center;

}