style.css

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

body {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    background: #111;
}

.piano {
    display: flex;
    box-shadow: 0 0 7px #000;
    overflow: hidden;
    position: fixed;
}

.key {
    font-family: Arial, Helvetica, sans-serif, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue';
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    font-size: 20px;
}

.key.white {
    width: 60px;
    height: 190px;
    background: #fff;
    border: 1px solid #000;
    cursor: pointer;
    transition: border .5s ease;
}

.key.white:hover {
    border-bottom: 30px solid #111;
}

.key.black {
    background: #000;
    width: 30px;
    height: 100px;
    position: absolute;
    cursor: pointer;
    color: #fff;
    transition: transform .3s ease;
}

.key.black:hover {
    transform: translateY(-10px) scaleY(0.8);
}

.key.black.key-1 {
    margin-left: 44px;
}

.key.black.key-2 {
    margin-left: 104px;
}

.key.black.key-3 {
    margin-left: 224px;
}

.key.black.key-4 {
    margin-left: 284px;
}

.key.black.key-5 {
    margin-left: 344px;
}