styles.css

body {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-color: black;
}

h1{
    margin: 40px;
    padding: 20px;
    color: white;
    text-shadow: 8px 8px 8px black;
    text-transform: uppercase;
    box-shadow: 10px 10px 10px pink;
    background-image: linear-gradient(to bottom right,rgb(222, 3, 246),rgb(255, 128, 0),blue,yellow,red);
    border: 2px solid white;
    border-radius: 20px;
}

#piano {
    height: 290px;
    padding: 90px 30px 0 30px;
    background-image: linear-gradient(to top,black, grey);
    border-radius: 10px;
    border: 2px solid white;
    box-shadow: 10px 10px 10px white;
}

.keys {
    position: relative;

}

.white-keys {
    display: flex;
}

.black-keys {
    position: relative;
    display: flex;
}

.white-key {
    width: 68px;
    height: 280px;
    background-color: #fff;
    border-radius: 0 0 5px 5px;
    border: solid #000 2px;
    box-sizing: border-box;
}

.black-key {
    width: 38px;
    height: 160px;
    border-radius: 0 0 5px 5px;
    box-sizing: border-box;
    position: absolute;
    background-color: #000;
}

.black-key:nth-child(1) {
    left: 48px;
}

.black-key:nth-child(2) {
    left: 117px;
}

.black-key:nth-child(3) {
    left: 253px;
}

.black-key:nth-child(4) {
    left: 320px;
}

.black-key:nth-child(5) {
    left: 389px;
}

.black-key:nth-child(6) {
    left: 525px;
}

.black-key:nth-child(7) {
    left: 594px;
}

.black-key:nth-child(8) {
    left: 662px;
}

.black-key:nth-child(9) {
    left: 797px;
}

.black-key:nth-child(10) {
    left: 865px;
}