body {
    max-height: 100vh;
    background: 
        linear-gradient(rgba(0,0,0,0.5), rgba(0,0,0,0.5)),
        url("forest_audio.jpg");
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
}

#piano {
    margin: auto;
    margin-top: 30vh;
    width: 70%;
    max-width: 800px;
    height: 300px;
    background: rgba( 255, 255, 255, 0.25);
    box-shadow: 0 8px 32px 0 rgba( 31, 38, 135, 0.37);
    backdrop-filter: blur( 4px);
    -webkit-backdrop-filter: blur( 4px);
    border-radius: 10px;
    border: 1px solid rgba( 255, 255, 255, 0.18);
    position: relative;
}

#keys {
    width: 90%;
    position: absolute;
    bottom: 5px;
    height: 60%;
    margin: 5%;
}

.whiteKeys {
    width: 7%;
    height: 100%;
    background-color: white;
    position: absolute;
    border: 2px solid black;
    cursor: pointer;
}

.whiteKeys:active {
    background: linear-gradient(to bottom, rgb(248, 248, 248), rgb(238, 238, 238), grey);
    box-shadow: 2px -2px black inset, -4px -2px black inset;
}

.whiteKeys:hover {
    background-color: rgb(228, 228, 228);
}

.blackKeys {
    width: 3.5%;
    height: 50%;
    background-color: rgb(71, 71, 71);
    position: absolute;
    cursor: pointer;
}

.blackKeys:hover {
    background-color: rgb(36, 36, 36);
}

.blackKeys:active {
    background-color: black;
}

#volumeBar {
    position: absolute;
    right: 50px;
    top: 50px;
}

.fa-volume-up {
    color: yellow;
    font-size: 36px;
}

.fa-plus {
    color: green;
    cursor: pointer;
}

.fa-minus {
    color: red;
    cursor: pointer;
}

#volume {
    font-weight: 800;
    font-size: 1.5rem;
    user-select: none;
    color: white;
}

.site-header {
    text-align: center;
    padding: 25px;
    color: white;
    background: rgba(0, 0, 0, 0.4);
    border-bottom: 2px solid lightgreen;
}

.site-header h1 {
    font-size: 38px;
    letter-spacing: 1px;
}

.site-header p {
    font-size: 18px;
    color: #90ee90;
}