body {
    font-family: Tahoma, sans-serif;
    text-align: center;
    background-color: #0b67bd;
    /* prevent selecting the text when swiping around */
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

.container {
    max-width: 600px;
    margin: 0 auto;
}

input[type=range] {
    width: 100%;
}

body,
html {
    margin: 0;
    padding: 0;
}

.osc {
    width: 40%;
    align-items: center;
}

.wave-btn {
    /* align-self: center; */
}

footer {
    position: fixed;
    bottom: 0;
    left: 0;
    /* Add this line */
    width: 100%;
    display: flex;
    justify-content: space-around;
    padding: 10px 0;
}