style.css

/* note: @media max-height and !important's required, probably due to ID-based specificity clashes */
@media only screen and (max-width: 768px) {
    #container {
        max-height: 92%;
    }
    #playerUI {
        max-height: 4em;
    }
    #playerUI img {
        max-height: 3em;
        max-width: 2.5em;
    }
    #slide-wrap {
        padding: 0 1.2em !important;
        max-height: 4em;
    }
    #slider {
        background-position: 0px 31px !important;
        max-height: 4em;
    }
    #leftHandle, #rightHandle, #timeHandle {
        max-width: 2.4em;                 /* custom slider width requirement: */
        margin-left: -1.2em !important;   /* margin-left must equal the negative half of width */
    }
}

@media only screen and (max-width: 425px) {
    #container {
        max-height: 95%;
    }
    #playerUI {
        max-height: 3em;
    }
    #playerUI img {
        margin-left: 0 !important;
        max-width: 1.7em;
    }
}

/* general page styling */
html, body {
    margin: 0;
    padding: 0;
    border: 0;
}

body {
    width: 100vw;
    height: 100vh;
    overflow-x: hidden;
    background-image: url('img/monotreme.jpg');
    background-size: cover;
    background-position: center;
    background-repeat: repeat;
}

#container {
    width: 93%;
    height: 95%;
    margin-left: auto;
    margin-right: auto;
}

p {
    font-family: 'Roboto', sans-serif;
    background-color: auto;
    color: white;
    margin: 0;
    padding: 0;
    border: 0;
}

/* centering / floating class */
.float {
    width: auto;
    display: inline-block;
    vertical-align: middle;
}

/* centered bar sections */
#timebar {
    height: 5%;
    text-align: center;
}

#timer {
    margin: 0;
    padding: 0;
    font-size: 2em;   
}

#bg {
    background-color: rgba(0, 82, 100, 0.5);
    color: auto;
    margin: 0;
    border: 0.05em solid white;
    padding: 0.3em 0.2em 0.5em 0.3em;
}

#startbar {
    height: 10%;
    text-align: center;
    background-image: url('img/circlebar.svg');
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
}

#startbar img {
    height: 100%;
    cursor: pointer;
}

/* canvas */
#canvas {
    height: 50%;
    width: 100%;
    background-color: transparent;
    color: auto;
}

/* slider */
#slide-wrap {
    background-color: #998BA1;
    color: auto;
    padding: 0 1.5em;
    height: 5em;
    border-radius: 0.8em;
    margin-top: 0.3em;
}

#slider {
    height: 5em;
    border: 0;
    background-image: repeating-linear-gradient(0deg,transparent,transparent 50px,#CCC 50px,#CCC 51px),
                      repeating-linear-gradient(-90deg,transparent,transparent 50px,#CCC 50px,#CCC 51px);
    background-size: 51px 51px;
    background-position: 0px 38.9px;
}

/* colored divs to show handle progress */
#leftDiv, #rightDiv {
    position: absolute;
    background-color: rgb(202, 190, 209);
    color: auto;
    z-index: 2;
    height: 100%;
    top: 0;
}

#leftDiv {
    left: 0;
    width: 0.0%;
}

#rightDiv {
    right: 0;
    width: 0.0%;
}

#timeDiv {
    position: absolute;
    background-color: rgba(94, 217, 191, 0.5);
    color: auto;
    z-index: 1;
    height: 100%;
    left: 0;
    width: 0.0%;
}

/* handles */
#leftHandle, #rightHandle, #timeHandle {
    top: -0.001em;       /* centering-fix for custom slider height */
    height: 100%;
    width: 3em;          /* custom slider width requirement: */
    margin-left: -1.5em; /* margin-left must equal the negative half of width */
    outline: none;
    border: 0;
    background-position: center;
    background-size: auto;
    cursor: pointer;
}

#leftHandle {
    background: transparent url('img/leftHandle.svg') no-repeat border-box scroll;
}

#rightHandle {
    background: transparent url('img/rightHandle.svg') no-repeat border-box scroll;
}

#timeHandle {
    background: transparent url('img/timeHandle.svg') no-repeat border-box scroll;
}

/* custom audio controls */
#playerUI {
    background-color: rgba(94, 217, 191, 0.3);
    color: auto;
    height: 10%;
    width: 100%;
    text-align: center;
    border-radius: 0.8em;
    margin-top: 0.3em;
}

#playerUI img {
    min-height: 100%;
    cursor: pointer;
    margin-left: 3vw;
}

#duration {
    background-color: auto;
    color: white;
    font-size: 1.3em;
}

#volume {
    min-width: 0.9em;
    width: 10%;
    background-color: transparent;
    color: auto;
    outline: none;
    border: 0;
}

/* keep / discard modal */
#keep-discard {
    overflow: hidden;
}

#keep-discard p {
    background-color: auto;
    color: black;
    margin-bottom: 1em;
}

#download-edit {
    margin-bottom: -4px;
    cursor: pointer;
}

#edited {
    margin-top: 1em;
    margin-left: -0.7em; /* pulls visible part of <audio> back in-line with text */
}

/* hide most functionality on init */
#slide-wrap, #slider, #playerUI, #editBtn, #storeBtn, #upBtn, #timer, #bg {
    visibility: hidden;
}

#stopBtn, #keep-discard {
    display: none;
}

/* hiding via margin due to a Firefox playback bug:
   if audio element is hidden on not displayed, then
   the custom JavaScript control play(); can break */
#source {
    margin-left: -9999px;
}