* {
    box-sizing: border-box;
}

#rusty-microphone {
    max-width: 320px;
}
#pitch-indicator-bar-container {
    width: calc(100% - 2px);
    height: 30px;
    position: relative;
    background: #C8C8C8;
    border-right: 2px solid #C8C8C8;
    box-sizing: content-box;
}
#pitch-indicator-bar {
    height: 100%;
    border: 1px solid black;
    width: 0;
    position: absolute;
    left: 50%;
}

#pitch-indicator-colours {
    width: 100%;
    height: 50px;
}

#flat-indicator {
    width: 50%;
    height: 100%;
    background: blue;
    float: left;
}

#sharp-indicator {
    width: 50%;
    height: 100%;
    background: red;
    float: left;
}

.error {
    border: 1px solid red;
    padding: 10px;
}