meter {
    /* Reset the default appearance */
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;

    margin: 0 auto 1em;
    width: 100%;
    height: .5em;

    /* Applicable only to Firefox */
    background: none;
    background-color: rgba(0,0,0,0.1);
}

meter::-webkit-meter-bar {
    background: none;
    background-color: rgba(0,0,0,0.1);
}

meter[value="1"]::-webkit-meter-optimum-value { background: red; }
meter[value="2"]::-webkit-meter-optimum-value { background: yellow; }
meter[value="3"]::-webkit-meter-optimum-value { background: orange; }
meter[value="4"]::-webkit-meter-optimum-value { background: green; }

meter[value="1"]::-moz-meter-bar { background: red; }
meter[value="2"]::-moz-meter-bar { background: yellow; }
meter[value="3"]::-moz-meter-bar { background: orange; }
meter[value="4"]::-moz-meter-bar { background: green; }

.feedback {
    font-size: 90%;
    padding: 0 .25em;
    margin-top: 1em;
    color: red;
}