VersaWhiteboard/public/css/main.css

.btn-group button {
    background-color: #808080; /* Green background */
    border: 1px solid #636060; /* Green border */
    color: black; /* White text */
    padding: 11px 14px; /* Some padding */
    cursor: pointer; /* Pointer/hand icon */
    float: left; /* Float the buttons side by side */
     font-size: 1.2em;
}

.btn-group button:not(:last-child) {
    border-right: none; /* Prevent double borders */
}

/* Clear floats (clearfix hack) */
.btn-group:after {
    content: "";
    clear: both;
    display: table;
}

/* Add a background color on hover */
.btn-group button:hover {
    background-color: #a5a3a3;
}

button {
    outline-width: 0;
}

.btn-group {
    background-color: #808080;
    margin-left: 5px;
    float: left;
    position: relative;
}

.whiteboardTool.active {
    background: #bfbfbf;
}

#whiteboardThicknessSlider {
    -webkit-appearance: none;
    width: 100%;
    height: 10px;
    border-radius: 3px;
    background: transparent;
    outline: none;
    opacity: 1;
    -webkit-transition: opacity .15s ease-in-out;
    transition: opacity .15s ease-in-out;
}