multiselect.css

/**
 * GreenInfo Network MultiSelect
 * https://github.com/GreenInfo-Network/MultiSelect
 * Inspired from code by Allison Ravenhall https://codepen.io/a11yally/pen/vmXPMR
 */

div.multi-select {
    position: relative;
}

div.multi-select button {
    border: 1px solid #ced4da;
    width: 100%;
    border-radius: 2px;
    height: 2.5em;
    background-color: #fff;
    position: relative;
    text-align: left;
}

div.multi-select button span.multi-select-arrow-collapsed,
div.multi-select button span.multi-select-arrow-expanded {
  	display: inline-block;
  	border-right: 2px solid black;
	border-bottom: 2px solid black;
  	width: 10px;
  	height: 10px;

    position: absolute;
    right: 1em;
    top: 0.9em;
    color: #a8a8a8;
    transition: transform .1s ease-out, color .1s ease-out;
    font-size: 0.85em;
}
div.multi-select button span.multi-select-arrow-collapsed {
  	transform: rotate(45deg);
  	margin-top: -2px;
}
div.multi-select button span.multi-select-arrow-expanded {
  	transform: rotate(-135deg);
  	margin-top: 3px;
}

div.multi-select .multi-select-readout {
    color: black;
}

div.multi-select .multi-select-readout.multi-select--placeholder {
    color: silver;
}

div.multi-select fieldset {
    border: none;
    padding: 0;
    margin: 0;

    position: absolute;
    top: 2.2rem;
    left: 0;
    z-index: 1;
    background: white;
}

div.multi-select fieldset input[type="text"] {
    width: calc(100% - 20px);
    margin: 0 10px 5px 5px;
}

div.multi-select fieldset > div {
	padding: 0.5em 0;
}

div.multi-select fieldset legend {
    display: none;
}

div.multi-select fieldset input[type="checkbox"] {
}

div.multi-select fieldset {
    border: 1px solid #ced4da;
    width: 100%;
    border-radius: 2px;

    max-height: 1in;
    overflow-y: auto;
    overflow-x: hidden;
}

div.multi-select fieldset label {
    display: block;
    width: 100%;
    padding: 0 10px 0 5px;
}