JSFiddle - React, Tailwind, and code Playground

HTML

<select multiple>
	<option>Opt 1</option>
	<option>Opt 2</option>
    <option>Opt 3</option>
</select>

CSS

/* Select-Box mit geänderter Hover-Farbe */
option:hover {
	background-color: rgba(0,190,255, .5);
}

/* Das gleiche etwas hübscher: */
/*
*{margin: 0; padding: 0;}body{width: 50%; margin: auto;line-height: 1.5em;font-size: 1.05em;background-color: rgba(35,35,35, 1);font-family: 'Avenir Light',Arial,sans-serif;}

select,
option {
	padding: 5px;
	width: 100%;
	border-radius: 4px;
	background-color: rgba(255,255,255,.1);
	border: none;
	color: rgba(255,255,255, .6);
    margin-top: 15px;
}
option {
	width: 100%;
	-webkit-box-sizing: border-box;
	-moz-box-sizing: border-box;
	box-sizing: border-box;
	margin-top: 3px;
}

option:hover {
	background-color: rgba(0,190,255, .5);
	color: rgba(255,255,255, 1);
	transition: all 0.4s;
}
option:focus {
	background-color: rgba(255,255,255, .03);
	color: rgba(255,255,255, 1);
	transition: all 0.3s;
}
*/