如何使用纯css美化select？css美化select的代码实现

<h2>Cars Select</h2>
    <div class="select">
        <select name="cars">
            <option value="volvo">Volvo</option>
            <option value="saab">Saab</option>
            <option value="opel" selected>Opel</option>
            <option value="audi">Audi</option>
        </select>
    </div>

	body {
		font-size: 20px;
		color: #090;
		background-color: #eee;
		text-align: center;
	}
	.select {
		display: inline-block;
		width: 300px;
		position: relative;
		vertical-align: middle;
		padding: 0;
		overflow: hidden;
		background-color: #fff;
		color: #555;
		border: 1px solid #aaa;
		text-shadow: none;
		border-radius: 4px;	
		transition: box-shadow 0.25s ease;
		z-index: 2;
	}

	.select:hover {
		box-shadow: 0 1px 4px rgba(0, 0, 0, 0.15);
	}

	.select:before {
		content: "";
		position: absolute;
		width: 0;
		height: 0;
		border: 10px solid transparent;
		border-top-color: #ccc;
		top: 14px;
		right: 10px;
		cursor: pointer;
		z-index: -2;
	}
	.select select {
		cursor: pointer;
		padding: 10px;
		width: 100%;
		border: none;
		background: transparent;
		background-image: none;
		-webkit-appearance: none;
		-moz-appearance: none;
	}

	.select select:focus {
		outline: none;
	}