css only minimum select

HTML

<div>
<label for="animals" class="select-group">
    <select id="animals" class="select">
        <option value="1">dog</option>
        <option value="2">cat</option>
        <option value="3">bear</option>
    </select>
</label>
</div>

CSS

.select-group
{
    position: relative;
    display: inline-block;
    overflow: hidden;

    box-sizing: border-box;
    width: 100%;
    padding: 0;

    vertical-align: middle;

    border: 1px solid #ddd;
    background-color: #fff;
    background-repeat: no-repeat;
}

.select
{
    position: relative;
    z-index: 1;  
  
    line-height: 1.8;

    display: block;

    width: 120%;
    padding: 0;

    text-indent: 8px;

    border: none;
    border-radius: 0;
    background-color: transparent;
    background-image: none;
    box-shadow: none;

    -webkit-appearance: none;
       -moz-appearance: none;
            appearance: none;
}

.select-group:after
{
    position: absolute;
    top: 0;
    right: 8px;
    bottom: 0;

    width: 0;
    height: 0;
    margin: auto;

    content: '▼ああああ';
    font-size: 36px;
}

div {
    width: 300px;
    height: 100px;
    padding: 10px;
    background-color: #eee;
}