从Opera中的选择下拉列表中删除标准箭头

Question

我正在尝试隐藏选择下拉列表中的标准箭头。

我已经为所有浏览器解决了这个问题，但仍然无法为Opera删除或隐藏它。

我需要JS或CSS desicion。任何黑客都会很好！

HTML

<div class="field select-field">
    <select id="pre_order_form_order_type" class="form-control">
        <option value="">Select Type of paper</option>
        <option value="1">Essay (any type)</option>
        <option value="2">Admission Essay</option>
        <option value="3">Annotated Bibliography</option>
    </select>
</div>

CSS

.select-field {
        background: url(images/arrow.png) no-repeat right #e6e7e9;
        position: relative;
        overflow: hidden !important;
        border-radius: 6px !important;
        display: inline-block !important;
    }

    select::-ms-expand {
        display: none;
    }

    .select-field select {
        cursor: pointer;
        overflow: hidden;
        -webkit-appearance: none;
        -moz-appearance: none;
        -o-appearance: none !important;
        -ms-appearance: none;
        appearance: none;
        text-indent: 1px;
        text-overflow: '';
        z-index: 10;
    }