Select CSS

 

**** HTML

<select name="txt_quanhuyen" class="form-control my-box-shadow sl-district" required="">

<option value="">Quận/Huyện</option>

</select>

****CSS

.sl-district {

    background: url(../images/Icon-material-district.png) 8px 10px, url(../images/caret-select.png) right 20px bottom 14px;

    background-repeat: no-repeat;

    text-indent: 18px;

    appearance: none;  // không hiện dropdown truyền thống

}

.my-box-shadow {

    box-shadow: 0 3px 5px 0 rgb(0 0 0 / 16%);

}