input[type="checkbox"] {
display: none;
}
span:before {
font-family: "FontAwesome";
font-style: normal;
content: 'O';
margin-right: 3px;
font-size: 30px;
}
input[type="checkbox"]:checked ~ span:before {
content: 'Z';
}
<label>
<input type="checkbox"/>
<span>Text</span>
</label>
如果添加'頂:5px的; position:relative;'to'span:before'it should llok well – Banzay