.must-icon{
    position: relative;
}
.must-icon::before {
	content: "必須";
    display: inline-block;
	color: #fff;
    background-color: #b92222;
	padding: 0.1rem 0.8rem;
    margin-right: 0.4rem;
	font-size: 0.7rem;
    vertical-align: text-top;
}