̟ PLUS SIGN BELOW UTF-8 character with hex code 031F

Using HEX code of PLUS SIGN BELOW in HTML file

<span> &#x031F; </span>

Using Decimal code of PLUS SIGN BELOW in HTML file

<span> &#799; </span>

Using HEX code of PLUS SIGN BELOW in CSS file for content

span { 
    content: '\031f';
}