/(@[^@{};]+(?:;|(({(?:(?>[^{}"']+|\s+|"(?:\\\\|\\"|\\\n|[^"\n])*?"|'(?:\\\\|\\'|\\\n|[^'\n])*?')|(?-2))*})))|[^@{}\s][^@{}]*(({(?:(?>[^{}"']+|\s+|"(?:\\\\|\\"|\\\n|[^"\n])*?"|'(?:\\\\|\\'|\\\n|[^'\n])*?')|(?-2))*})))/su

【1】 @font-face{font-family:"Font Awesome 5 Free";font-style:normal;font-weight:400;font-display:block;src:url(../webfonts/fa-regular-400.eot);src:url(../webfonts/fa-regular-400.eot?#iefix) format("embedded-opentype"),url(../webfonts/fa-regular-400.woff2) format("woff2"),url(../webfonts/fa-regular-400.woff) format("woff"),url(../webfonts/fa-regular-400.ttf) format("truetype"),url(../webfonts/fa-regular-400.svg#fontawesome) format("svg")}
【2】 .far{font-family:"Font Awesome 5 Free";font-weight:400}