.frm{top:-.16em;right:-.16em;bottom:-.16em;left:-.16em;color:red;filter:hue-rotate(180deg)}
.frm:after{border:solid .04em;background:
url(../mask/corner4a.svg)0 0/.8em border-box,
url(../mask/corner4b.svg)100% 0/.8em border-box,
url(../mask/corner4c.svg)100% 100%/.8em border-box,
url(../mask/corner4d.svg)0 100%/.8em border-box;
background-repeat:no-repeat;
filter:drop-shadow(0 0 .2px)brightness(.7)url(#lightA2)
}