.frm{color:#603;top:-.25em;right:-.25em;bottom:-.25em;left:-.25em}
.frm:before{border-width:.25em;filter:url(#rainbow)url(#diffused1)contrast(1.5)}
.frm p:after{background:
linear-gradient(to bottom left,transparent 49%,currentColor 50%,transparent 51%),
linear-gradient(to bottom right,transparent 49%,currentColor 50%,transparent 51%)100% 0,
linear-gradient(to left bottom,transparent 49%,currentColor 50%,transparent 51%)100% 100%,
linear-gradient(to right bottom,transparent 49%,currentColor 50%,transparent 51%)0 100%;
background-repeat:no-repeat;background-size:.25em .25em}