This should be white on black underlined italic cursive, i.e. basically the same outcome as if this document and sibling files contained

/* style element content: */ @import url("a.css"); body { font-family: cursive; }
/* a.css file content: */ @import url("b.css"); body { background-color: black; }
/* b.css file content: */ @import url("c.css"); body { color: white; }
/* c.css file content: */ @import url("d.css"); body{ text-decoration: underline; }
/* d.css file content: */ body{ font-style: italic; }