If given the HTML input
<span>text</span>
<style>
body { color: blue; }
span {
border-width: 10px;
border-style: solid;
border-color: inherit;
}
</style>
The resulting svg does not include the given border definition:
<svg xmlns="http://www.w3.org/2000/svg" width="600" height="200" font-size="16px"><foreignObject x="0" y="0" width="600" height="200" style="float: left;"><html xmlns="http://www.w3.org/1999/xhtml"><head/><body><span>text</span>
<style>body { color: blue; }span { }</style></body></html></foreignObject></svg>
It is unclear wether inherit is an available options for color (MDN says so) but at least the other valid options should not be deleted.