fix(styles/respec.css): defer default styles to W3C

[marcoscaceres]

We should just let the W3C's base.css handle styling things on the page. That way we get consistent styling across all docs, and don't need to worry if base.css changes... and we can upstream styling issues to the W3C

Closes #4667

[sidvishnoi]

I think it should still be a breaking change, as the table.simple design changed? In case people are relying on that to be styled like this..

[tfrancart]

@marcoscaceres which additionnal CSS should we include to have our tables properly styled ? we use respec in a non-W3C spec (http://linked-statistics.github.io/xkos/xkos-best-practices.html) and that change broke our document. Thanks

[sidvishnoi]

@tfrancart Please add following CSS to your documents

/* --- TABLE --- */
table.simple {
  border-spacing: 0;
  border-collapse: collapse;
  border-bottom: 3px solid #005a9c;
}
.simple th {
  background: #005a9c;
  color: #fff;
  padding: 3px 5px;
  text-align: left;
}
.simple th a {
  color: #fff;
  padding: 3px 5px;
  text-align: left;
}
.simple th[scope="row"] {
  background: inherit;
  color: inherit;
  border-top: 1px solid #ddd;
}
.simple td {
  padding: 3px 10px;
  border-top: 1px solid #ddd;
}
.simple tr:nth-child(even) {
  background: #f0f6ff;
}