[web-animations-1] Copy a bunch of styles from web-animations.css to Overview.bs

Whatever builds the spec for us on csswg-drafts seems to be dropping our
header.include so web-animations.css doesn't get included.

Author: birtles

web-animations-1/Overview.bs

@@ -1,5 +1,70 @@
-<h1>Web Animations</h1>
+<style type="text/css">
+.informative-bg {
+  margin: 1.5em 0 1em;
+  padding: 1em;
+  margin-top: 1em;
+  background: #efe;
+  border: green 1px dotted;
+}
+
+div.informative-bg *:last-child {
+  margin-bottom: 0;
+}
+
+div.informative-bg p:first-child {
+  margin-top: 0;
+}
+
+div.informative-bg h2,
+div.informative-bg h3,
+div.informative-bg h4 {
+  background: none;
+}
+
+div.switch > dl {
+  padding-left: 2em;
+}
+
+div.switch > dl > dt > p {
+  display: inline;
+}
+
+div.switch > dl > dt:before {
+  content: '\21AA';
+  padding: 0 0.5em 0 0;
+  display: inline-block;
+  width: 1em;
+  text-align: right;
+  line-height: 0.5em;
+  margin-left: -1.3em;
+}
+
+.attributes::before, .methods::before,
+.parameters::before, .exceptions::before,
+.constructors::before, .members::before {
+  font: bold 100% sans-serif;
+  text-align: left;
+  margin: 1.33em 0px;
+  color: #005A9C;
+}
+
+.attributes::before { content: 'Attributes' }
+.methods::before { content: 'Methods' }
+.parameters::before { content: 'Parameters' }
+.exceptions::before { content: 'Exceptions' }
+.constructors::before { content: 'Constructors' }
+.members::before { content: 'Dictionary members' }
+
+.param,
+.exceptionname,
+.estype,
+.esvalue {
+  font-weight: bold;
+}
+</style>
+
 <pre class='metadata'>
+Title: Web Animations
 Status: ED
 Work Status: Refining
 Shortname: web-animations