fix: add bottom spacing to the top-level @since tag

The "Added in" tag on top-level symbols (classes, interfaces, enums,
type aliases) is followed by other sections, so without a bottom margin
it sat flush against the next block. Add a `tsd-comment-since-root`
modifier with a bottom margin for that case only; member tags close out
a panel and are left untouched.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: barjin

src/components/Reflection.tsx

@@ -34,7 +34,7 @@ export function Reflection({ reflection }: ReflectionProps) {
 			{hasComment(reflection.comment) && <Comment root comment={reflection.comment} />}
 
 			{sinceContent && (
-				<div className="tsd-comment-since">
+				<div className="tsd-comment-since tsd-comment-since-root">
 					<Markdown content={displayPartsToMarkdown(sinceContent)} />
 				</div>
 			)}

src/components/styles.css

@@ -199,6 +199,12 @@ html[data-theme='light'] .tsd-panel-content {
 	border-top: 1px solid rgba(0, 0, 0, 0.05);
 }
 
+/* Top-level symbols render the tag inline above other sections, so it needs a
+   bottom margin to sit evenly; member tags close out a panel and don't. */
+.tsd-comment-since-root {
+	margin-bottom: 1em;
+}
+
 .tsd-comment-root {
 	margin-top: 0;
 	margin-bottom: var(--tsd-spacing-vertical-full);