タグが見切れる問題対応 (#76) (#395)

Reviewed-on: http://git.miteruzo.com/miteruzo/btrc-hub/pulls/395

frontend/src/index.css

@@ -132,3 +132,20 @@ body
   0%, 100% { color: #f87171; }
   50% { color: #60a5fa; }
 }
+
+.tag-marquee
+{
+  position: relative;
+}
+
+.tag-marquee__animated
+{
+  position: absolute;
+  inset: 0 auto 0 0;
+  min-width: 100%;
+  width: max-content;
+  opacity: 0;
+  pointer-events: none;
+  white-space: nowrap;
+  will-change: transform;
+}