1 files changed, 16 insertions, 0 deletions
diff --git a/src/content/style.css b/src/content/style.css
index df82637..1232457 100644
--- a/src/content/style.css
+++ b/src/content/style.css
@@ -248,6 +248,22 @@ pre.lineno {
   background-color: var(--color-code-bg);
 }
 
+/* A line wider than the page scrolls inside the box that frames it.
+   Saying so on the pre alone is not enough: the line numbers sit in a
+   table cell beside the code, and a table grows to fit what it holds,
+   so the pre is never narrower than its longest line and never has
+   anything to scroll.  The box scrolls instead, and the numbers stay
+   where they are while the code moves under them. */
+.highlight, .listingblock .content {
+  overflow-x: auto;
+}
+
+.listingblock td:first-child {
+  position: sticky;
+  left: 0;
+  background-color: var(--color-code-bg);
+}
+
 pre {
   overflow: auto;
 }