diff --git a/landing/src/app/ui/_detail.scss b/landing/src/app/ui/_detail.scss
index f74472d..4954810 100644
--- a/landing/src/app/ui/_detail.scss
+++ b/landing/src/app/ui/_detail.scss
@@ -32,6 +32,10 @@
 // ending in a dead end.
 .content-page__layout {
   display: grid;
+  // One column below the desktop layout, and one that may shrink: an
+  // implicit `auto` track grows to its widest line, and a code block in a
+  // post pushed the whole text past the edge of a phone.
+  grid-template-columns: minmax(0, 1fr);
   gap: 3rem;
   padding-bottom: 5rem;