Bare `1fr` columns can collapse to near-zero on intermediate
viewports before the 48rem stacking breakpoint applies.

Closes #21

Assisted-by: Claude Opus 4.6 via Claude Code

diff --git a/public/css/app.css b/public/css/app.css
index 68a8349..345f6d6 100644
--- a/public/css/app.css
+++ b/public/css/app.css
@@ -89,7 +89,7 @@ h2 { font-size: var(--step-0); font-weight: 600; }
 
 .home {
   display: grid;
-  grid-template-columns: 1fr 1fr auto;
+  grid-template-columns: minmax(14rem, 1fr) minmax(14rem, 1fr) auto;
   align-items: start;
   gap: var(--space-xl);
   padding: var(--space-m) var(--grid-gutter);