diff --git a/src/generate_repo_overview/templates/styles.css b/src/generate_repo_overview/templates/styles.css
index 0206bcf..42cde22 100644
--- a/src/generate_repo_overview/templates/styles.css
+++ b/src/generate_repo_overview/templates/styles.css
@@ -410,6 +410,8 @@ th[data-tooltip]::after, td[data-tooltip]::after {
   text-transform: none;
   letter-spacing: 0;
   padding: 0.5rem 0.85rem;
+  /* Keep hidden tooltips from becoming very tall scrollable overflow on narrow cells. */
+  width: min(32rem, calc(100vw - 2rem));
   max-width: min(32rem, calc(100vw - 2rem));
   white-space: pre-line;
   overflow-wrap: anywhere;
diff --git a/tests/test_policy_sync.py b/tests/test_policy_sync.py
index cc19389..0b13dfc 100644
--- a/tests/test_policy_sync.py
+++ b/tests/test_policy_sync.py
@@ -332,6 +332,7 @@ def test_policy_sync_matrix_compacts_long_policy_columns() -> None:
     assert "table-layout: fixed;" in page
     assert "overflow-wrap: anywhere;" in page
     assert "white-space: normal;" in page
+    assert "width: min(32rem, calc(100vw - 2rem));" in page
     assert "minimum-bazel-version" in page