diff --git a/frontend/src/views/ProjectView.vue b/frontend/src/views/ProjectView.vue
index 4dd1bd0..f3047ec 100644
--- a/frontend/src/views/ProjectView.vue
+++ b/frontend/src/views/ProjectView.vue
@@ -956,13 +956,25 @@ async function confirmDelete() {
 .stat-notes     { background: color-mix(in srgb, var(--color-primary) 8%, transparent); color: var(--color-primary); border-color: color-mix(in srgb, var(--color-primary) 22%, transparent); }
 
 /* ── Two-column body ─────────────────────────────────────────── */
+/* `minmax(0, 1fr)`, not `1fr`. A bare `1fr` track has an AUTO minimum, so it
+   cannot shrink below its content — one wide descendant anywhere in the
+   content column widens the whole column past the grid, and everything inside
+   it then overflows the page and gets cut by `.project-view`'s
+   `overflow-x: clip`.
+   This is the same property the header nav relies on and wants (neither side
+   squeezed under its content); here it is exactly wrong, because the column
+   holds a kanban whose own tracks push outward. `min-width: 0` on the item is
+   the twin half — a grid item's default `min-width: auto` refuses to shrink
+   even when its track will. */
 .project-body {
   display: grid;
-  grid-template-columns: 248px 1fr;
+  grid-template-columns: 248px minmax(0, 1fr);
   gap: 1.25rem;
   align-items: start;
 }
 
+.content-area { min-width: 0; }
+
 /* ── Edit panel ──────────────────────────────────────────────── */
 .edit-panel {
   background: var(--color-bg-card);
@@ -1190,7 +1202,10 @@ async function confirmDelete() {
 /* ── Kanban ──────────────────────────────────────────────────── */
 .kanban {
   display: grid;
-  grid-template-columns: repeat(3, 1fr);
+  /* Same reason as .project-body: three auto-minimum tracks add up to more
+     than the column when a card title or a column header won't compress, and
+     the excess pushes the whole milestone card wider than the page. */
+  grid-template-columns: repeat(3, minmax(0, 1fr));
   gap: 0.75rem;
   align-items: start;
   padding: 0.75rem;