diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7dd4980c..483bd0b8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -37,6 +37,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- **Column resizing in `CustomTable`**: column widths are now propagated to body cells via CSS custom properties (`--header-{id}-size`) injected on the table wrapper, rather than reading `column.getSize()` directly in each cell's React style. This decouples body-cell widths from React renders so that memoized rows (which skip re-renders for performance) still reflect resize changes instantly via CSS cascade.
 - Decoupled row expansion from row selection in `CustomTable`, expanding a channel row no longer also selects it. Added an `onRowExpansionChange` callback to `useTable` so callers can react to expansion changes independently of selection state.
 - Fixed a stale-closure bug in memoized channel row checkboxes, `selectedTableIdsRef` now ensures the checkbox `onChange` handler and `handleShiftSelect` always read the current selection set rather than the stale set captured at render time. Without this, clicking any checkbox after the first would silently deselect previously checked rows.
 - Fixed the "Add to Channel" per-row and bulk buttons in the Streams table not activating when a channel row is expanded. `StreamRowActions` now subscribes to the Zustand store directly (bypassing `React.memo`) so button state updates when `expandedChannelId` or `selectedChannelIds` change without any parent row props changing. Added `targetChannelId` (expanded channel takes priority; falls back to a single selected channel) used by both the per-row and bulk add paths.
diff --git a/frontend/src/components/tables/CustomTable/CustomTable.jsx b/frontend/src/components/tables/CustomTable/CustomTable.jsx
index 55af4724..8b0a9f0c 100644
--- a/frontend/src/components/tables/CustomTable/CustomTable.jsx
+++ b/frontend/src/components/tables/CustomTable/CustomTable.jsx
@@ -27,6 +27,20 @@ const CustomTable = ({ table }) => {
     return width;
   }, [table, columnSizing]);
 
+  // CSS custom properties for each fixed-width column's current size.
+  // These are injected on the table wrapper and cascade to all descendant cells,
+  // so body cells (which are memoized and don't re-render on resize) still pick
+  // up the new width via CSS cascade without needing a React re-render.
+  const columnSizeVars = useMemo(() => {
+    void columnSizing;
+    return table.getFlatHeaders().reduce((vars, header) => {
+      if (!header.column.columnDef.grow) {
+        vars[`--header-${header.id}-size`] = `${header.getSize()}px`;
+      }
+      return vars;
+    }, {});
+  }, [table, columnSizing]);
+
   return (
     <Box
       className={`divTable table-striped table-size-${tableSize}`}
@@ -36,6 +50,7 @@ const CustomTable = ({ table }) => {
         minWidth: `${minTableWidth}px`,
         display: 'flex',
         flexDirection: 'column',
+        ...columnSizeVars,
       }}
     >
       <CustomTableHeader
diff --git a/frontend/src/components/tables/CustomTable/CustomTableBody.jsx b/frontend/src/components/tables/CustomTable/CustomTableBody.jsx
index 40fd5678..cae17e67 100644
--- a/frontend/src/components/tables/CustomTable/CustomTableBody.jsx
+++ b/frontend/src/components/tables/CustomTable/CustomTableBody.jsx
@@ -60,9 +60,9 @@ const MemoizedTableRow = React.memo(
                         }),
                       }
                     : {
-                        flex: `0 0 ${cell.column.getSize ? cell.column.getSize() : 150}px`,
-                        width: `${cell.column.getSize ? cell.column.getSize() : 150}px`,
-                        maxWidth: `${cell.column.getSize ? cell.column.getSize() : 150}px`,
+                        flex: `0 0 var(--header-${cell.column.id}-size)`,
+                        width: `var(--header-${cell.column.id}-size)`,
+                        maxWidth: `var(--header-${cell.column.id}-size)`,
                       }),
                   ...(tableCellProps && tableCellProps({ cell })),
                 }}
diff --git a/frontend/src/components/tables/CustomTable/CustomTableHeader.jsx b/frontend/src/components/tables/CustomTable/CustomTableHeader.jsx
index 8df6357a..0083abb4 100644
--- a/frontend/src/components/tables/CustomTable/CustomTableHeader.jsx
+++ b/frontend/src/components/tables/CustomTable/CustomTableHeader.jsx
@@ -117,9 +117,9 @@ const CustomTableHeader = ({
                         }),
                       }
                     : {
-                        flex: `0 0 ${header.getSize ? header.getSize() : 150}px`,
-                        width: `${header.getSize ? header.getSize() : 150}px`,
-                        maxWidth: `${header.getSize ? header.getSize() : 150}px`,
+                        flex: `0 0 var(--header-${header.id}-size)`,
+                        width: `var(--header-${header.id}-size)`,
+                        maxWidth: `var(--header-${header.id}-size)`,
                       }),
                   position: 'relative',
                   // ...(tableCellProps && tableCellProps({ cell: header })),