fix(front): layout for section in explore page

front/ui-docs/components/ui/layout/section.md

@@ -121,7 +121,14 @@ Sections divide the page vertically. Choose an appropriate heading level for eac
 
 ### Make the section header align with the section contents
 
-Do you want to align the header to no, tiny, small or medium items?
+The section aligns its title and items to a grid, following the designs. To make sure the header of a section exactly aligns with its contents, set the item width:
+
+Do you want to align the header to
+
+- `no-items` (mixed content),
+- `tiny-items` (each item is one column wide),
+- `small-items` (each item is two columns wide, e.g. default cards),
+- `medium-items` (each item is three columns wide, such as Activities or medium cards)?
 
 If all items stretch all columns (`style=grid-column: 1 / -1`), use `no-items`.