diff --git a/src/pyj/read_book/view.pyj b/src/pyj/read_book/view.pyj
index 984d505566..21109153cd 100644
--- a/src/pyj/read_book/view.pyj
+++ b/src/pyj/read_book/view.pyj
@@ -152,22 +152,26 @@ def show_controls_help():
 # }}}
 
 
-def maximum_font_size():
-    ans = maximum_font_size.ans
+def body_font_size():
+    ans = body_font_size.ans
     if not ans:
         q = window.getComputedStyle(document.body).fontSize
         if q and q.endsWith('px'):
             q = parseInt(q)
             if q and not isNaN(q):
-                ans = maximum_font_size.ans = q
+                ans = body_font_size.ans = q
                 return ans
-        ans = maximum_font_size.ans = 12
+        ans = body_font_size.ans = 12
     return ans
 
 
+def header_footer_font_size(sz):
+    return min(max(0, sz - 6), body_font_size())
+
+
 def margin_elem(sd, which, id, onclick, oncontextmenu):
     sz = sd.get(which, 20)
-    fsz = min(max(0, sz - 6), maximum_font_size())
+    fsz = header_footer_font_size(sz)
     s = '; text-overflow: ellipsis; white-space: nowrap; overflow: hidden'
     ans = E.div(
         style=f'height:{sz}px; overflow: hidden; font-size:{fsz}px; width:100%; padding: 0; display: flex; justify-content: space-between; align-items: center; user-select: none',
@@ -782,8 +786,8 @@ class View:
             extra = (tw - max_text_width) // 2
             margin_left += extra
             margin_right += extra
-        set_css(document.getElementById('book-top-margin'), height=margin_top + 'px')
-        set_css(document.getElementById('book-bottom-margin'), height=margin_bottom + 'px')
+        set_css(document.getElementById('book-top-margin'), height=margin_top + 'px', font_size=header_footer_font_size(margin_top) + 'px')
+        set_css(document.getElementById('book-bottom-margin'), height=margin_bottom + 'px', font_size=header_footer_font_size(margin_bottom) + 'px')
         def side_margin(which, val):
             m = document.getElementById('book-{}-margin'.format(which))
             if which is 'left':
@@ -969,6 +973,7 @@ class View:
                 sd.set('controls_help_shown_count' + ('_rtl_page_progression' if rtl_page_progression() else ''), c + 1)
 
     def preferences_changed(self):
+        self.set_margins()
         ui_operations.update_url_state(True)
         ui_operations.redisplay_book()