diff --git a/themes/tiddlywiki/vanilla/base.tid b/themes/tiddlywiki/vanilla/base.tid
index 112233016..087a8faa2 100644
--- a/themes/tiddlywiki/vanilla/base.tid
+++ b/themes/tiddlywiki/vanilla/base.tid
@@ -23,13 +23,9 @@ background-size:` {{$:/themes/tiddlywiki/vanilla/settings/backgroundimagesize}}`
 </$set>
 \end
 
-\define sidebarbreakpoint()
-<$text text={{$:/themes/tiddlywiki/vanilla/metrics/sidebarbreakpoint}}/>
-\end
+\function sidebarbreakpoint() [{$:/themes/tiddlywiki/vanilla/metrics/sidebarbreakpoint}]
 
-\define sidebarbreakpoint-minus-one()
-<$text text={{{ [{$:/themes/tiddlywiki/vanilla/metrics/sidebarbreakpoint}removesuffix[px]subtract[1]addsuffix[px]] ~[{$:/themes/tiddlywiki/vanilla/metrics/sidebarbreakpoint}] }}}/>
-\end
+\function sidebarbreakpoint-minus-one() [{$:/themes/tiddlywiki/vanilla/metrics/sidebarbreakpoint}removesuffix[px]subtract[0.02]addsuffix[px]] ~[{$:/themes/tiddlywiki/vanilla/metrics/sidebarbreakpoint}]
 
 \define if-fluid-fixed(text,hiddenSidebarText)
 <$reveal state="$:/themes/tiddlywiki/vanilla/options/sidebarlayout" type="match" text="fluid-fixed">