Fix full screen background

themes/tiddlywiki/seamless/base.tid

@@ -1,5 +1,6 @@
 title: $:/themes/tiddlywiki/seamless/base
 tags: [[$:/tags/stylesheet]]
+list-after: $:/themes/tiddlywiki/vanilla/base
 
 \rules only filteredtranscludeinline transcludeinline macrodef macrocallinline
 
@@ -91,6 +92,10 @@ html body.tw-body {
 	background-color: <<colour background>>;
 }
 
+html:-webkit-full-screen {
+	background-color: <<colour background>>;
+}
+
 /* Adjust the colour of the page controls */
 body.tw-body .tw-page-controls svg {
 	fill: <<colour muted-foreground>>;

themes/tiddlywiki/vanilla/base.tid

@@ -27,6 +27,10 @@ html {
 	text-rendering: optimizeLegibility; /* Enables kerning and ligatures etc. */	
 }
 
+html:-webkit-full-screen {
+	background-color: <<colour page-background>>;
+}
+
 body.tw-body {
 	font-size: {{$:/themes/tiddlywiki/vanilla/metrics##fontsize}};
 	line-height: {{$:/themes/tiddlywiki/vanilla/metrics##lineheight}};