{#if $request.isMobile}}
This is mobile specific title
{{/if}}
====== How to add desktop specific code ? ======
{{#unless $request.isMobile}}
This is desktop specific heading
{{/unless}}
If you want to use if/else condition for mobile detect, you should use it like follow.
{{#ifeq $request.isMobile 'true'}}
How to add mobile specific code ?
This is mobile specific title
{{else}}
How to add desktop specific code ?
This is desktop specific title
{{/ifeq}}