did i understand correct, a page work on the desktop, but show a blank page on mobiles?
if YES, i think, it is a browser intern time out. Egde on a desktop has, for example, a timeout = one minute to start loading the page of for a stop, when its loading the content, if nothing happens in this time, you get a white screen, normalize with a message like Ups....,
in the spacial link from your post in the top, i think, it's too much work for the output filter - you can try to play with the outputfilter settings or deactivate something in modules/outputfilter/index.php (not recommendable)
CSStoHead is here the point. this filter try to move all <link> to css-files into the <head>Area of WB
another and better solution: i see it sometime's in older modules - a link to a css-file inside of the code in view.php like this
<link rel="stylesheet" href="style.css" />or this (somewhere in a functions.php etc)
echo "<link rel=\"stylesheet\" href=\"style.css\" />";
This method comes from times when a <link> in the content from the browser has not yet been criticized in HTML and is outdated now. you do not save anything with this method, because, you need this css, to display a special design
use here the frontend.css and @import-method instead of links inside of the output code in a module like
or add the css-definitions directly into the frondend.css-File
the logic behind... to show a special design, you need the css in every case. if your file has a size = 50kB, you load it - doesn't matter, how. (with import, with <link> or directly from frontend.css)
but with a <link>-methode inside of the <body>-code, you give the filter the job, to move it into the head area. not a big job, if you have only one, but if i look to the source from the link, it's maybe 50 or more <link> and thats needs a couple of time.
you know the structure of your project, you see, this code comes from module XY (directly or in a Iframe) - take a look into the view.php of this module(s) and the used files there like a functions.php and replace possible <link> there
P.S.: if you not use the default CSS-Definition from a module xy, you can put everything in a file called frontendUser.css (for frontend) or backendUser.css (for backend only) . these files are "private" user-files and will not be overwritten in an next possible upgrade of this module