Why does the template on Bitrix fall?

Question

1C-Bitrix

Good evening, the essence of the problem is as follows:
There is a combat site (on Bitrix), on which the made-up template works, everything is adequate. There was a task to fasten the template for the mobile version (yes, the basic template is not adaptive). I killed all day, I just can’t understand what the problem is - the layout just doesn’t stand up adequately, other component styles are called (it can be seen on the screenshots ).
Z.Y.
And here is the archive with the files
https://yadi.sk/d/uXEaNbvmFsRHmA
Help, good people

Answer 1

The problem was in the clumsy multi-site Bitrix. At the moment, everything is implemented through a symbolic connection to the /bitrix and /upload directories in a third-party folder. This course from Bitrix helped (if it doesn’t start, delete the site in the admin panel and add a new one, it’s not stable)
and also check the php version on the hosting
Thank you for your time

Answer 2

Maybe there is a bug in the code!

Answer 3

What was in the comments? I'm talking about generated html in general. Do you have styles there? Here are the three styles with the correct paths:
<?=SITE_TEMPLATE_PATH?>/css/swiper.min.css
<?=SITE_TEMPLATE_PATH?>/css/styles.css
<?=SITE_TEMPLATE_PATH?>/css/site.css
?
Why do you have 5 style files in your layout, but in the fact that you threw off only 3?
Where is your selectize and bootstrap connection?
Who pulled the layout?
UPD : Wang that the layout is not integrated into the template at all. A template was simply created with exactly the same layout as it was and its styles were replaced.