[SOLVED] Use custom stylesheets in the checkout

I have updated to the latest LC 2.2.11 my custom template (as you suggested in my last post) but I can't force my styles to the pages that handle the checkout procedure. 
It seems that the style sheets I have worked in (app.css - framework.css - variables.less) no have effect on those checkout pages. 
I also notice the presence of style sheets (.min.css and .min.css.map) that aren't present in the default.catalog. And although these min files aren't present, if I use the default template, my e-shop works correctly. But if I delete these files from my custom.catalog, the checkout pages don't work.

Can you clarify for me how to move?
How can I make my custom stylesheet working on these checkout pages?

During your upgrade, did you choose ".css" or ".less + .min.css" ?

I didn't make any choice and left the default upgrade procedure. Frankly speaking, I never changed the settings proposed by the automatic procedure.

I continued the customization on my shop style but I had to put my hand to all the CSS, as well as on the less.

very likely you need this

https://www.litecart.net/en/addons/163/developer-kit

Thanks for the suggestion jsl and partial explanation of these compressed files.
In these first answers I can so deduce that a part of LC (home and product pages) uses the simple style sheet while a second part (checkout and order) instead gives prevalence to compressed .min files.

In my custom style interventions, I always try to be as less invasive as possible and may prefer to use a simple personalized style sheet, which I always use well commented on in a single position (in bottom of the app.css file).

So I have this question for Tim:
Considering that it's seems possible to choose whether or not to activate these .min compressions, I ask if this setting is variable even after installation,  to avoid the use of the compressed style sheets (without the use of .min files).

The default option in later versions is that LiteCart makes the default template use .css only. During install and upgrade you have an option to choose .less + .min.css. There is no such option after installation. You would simply have to upload the template again and edit the paths inside the layouts of which one to use.

Then I'll wait for your next upgrade and won't set this compressor option. After that I will see how LC will behave and continue with the adjustment.

It would be nice if it were possible to provide a custom.css by design in the next LC versions, as is now available in many other CMS platforms.

It is possible you are overcomplicating it. Why not just implement custom.css? It's just a line in the layout you need to add.
https://github.com/litecart/litecart/blob/dev/public_html/includes/templates/default.catalog/layouts/default.inc.php

<link rel="stylesheet" href="/path/to/your/custom.css" />

Of course I had thought of that too (would be the best setting to make any future adjustments easier). But I came across the style .min compression system. If the LC updates could also see the custom templates without overwriting the personalized style changes (i.e. an integrated procedure), that could be a great idea in my opinion. But of course that's just my thought.
In the next update I will follow your advice and choose the simple CSS option during installation. Then I'll add a separate stylesheet and make any style corrections. Very thanks for your support!

custom.css is a solution I sometimes use myself. It's nice to have all overrides in a separate file that is not overwritten.
It hasn't been implemented because it's so simple to add.

I made the latest update by choosing simple installation - with only the use of css. I didn't choose the development option.
However, I noticed that without the min files the printing of the order loses the style settings. I think there are parts that still use some of these min files.

The demo uses CSS only. Can you reproduce the problem there?

My test I took is simple. I created an order and clicked on the "click here for a printable copy"; with and without the .min files. As you can see, without these files the style is lost.

Not able to reproduce. That looks like a custom template.
If so make sure your layouts are accessing the right css file.

Reading the printable copy page source code, the page looks for the min style sheets:

...
<link rel="stylesheet" href="/litecart/includes/templates/custom.catalog/css/framework.min.css" />
<link rel="stylesheet" href="/litecart/includes/templates/custom.catalog/css/printable.min.css" />
<link rel="stylesheet" href="/litecart/ext/fontawesome/font-awesome.min.css" />```
and I haven't touched any part of the core code.

"custom.catalog" <------
LiteCart don't go rewriting custom templates.

[quote]That looks like a custom template.
If so make sure your layouts are accessing the right css file.[/quote]

Thanks for your tips Tim! I found the issue.
As I cloned the template folder (for the creation from my custom template) obviously I had installed in developer mode (with the use of .min files). In fact, I found the references of files in the \layouts folder that pointed to these formats. After correcting these two lines of code (in the 4 .php files), pointing to the .css, now the printable copy works correctly and the style is respected.
Have a good weekend Tim!