For some reason that WP theme has a font size for the container at zero. Simple:Press uses whatever the container size is as the main size for it’s fonts. It does so by using font-size:100%.
In your case 100% of zero is zero.

You would need to change the font-size to a specific number.

You are using the silver.php overlay. You would need to go into that file and change

$mainFontSize            = ‘100%’;

to something like

$mainFontSize            = ’14px’;

You should have a custom theme though once you start making changes. See http://codex.simple-press.com/codex/themes/theme-basics/creating-a-theme/ on hot to or https://simple-press.com/custom-simplepress-themes-for-every-need/ on how to get one made.

Thank you so much! It helped.

It remains only to stretch the forum on the whole width of the page. There is currently no. Although the page settings specified – “Full-wigth Page (Default)”.

Good deal. I had a feeling you were going to ask about the width.
Try adding this to to your theme’s main php file. IE: default.php

#container #spMainContainer {
display: block !important;
}

added to – /sp-resources/forum-themes/default/styles/default.php

but it does not work

I just went to your site and I see it’s now full width but still not showing the text.

Which isn’t working for you now? The text or the width.

Also, just as a reminder, you are making changes in the default theme. Without a custom theme these changes will all be overwritten when you update.

Thanks, it works!

Despite the fact that the support of the theme, said that it is impossible to do

I love SImple:Press!

Even better !