add_filter( 'avf_google_heading_font',  'avia_add_heading_font');
function avia_add_heading_font($fonts)
{
$fonts['Roboto'] = 'Roboto:400,600&subset=latin,latin-ext';
return $fonts;
}

add_filter( 'avf_google_content_font',  'avia_add_content_font');
function avia_add_content_font($fonts)
{
$fonts['Roboto'] = 'Roboto:400,600&subset=latin,latin-ext';
return $fonts;
}

On the last line of functions.php

A little problem still persists – padding on top of the logo is ok, on the bottom, there is still some padding.

1st problem solved.
2nd problem – this does not solve the problem.

Resolved. Thank you.

Problem is with compatiability with WPML. This is a big problem which should be fixed asap.