Some browsers do not render my page correctly. Why?

Question

css

I am writing a page with css and js inserts, all inserts are external.
In order not to describe the problem for a long time and incomprehensibly, I took a photo:

Here is the code:
HTML:

<p class="one">Пример</p>
<p class="one">Почему мы:
<ul>
   <li>Качество продукции для нас на первом месте.</li>
   <li>Более сотни успешных подключений..</li>
</ul>
</p>
<p class="one">Звоните!</p>

CSS:

p{
  font-family: Helvetica, Arial, sans-serif;
}

*I did not find anything else related to these paragraphs.*

Answer 1

Set file encoding to UTF-8 without BOM, in HTML in head set <meta charset="utf-8">.
If it does not help, then force your server to give the header Content-Type: text/html; charset=utf-8in any known way.