How do search engines react to the title of the site?

Question

HTML

The first question I would like to ask is whether it is advisable to use a double colon as a separator?
For example, DOMAIN::PAGE_TITLE? (Where DOMAIN is the title of the site and PAGE_TITLE is the title of the site)
The next question is how would it be more "pleasant" for search engines to see my title?
For example, we have a CATEGORY category and an ARTICLE article.
1. DOMAIN :: CATEGORY :: ARTICLE
2. DOMAIN :: ARTICLE
Which of these options is best?

Answer 1

It seems to me more logical to separate not with a colon but with a hyphen. And the order from particular to general is preferable. Because exactly the title will be visible in the search result. And the visitor is more interested in the title of the article than, say, the name of the site, and the entire concatenated string may not fit. Therefore, with your order, the most important part of the title will be lost.
ARTICLE - CATEGORY - DOMAIN