I'm afraid 2013 is gone and is not coming back
The article you mention is valid for HESK v2 (up to 2.8.10). In Hesk 3, the design had changed.
To modify the colors, you will need to modify the style files:
https://www.hesk.com/knowledgebase/?article=33
This indeed requires some CSS knowledge. I recommend that you get help of a designer if this is not your thing.
Also, you can fully customize the look in Hesk 3 by modifying the theme files:
https://www.hesk.com/knowledgebase/?article=102
Again, this requires some HTML/CSS knowledge.
If you don't use multi-language features, perhaps the easiest way to hide the title would be to just hide the entire .cust-help .header in the theme CSS by adding display:none to it.