I want to know SHOULD I use these lines of code to include standard Joomla CSS rules?
<link rel="stylesheet" href="<?php echo $this->baseurl ?>/templates/system/css/system.css" type="text/css" />
<link rel="stylesheet" href="<?php echo $this->baseurl ?>/templates/system/css/general.css" type="text/css" />
We know that after the lines, we will of course override some of the rules using our own template specific CSS file like this:
<link rel="stylesheet" href="<?php echo $this->baseurl ?>/templates/<?php echo $this->template; ?>/css/template.css" type="text/css" />
IMPORTANT: Suppose that I don’t want to publish the template for everyone, and I will use it only on my special needs. So I will define necessary rules wherever there was a need.
With this assumption, should I still include the first two CSSs? and why?
If you don’t need the styles, there’s no reason to include the stylesheets. The worst that could happen is that you’d see some broken formatting and you’d have to fix it in your own css.