On the dashboard where are the original stylesheets or style located? So that you can copy and edit the styles you want???
They are located in the Edit link next to "Mode: Add-on" on the right side of the Appearance → Custom Design → CSS page. However, note that you can also use browser tools to look at CSS and it often makes it even easier to work with the styles to find what you're looking for. Most modern web browsers have a web inspector. To try it out, right-click on an element on a page and look for an option called "Inspect Element." When you click that, it will show you the HTML for what you clicked on as well as all of the CSS that applies to that HTML, including the rules that have been overridden and what order they were applied. It's the best way to find specific CSS rules. The original stylesheet is also handy sometimes, but I find that a web inspector is indispensable. In addition to the link inside the WordPress.com CSS page, note that most (almost all) websites also have their stylesheets linked in the "head" section of the HTML if you view the page source.
We're trying to encourage using browser tools and viewing page source instead of looking at the theme's stylesheet in the dashboard because often beginners will copy and paste the entire stylesheet from there and that tends to cause more problems for them. If you copy original styles from the original theme CSS, you need to know what you're doing to make everything work. You should not copy and paste the entire stylesheet into the CSS editor.