Update guidance on <hr> styling (mdn#42708)

* Update guidance on <hr> styling

* Update index.md

Co-authored-by: Chris Mills <chrisdavidmills@gmail.com>

* Another small tweak

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Co-authored-by: Chris Mills <chrisdavidmills@gmail.com>

Author: pepelsbey

files/en-us/web/html/reference/elements/hr/index.md

@@ -37,7 +37,9 @@ hr::after {
 }
 ```
 
-Historically, this has been presented as a horizontal rule or line. While it may still be displayed as a horizontal rule in visual browsers, this element is now defined in semantic terms, rather than presentational terms, so if you wish to draw a horizontal line, you should do so using appropriate CSS.
+Historically, the `<hr>` element has always been presented as a horizontal rule or line. While it may still be displayed as a horizontal rule in visual browsers, this element is now defined in semantic terms, rather than presentational terms. Therefore, if you wish to draw a horizontal line, you should do so by adding a border to an existing element using CSS.
+
+The `border-*` properties (for example, {{cssxref("border-style")}} and {{cssxref("border-color")}}) allow you to significantly customize a line's appearance, whether you are customizing an `<hr>` element or a border drawn on a different element.
 
 ## Attributes