Please note that I am NOT using hex codes here. I am doing this to make it easier for purposes of this discussion.
The first thing you may notice is that the background color for this page is 'peachpuff'. This is an example where the external style says one thing (silver) and the internal says another (peachpuff). Remember that inline "beats" internal, and internal "beats" external.
Note that there is no reference to an h1 color here on this document. The color you see here is generated by the external stylesheet.
Note that the h3 color here is generated by the internal stylesheet.
Note that this h3 color is still the same color... This is an advantage of internal/external styles over inline styles. EVERY instance of the tag on the page displays using the styles indicated.
And yet, if we want to apply inline styles, we can. We can either add additional styles inline, and/or we can override styles from the internal/external stylesheets. In this case, we override the font from the internal style in favor of the one written in the inline style.