Challenge: Classes of elements

Make more specific rules

This webpage describes one classification of elements in the periodic table: metals, non-metals, and semi-metals.
It uses classes to color those words, both in the top paragraph and the headings. Add three more rules to style the headings to add a border-bottom that's the same color as the text color (so that the 'Metals' heading has a red border, 'Non-metals' has a blue border, and 'Semi-metals' has a purple border). The border should not apply to the <strong> tags.