Sort of a rudimentary question, so I apologize in advance. Just curious what the
A mean and maybe more broadly, are there any design implications I should be considering in relation to the meaning. Like, does
A denote that it is an accent color?
They are used for 'accent' colors.
See this video, which explains the number system, all the way to the A (accent) colors. It's an approach to build the proper amount of harmony and contrast where needed.
500 series colors are considered 'Primary' and scales from there to lighter or darker colors. Used for the dominant theme in your UI.
700 series is recommended for elements like status bars.
300 series for secondary info elements.
A series colors are designed to indicate interaction. They recommend this series for highlighting primary action buttons. They describe them as giving a 'pop' of color.