"Her legs are long and this dress is too small for her."
Translation:У неё длинные ноги, а это платье ей мало.
I asked in a different thread if «мало» meant that something was insufficient, but was told it doesn't mean there's an insufficient amount, it means there's not a lot of something. EX: В Европе мало кошек (and this is much better than немного кошек)
However, here it seems that «мало» means insufficient since we say «платье ей мало» = too small.
In the first example is «мало» an adverb and in the second it's an adjective? Is this the key difference?