ames:
Wearing pants & sneakers under your skirt may be normal where you live & therefore Tzanuah. Without a location (please don’t give it:) there is no way to know.
aussieboy & SJS:
First prove that women have Tznius (Legabey other women). They do not (as long as they are not showing Ervah (lower) MB 75:8. Women only have Tznius OUTSIDE (R. E. Falk argues) due to Daas Moshe V’Yehudis, but no specific MITZVA per say (MB 75:10) to the best of my knowledge, or from what the MB seems to say (Of course there is a requirement to follow Da’as Moshe V’Yehudis). Men HAVE TO not look at women, either for Han’nah or while reading Shema (and the sort).
R. E. Falk says that women have to be Tzanuah indoors so that men who are inside will not be nichshal to make a brocha before them, but the mekor he brings (MB 75:10) says nothing of the sort. If anyone has a mekor….