observanteen- I do not expect to find written in the Torah “every detail of untznius clothing”. However I DO want to know if there are sources for covering knees and elbows and toes. Like you said, tznius is a sensitivity and maturity. Therefore I try not to attract attention to myself, and I do not expose 90% of my body like a non-Jew would. But I have a hard time understanding why my toes, knees and elbows must be covered.
Personally I think these guidelines were instituted as gedarim (please tell me if I am wrong) but are they as serious as gedarim on hilchos shabbos (muktzah), or are they more lenient like the gedarim between an engaged couple (only speak every other day)?
If someone would show me a source for these guidelines, I (and I think many other women) would have an easier time dressing accordingly.