Try this for starters:
Code:
#loginDefault>fieldset {margin-top: 9em; padding: 0 2em; border-radius: 2em; border: none; background: #8899ff; height:21em;}
#loginDefault>fieldset>legend {margin: 4em 0 0 0; background: transparent; font-size: 1.7em;}
#loginDefault>fieldset>form>input {border-radius: 0.7em;}
Adjust to taste.

It looks like you are currently making edits, as I just saw the font size jump, so your effect may be different from what I was playing with.