format of date field in search box

hello 7th queen,

I recently got a problem on search form.

format of birthday is kinda weird! day in one line, month in one line and year in separate line. (pic.jpg in attachment)

I tried to make width’s of them 30% so they can be all next each other at least!

but the result was boxes with less width, but yet day in one line, month in one line under it and year in another line under month! (pic2.jpg in attachment)

i will send u what i see in the attachment for better understanding

how can i reset it to original format? what happen to it?! all of my customizing css are empty!!!

thank you