3 exciting questions.. Theme reset | custom css | layout creation/reuse

1. Theme reset:

I am really starting to get my head round the themes (yay!) - basically by binning the mess I made yesterday and changing theme - is there a reset button anywhere on the themes? if I do mess about so I can put the theme back to the default settings?

2. Adding custom css:-

I cannot get any custom css added to be picked up - so if I add a text element, create a new preset, click custom css>click on edit preset - then add a font colour to the box in the footer - it just doesn't pick up - I am struggling a little to know what class to use so that it does - i.e if I name my newpreset - whitetext

do I then enter #whitetext{color:#ffffff; } to get this picked up? I am so used to picking up the class and adding custom css in when building sites ( I use the bytesforall themes or elegant themes divi)

If I can get this going I will be cooking !

3. Creating your own layout

Also is there anyway to create your own layout with the themes and save it to be used again.

I can see how to create and set global regions, but not how to create a new layout that I can then add to pages and then amend.

So if I create a particular layout I can then apply this to a certain page?

I.e I create a page with a global header/slideshow/text/ 3 widgets/footer

I then want to use this exact same layout on another page.

I know the global elements will come through (header/menu/footer) - but how do I get the text box/3widgets to also come through to be used on another page?

Thanks again.