changing Font, Image formatting and Drop shadow

So I’m not completely dumb when it comes to CSS, but definitely a Novice.
I’m using Twenty Ten theme

I’m trying to figure out a couple of things:

1- the code and location to put a drop shadow between the main page and background
i.e – https://lauralesliephotography.com/blog/
2- how can i set all the text in the post to a different font? i want geosans light, i believe.
3- How can i get my images to pop up at their intended size (already checked the max size per column and they are sized appropriately) to sit on top of each other without having to click each individual image? – Or, one or two main images at full-size then a “read entire post” where they can all be seen as a whole ?
i.e.- https://lauralesliephotography.com/blog/

Here is the link to my blog:

https://www.pridefulengagements.com/blog

Thanks so much !