div organization inside a post

hello.
this is the site i am working on: BETA VERSION
When you look at the hmtl text of the first top post you see it contains:

– sticky (z-index5)
– my name + scénographie
– a gif animation.

i have desperately and naively tried to make this whole layout responsive !
– I want the white area (background) to be 100% height (on any medium)
– i want the animation to sit on the bottom, with a distance I define (the menu you see there will most likely vanish).
– i want my name to be centered vertically, for this i use many BR tags at the moment, as i do not know how to do so with div tag placing only.. i tried !

as you see, the result is crooked code ending up in weird layout on iPhone or other small device.

please help ?

thank you ??