Landing sign in/sign up page

EvalDB

It allows company/club members to provide private feedback on any topic (project)

evaldb.com

Feel free to checkout current website http://evaldb.com. It is built
with the help of latest Bootstrap CSS default theme. Though the theme
look nice by itself the website - not so much yet. I'm open to any
suggestions. My only desire is that it should be beautiful, pleasure
to look at, inviting, it can be nice/warm.

http://localizerr.com
Nice view. However usability is way worse since signin/signup fields are not shown on landing page.

http://facebook.com
(Log out to see it :) ) I like the fact that it is very much usable concise and professional. However, it does not look inviting (if you don't know what you are doing) and description of what it does does not standout enough to catch attention.

http://grubhub.com
Warm, personal, inviting. However a bit overloaded with colors and flashy graphics.

It must be mobile friendly. I would even say mobile first, since target audience mostly use it on mobile. I.e. it must be responsive with most emphasis on mobile version.

It must have:
1. Sign in fields;
2. Sing up fields;
3. Currently missing links to "Who we are" page, "Privacy policy" page, "Contact us" page, etc.

It probably should have logo/header, since all other pages do. I'm open to different versions here.

It must be responsive with most emphasis on mobile version.
It should be very clear on what actions can be taken on the page and
how (like on facebook page) and it also should communicate the
purpose
of the site clearly (might be with pictures as well as text?).
To get the idea what this site is about try sign up, join evaldb.com
or Test company create topic for me (Artem) and give some feedback.
Site is currently already being used.

Design should be clean and unclattered.

Design should be contrast enough to users to see contents without
efforts.

There should be 2 versions (mobile/desktop) of the same responsive
page.

The mobile page should fit on at most 2 screens (one if possible) of
iphone 5 (2nd/3rd might be used for additional info/links).

The desktop version should have both forms on the first page.

I prefer slightly larger/more readable fonts.

It's not necessarily to have to be corporate. It could be grubhub.com
style.

Login and register forms must be on the same page for desktop with no
additional clicks required. In any case they must be on the same page
visible at the same time.

I did not ever do any design before, therefore I do not have logo,
colors or anything else available.

It'd be nice to see explanation how site works on this page as I
described on the comment below:

1. Signup;

2. Select company;

3. Create topic;

4. Provide feedback.