I think that the solution of what you want is more simple than what you are thinking about. 

If you wanna ensure that an user is authenticated before do something you just need to do something like this into the controller of the url for that something, like the following scenario:

#making sure that the user is registered and authenticated before checkout in the shop:

from openerp import http
from openerp.http import request
from openerp.addons.website_sale.controllers.main import website_sale
class solt_website_sale(website_sale):
    @http.route(['/shop/checkout'], type='http', auth="user", website=True)
    def checkout(self, **post):
        return super(solt_website_sale, self).checkout(**post)

For the separation of features depending of the type of users, you will need to get more familiar with Odoo security stuffs like groups, and how to use it to restrict the content that you deliver to your users

In .PY

fields-->

user_name=fields.Char(string="User name",required=True,help="This field has ADMIN authenticity, Provide valid user name and password")

password_login=fields.Char(string="Password",required=True,help="This field has ADMIN authenticity, Provide valid user name and password")

check_valid=fields.Char(compute="check_user_password",string=" Login",help="If USER NAME and PASSWORD are Matched, Then it will show you LOGIN BUTTON")

@api.one

@api.depends('user_name','password_login')

def check_user_password(self):

    if self.user_name=='vicky' and self.password_login=='vicky':

    self.check_valid=True 

AND in XML

<field name="user_name" style="width:60%%;height:5%%;font-size:15px" placeholder=" USER NAME"/>

<field name="password_login" style="width:60%%;height:5%%;font-size:15px" placeholder=" PASSWORD" password="1"/>

<field name="check_valid" />

<button name="%(customer_action_window)d" type="action"

class="oe_highlight oe_stat_info oe_right o_wow" style="background-color:#32CD32"

icon="fa-sign-in" attrs="{'invisible':[('check_valid','=',False)]}" />

 You may fetch records from db and check it for login... whenever the condition is "True", it automaticlly Shows the Button to login... Hope this will give some Idea to u...

Axel Mendoza thanks for the reply. This is also required for me. But I am asking for the basic authentication. i.e., the login process itself. You are saying about the process after the login for holding up the authentication.

You can use these apps (search apps in odoo apps by names provided below) to change the whole login page style.

Moreover, these apps provide the ability to define your own favicon and logo as you wish.

Apps Name:

Minimalist Login Form

Creative Login Form

Advanced Login Form