Rails 4: devise sign up form styling issues - html

Question

I used to roll my own authentication following Hartl's tutorial, but now that I need more advanced features such as password retrieval or email confirmation, I moved on to the Devise gem. However, I'm having some hard time navigating around what is already provided by devise. I'm doing some research in order to better understand it.
Meanwhile, I'm having problems with styling the sign in and sign up forms. For the sign up form, it looks fine at first, but the spacing becomes weird once I submit an invalid form.
For the sign in form, I cannot seem to figure out how to put the checkbox and the label on the same line. I tried all different kinds of divs and inline block. Please help me out. Thanks!
/devise/registrations/new.html.erb
<div class="center">
<h2>Sign up</h2>
<%= form_for(resource, :as => resource_name, :url => registration_path(resource_name)) do |f| %>
<%= devise_error_messages! %>
<%= field_set_tag "Name" do %>
<%= f.text_field :first_name, placeholder: "First Name*", autofocus: true %><br>
<%= f.text_field :middle_name, placeholder: "Middle Name" %><br>
<%= f.text_field :last_name, placeholder: "Last Name*" %><br>
<% end %>
<%= field_set_tag "Account" do %>
<%= f.email_field :email, placeholder: "Email*" %><br>
<%= f.password_field :password, placeholder: "Password*" %><br>
<%= f.password_field :password_confirmation, placeholder: "Password Confirmation*" %>
<% end %>
<div><%= f.submit "Sign up", class: "btn btn-large btn-primary" %></div>
<% end %>
Already a user? <%= render "devise/shared/links" %>
</div>
/devise/sessions/new.html.erb
<div class="center">
<h2>Sign in</h2>
<%= form_for(resource, :as => resource_name, :url => session_path(resource_name)) do |f| %>
<%= devise_error_messages! %>
<%= f.email_field :email, placeholder: "Email", autofocus: true %><br>
<%= f.password_field :password, placeholder: "Password" %><br>
<div class="row">
<% if devise_mapping.rememberable? %>
<div>
<div class="remember-me">
<div><%= f.label :remember_me %></div>
<div><%= f.check_box :remember_me %></div>
</div>
</div>
<% end -%>
<%= f.submit "Sign in", class: "btn btn-primary" %>
</div>
<% end %>
<%= render "devise/shared/links" %>
</div>

Answer 1

Check this stackoverflow link you will find the solution for the sign in page issue.
For the sign up page you are getting the spacing issue when input are not correct because your form is not showing the error messeges properly check out this image you will understand.