app/views/devise/sessions/new.html.erb
<div class = "panel panel-default container-box">
<center>
<%= image_tag("/assets/logos/logo-128.png", size: "64") %>
<%= form_for(resource, as: resource_name, url: session_path(resource_name)) do |f| %>
<div class="form-group">
<br />
<%= f.email_field :email, autofocus: true, autocomplete: "email", class: "form-control", placeholder: :email %><br />
<%= f.password_field :password, autocomplete: "current-password", class: "form-control", placeholder: :senha %>
<%- if devise_mapping.recoverable? && controller_name != 'passwords' && controller_name != 'registrations' %>
<%= link_to "Esqueceu sua senha?", new_password_path(resource_name) %><br />
<% end -%>
<br />
<% if devise_mapping.rememberable? -%>
<%= f.check_box :remember_me %>
<%= f.label :Lembre_de_mim %>
<% end -%>
</div>
<div class="actions">
<%= f.submit "ENTRAR", class: "btn btn-primary-evegano btn-75" %>
</div>
<% end %>
</center>
<%= render "devise/shared/links" %>
</div>