app/views/devise/sessions/new.html.erb
<div class="page-header">
<h1><%=t ".title", default: "Login" %></h1>
</div>
<%= form_for(resource, as: resource_name, url: session_path(resource_name), html: {class: "form-horizontal form-user"}) do |f| %>
<div class="form-group">
<%= f.label :login, "Username or Email", class: "control-label col-md-4" %>
<div class="col-md-8">
<%= f.text_field :login, class: "text-field form-control", html: {spellcheck: "false"} %>
</div>
</div>
<div class="form-group">
<%= f.label :password, class: "control-label col-md-4" %>
<div class="col-md-8">
<%= f.password_field :password, class: "text-field form-control", html: {autocomplete: "off"} %>
</div>
</div>
<% if devise_mapping.rememberable? -%>
<div class="form-group">
<%= f.label :remember_me, "Remember Me", class: "control-label col-md-4" %>
<div class="col-md-8">
<%= f.check_box :remember_me %>
</div>
</div>
<% end -%>
<div class="form-group">
<div class="col-md-offset-4 col-md-8">
<%= f.submit "Login", class: "btn btn-primary" %>
</div>
</div>
<div class="form-group">
<div class="col-md-offset-4 col-md-8">
<%= render "devise/shared/links" %>
</div>
</div>
<% end %>