[Rails] 新規登録画面のめっちゃシンプルなレイアウトテンプレート作ってみた [コード載ってます]

GOAL

※devise使ってます。
※bootstrap4使ってます。導入方法はこちらをどうぞ。

#HTML

app/views/devise/registrations/new.html.erb

<%= render 'articles/header' %>  👈　これはNavbarです


<%= form_with model: @user, url: user_registration_path do |f| %>
  <%= render "devise/shared/error_messages", resource: resource %>
  <div class="container">
    <div class="card-container">
      <div class="card-body">
          <h3 class="card-title text-center mb-4 mt-1">新規登録</h3>
          <hr>
          <form>
            <div class="form-group">
              <div class="input-group">
                <div class="input-group-prepend">
                  <span class="input-group-text"> 
                    <svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="currentColor" class="bi bi-person" viewBox="0 0 16 16">
                      <path d="M8 8a3 3 0 1 0 0-6 3 3 0 0 0 0 6zm2-3a2 2 0 1 1-4 0 2 2 0 0 1 4 0zm4 8c0 1-1 1-1 1H3s-1 0-1-1 1-4 6-4 6 3 6 4zm-1-.004c-.001-.246-.154-.986-.832-1.664C11.516 10.68 10.289 10 8 10c-2.29 0-3.516.68-4.168 1.332-.678.678-.83 1.418-.832 1.664h10z"/>
                    </svg>
                  </span>
                </div>
                <%= f.text_field :nickname, class: "form-control", placeholder: "ニックネーム", type: "nickname" %>
              </div> <!-- input-group.// -->
            </div> <!-- form-group// -->          
            <div class="form-group">
              <div class="input-group">
                <div class="input-group-prepend">
                  <span class="input-group-text"> 
                    <svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="currentColor" class="bi bi-envelope" viewBox="0 0 16 16">
                      <path d="M0 4a2 2 0 0 1 2-2h12a2 2 0 0 1 2 2v8a2 2 0 0 1-2 2H2a2 2 0 0 1-2-2V4zm2-1a1 1 0 0 0-1 1v.217l7 4.2 7-4.2V4a1 1 0 0 0-1-1H2zm13 2.383l-4.758 2.855L15 11.114v-5.73zm-.034 6.878L9.271 8.82 8 9.583 6.728 8.82l-5.694 3.44A1 1 0 0 0 2 13h12a1 1 0 0 0 .966-.739zM1 11.114l4.758-2.876L1 5.383v5.73z"/>
                    </svg>                  
                  </span>
                </div>
                <%= f.email_field :email, autofocus: true, autocomplete: "email", class: "form-control", placeholder: "メールアドレス", type: "email" %>
              </div> <!-- input-group.// -->
            </div> <!-- form-group// -->
            <div class="form-group">
              <div class="input-group">
                <div class="input-group-prepend">
                  <span class="input-group-text">
                    <svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="currentColor" class="bi bi-lock" viewBox="0 0 16 16">
                      <path d="M8 1a2 2 0 0 1 2 2v4H6V3a2 2 0 0 1 2-2zm3 6V3a3 3 0 0 0-6 0v4a2 2 0 0 0-2 2v5a2 2 0 0 0 2 2h6a2 2 0 0 0 2-2V9a2 2 0 0 0-2-2zM5 8h6a1 1 0 0 1 1 1v5a1 1 0 0 1-1 1H5a1 1 0 0 1-1-1V9a1 1 0 0 1 1-1z"/>
                    </svg> 
                  </span>
                </div>             
                <%= f.password_field :password, autocomplete: "new-password", class: "form-control", placeholder: "パスワード（6文字以上）", type: "password" %>
              </div> <!-- input-group.// -->
            </div> <!-- form-group// -->
            <div class="form-group">
              <%= f.submit "登録する", class: "btn btn-outline-secondary btn-block" %>
            </div> <!-- form-group// -->
          </form>
      </div>
    </div>
  </div>
<% end %>

#CSS

app/assets/stylesheets/user.css

.card-container {
  max-width: 600px;
  padding: 40px 40px;
}

.card-body {
  padding: 20px 25px 30px;
  margin: 0 auto 25px;
  margin-top: 100px;
}

.card-container {
  margin: 0 auto;
  padding: 20px 25px 30px;
  margin: 0 auto 25px;
  margin-top: 50px;
  -moz-box-shadow: 0px 2px 2px rgba(0, 0, 0, 0.3);
  -webkit-box-shadow: 0px 2px 2px rgba(0, 0, 0, 0.3);
  box-shadow: 0px 2px 2px rgba(0, 0, 0, 0.5);
}

.form-group {
  margin-top: 40px;
}