Untitled

I created a form template with HTML5 validation:

```html
<body>
  <form class="register-form" action="/somewhere" method="post">
    <h1 class="register-form__title">Register account</h1>
    <div class="register-form__wrap-question">
      <label class="register-form__label" for="first-name">First name</label>
      <input class="register-form__input name-input"
             type="text"
             name="first_name"
             required
             pattern="[A-Za-z]+$"
             placeholder="Enter a valid first name"
             title="First name should only contain letters">
    </div>
    <div class="register-form__wrap-question">
      <label class="register-form__label" for="last-name">Last name</label>
      <input class="register-form__input name-input"
             type="text"
             name="last_name"
             required
             pattern="[A-Za-z]+$"
             placeholder="Enter a valid last name"
             title="Last name should only contain letters">
    </div>
    <div class="register-form__wrap-question">
      <label class="register-form__label" for="mail">Email</label>
      <input class="register-form__input mail-input"
             type="email"
             name="mail"
             required
             placeholder="Enter a valid email address"
             pattern="[a-z0-9._%+-]+@[a-z0-9.-]+\.[a-z]{2,3}$">
    </div>
    <div class="register-form__wrap-button">
      <button class="register-form__button" type="submit" id="user_submit">Submit!</button>
    </div>
  </form>
</body>
```