Bulma is a free, open source CSS framework based on Flexbox and built with Sass. It's 100% responsive, fully modular, and available for free.

For the best results using Bulma, it's recommended to use the control element as often as possible.

<div class="field">
  <label class="label">Username</label>
  <div class="control has-icons-left has-icons-right">
    <input class="input is-success" type="text" placeholder="Text input" value="bulma">
    <span class="icon is-small is-left">
      <i class="fas fa-user"></i>
    </span>
    <span class="icon is-small is-right">
      <i class="fas fa-check"></i>
    </span>
  </div>
  <p class="help is-success">This username is available</p>
</div>