18F/calc

<fieldset{% if field.errors %} class="fieldset-error"{% endif %}>
  {{ field.errors }}
  {% if use_legend %}
    {# <legend>s are difficult/impossible to style but are great for screen readers, so we'll make them invisible to sighted users. #}
    <legend class="usa-sr-only">{{ field.label }}</legend>
    <label aria-hidden="true">{{ field.label }}</label>
  {% else %}
    {{ field.label_tag }}
  {% endif %}
  {{ field }}
  {% if field.help_text %}
    <p class="helptext">{{ field.help_text }}</p>
  {% endif %}
</fieldset>