Remove the styles for "details summary:focus span"

Problem/Motivation

The css/base/elements.css file contains the following comment.

/**
 * Unfortunately, text-decoration for details summary is not supported on all
 * browsers. So we add a span (which can handle text-decoration) in Seven's
 * templates/details.html.twig. In case there are other details templates that
 * don't have the span, we provide text-decoration in the parent selector.
 * This provides maximum compatibility and coverage with minimal disruption.
 */

It is no longer true that a <span> is added in the templates/details.html.twig file. In fact, the currently used markup is the following one.

<details{{ attributes.addClass('seven-details') }}>
  {%- if title -%}
    {%
      set summary_classes = [
        'seven-details__summary',
        required ? 'js-form-required',
        required ? 'form-required',
      ]
    %}
    <summary{{ summary_attributes.addClass(summary_classes) }}>
      {{- title -}}
    </summary>
  {%- endif -%}
  <div class="seven-details__wrapper details-wrapper">
    {% if errors %}
      <div class="form-item form-item--error-message">
        <strong>{{ errors }}</strong>
      </div>
    {% endif %}
    {%- if description -%}
      <div class="seven-details__description">{{ description }}</div>
    {%- endif -%}
    {%- if children -%}
      {{ children }}
    {%- endif -%}
    {%- if value -%}
      {{ value }}
    {%- endif -%}
  </div>
</details>

The content of the <summary> tag is the following one.

    <summary{{ summary_attributes.addClass(summary_classes) }}>
      {{- title -}}
    </summary>

Proposed resolution

Remove the following lines from the css/base/elements.css file.

/**
 * Unfortunately, text-decoration for details summary is not supported on all
 * browsers. So we add a span (which can handle text-decoration) in Seven's
 * templates/details.html.twig. In case there are other details templates that
 * don't have the span, we provide text-decoration in the parent selector.
 * This provides maximum compatibility and coverage with minimal disruption.
 */

details summary:focus span,
details summary:hover span {
  text-decoration: underline;
}