{# Shared cover renderer for list cards (feed + portfolio).

   Single source of truth for the three-way image branch so the favicon
   chip / og-image / glyph fallback never drifts between surfaces. Before
   this macro the portfolio template lacked the favicon branch and stretched
   a 32px /favicon.ico across the full cover, rendering it blurry.

   Args:
     image_url  — tech_items.image_url (attacker-controllable; crawled).
     category   — CategoryType enum or None (tints the fallback gradient).
     href       — in-app reader URL for the card tap target.
     source_url — used only to label the favicon chip with its domain.
#}
{% macro cover(image_url, category, href, source_url) %}
{%- set cat = (category.value if category else 'none')|lower -%}
{%- if image_url and image_url | is_favicon -%}
<a class="cover cover--favicon cover--{{ cat }}" href="{{ href }}">
  <span class="scrim" aria-hidden="true"></span>
  {# image_url is attacker-controllable (crawled): escaped <img src> only, never CSS url(). #}
  <span class="favicon-chip">
    <img class="favicon-chip__img" src="{{ image_url }}" alt="" loading="lazy" width="32" height="32">
    <span class="favicon-chip__domain">{{ source_url | domain }}</span>
  </span>
</a>
{%- elif image_url -%}
<a class="cover" href="{{ href }}">
  {# og:image is attacker-controllable (crawled): render via an HTML-escaped
     <img src> rather than inline CSS url() to avoid CSS-context injection. #}
  <img class="cover__img" src="{{ image_url }}" alt="" loading="lazy">
  <span class="scrim" aria-hidden="true"></span>
</a>
{%- else -%}
<a class="cover cover--fallback cover--{{ cat }}" href="{{ href }}">
  <span class="scrim" aria-hidden="true"></span>
  <span class="cover__glyph" aria-hidden="true">◎</span>
</a>
{%- endif -%}
{% endmacro %}