{# heatmap: 7 rows (Mon–Sun) × 24 cols. intensity 0–5. #}
<div class="heatmap-wrap">
  <div class="heatmap-ylabels">
    <span>Mon</span><span>Tue</span><span>Wed</span>
    <span>Thu</span><span>Fri</span><span>Sat</span><span>Sun</span>
  </div>
  <div class="heatmap-grid">
    {% for row in heatmap %}
      {% for cell in row %}
        <div class="hm-cell hm-{{ cell }}" title="intensity {{ cell }}"></div>
      {% endfor %}
    {% endfor %}
  </div>
  <div class="heatmap-xlabels">
    {% for h in range(0, 24, 3) %}
      <span>{{ '%02d'|format(h) }}</span>
    {% endfor %}
  </div>
</div>