{# ── TITLE BLOCK ── #}
{{ title | default("📉 Gradient Descent") }}
{{ subtitle | default("Machine Learning · How models learn") }}
{# ══════════════════════════════════════════════════════
DIAGRAM SLOT — full board width
Pass diagram_content (raw SVG/HTML) to fill.
Dimensions: full width, height: 300px
══════════════════════════════════════════════════════ #}
{%- if diagram_content is defined and diagram_content -%}
{{ diagram_content | safe }}
{%- else -%}
diagram slot
pass diagram_content to fill this area
{%- endif -%}
{# end diagram slot #}