{#
  How a number moved, as an arrow, a sign and a percentage.

  Never colour alone: the arrow says the direction and the sign is printed, so
  the badge still reads in monochrome, in print, and to anyone who cannot tell
  the green from the red. Nothing is rendered when there is nothing to compare
  against -- the first half of the window being empty makes every percentage
  infinite, and "+∞%" is a worse answer than no badge.
#}
{% if series.delta is not none %}
  {% set direction = "up" if series.delta > 0 else ("down" if series.delta < 0 else "flat") %}
  <span class="ff-delta ff-delta--{{ direction }}">
    {{ ff_icon("trending-up" if direction == "up" else ("trending-down" if direction == "down" else "minus"), size=14) }}
    {{ "+" if series.delta > 0 }}{{ series.delta }}%
    <span class="ff-delta__note">{{ _("vs previous {days} days", days=series.half) }}</span>
  </span>
{% endif %}