/ggplot2.tidyverse.org/reference/scale_gradient.html" class="external-link">scale_colour_gradient2</a></span><span class="op">(</span><span class="st">"mpg"</span>, mid<span class="op">=</span><span class="st">"grey80"</span>, midpoint <span class="op">=</span> <span class="fl">20</span>, low<span class="op">=</span><span class="st">"darkred"</span>, high<span class="op">=</span><span class="st">"darkblue"</span><span class="op">)</span> <span class="op">+</span></span>
<span>  <span class="fu"><a href="htt