Source: dist/css/library_boot.css, line 8646
10.15.3.1 Section Header Down
Section Headers are styled the same
Example s
default
plan header
default
<header class="p-x_4 font_display font_regular c_primary-n2 m-b_2 lh_1 m-b_3:lg m-t_2 "><h3 class="lh_1 m_0 font_regular lowercase font_2:lg font_1:md font_0">[modifier]</h3></header>