Heading levels and special cases

Level
Size
Weight
Example
1
96
Bold
h1 Heading
2
60
Regular
h2 Heading
3
48
Bold
h3 Heading
4
34
Regular
h4 heading
5
24
Regular
h5 heading
6
20
Regular
h6 heading
7
18
Regular
p1 - Typography in Design Systems
8
16
Light
p2 - Typography in Design Systems
9
16
Regular
p3 - Typography in Design Systems
10
16
Regular
While systems can vary fonts based on theming, most ground themselves initially by identifying primary serif and/or sans-serif font family. Each font is augmented with a cascade of fallbacks (Hello, Arial and Times), and many systems throw in a monospace font for code displays (even if only their own).