`line-height: 1.9824;` is the result of `calc(1em * 1.4 + 2 * 0.1em + 2 * 1px / 16px / 0.85 + 2 * 0.1em / 0.85)` (`1em * 1.4` equals the line height for code (= `1.4` times), plus `0.1em` vertical padding on top and bottom, plus `1px` border width on top and bottom (`1rem` equals `16px` and considering the smaller font size (= `0.85rem`)), plus `0.1em` vertical margin on top and bottom (also considering the smaller font size).
`line-height: 1.9778;` is the result of `calc(1rem * 1.6 / 0.9 + 2 * 0.1em)` (`1rem * 1.6 / 0.9` equals the default line height (= `1.6` times) adjusted by the smaller font size (= `0.9rem`), plus `0.1em` vertical space on top and bottom)
Daniel Rudolf