CSS
Layout, positioning, lists and the browser differences that still break them.
Styling list markers in CSS
We drew the same lists in Chrome, Firefox and WebKit, read each marker's position from the pixels, and recorded which ::marker rules each engine applied.
gunlaug team · 8 Nov 2026 · 8 min
Quirks mode and the DOCTYPE
A missing or outdated DOCTYPE changes how a page is laid out and how its CSS is parsed. We ran 34 variants through Chrome, Firefox and WebKit and measured the three modes side by side.
gunlaug team · 8 Nov 2026 · 7 min
Block formatting contexts in CSS
A block formatting context fixes collapsed parents, escaping margins and content running under floats. We measured the common triggers in three browser engines, and what each one breaks.
gunlaug team · 8 Nov 2026 · 7 min
Centering anything in CSS
Nearly every CSS centering method puts a small box in the right place. They differ when the content is bigger than its container, because some push part of it where scrolling can't reach. We measured both in three browser engines.
gunlaug team · 8 Nov 2026 · 7 min
position: fixed and position: sticky
A fixed box that scrolls away and a sticky box that won't stick usually come down to one line of CSS on an ancestor. We scrolled test pages in three browser engines and measured which lines do it.
gunlaug team · 8 Nov 2026 · 8 min