201637 2019-09-10 03:42:23 -0700 WebKit incorrectly ignores percentages during calc() serialization 2022-07-01 13:45:28 -0700 1 1 1 Unclassified WebKit CSS WebKit Nightly Build Unspecified Unspecified RESOLVED CONFIGURATION CHANGED P2 Normal --- 1 emilio webkit-unassigned bfulgham oldest_to_newest 1569491 0 emilio 2019-09-10 03:42:23 -0700 Chrome also has this bug, see https://bugs.chromium.org/p/chromium/issues/detail?id=1002430 1. Open data:text/html,<div style="background-position: calc(0% + 0px) calc(0% + 0px)"></div> 2. Run on the terminal: getComputedStyle(document.querySelector("div")).backgroundPosition Expected: calc(0% + 0px) calc(0% + 0px) Actual: 0px 0px Per https://drafts.csswg.org/css-values-4/#calc-computed-value: > Where percentages are not resolved at computed-value time, they are not resolved in math functions, e.g. calc(100% - 100% + 1px) resolves to calc(0% + 1px), not to 1px. If there are special rules for computing percentages in a value (e.g. the height property), they apply whenever a math function contains percentages. See also https://github.com/w3c/csswg-drafts/issues/3482, and https://bugzilla.mozilla.org/show_bug.cgi?id=1574913 which is where this came up. 1880126 1 bfulgham 2022-07-01 13:45:28 -0700 Safari, Chrome, and Firefox all agree on the output: "0% 0%" I believe this now works properly. Please REOPEN if I am misunderstanding the issue.