https://developer.mozilla.org/en-US/docs/Web/API/CSSStyleSheet
CSSStyleSheet - Web APIs | MDN
The CSSStyleSheet interface represents a single CSS stylesheet, and lets you inspect and modify the list of rules contained in the stylesheet. It inherits...
web apiscssstylesheetmdn
https://pdfium.googlesource.com/pdfium/+/refs/heads/chromium/6576/core/fxcrt/css/cfx_cssstylesheet.cpp
core/fxcrt/css/cfx_cssstylesheet.cpp - pdfium - Git at Google
corecsscfxcpppdfium