Test for Safari CSS Bug

If you're reading this, your browser does not have the bug which occurs when using the CSS calc() function with ch or ex units.

Browsers that experience this bug will not load this page.

This page is a test for checking this issue in PDF.js:

• PDFs with form fields crash in Safari #13726

WebKit bug report and patch related to the crashing behavior:

• https://bugs.webkit.org/show_bug.cgi?id=216659
• https://trac.webkit.org/changeset/271688/webkit/