x/pkgsite: various UI cleanups due to new fixed header on details page

[andybons]

• The version string in the sticky header is all uppercase, which renders as GO1.14.6 on standard library packages. This should preserve the original casing
• The :target selector in stylesheet.css (and in sidenav.css) that’s used to ensure that anchor targets aren’t scrolled below the sticky headers isn’t needed for pages that don’t have them (and need to be adjusted for the new sticky header on the details pages)
• Should the homepage should have smart quotes around example searches? (unrelated to header but just noticed it)
• overflow: auto on the html and body elements (used to fix an iOS focus bug) is causing other focus issues and the fixed header to appear over scrollbars
• Search text is shown on mobile when the search input is collapsed
• Ensure sidenav height is properly calculated
• The IntersectionObserver logic to show the sticky header will trigger it if the inline nav is below the fold. Ensure it only shows if it is off the top of the screen
• The search bar in the primary header looks a bit off re: spacing on iOS
• Determine whether to keep uppercase “Package”, “Command”, etc.
• Adjust IntersectionObserver margin on fixed header to have it show earlier
• Fixed header hack to fix focus bug on iOS Safari breaks tap-to-top behavior

/cc @julieqiu @jamalc

[julieqiu]

The version string in the sticky header is all uppercase, which renders as GO1.14.6 on standard library packages. This should just be all lowercase

Would it be possible to keep the casing as it is in the main header? For pseudoversions, the version string will contain the commit hash, which may be a mix of uppercase and lowercase characters. Same with build metadata and pre-release identifiers.

[andybons]

Sorry yeah. I meant to say casing should be preserved.

[gopherbot]

Change https://golang.org/cl/246478 mentions this issue: content/static/css: update CSS to only overflow: auto on mobile

[gopherbot]

Change https://golang.org/cl/246577 mentions this issue: content/static/css: update target padding and restrict to details pages

[gopherbot]

Change https://golang.org/cl/246578 mentions this issue: content/static/css: preserve casing of version in fixed header

[gopherbot]

Change https://golang.org/cl/246580 mentions this issue: content/static/css: hide search text in header on small viewports