Check page speed + mobile

[rootwork]

Issues identified by Lighthouse:

• [x] Author image doesn't have explicit width and height, and needs to be 2x the apparent size (e.g. 256 for 128px).
• [x] Add visually-hidden descriptive text to the "about" section in the sidebar, similar to what I did on the home page.
• [ ] Blog entry thumbnail images don't have explicit width and height. (Hugo Clarity issue)
• [ ] Cache policy is very short, 10 minutes. Need to analyze and understand more.
• [ ] user-scalable: no is on the viewport meta tag. (HC)
• [x] Heading elements are not sequentially descending. This is probably a won't-fix.
• [ ] No content security policy (CSP). Need to analyze and understand more; first attempts generated more issues than they fixed.
• [ ] Add a service-worker. Resources: Google, gohugohq (blog), Bill Bär (blog)
• [x] Subheader-links (the "permalink" item that appears on hover) need actual text content in the <a> tag; I think right now I'm using CSS content to insert the text. Additionally the link.svg file seems to be missing. (HC...though I might be able to tweak it)

[rootwork]

Lighthouse is actually better for this as it checks performance, a11y, best practices, SEO, and PWA setup.

After fixing several issues, the current rating for the home page is:

Performance: 100 A11y: 91 Best Practices: 92 SEO: 100

And the current rating for a blog entry is:

Performance: 99 A11y: 89 Best Practices: 92 SEO: 92

[rootwork]

[moved issues into issue itself]

[rootwork]

New ratings--

Home page:

Performance: 100 A11y: 91 Best Practices: 100 SEO: 100

Blog entry:

Performance: 97 A11y: 91 Best Practices: 92 SEO: 100

(No idea how performance went down on the blog.)

[rootwork]

I'm going to call this good enough for launch, and move this into v1.1 for addressing these other issues, some of which will be pretty involved.