diff --git a/content/posts/website-best-practices.gmi b/content/posts/website-best-practices.gmi
index d1ee111..fcd45d9 100644
--- a/content/posts/website-best-practices.gmi
+++ b/content/posts/website-best-practices.gmi
@@ -775,7 +775,7 @@ I personally like a foreground and background of "#E9E9E9" and "#191919", respec
If you use JavaScript: avoid setting colors, especially dark-mode colors, using JavaScript. Using JavaScript to set a styles risks introducing a "Flash of Unstyled Content" (FOUC). In the case of a dark theme, this FoUC manifests as a "White Flash of Death" (WFoD). A WFoD is incredibly irritating for dark-mode users; at worst, it could put photosensitive epileptic users at risk. CSS is a render-blocking resource for a reason.
-### Contrast is complex
+### Use the Advanced Perceptual Contrast Algorithm
When setting colors, especially for a dark background, I recommend checking your page's contrast using Accessible Perceptual Contrast Algorithm (APCA) values. You can do so in an online APCA checker or Chromium's developer tools (you might have to enable them in a menu for experimental preferences. I recommend using the web app.
@@ -793,6 +793,8 @@ Note that the APCA isn't fully mature as of early 2022. Until version 3.0 of the
=> https://yatil.net/blog/wcag-3-is-not-ready-yet WCAG 3 is not ready yet
+### What contrast algorithms don't cover: over-saturation
+
Even if the APCA is much better than the WCAG's current naive contrast algorithms, it still doesn't account for all aspects of the relationship between perceptual contrast and color. This discussion on the SAPC-APCA repository covers some shortcomings; for instance, the current APCA doesn't account for the Helmholtz–Kohlrausch effect:
=> https://github.com/Myndex/SAPC-APCA/discussions/74 Dark Mode Color Palettes and APCA
@@ -800,12 +802,12 @@ Even if the APCA is much better than the WCAG's current naive contrast algorithm
The Helmholtz–Kohlrausch effect describes how highly-saturated colors appear "brighter" than de-saturated colors with the same brightness. Excessive perceptual brightness against dark backgrounds can trigger halation, eye-strain, and overstimulation.
-Yellow may have great contrast on dark backgrounds, but yellow and red can cause problems among people who deal with overstimulation; this includes many on the autism spectrum.
+Yellow may have great contrast on dark backgrounds, but yellow and red can cause problems among people who deal with overstimulation; this includes many on the autism spectrum. This issue is a bit personal, since I do deal with overstimulation quite a bit.
=> https://www.tpgi.com/beyond-wcag-losing-spoons-online/ Beyond WCAG: Losing Spoons Online
=> https://www.experia.co.uk/blog/ultimate-guide-to-autism-friendly-colours/ The Ultimate Guide to Autism Friendly Colours
-If you want to use yellow and red, de-saturate them so that their color feels muted. This site's dark theme uses pale, washed-out yellow and pink for maximum contrast with minimal harshness.
+If you want to use significant amounts of "emergency colors" like yellow and red, de-saturate them so their color feels muted. This site's dark theme uses very pale, washed-out yellow and violet for maximum contrast with minimal harshness.
Accounting for halation, overstimulation, and high-contrast needs is hard to do if you prioritize minute aesthetics before inclusivity.
diff --git a/content/posts/website-best-practices.md b/content/posts/website-best-practices.md
index 53bc6e0..2fe5348 100644
--- a/content/posts/website-best-practices.md
+++ b/content/posts/website-best-practices.md
@@ -825,7 +825,7 @@ If you can't bear the thought of parting with your solid-black background, worry
I personally like a foreground and background of `#E9E9E9` and `#191919`, respectively. These shades seem to be as far apart as possible without causing accessibility issues: `#191919` is barely bright enough to create a soft "glow" capable of minimizing halos among slightly astigmatic users, but won't ruin contrast on cheap displays. I also support a `prefers-contrast: less` media query which lightens the background to `#333`.[^24]
-### Contrast is complex
+### Use the Advanced Perceptual Contrast Algorithm
Color is a nuanced topic that deserves more attention than current guidelines give.
@@ -841,9 +841,13 @@ The APCA takes several factors into account:
Note that [the APCA isn't fully mature](https://yatil.net/blog/wcag-3-is-not-ready-yet) as of early 2022. Until version 3.0 of the WCAG is ready, pages that are required to comply with the WCAG should also conform to the contrast ratios described in the WCAG 2.2's success criteria 1.4.3 (Contrast: Minimum, level AA) or 1.4.6 (Contrast: Enhanced, level AAA). This site's dark-mode stylesheet is an example of a palette that conforms to both the WCAG 2.2 AAA contrast requirements and APCA recommendations.
+### What contrast algorithms don't cover: over-saturation
+
Even if the APCA is much better than the WCAG's current naive contrast algorithms, it still doesn't account for all aspects of the relationship between perceptual contrast and color. [Discussion no. 74 on the SAPC-APCA repository](https://github.com/Myndex/SAPC-APCA/discussions/74) covers some shortcomings. For instance, the current APCA version does not account for [the Helmholtz–Kohlrausch effect](https://en.wikipedia.org/wiki/Helmholtz%E2%80%93Kohlrausch_effect): highly-saturated colors appear "brighter" than de-saturated colors with the same brightness. Excessive perceptual brightness against dark backgrounds can trigger halation, eye-strain, and overstimulation.
-Yellow may have great contrast on dark backgrounds, but vivid yellow and red can cause problems among [people who deal with overstimulation](https://www.tpgi.com/beyond-wcag-losing-spoons-online/); this includes [many on the autism spectrum](https://www.experia.co.uk/blog/ultimate-guide-to-autism-friendly-colours/). If you want to use yellow and red, de-saturate them so that their color feels muted. This site's dark theme uses pale, washed-out yellow and pink for maximum contrast with minimal harshness.
+Yellow may have great contrast on dark backgrounds, but vivid yellow and red can cause problems among people who deal with overstimulation; this includes [many on the autism spectrum](https://www.experia.co.uk/blog/ultimate-guide-to-autism-friendly-colours/). {{}}{{}} wrote about the issue on the TPGi blog: {{}}{{}}.[^25]
+
+If you want to use significant amounts of "emergency colors" like yellow and red, de-saturate them so their color feels muted. This site's dark theme uses very pale, washed-out yellow and violet for maximum contrast with minimal harshness.
Accounting for halation, overstimulation, and high-contrast needs is hard to do if you prioritize minute aesthetics before inclusivity.
@@ -851,7 +855,7 @@ Accounting for halation, overstimulation, and high-contrast needs is hard to do
Color palettes need to be effective for different types of vision deficiencies (e.g. color blindnesses) and screens. Color blindness is a far more nuanced topic than "the inability to see some colors". {{}}{{}} describes his experience in {{}}{{}}. Color blindness manifests in complex ways. Testing in grayscale is a great start, but it doesn't account for all kinds of color vision deficiencies.
-Different screens and display-calibrations render color differently; what may look like a light-gray on a cheap monitor could look nearly black on a high-end OLED screen. Try to test on both high- and low-end displays, especially when designing a dark color scheme.[^25]
+Different screens and display-calibrations render color differently; what may look like a light-gray on a cheap monitor could look nearly black on a high-end OLED screen. Try to test on both high- and low-end displays, especially when designing a dark color scheme.[^26]
Color schemes should also look good to users who apply gamma adjustments. Most operating systems and desktop environments bundle a feature to reduce the screen color temperature at night, while some individuals may select a higher one in the morning.
@@ -873,7 +877,7 @@ A basic WCAG Level A requirement is for information to not be conveyed solely th
### In defense of link underlines
-Some typographers insist that [underlined on-screen text is obsolete](https://practicaltypography.com/underlining.html),[^26] and that hyperlinks are no exception. I disagree.
+Some typographers insist that [underlined on-screen text is obsolete](https://practicaltypography.com/underlining.html),[^27] and that hyperlinks are no exception. I disagree.
Readers already expect underlined text to signify a hyperlink. Don't break fundamental affordances for aesthetics. Underlines are also necessary to distinguish the beginnings and ends of multiple consecutive links, especially among color-blind users.
@@ -958,9 +962,9 @@ Someone using the GitHub issues interface for the first time will struggle to id
### Against focusable containers
-Screen readers like iOS VoiceOver[^27] fail to follow in-page links whose targets are not focusable. Designers often work around this by annotating link targets with the `tabindex="-1"` HTML attribute. This is a good idea when a link target is a heading or piece of [phrasing content](https://html.spec.whatwg.org/dev/dom.html#phrasing-content). Unfortunately, making large containers focusable ruins keyboard-navigability.
+Screen readers like iOS VoiceOver[^28] fail to follow in-page links whose targets are not focusable. Designers often work around this by annotating link targets with the `tabindex="-1"` HTML attribute. This is a good idea when a link target is a heading or piece of [phrasing content](https://html.spec.whatwg.org/dev/dom.html#phrasing-content). Unfortunately, making large containers focusable ruins keyboard-navigability.
-Normally, if you select some text in a page and press Tab, the tab-focusable element _after_ the selected text will receive focus. However, if the selectable text is inside a focusable container---even a container with a negative `tabindex`---pressing Tab will move focus to the _start_ of the container. If you're reading this on a desktop browser, you can experience this first-hand: select some text in this paragraph and press Tab. Then, do the same in [this snapshot of an excellent _Smashing Magazine_ article](https://web.archive.org/web/20220808163715/https://www.smashingmagazine.com/2022/06/voice-control-usability-considerations-partially-visually-hidden-link-names/).[^28]
+Normally, if you select some text in a page and press Tab, the tab-focusable element _after_ the selected text will receive focus. However, if the selectable text is inside a focusable container---even a container with a negative `tabindex`---pressing Tab will move focus to the _start_ of the container. If you're reading this on a desktop browser, you can experience this first-hand: select some text in this paragraph and press Tab. Then, do the same in [this snapshot of an excellent _Smashing Magazine_ article](https://web.archive.org/web/20220808163715/https://www.smashingmagazine.com/2022/06/voice-control-usability-considerations-partially-visually-hidden-link-names/).[^29]
{{}} {{