Originally Posted by WiredGuy

No chance this works in 2020, this would fall under the color-contrast ratio, it needs to be 3:1 for small text or 4.5:1 for everything else or you can expect those links to be disregarded. See this page for reference: https://web.dev/color-contrast/

And if you're wondering if they actually do use this, yes, right from their API that I just ran (in my case I passed their test):

'color-contrast' => {
'id' => 'color-contrast',
'score' => 1,
'weight' => 3,
'description' => 'Low-contrast text is difficult or impossible for many users to read. [Learn more](https://web.dev/color-contrast/).',
'title' => 'Background and foreground colors have a sufficient contrast ratio',
'details' => {
'type' => 'table',
'headings' => [],
'items' => []
},
},

There's about 200 other factors to consider, but in this case, hidden links will no longer work.
WG