gh-142927: Tachyon: Fix contrast ratio in top panel

[hugovk]

Before

In dark mode, the samples/sec numbers has contrast ratio of 2.9.

In light mode, duration and missed samples are 1.63 and 2.15 respectively.

They should be at least 4.5 to meet WCAG AA guidelines.

After

The values suggested by Chrome:

• Issue: Improve Tachyon UX #142927

[pablogsal]

Thanks a lot @hugovk 🖤

[StanFromIreland]

This also affects the flamegraph output.

[hugovk]

This also affects the flamegraph output.

In what way? For better, or worse? Please share more details.

[StanFromIreland]

As in, the CSS is copy-pasted:

cpython/Lib/profiling/sampling/_flamegraph_assets/flamegraph.css

Lines 349 to 352 in 14f0b51

	.summary-card:nth-child(1) { --i: 0; --card-color: 55, 118, 171; }
	.summary-card:nth-child(2) { --i: 1; --card-color: 40, 167, 69; }
	.summary-card:nth-child(3) { --i: 2; --card-color: 255, 193, 7; }
	.summary-card:nth-child(4) { --i: 3; --card-color: 111, 66, 193; }