HEX and RGB tie lightness, strength and hue together. Here each is its own control, and you can see the point where a screen runs out of colour.
At this lightness and hue, sRGB reaches chroma 0.176.
This colour fits in sRGB, so every ordinary screen can show it.
Text on light
Text on dark
Nearest named colour: Steel Blue #4682b4, ΔE00 5.2
Use it to darken a colour without greying it, to find how vivid a hue can get at a given lightness, or to learn how OKLCH behaves before writing it in CSS.
Colours beyond sRGB depend on the screen you are looking at, so the swatch here only shows them accurately on a wide-gamut display. OKLCH is a model of average vision. Its lightness is a close guide to what people see and not an exact measure for every colour.
OKLCH is OKLab in polar form: L is lightness, C is chroma, and h is the hue angle. Every value is converted to linear RGB and tested against each screen standard. The limit line is found by searching for the highest chroma that still fits at each lightness.