A tint is pure hue + white, so it always gets lighter and less saturated. A shade is pure hue + black, so it gets darker and heavier. A tone is pure hue + gray, so lightness barely moves but saturation drops — reads as "muted."
CSS color-mix() implements this directly: color-mix(in srgb, red 70%, white 30%) lets you dial the ratio exactly. You can fake it with HSL (raising lightness approximates a tint) but it isn't identical — a real mix blends the actual white/black/gray into the result.
Using these three axes to derive every state of a single brand color — hover, disabled, background — keeps a whole palette consistent.
When to use
For generating a design-token scale — brand-50 through brand-900 — from a single base color.