Color Shades & Harmonies turns one colour into a usable set. Get an 11-step ramp from near-white to near-black, lighter tints, darker shades, muted tones, or a harmony set (complementary, analogous, triadic, tetradic, split-complementary, square).
Steps are computed in HSL so the hue stays constant within tints, shades, and tones. Nothing is uploaded.
In HSL. Shades lower the lightness, tints raise it, tones lower the saturation, all keeping the hue.
Complementary, analogous, triadic, tetradic, split-complementary, and square, by rotating the hue.
Yes. Copy the plain list, or copy it as :root CSS custom properties.
No. It is a local calculation in your browser.