A color code converter that answers "how do I write this color in CSS?" in one step. Paste any one format — a HEX like `#3b82f6`, `rgb(59, 130, 246)`, `hsl(217, 91%, 60%)`, or `hsv(217, 76%, 96%)` — and it converts the color into all four formats (HEX, RGB, HSL, HSV) at once, each with a one-click copy button. The input format is auto-detected, so you never have to pick which box to use. It accepts six-digit HEX, the three-digit shorthand like `#39f`, eight-digit HEX with alpha such as `#3b82f680`, and the alpha in `rgba()` / `hsla()` — when alpha is present it is carried into each output. A color picker next to the input lets you choose a color visually and fills in every code in reverse, while a large swatch shows how it actually looks. You can toggle whether HEX is output in upper- or lower-case, and that preference is saved in your browser so it opens the same way next time. HSL is shown in CSS-ready `hsl(hue, sat%, light%)` notation, and HSV (also known as HSB) is shown as the hue/saturation/value triple used by most color pickers. RGB↔HSL↔HSV conversions use the standard formulas; because values are rounded to integers, a round trip can shift the last digit by one (e.g. 60% becoming 59%), which is normal for color tools. Importantly, the color values you enter are never uploaded, stored, or sent to a server — all conversion happens with JavaScript entirely inside your browser, so brand colors and unreleased palettes stay on your device. CMYK, Lab, and named colors are out of scope; this tool focuses on the four formats you use most on the web.