CSS Generator
Pick one color and see it styled live on a real page mock — cover, title, subtitle, body, quote, links and lists. Fine-tune the background and every element, check every text role against strict AA contrast, then copy the CSS or an exact-state share link. Everything runs in your browser; nothing is uploaded.
What is the CSS Generator?
The CSS Generator turns a single color into a full, copy-paste CSS theme. You pick a brand or book-cover color, and the tool renders it live on a realistic 16:9 page mock — a cover image, a title, a subtitle, body text, a quote, bold and underlined text, and a list. You can switch the background, tune any element's color, verify all eight text roles against a strict WCAG AA target, and then copy clean CSS or a share link that reopens the exact studio state.
How to use it
- Pick your color — type a HEX, use the visual HSB picker, eyedrop it from your screen, or roll a random one. This becomes your cover and brand color.
- Choose a background from the five tabs — a neutral grey ramp auto-tinted toward your color — or fine-tune any tab with the hue bar and HSB wheel.
- Recolor each element — tap the cover, the title, subtitle, body, quote, strong, link, or list to open a color editor for just that piece.
- Review Text contrast; if a role misses 4.5:1, press Fix AA failures to adjust only the failing foreground color.
- Press Copy CSS for AI / LLM for the code, or Copy share link to hand off the exact theme without an account.
The method behind it
The five background tabs start from Leo's Five Shades of Grey — Anti-Flash White, Super Silver, Placebo, Elephant in the Room, and Argent — a neutral ramp that pairs cleanly with almost any cover color. The tool keeps each shade's lightness but tints it slightly toward your color's hue, so the five feel coordinated with your choice instead of flatly grey. Every color you touch — the brand, each background, and each text element — runs through the same HSB editor, so saturation and brightness move independently of hue, and a hex field, a random button, and the browser's eyedropper are always one click away. The contrast guard checks each exported text/background pair and can move only a failing foreground to its smallest passing HSL-lightness boundary. The export writes descriptive CSS custom properties, while the share link keeps the full design in the URL rather than sending it to a server.
Common use cases
- Authors and self-publishers building a landing page around a book cover's color.
- Indie makers turning one brand color into a coherent page theme to feed an AI coding assistant.
- Designers sanity-checking how a color reads as a title, as body copy, and behind a cover before committing.
- Anyone prompting an LLM to build a site who wants to hand it exact CSS variables instead of vague color descriptions.
Why use this one
Most CSS generators make a gradient, a shadow, or a button. This one turns one color into a whole page theme you can see, verify, and tune in context, then exports clean CSS or an exact-state link. It runs entirely in your browser, needs no sign-up, and works on mobile. To name the exact shade you are using, open the Color Namer; to explore full schemes from your base color, try the Color Palette Generator; and to see the named system the backgrounds come from, visit Leo's Visual Palette.
Frequently asked questions
What does the CSS Generator actually produce?
It turns one color into a full, copy-paste CSS theme. You pick a brand or cover color, preview it live on a realistic page mock — cover image, title, subtitle, body text, a quote, bold and underlined text, and a list — then fine-tune the background and any element. When it looks right, one button copies the whole page's CSS as clean custom properties (variables) plus element rules, ready to paste straight into a stylesheet or an AI prompt.
Why does it show my color on a page layout instead of just a swatch?
A color rarely tells you how it will feel as a title, as body copy, or behind a cover until you see it in context. The 16:9 page mock renders your color across real elements on a chosen background, so you can judge readability and mood the way visitors will — and adjust until it works, rather than guessing from a single square.
Where do the five background colors come from?
They start from Leo's Five Shades of Grey — a neutral ramp (Anti-Flash White, Super Silver, Placebo, Elephant in the Room, Argent) that pairs cleanly with almost any cover color. The tool keeps each shade's lightness but tints it slightly toward your color's hue so the five harmonize with your choice. You can then fine-tune any tab with a hue bar, an HSB wheel, a hex field, random, or the eyedropper.
How do I use the copied CSS with an AI or LLM?
Press Copy CSS for AI / LLM, then paste it into your prompt with an instruction like 'build a landing page using these CSS variables'. The export uses descriptive custom properties — --brand, --page-bg, --title, --body, --quote and so on — so the model has an unambiguous, ready-to-apply theme instead of vague color descriptions.
Is my color uploaded anywhere?
No. Color parsing, the HSB and HSL math, the live preview, and the CSS export all run entirely in your browser. Nothing is sent to a server, there is no sign-up, and you can share a starting color by adding ?color=2D6CDF to the URL. The eyedropper uses your browser's built-in screen picker where available (Chrome and Edge).
Does the generated theme meet WCAG text contrast?
The Text contrast panel checks the cover title plus all seven exported page-text roles against the strict 4.5:1 WCAG AA normal-text target. If any role fails, Fix AA failures changes only that foreground token to the nearest passing HSL-lightness boundary and leaves its background fixed.
Can I save or share the exact theme without an account?
Yes. Copy share link encodes the full studio state in the URL — brand, background, text roles, bands, cover title, and dividers — so the same design reopens without an account or server-side storage. The ordinary ?color= link remains available for a brand-color-only starting point.