Rainbow Border
A copy-paste borders & outlines component in pure HTML & CSS. Zero dependencies, framework-agnostic, MIT-licensed.
Borders & OutlinesHTMLCSSany framework
Rainbow Border
Copy into your project
HTML
<div class="nuda-rainbow-border">
Your content here
</div>CSS
/* Rainbow Border
Rainbow color cycling border.
Customize: gradient colors */
.nuda-rainbow-border {
position: relative;
background: #111;
border-radius: 12px;
padding: 24px 32px;
isolation: isolate;
}
.nuda-rainbow-border::before {
content: '';
position: absolute;
inset: -2px;
border-radius: inherit;
background: linear-gradient(
90deg,
#ef4444, #f59e0b, #22c55e,
#06b6d4, #6366f1, #ec4899,
#ef4444
);
background-size: 300% 100%;
z-index: -1;
animation: nuda-rainbow-shift 4s linear infinite;
will-change: background-position;
}
@keyframes nuda-rainbow-shift {
to { background-position: 300% 0; }
}
@media (prefers-reduced-motion: reduce) {
.nuda-rainbow-border::before { animation: none; }
}How to use Rainbow Border
Paste the HTML where you need it and the CSS into a global stylesheet (or a <style> tag). Every class is prefixed nuda- so it never collides with Tailwind or your own styles. Tweak the CSS custom properties to match your design system.
Works in React, Vue, Svelte, Astro, Next.js, Nuxt, Laravel Blade, Django, Rails — or a single .html file. No npm install, no build step.