# Cascading dropdown menu

> The menu scales open from the top and its options drop in one after another.

- Category: [Filters](https://library.aimran.es/components/filters)
- Built with: HTML + CSS
- Live editor: https://library.aimran.es/blocks/uv-f-dd-scale
- Library: AIMRAN Library (https://library.aimran.es), free, no sign-up, by Aimran Oukham

## Where to use it

A dropdown for when a single choice is all you need. The category picker on an online course catalogue, for instance: All, Design, Development, Photography. The staggered entrance makes a plain list feel considered, and the arrow flips so it is clear the menu is open. Handy if you need an animated dropdown menu in HTML and CSS.

Keep the list short, six or seven options at most, or the cascade drags on. For longer lists, look at the dropdown with a search field instead. If your audience is in a hurry, speed the animation up.

## Code

### HTML

```html
<div class="uv-fdd"><button class="tg">Category <i><svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.2" stroke-linecap="round" stroke-linejoin="round"><path d="M6 9l6 6 6-6"/></svg></i></button><div class="mn"><button style="--i:0">All</button><button style="--i:1">Design</button><button style="--i:2">Code</button><button style="--i:3">Photos</button></div></div>
```

### CSS

```css
.uv-fdd {
  --c1: #0071e3;
  --c2: #8ec5ff;
  --s: 16px;
  /* tamaño */
  --k: 1;
  /* velocidad */
  --fg: #1d1d1f;
  /* texto */
  --bg: #f5f5f7;
  /* fondo */
}

.uv-fdd {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  font-size: var(--s);
  color: var(--fg);
  -webkit-tap-highlight-color: transparent;
  position: relative;
  display: inline-block;
}

.uv-fdd .tg {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  font-size: var(--s);
  font-weight: 550;
  line-height: 1;
  padding: .72em 1.25em;
  border: 0;
  border-radius: 999px;
  cursor: pointer;
  background: transparent;
  color: var(--fg);
  position: relative;
  transition: color calc(0.32s / var(--k)) cubic-bezier(.25,.1,.25,1),transform calc(0.32s / var(--k)) cubic-bezier(.34,1.56,.64,1);
  display: inline-flex;
  align-items: center;
  gap: .5em;
  background: var(--bg);
  box-shadow: inset 0 0 0 1.5px color-mix(in srgb,var(--fg) 13%,transparent);
}

.uv-fdd .tg:hover {
  box-shadow: inset 0 0 0 1.5px var(--c1);
  color: var(--c1);
}

.uv-fdd .tg i {
  display: grid;
  place-items: center;
  transition: transform calc(0.35s / var(--k)) cubic-bezier(.34,1.56,.64,1));
}

.uv-fdd .tg svg {
  width: 1em;
  height: 1em;
}

.uv-fdd.open .tg i {
  transform: rotate(180deg);
}

.uv-fdd .mn {
  position: absolute;
  top: calc(100% + .5em);
  left: 0;
  min-width: 100%;
  display: flex;
  flex-direction: column;
  padding: .4em;
  border-radius: 1em;
  background: var(--bg);
  box-shadow: 0 18px 40px rgba(0,0,0,.16);
  transform-origin: top center;
  transform: scale(.92) translateY(-.4em);
  opacity: 0;
  pointer-events: none;
  transition: transform calc(0.35s / var(--k)) cubic-bezier(.34,1.56,.64,1),opacity calc(0.25s / var(--k)) cubic-bezier(.25,.1,.25,1);
  z-index: 3;
}

.uv-fdd.open .mn {
  transform: none;
  opacity: 1;
  pointer-events: auto;
}

.uv-fdd .mn button {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  font-size: var(--s);
  font-weight: 550;
  line-height: 1;
  padding: .72em 1.25em;
  border: 0;
  border-radius: 999px;
  cursor: pointer;
  background: transparent;
  color: var(--fg);
  position: relative;
  transition: color calc(0.32s / var(--k)) cubic-bezier(.25,.1,.25,1),transform calc(0.32s / var(--k)) cubic-bezier(.34,1.56,.64,1);
  text-align: left;
  border-radius: .65em;
  padding: .6em .9em;
  white-space: nowrap;
  opacity: 0;
  transform: translateY(-.35em);
}

.uv-fdd.open .mn button {
  animation: uv-fdd calc(0.35s / var(--k)) cubic-bezier(.25,.1,.25,1) forwards;
  animation-delay: calc(var(--i) * .05s / var(--k));
}

.uv-fdd .mn button:hover {
  background: color-mix(in srgb,var(--c1) 12%,transparent);
  color: var(--c1);
}

@keyframes uv-fdd {
  to {
    opacity: 1;
    transform: none;
  }
}
```

### JavaScript

```js
document.querySelectorAll(".uv-fdd").forEach(el => {
  const tg=el.querySelector(".tg");tg.addEventListener("click",e=>{e.stopPropagation();el.classList.toggle("open")});el.querySelectorAll(".mn button").forEach(b=>b.addEventListener("click",()=>{tg.childNodes[0].textContent=b.textContent+" ";el.classList.remove("open")}));document.addEventListener("click",e=>{if(!el.contains(e.target))el.classList.remove("open")})
});
```

### React

```tsx
// @ts-nocheck: setup() es JavaScript del DOM sin tipos, el mismo de la pestaña JS.
import { useEffect, useRef, type CSSProperties } from "react";

const css = `
.uv-fdd {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  font-size: var(--s);
  color: var(--fg);
  -webkit-tap-highlight-color: transparent;
  position: relative;
  display: inline-block;
}

.uv-fdd .tg {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  font-size: var(--s);
  font-weight: 550;
  line-height: 1;
  padding: .72em 1.25em;
  border: 0;
  border-radius: 999px;
  cursor: pointer;
  background: transparent;
  color: var(--fg);
  position: relative;
  transition: color calc(0.32s / var(--k)) cubic-bezier(.25,.1,.25,1),transform calc(0.32s / var(--k)) cubic-bezier(.34,1.56,.64,1);
  display: inline-flex;
  align-items: center;
  gap: .5em;
  background: var(--bg);
  box-shadow: inset 0 0 0 1.5px color-mix(in srgb,var(--fg) 13%,transparent);
}

.uv-fdd .tg:hover {
  box-shadow: inset 0 0 0 1.5px var(--c1);
  color: var(--c1);
}

.uv-fdd .tg i {
  display: grid;
  place-items: center;
  transition: transform calc(0.35s / var(--k)) cubic-bezier(.34,1.56,.64,1));
}

.uv-fdd .tg svg {
  width: 1em;
  height: 1em;
}

.uv-fdd.open .tg i {
  transform: rotate(180deg);
}

.uv-fdd .mn {
  position: absolute;
  top: calc(100% + .5em);
  left: 0;
  min-width: 100%;
  display: flex;
  flex-direction: column;
  padding: .4em;
  border-radius: 1em;
  background: var(--bg);
  box-shadow: 0 18px 40px rgba(0,0,0,.16);
  transform-origin: top center;
  transform: scale(.92) translateY(-.4em);
  opacity: 0;
  pointer-events: none;
  transition: transform calc(0.35s / var(--k)) cubic-bezier(.34,1.56,.64,1),opacity calc(0.25s / var(--k)) cubic-bezier(.25,.1,.25,1);
  z-index: 3;
}

.uv-fdd.open .mn {
  transform: none;
  opacity: 1;
  pointer-events: auto;
}

.uv-fdd .mn button {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  font-size: var(--s);
  font-weight: 550;
  line-height: 1;
  padding: .72em 1.25em;
  border: 0;
  border-radius: 999px;
  cursor: pointer;
  background: transparent;
  color: var(--fg);
  position: relative;
  transition: color calc(0.32s / var(--k)) cubic-bezier(.25,.1,.25,1),transform calc(0.32s / var(--k)) cubic-bezier(.34,1.56,.64,1);
  text-align: left;
  border-radius: .65em;
  padding: .6em .9em;
  white-space: nowrap;
  opacity: 0;
  transform: translateY(-.35em);
}

.uv-fdd.open .mn button {
  animation: uv-fdd calc(0.35s / var(--k)) cubic-bezier(.25,.1,.25,1) forwards;
  animation-delay: calc(var(--i) * .05s / var(--k));
}

.uv-fdd .mn button:hover {
  background: color-mix(in srgb,var(--c1) 12%,transparent);
  color: var(--c1);
}

@keyframes uv-fdd {
  to {
    opacity: 1;
    transform: none;
  }
}
`;

// Interacción en JavaScript del DOM: la misma que en la pestaña JS.
// eslint-disable-next-line @typescript-eslint/no-explicit-any
function setup(el: any) {
  const tg=el.querySelector(".tg");tg.addEventListener("click",e=>{e.stopPropagation();el.classList.toggle("open")});el.querySelectorAll(".mn button").forEach(b=>b.addEventListener("click",()=>{tg.childNodes[0].textContent=b.textContent+" ";el.classList.remove("open")}));document.addEventListener("click",e=>{if(!el.contains(e.target))el.classList.remove("open")})
}

export default function FDdScale() {
  const ref = useRef<HTMLDivElement>(null);

  useEffect(() => {
    const el = ref.current?.firstElementChild;
    return el ? setup(el) : undefined;
  }, []);

  return (
    <>
      <style>{css}</style>
      <div
        ref={ref} style={{
          "--c1": "#0071e3",
          "--c2": "#8ec5ff",
          "--s": "16px",
          "--k": "1",
          "--fg": "#1d1d1f",
          "--bg": "#f5f5f7",
        } as CSSProperties}
      >
        <div className="uv-fdd"><button className="tg">Category <i><svg viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2.2" strokeLinecap="round" strokeLinejoin="round"><path d="M6 9l6 6 6-6" /></svg></i></button><div className="mn"><button style={{ "--i": "0" } as CSSProperties}>All</button><button style={{ "--i": "1" } as CSSProperties}>Design</button><button style={{ "--i": "2" } as CSSProperties}>Code</button><button style={{ "--i": "3" } as CSSProperties}>Photos</button></div></div>
      </div>
    </>
  );
}
```

## Prompt for AI assistants

Paste this into ChatGPT, Claude, Cursor, v0 or Lovable to adapt the block to your stack (Tailwind, Vue, Svelte…):

````text
I want to add the “Cascading dropdown menu” block (Filters) from AIMRAN Library to my project.

## What it is
The menu scales open from the top and its options drop in one after another.

## Chosen settings
- Main color: #0071e3
- Secondary color: #8ec5ff
- Size: 16px (from 12 to 24px)
- Speed: 1x (from 0.5 to 2x)

## What I need
1. Add it to my project with the same look and animation as the reference code: same sizes, colours, radii, shadows, timings and easing.
2. It is built with plain HTML and CSS (the reference wraps it in a React component with its CSS). If my project uses something else (Vue, Svelte, Astro, plain HTML…), translate it without losing any behaviour. If I use Tailwind, turn the styles into classes; if not, keep the CSS in its own file.
3. Expose the settings above as props (or CSS variables) with those values as defaults.
4. Make it work well on phones: nothing that depends only on hover, touch targets of at least 44 px and no overflow on 320 px screens.
5. Make it look right in light and dark mode.
6. Keep it accessible: semantic HTML, roles and aria-* where needed, visible focus and keyboard support.
7. Respect prefers-reduced-motion: with reduced motion, no big animations but the same end result.

## Reference code
```tsx
// @ts-nocheck: setup() es JavaScript del DOM sin tipos, el mismo de la pestaña JS.
import { useEffect, useRef, type CSSProperties } from "react";

const css = `
.uv-fdd {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  font-size: var(--s);
  color: var(--fg);
  -webkit-tap-highlight-color: transparent;
  position: relative;
  display: inline-block;
}

.uv-fdd .tg {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  font-size: var(--s);
  font-weight: 550;
  line-height: 1;
  padding: .72em 1.25em;
  border: 0;
  border-radius: 999px;
  cursor: pointer;
  background: transparent;
  color: var(--fg);
  position: relative;
  transition: color calc(0.32s / var(--k)) cubic-bezier(.25,.1,.25,1),transform calc(0.32s / var(--k)) cubic-bezier(.34,1.56,.64,1);
  display: inline-flex;
  align-items: center;
  gap: .5em;
  background: var(--bg);
  box-shadow: inset 0 0 0 1.5px color-mix(in srgb,var(--fg) 13%,transparent);
}

.uv-fdd .tg:hover {
  box-shadow: inset 0 0 0 1.5px var(--c1);
  color: var(--c1);
}

.uv-fdd .tg i {
  display: grid;
  place-items: center;
  transition: transform calc(0.35s / var(--k)) cubic-bezier(.34,1.56,.64,1));
}

.uv-fdd .tg svg {
  width: 1em;
  height: 1em;
}

.uv-fdd.open .tg i {
  transform: rotate(180deg);
}

.uv-fdd .mn {
  position: absolute;
  top: calc(100% + .5em);
  left: 0;
  min-width: 100%;
  display: flex;
  flex-direction: column;
  padding: .4em;
  border-radius: 1em;
  background: var(--bg);
  box-shadow: 0 18px 40px rgba(0,0,0,.16);
  transform-origin: top center;
  transform: scale(.92) translateY(-.4em);
  opacity: 0;
  pointer-events: none;
  transition: transform calc(0.35s / var(--k)) cubic-bezier(.34,1.56,.64,1),opacity calc(0.25s / var(--k)) cubic-bezier(.25,.1,.25,1);
  z-index: 3;
}

.uv-fdd.open .mn {
  transform: none;
  opacity: 1;
  pointer-events: auto;
}

.uv-fdd .mn button {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  font-size: var(--s);
  font-weight: 550;
  line-height: 1;
  padding: .72em 1.25em;
  border: 0;
  border-radius: 999px;
  cursor: pointer;
  background: transparent;
  color: var(--fg);
  position: relative;
  transition: color calc(0.32s / var(--k)) cubic-bezier(.25,.1,.25,1),transform calc(0.32s / var(--k)) cubic-bezier(.34,1.56,.64,1);
  text-align: left;
  border-radius: .65em;
  padding: .6em .9em;
  white-space: nowrap;
  opacity: 0;
  transform: translateY(-.35em);
}

.uv-fdd.open .mn button {
  animation: uv-fdd calc(0.35s / var(--k)) cubic-bezier(.25,.1,.25,1) forwards;
  animation-delay: calc(var(--i) * .05s / var(--k));
}

.uv-fdd .mn button:hover {
  background: color-mix(in srgb,var(--c1) 12%,transparent);
  color: var(--c1);
}

@keyframes uv-fdd {
  to {
    opacity: 1;
    transform: none;
  }
}
`;

// Interacción en JavaScript del DOM: la misma que en la pestaña JS.
// eslint-disable-next-line @typescript-eslint/no-explicit-any
function setup(el: any) {
  const tg=el.querySelector(".tg");tg.addEventListener("click",e=>{e.stopPropagation();el.classList.toggle("open")});el.querySelectorAll(".mn button").forEach(b=>b.addEventListener("click",()=>{tg.childNodes[0].textContent=b.textContent+" ";el.classList.remove("open")}));document.addEventListener("click",e=>{if(!el.contains(e.target))el.classList.remove("open")})
}

export default function FDdScale() {
  const ref = useRef<HTMLDivElement>(null);

  useEffect(() => {
    const el = ref.current?.firstElementChild;
    return el ? setup(el) : undefined;
  }, []);

  return (
    <>
      <style>{css}</style>
      <div
        ref={ref} style={{
          "--c1": "#0071e3",
          "--c2": "#8ec5ff",
          "--s": "16px",
          "--k": "1",
          "--fg": "#1d1d1f",
          "--bg": "#f5f5f7",
        } as CSSProperties}
      >
        <div className="uv-fdd"><button className="tg">Category <i><svg viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2.2" strokeLinecap="round" strokeLinejoin="round"><path d="M6 9l6 6 6-6" /></svg></i></button><div className="mn"><button style={{ "--i": "0" } as CSSProperties}>All</button><button style={{ "--i": "1" } as CSSProperties}>Design</button><button style={{ "--i": "2" } as CSSProperties}>Code</button><button style={{ "--i": "3" } as CSSProperties}>Photos</button></div></div>
      </div>
    </>
  );
}
```

Give me the complete final code, ready to paste, and tell me in one line where to put it in my project.
````