Web & UI Design

Animate

Emil KowalskiMITSkill language: English
License verifiedNo scriptsLow risk
DemoReal run · claude-sonnet-5-5 · October 2026
I'm building a React app with Tailwind and Motion is not installed. When the user clicks the profile avatar in the header, a small dropdown menu (Profile, Settings, Log out) opens below it. Please build the open and close animation for that dropdown. Give me the code.
Skill: animate
Read: RECIPES.md
import { useEffect, useRef, useState } from "react";

export function ProfileMenu({ src }) {
  const [open, setOpen] = useState(false);
  const ref = useRef(null);

  useEffect(() => {
    if (!open) return;
    const onPointerDown = (e) => {
      if (!ref.current?.contains(e.target)) setOpen(false);
    };
    const onKeyDown = (e) => e.key === "Escape" && setOpen(false);
    document.addEventListener("pointerdown", onPointerDown);
    document.addEventListener("keydown", onKeyDown);
    return () => {
      document.removeEventListener("pointerdown", onPointerDown);
      document.removeEventListener("keydown", onKeyDown);
    };
  }, [open]);

  return (
    <div ref={ref} className="relative">
      <button
        onClick={() => setOpen((o) => !o)}
        aria-haspopup="menu"
        aria-expanded={open}
        className="rounded-full transition-transform duration-150 ease-[cubic-bezier(0.23,1,0.32,1)] active:scale-95"
      >
        <img src={src} alt="Profile" className="size-9 rounded-full" />
      </button>

      <div
        role="menu"
        data-state={open ? "open" : "closed"}
        className={[
          "absolute right-0 top-full mt-2 w-44 origin-top-right rounded-lg border bg-white p-1 shadow-lg",
          "transition-[opacity,transform,visibility] ease-[cubic-bezier(0.23,1,0.32,1)]",
          open
            ? "visible scale-100 opacity-100 duration-200"
            : "invisible pointer-events-none scale-95 opacity-0 duration-150",
          // reduced motion: keep the fade, drop the scale
          "motion-reduce:scale-100",
        ].join(" ")}
      >
        {["Profile", "Settings", "Log out"].map((label) => (
          <button
            key={label}
            role="menuitem"
            tabIndex={open ? 0 : -1}
            onClick={() => setOpen(false)}
            className="block w-full rounded-md px-3 py-2 text-left text-sm hover:bg-gray-100"
          >
            {label}
          </button>
        ))}
      </div>
    </div>
  );
}

If you'd rather use a gated hover, swap hover:bg-gray-100 for [@media(hover:hover)]:hover:bg-gray-100. The color change is subtle enough that I left it plain.

Gate: An avatar click happens occasionally and isn't keyboard-driven, so a standard animation is fine. The purpose is spatial consistency: the menu should look like it came out of the avatar.

Ingredients:

  • Tool: CSS transitions toggled by state. The menu stays mounted, so no exit-animation library is needed. Transitions also retarget if the user double-clicks, where keyframes would restart.
  • Properties: opacity and transform: scale(0.95 → 1), never scale(0). visibility flips at the end of the transition, which keeps the closed menu out of the tab order and screen readers without cutting off the exit.
  • Origin: origin-top-right, assuming the avatar sits at the right edge of the header. Use origin-top-left if it's on the left.
  • Curve and timing: cubic-bezier(0.23, 1, 0.32, 1), 200ms to open and 150ms to close. Closing is a bit faster because the user has already decided.
  • Reduced motion: motion-reduce:scale-100 drops the scale and keeps the fade.

Feel-check: Play it at 3–5× duration in the DevTools animation inspector. Confirm the menu grows out of the avatar corner and that rapid open/close clicks reverse smoothly.

This is hand-rolled, so it lacks arrow-key navigation and focus return to the avatar. If you want those, a headless primitive like Radix or Base UI gives you them, and the same classes work on its data-[state] attributes.

Test run: a profile dropdown in React and Tailwind with no animation library installed. The model read the Skill's RECIPES.md, chose CSS transitions and gave the gate, ingredients and a feel-check. The code was not run in a browser. The model noted that the hand-rolled menu lacks arrow-key navigation and focus return.

What it does

Turns a request for motion into an implementation that would survive a strict review. It runs a build sequence: a frequency gate (no animation for things used hundreds of times a day), a named purpose (feedback, spatial consistency, state, preventing a jarring change, explanation, delight), the cheapest tool that works (CSS transition, @starting-style, CSS animation, WAAPI, Motion), the properties (transform and opacity only, never scale from zero), then easing and duration from fixed tables or a spring, interruption and exit behavior, and reduced-motion and hover gating. It ships a "never ship" table and a RECIPES file for common cases such as buttons, dropdowns, tooltips, modals, drawers, toasts, accordions and tab indicators.

Output

The code, then a few lines on the gate result, the ingredients and what to feel-check.

Good for

Developers adding motion to a component who want a confident, opinionated answer rather than a menu of options.

Notes & risks

Low risk: pure instructions with no scripts, no network access and no file writes. It writes front-end code and does not run it, so check the result in a browser and on a real device. Test-run once on a React and Tailwind profile dropdown: it read its RECIPES file, chose CSS transitions and gave the gate, ingredients and a feel-check; the model noted the hand-rolled menu lacks arrow-key navigation and focus return. When invoked with no question it replies only with a greeting. By Emil Kowalski, MIT.

SKILL.md original3 files in this package