Anatomy of the Magic Input

Most inputs draw a border and change its color on focus. Magic Input does something physical instead: the field lifts off the page, casts a shadow, and reveals a colored edge underneath — then reuses that same edge as a progress bar when you submit. None of it touches layout. It's three stacked layers and a handful of transform / opacity transitions.

The three-layer stack

The component renders one group wrapper containing three absolutely-positioned layers pinned to the same bounds: a blurred shadow, a colored edge, and the real <input> on top. At rest the shadow and edge are hidden; the field looks flat.

<div className="group relative inline-block rounded-xl">
  <span className={shadowClass} aria-hidden="true" />
  <span className={edgeClass} aria-hidden="true" />
  <input className={frontClass} {...props} />
</div>

Because all three share inset-0, they stack perfectly. The 3D illusion is entirely a matter of how far apart they sit on the Y axis — which is what the lift animates.

The lift

Focus lives on group-focus-within, so tabbing into the <input> drives every layer at once. The front translates up, the shadow drops down + fades in + blurs, and the edge fades in. That divergence — front going one way, shadow the other — is what sells the depth.

// front: springy overshoot into the lifted position
"group-focus-within:-translate-y-[4px] " +
  "group-focus-within:[transition:translate_250ms_cubic-bezier(0.3,0.7,0.4,1.5)]";

// shadow: opacity 0 → 1, translate-y 0 → 4px, on a slower settle
"opacity-0 translate-y-0 group-focus-within:opacity-100 " +
  "group-focus-within:translate-y-[4px] " +
  "[transition:translate_600ms_cubic-bezier(0.3,0.7,0.4,1),opacity_250ms_ease]";

The front uses an overshoot bezier (…,1.5) so it springs slightly past its target and settles — the "pop" you feel on focus. The shadow rides a calmer …,1 curve over 600ms, because a shadow that snapped would read as a glitch rather than a cast. depth="always" simply moves the resting position to the lifted one, so the field is raised before you ever focus it.

Everything is transform and opacity

There's no box-shadow transition, no width or top animation, no clip-path. The shadow is a solid blurred span whose translate and opacity change; the edge only fades. That's deliberate: transform and opacity are the two properties the browser can animate on the compositor without touching layout or paint, so the lift stays smooth even with several fields on screen.

const frontClass =
  "… [will-change:translate] " +
  "[transition:translate_600ms_cubic-bezier(0.3,0.7,0.4,1)] " +
  "motion-reduce:[transition:none] …";

will-change: translate promotes the layer up front so the first frame doesn't hitch, and motion-reduce:[transition:none] drops the whole thing to an instant state change for anyone who asks for reduced motion.

The rainbow edge

With rainbow (the default), focus swaps the edge and shadow fill for a single 200%-wide linear gradient, and animate-magic-rainbow slides background-position across it. The front stays neutral, so the color reads as a glowing edge peeking out from under a plain field — not a tinted input.

const RAINBOW_FOCUS_FILL =
  "group-focus-within:[background-image:linear-gradient(90deg," +
  "var(--rainbow-1),var(--rainbow-5),var(--rainbow-3)," +
  "var(--rainbow-4),var(--rainbow-2))] " +
  "group-focus-within:[background-size:200%_100%] " +
  "group-focus-within:animate-magic-rainbow " +
  "motion-reduce:group-focus-within:animate-none";

The gradient is a full literal, not an interpolated string, because Tailwind's class scanner can't resolve a ${var} nested inside an arbitrary value — so the colors are written out. Only background-position animates; the gradient itself never re-renders.

The submit lifecycle

Pass onSubmit (or submitButton) and the field grows a submit button. Drive status and it runs a lifecycle: loading → success / error. The elegant part is that the same edge/shadow layer that draws the depth becomes the progress bar — its background-size grows for determinate progress, or a segment bounces end to end for indeterminate — while the button's icon cross-fades arrow → ring → check.

const statusFill =
  isLoading && isDeterminate
    ? "[background-position:right_center] " +
      "[background-size:var(--magic-progress,0%)_100%]"
    : isLoading
      ? "[background-image:linear-gradient(90deg,transparent," +
        "var(--magic-fill),transparent)] " +
        "[background-size:45%_100%] animate-magic-input-indeterminate"
      : "[background-color:var(--primary)] animate-magic-input-sweep";

The four submit icons — arrow, ring/spinner, check, X — are all stacked in the same box; only the active one is opacity-100 scale(1), the rest sit at opacity-0 scale(0.4) rotate(-35deg). Switching status just changes which one is active, so they morph into each other instead of popping.

const iconClass = (active: boolean) =>
  active
    ? "… opacity-100 [transform:scale(1)_rotate(0deg)]"
    : "… opacity-0 [transform:scale(0.4)_rotate(-35deg)]";

Locked, not disabled

While loading or success, the field has to stop accepting input without losing its lifted 3D look — a disabled input would flatten and gray out. So it uses readOnly instead:

const lock = readOnly || isLoading || status === "success";
// …
<input readOnly={lock} aria-busy={isLoading || undefined} … />

The visuals stay live, the value is frozen, and aria-busy plus an sr-only role="progressbar" (with aria-valuenow when determinate) tell assistive tech what the animation is showing. Focus rings come from focus-visible so keyboard users get an outline without mouse clicks painting one.

The result

Three stacked layers, a focus-driven lift, and a progress bar that's really just the depth layer wearing a different fill — the whole component is transform and opacity doing the work that borders and box-shadows usually fake.