Wax Seal

<button class="btn-sig-wax" type="button">
  <span class="btn-sig-wax__crack" aria-hidden="true"></span>
  <span class="btn-sig-wax__word">Open me</span>
</button>

.btn-sig-wax {
  --btn-bg: #8e1b22;
  --btn-fg: #f3c9a8;
  --btn-font: Georgia, serif;
  --btn-size: 15px;
  --btn-weight: 600;
  --btn-px: 12px;
  --btn-py: 11px;
  --btn-w: 116px;
  --btn-h: 116px;
  --btn-bw: 0px;
  --btn-line: #8b6cff;
  --btn-speed: 180ms;
}

.btn-sig-wax {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5em;
  box-sizing: border-box;
  width: var(--btn-w);
  height: var(--btn-h);
  padding: var(--btn-py) var(--btn-px);
  font-family: var(--btn-font);
  font-size: var(--btn-size);
  font-weight: var(--btn-weight);
  line-height: 1.2;
  color: var(--btn-fg);
  background: var(--btn-bg);
  border: var(--btn-bw) solid var(--btn-line);
  border-radius: 47% 53% 50% 50% / 52% 46% 54% 48%;
  box-shadow: inset 3px 4px 6px color-mix(in srgb, var(--btn-bg) 70%, #fff), inset -4px -5px 8px color-mix(in srgb, var(--btn-bg) 55%, #000), 0 5px 10px rgba(0,0,0,.35);
  cursor: pointer;
  text-decoration: none;
  white-space: normal;
  transition: all var(--btn-speed) ease;
  text-align: center;
}

.btn-sig-wax:focus-visible {
  outline: 2px solid var(--btn-bg);
  outline-offset: 2px;
}

.btn-sig-wax:disabled {
  opacity: 0.5;
  pointer-events: none;
}

.btn-sig-wax__icon {
  width: 1.15em;
  height: 1.15em;
  flex-shrink: 0;
}

.btn-sig-wax::before {
  content: "";
  position: absolute;
  inset: 12px;
  border: 2px solid color-mix(in srgb, var(--btn-bg) 55%, #000);
  border-radius: 50%;
  box-shadow: 0 1px 0 color-mix(in srgb, var(--btn-bg) 72%, #fff);
}

.btn-sig-wax[data-state=stamped] {
  --crack: btn-crack 1100ms ease both;
  animation: btn-seal 1100ms ease;
}

.btn-sig-wax__crack {
  position: absolute;
  inset: 0;
  opacity: 0;
  background: color-mix(in srgb, var(--btn-bg) 35%, #000);
  clip-path: inset(0);
  mask: linear-gradient(115deg, transparent 47%, #000 48%, #000 50%, transparent 51%) 0 0 / 100% 34%, linear-gradient(65deg, transparent 47%, #000 48%, #000 50%, transparent 51%) 0 50% / 100% 34%, linear-gradient(115deg, transparent 47%, #000 48%, #000 50%, transparent 51%) 0 100% / 100% 34%;
  mask-repeat: no-repeat;
  animation: var(--crack, none);
  pointer-events: none;
}

@keyframes btn-seal {
  0% { transform: scale(1); }
  30% { transform: scale(0.94); }
  100% { transform: scale(1); }
}

@keyframes btn-crack {
  0% { clip-path: inset(0 0 100% 0); opacity: 1; }
  35% { clip-path: inset(0); opacity: 1; }
  80% { opacity: 1; }
  100% { clip-path: inset(0); opacity: 0; }
}

@media (prefers-reduced-motion: reduce) {
  .btn-sig-wax,
  .btn-sig-wax__crack {
    animation: none !important;
    transition: none !important;
  }
}

document.querySelectorAll(".btn-sig-wax").forEach((el) => {
  const land = () => {
    el.removeAttribute("data-state");
    void el.offsetWidth;
    el.dataset.state = "stamped";
  };
  const clear = () => el.removeAttribute("data-state");
  el.addEventListener("click", land);
  el.addEventListener("animationend", clear);
  return () => {
    el.removeEventListener("click", land);
    el.removeEventListener("animationend", clear);
  };
});

import { useEffect, useRef } from "react";
import type React from "react";
import "./sig-wax.css"; // the CSS tab

function attach(el: HTMLElement) {
  const land = () => {
    el.removeAttribute("data-state");
    void el.offsetWidth;
    el.dataset.state = "stamped";
  };
  const clear = () => el.removeAttribute("data-state");
  el.addEventListener("click", land);
  el.addEventListener("animationend", clear);
  return () => {
    el.removeEventListener("click", land);
    el.removeEventListener("animationend", clear);
  };
}

export function BtnSigWax({ children = "Open me", ...props }: React.ComponentProps<"button">) {
  const ref = useRef<HTMLButtonElement>(null);
  useEffect(() => attach(ref.current!), []);

  return (
    <button className="btn-sig-wax" type="button" ref={ref} {...props}>
      <span className="btn-sig-wax__crack" aria-hidden="true" />
      <span className="btn-sig-wax__word">{children}</span>
    </button>
  );
}

<button class="btn-sig-wax relative inline-flex items-center justify-center gap-[0.5em] [box-sizing:border-box] w-[116px] h-[116px] [padding:11px_12px] [font-family:Georgia,_serif] text-[15px] font-[600] [line-height:1.2] text-[#f3c9a8] bg-[#8e1b22] [border:0px_solid_#8b6cff] rounded-[47%_53%_50%_50%_/_52%_46%_54%_48%] [box-shadow:inset_3px_4px_6px_color-mix(in_srgb,_#8e1b22_70%,_#fff),_inset_-4px_-5px_8px_color-mix(in_srgb,_#8e1b22_55%,_#000),_0_5px_10px_rgba(0,0,0,.35)] cursor-pointer no-underline [white-space:normal] [transition:all_180ms_ease] [text-align:center] focus-visible:[outline:2px_solid_#8e1b22] focus-visible:[outline-offset:2px] disabled:[opacity:0.5] disabled:[pointer-events:none] before:content-[''] before:absolute before:[inset:12px] before:[border:2px_solid_color-mix(in_srgb,_#8e1b22_55%,_#000)] before:rounded-[50%] before:[box-shadow:0_1px_0_color-mix(in_srgb,_#8e1b22_72%,_#fff)] [&[data-state=stamped]]:[--crack:btn-crack_1100ms_ease_both] [&[data-state=stamped]]:[animation:btn-seal_1100ms_ease] motion-reduce:[animation:none!important] motion-reduce:[transition:none!important]" type="button">
  <span class="absolute [inset:0] [opacity:0] [background:color-mix(in_srgb,_#8e1b22_35%,_#000)] [clip-path:inset(0)] [mask:linear-gradient(115deg,_transparent_47%,_#000_48%,_#000_50%,_transparent_51%)_0_0_/_100%_34%,_linear-gradient(65deg,_transparent_47%,_#000_48%,_#000_50%,_transparent_51%)_0_50%_/_100%_34%,_linear-gradient(115deg,_transparent_47%,_#000_48%,_#000_50%,_transparent_51%)_0_100%_/_100%_34%] [mask-repeat:no-repeat] [animation:var(--crack,_none)] [pointer-events:none] motion-reduce:[animation:none!important]" aria-hidden="true"></span>
  <span>Open me</span>
</button>

<!-- A class cannot hold keyframes: keep this in your CSS. -->
<style>
@keyframes btn-seal {
  0% { transform: scale(1); }
  30% { transform: scale(0.94); }
  100% { transform: scale(1); }
}

@keyframes btn-crack {
  0% { clip-path: inset(0 0 100% 0); opacity: 1; }
  35% { clip-path: inset(0); opacity: 1; }
  80% { opacity: 1; }
  100% { clip-path: inset(0); opacity: 0; }
}
</style>

<!-- Needs the script from the JS tab. -->