8-Bit

<button class="btn-sig-pixel" type="button">
  <span>Press start</span>
</button>

.btn-sig-pixel {
  --btn-bg: #2e9e6b;
  --btn-fg: #ffffff;
  --btn-font: ui-monospace, monospace;
  --btn-size: 14px;
  --btn-weight: 600;
  --btn-px: 20px;
  --btn-py: 14px;
  --btn-w: auto;
  --btn-h: auto;
  --btn-bw: 0px;
  --btn-line: #8b6cff;
  --btn-radius: 0px;
}

.btn-sig-pixel {
  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: var(--btn-radius);
  box-shadow: inset -4px -4px 0 color-mix(in srgb, var(--btn-bg) 62%, #000), inset 4px 4px 0 color-mix(in srgb, var(--btn-bg) 72%, #fff);
  cursor: pointer;
  text-decoration: none;
  white-space: nowrap;
  transition: none;
  clip-path: polygon(0 8px, 4px 8px, 4px 4px, 8px 4px, 8px 0, calc(100% - 8px) 0, calc(100% - 8px) 4px, calc(100% - 4px) 4px, calc(100% - 4px) 8px, 100% 8px, 100% calc(100% - 8px), calc(100% - 4px) calc(100% - 8px), calc(100% - 4px) calc(100% - 4px), calc(100% - 8px) calc(100% - 4px), calc(100% - 8px) 100%, 8px 100%, 8px calc(100% - 4px), 4px calc(100% - 4px), 4px calc(100% - 8px), 0 calc(100% - 8px));
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.btn-sig-pixel:focus-visible {
  outline: 2px solid var(--btn-fg);
  outline-offset: -6px;
}

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

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

.btn-sig-pixel::before {
  content: "▶";
  font-size: 0.7em;
  opacity: 0;
}

.btn-sig-pixel:hover::before {
  opacity: 1;
  animation: btn-blink 700ms steps(2, jump-none) infinite;
}

.btn-sig-pixel:active {
  transform: translateY(4px);
  box-shadow: inset 4px 4px 0 color-mix(in srgb, var(--btn-bg) 62%, #000), inset -4px -4px 0 color-mix(in srgb, var(--btn-bg) 72%, #fff);
}

@keyframes btn-blink {
  from { opacity: 1; }
  to { opacity: 0; }
}

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

// No JavaScript needed: this one is CSS only.

import type React from "react";
import "./sig-pixel.css"; // the CSS tab

export function BtnSigPixel({ children = "Press start", ...props }: React.ComponentProps<"button">) {
  return (
    <button className="btn-sig-pixel" type="button" {...props}>
      <span>{children}</span>
    </button>
  );
}

<button class="relative inline-flex items-center justify-center gap-[0.5em] [box-sizing:border-box] [padding:14px_20px] [font-family:ui-monospace,_monospace] text-[14px] font-[600] [line-height:1.2] text-[#ffffff] bg-[#2e9e6b] [border:0px_solid_#8b6cff] rounded-[0px] [box-shadow:inset_-4px_-4px_0_color-mix(in_srgb,_#2e9e6b_62%,_#000),_inset_4px_4px_0_color-mix(in_srgb,_#2e9e6b_72%,_#fff)] cursor-pointer no-underline whitespace-nowrap [transition:none] [clip-path:polygon(0_8px,_4px_8px,_4px_4px,_8px_4px,_8px_0,_calc(100%_-_8px)_0,_calc(100%_-_8px)_4px,_calc(100%_-_4px)_4px,_calc(100%_-_4px)_8px,_100%_8px,_100%_calc(100%_-_8px),_calc(100%_-_4px)_calc(100%_-_8px),_calc(100%_-_4px)_calc(100%_-_4px),_calc(100%_-_8px)_calc(100%_-_4px),_calc(100%_-_8px)_100%,_8px_100%,_8px_calc(100%_-_4px),_4px_calc(100%_-_4px),_4px_calc(100%_-_8px),_0_calc(100%_-_8px))] [letter-spacing:0.06em] [text-transform:uppercase] focus-visible:[outline:2px_solid_#ffffff] focus-visible:[outline-offset:-6px] disabled:[opacity:0.5] disabled:[pointer-events:none] before:content-['▶'] before:text-[0.7em] before:[opacity:0] hover:before:[opacity:1] hover:before:[animation:btn-blink_700ms_steps(2,_jump-none)_infinite] active:[transform:translateY(4px)] active:[box-shadow:inset_4px_4px_0_color-mix(in_srgb,_#2e9e6b_62%,_#000),_inset_-4px_-4px_0_color-mix(in_srgb,_#2e9e6b_72%,_#fff)] motion-reduce:[transition:none!important] motion-reduce:before:[animation:none!important]" type="button">
  <span>Press start</span>
</button>

<!-- A class cannot hold keyframes: keep this in your CSS. -->
<style>
@keyframes btn-blink {
  from { opacity: 1; }
  to { opacity: 0; }
}
</style>