<button class="btn-key">
  <span class="btn-key-cap">
    <span class="btn-key-letter">RETURN</span>
  </span>
</button>

.btn-key {
  display: inline-block;
  padding: 0;
  border: none;
  background: transparent;
  cursor: pointer;
  perspective: 200px;
}
.btn-key-cap {
  display: inline-flex; align-items: center; justify-content: center;
  width: 130px; height: 56px;
  background: radial-gradient(ellipse at 50% 30%, #fff8e8 0%, #f0e8d8 60%, #d4c8a8 100%);
  border: 3px solid #1a1a1a;
  border-radius: 8px;
  box-shadow:
    inset 0 -8px 12px rgba(0,0,0,0.15),
    inset 0 2px 4px rgba(255,255,255,0.6),
    0 5px 0 #1a1a1a,
    0 8px 14px rgba(0,0,0,0.25);
  transition: transform 0.08s ease, box-shadow 0.08s ease;
}
.btn-key-letter {
  font-family: ui-serif, 'Courier New', Georgia, monospace;
  font-size: 13px; font-weight: 800;
  letter-spacing: 0.16em;
  color: #1a1a1a;
}
.btn-key:hover .btn-key-cap {
  transform: translateY(-1px);
}
.btn-key:active .btn-key-cap {
  transform: translateY(4px);
  box-shadow:
    inset 0 -2px 6px rgba(0,0,0,0.25),
    inset 0 2px 4px rgba(255,255,255,0.4),
    0 1px 0 #1a1a1a,
    0 2px 4px rgba(0,0,0,0.2);
}