FAB classic

FAB classic: a CSS button. Copy the rules, or the prompt that rebuilds it.

fabcircleiconelevatedfloating

CSS

.btn-166 {
  width: 56px;
  height: 56px;
  display: inline-grid;
  place-items: center;
  color: #fff;
  background: #6366f1;
  border: 0;
  border-radius: 50%;
  cursor: pointer;
  box-shadow: 0 6px 16px -4px #6366f1aa,0 2px 4px #0002;
  transition: box-shadow .2s,transform .2s,background .2s
}
.btn-166:hover {
  background: #4f46e5;
  box-shadow: 0 10px 24px -6px #6366f1cc,0 3px 6px #0003;
  transform: translateY(-2px)
}
.btn-166:focus-visible {
  outline: 3px solid #6366f1;
  outline-offset: 3px
}
.btn-166:active {
  transform: translateY(0) scale(.96);
  box-shadow: 0 3px 8px -2px #6366f1aa
}

HTML

<button class="btn-166" aria-label="Create"><svg width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.5" stroke-linecap="round"><path d="M12 5v14M5 12h14"/></svg></button>

Prompt

A classic 56px round floating action button in indigo #6366f1 with a white 24px inline plus icon and a layered indigo shadow (0 6px 16px plus a small dark 2px). Hover darkens to #4f46e5, lifts 2px and deepens the shadow; active scales 0.96 with a tight shadow. Focus 3px indigo outline offset 3px.

FAB classic

Same shelf