<fieldset class="crb-avatar">
  <legend class="crb-sr">Avatar</legend>
  <label style="--c: #7c6cff"><input type="radio" name="crb-avatar" /><span>A</span></label>
  <label style="--c: #ff6c8a"><input type="radio" name="crb-avatar" checked /><span>B</span></label>
  <label style="--c: #2ecc8a"><input type="radio" name="crb-avatar" /><span>C</span></label>
  <label style="--c: #f5a623"><input type="radio" name="crb-avatar" /><span>D</span></label>
</fieldset>

.crb-avatar { display: flex; gap: 10px; border: 0; padding: 0; }
.crb-avatar input { appearance: none; -webkit-appearance: none; position: absolute; opacity: 0; }
.crb-avatar label { cursor: pointer; }
.crb-avatar span {
  display: flex; align-items: center; justify-content: center;
  width: 40px; height: 40px; border-radius: 50%;
  background: linear-gradient(135deg, var(--c), color-mix(in srgb, var(--c), white 30%));
  font: 700 14px/1 system-ui, sans-serif; color: #fff;
  box-shadow: 0 0 0 0 var(--c);
  transition: transform 0.3s cubic-bezier(0.34,1.56,0.64,1), box-shadow 0.3s, opacity 0.25s;
  opacity: 0.55;
}
.crb-avatar label:hover span { opacity: 0.85; }
.crb-avatar input:checked + span {
  opacity: 1; transform: scale(1.15);
  box-shadow: 0 0 0 3px #15151d, 0 0 0 5px var(--c), 0 0 18px var(--c);
}

.crb-sr {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}