<div class="radikalwp-fm-icon"><span>✉<//span><input type="email" placeholder="you@example.com" /><//div>

.radikalwp-fm-icon {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 260px;
  padding: 0 14px;
  background: #fff;
  border: 1.5px solid #e2e8f0;
  border-radius: 12px;
  transition: border-color .25s ease;
}
.radikalwp-fm-icon span { color: #94a3b8; transition: color .25s ease; }
.radikalwp-fm-icon input {
  flex: 1;
  min-width: 0;
  padding: 12.5px 0;
  border: none;
  outline: none;
  font-family: inherit;
  font-size: 13.5px;
  color: #0f172a;
  background: transparent;
}
.radikalwp-fm-icon:focus-within { border-color: #4f46e5; }
.radikalwp-fm-icon:focus-within span { color: #4f46e5; }