<div class="radikalwp-fm-otp"><input maxlength="1" value="۴" /><input maxlength="1" value="۲" /><input maxlength="1" class="radikalwp-fm-otp-on" /><input maxlength="1" /><input maxlength="1" /><input maxlength="1" /><//div>

.radikalwp-fm-otp { display: flex; gap: 9px; direction: ltr; }
.radikalwp-fm-otp input {
  width: 42px;
  height: 50px;
  text-align: center;
  font-family: inherit;
  font-size: 20px;
  font-weight: 700;
  color: #0f172a;
  background: #fff;
  border: 1.5px solid #e2e8f0;
  border-radius: 12px;
  outline: none;
  transition: all .2s ease;
}
.radikalwp-fm-otp input:focus {
  border-color: #4f46e5;
  box-shadow: 0 0 0 3px rgba(79, 70, 229, .15);
  transform: translateY(-2px);
}
.radikalwp-fm-otp-on { border-color: #10b981; background: #ecfdf5; color: #059669; }