```css
.payment-router-section {
  padding: 50px 0;
}

.payment-router {
  width: 100%;
  max-width: 640px;
  margin: 0 auto;
}

.payment-router__field {
  margin-bottom: 24px;
}

.payment-router__field[hidden],
.payment-router__error[hidden] {
  display: none;
}

.payment-router__field label {
  display: block;
  margin-bottom: 8px;
  font-weight: 600;
}

#payment-invoice,
#payment-amount {
  box-sizing: border-box;
  width: 100%;
  min-height: 52px;
  padding: 12px 16px;
  font-family: inherit;
  font-size: 18px !important;
  line-height: 1.5 !important;
}

#payment-invoice::placeholder,
#payment-amount::placeholder {
  font-family: inherit;
  font-size: 18px !important;
}

.payment-router__button {
  display: inline-block;
  min-width: 168px;
  padding: 12px 30px;
  border: none;
  border-radius: 8px;
  background-color: var(--btn_bg);
  color: var(--btn_color);
  font-family: Poppins;
  font-size: 15px;
  font-weight: 700;
  text-align: center;
  text-transform: uppercase;
  cursor: pointer;
  appearance: none;
  -webkit-appearance: none;
  transition: var(--primary_transition);
}

.payment-router__button:hover,
.payment-router__button:focus {
  background-color: var(--btn_hover_bg);
  color: var(--btn_color);
}

.payment-router__button:focus-visible {
  outline: 2px solid var(--theme-4, #114097);
  outline-offset: 3px;
}

.payment-router__error {
  margin: 0 0 20px;
  color: var(--theme-5, #02205A);
  font-size: 18px;
  line-height: 1.5;
  font-weight: 600;
}

.payment-router__noscript {
  margin-bottom: 24px;
  padding: 16px;
  border: 2px solid var(--theme-4, #114097);
  background-color: var(--theme-1, #E6EFFE);
  color: var(--theme-5, #02205A);
  font-size: 18px;
  line-height: 1.5;
  font-weight: 600;
}
```