* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: #f4f7fb;
  color: #0f172a;
}

.topbar {
  background: #0f172a;
  color: white;
  padding: 16px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.brand {
  font-size: 20px;
  font-weight: bold;
}

.brand span {
  color: #38bdf8;
}

.secure-badge {
  background: #1d4ed8;
  padding: 7px 13px;
  border-radius: 999px;
  font-size: 13px;
  font-weight: bold;
}

.main {
  padding: 25px 15px;
}

.checkout {
  max-width: 850px;
  margin: auto;
  background: white;
  padding: 28px;
  border-radius: 20px;
  box-shadow: 0 10px 30px rgba(15, 23, 42, 0.12);
}

.checkout-header {
  margin-bottom: 25px;
}

.eyebrow {
  color: #2563eb;
  font-weight: bold;
  text-transform: uppercase;
  font-size: 13px;
  margin: 0 0 6px;
}

h1 {
  margin: 0 0 8px;
  font-size: 32px;
}

.checkout-header p {
  color: #64748b;
}

.section-title {
  font-weight: bold;
  margin: 25px 0 15px;
  color: #1e293b;
  border-bottom: 1px solid #e2e8f0;
  padding-bottom: 8px;
}

.grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 15px;
}

.field {
  margin-bottom: 15px;
}

label {
  display: block;
  font-weight: bold;
  margin-bottom: 6px;
}

input {
  width: 100%;
  padding: 13px;
  border: 1px solid #cbd5e1;
  border-radius: 10px;
  font-size: 16px;
  outline: none;
}

input:focus {
  border-color: #2563eb;
  box-shadow: 0 0 0 3px #dbeafe;
}

input.invalid {
  border-color: #dc2626;
  background: #fff5f5;
}

small {
  color: #dc2626;
  min-height: 18px;
  display: block;
  margin-top: 4px;
}

.payment-options {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 15px;
}

.payment-card {
  border: 1px solid #cbd5e1;
  border-radius: 14px;
  padding: 18px;
  text-align: center;
  cursor: pointer;
  transition: 0.2s;
}

.payment-card input {
  display: none;
}

.payment-card span {
  font-weight: bold;
}

.payment-card:has(input:checked) {
  background: #eff6ff;
  border-color: #2563eb;
  color: #1d4ed8;
}

.payment-error {
  margin-top: 6px;
}

.payment-box {
  background: #eff6ff;
  border: 1px solid #bfdbfe;
  padding: 18px;
  border-radius: 14px;
  margin: 15px 0;
}

.payment-box p {
  margin: 0 0 6px;
  color: #64748b;
}

.payment-box strong {
  display: block;
  font-size: 22px;
  color: #1d4ed8;
  margin-bottom: 6px;
}

.payment-box span {
  color: #475569;
  font-size: 14px;
}

button {
  width: 100%;
  padding: 15px;
  border: none;
  border-radius: 14px;
  background: #2563eb;
  color: white;
  font-size: 17px;
  font-weight: bold;
  cursor: pointer;
  margin-top: 15px;
}

button:hover {
  background: #1d4ed8;
}

.resultado {
  margin-top: 20px;
  padding: 18px;
  border-radius: 14px;
  font-weight: bold;
}

.resultado.ok {
  background: #ecfdf5;
  color: #166534;
  border: 1px solid #86efac;
}

.resultado.error {
  background: #fef2f2;
  color: #991b1b;
  border: 1px solid #fecaca;
}

.hidden {
  display: none;
}

@media (max-width: 650px) {
  .checkout {
    padding: 20px;
  }

  h1 {
    font-size: 28px;
  }

  .grid,
  .payment-options {
    grid-template-columns: 1fr;
  }

  .topbar {
    flex-direction: column;
    gap: 8px;
  }
}