html, body {
  margin: 0;
  min-height: 100%;
  background: #101318;
  color: #edf1f6;
  font: 15px/1.45 Inter, Arial, sans-serif;
}

.checkout {
  max-width: 1040px;
  margin: 0 auto;
  padding: 28px;
}

.header {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 16px;
  align-items: end;
  margin-bottom: 18px;
}

.eyebrow {
  margin: 0 0 4px;
  color: #80b6ff;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0;
}

h1 {
  margin: 0;
  font-size: 32px;
  font-weight: 650;
}

.status-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
  margin-bottom: 16px;
}

.metric, .payment, .catalog-panel {
  border: 1px solid #2a3340;
  border-radius: 8px;
  background: #171c24;
}

.metric {
  padding: 14px;
}

.metric span {
  display: block;
  color: #9dadc0;
  font-size: 12px;
  margin-bottom: 6px;
}

code {
  color: #d7e4f5;
  font: 13px/1.35 ui-monospace, SFMono-Regular, Menlo, monospace;
}

.payment, .catalog-panel {
  padding: 18px;
}

.catalog-panel {
  margin-bottom: 16px;
}

h2 {
  margin: 0 0 12px;
  font-size: 18px;
}

.catalog {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
}

.catalog-item {
  display: grid;
  gap: 6px;
  min-height: 118px;
  text-align: left;
  border: 1px solid #314052;
  border-radius: 6px;
  background: #111820;
  color: #edf1f6;
  padding: 12px;
  cursor: pointer;
}

.catalog-item:hover {
  background: #172130;
}

.catalog-item span, .muted {
  color: #9dadc0;
}

form {
  display: grid;
  grid-template-columns: 180px 1fr auto;
  gap: 12px;
  align-items: end;
}

label {
  display: grid;
  gap: 6px;
  color: #9dadc0;
  font-size: 12px;
}

input {
  box-sizing: border-box;
  min-height: 40px;
  border: 1px solid #2d3745;
  border-radius: 6px;
  background: #101318;
  color: #edf1f6;
  padding: 8px 10px;
}

.actions {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.button {
  min-height: 40px;
  border: 1px solid #33445c;
  border-radius: 6px;
  background: #223149;
  color: #edf1f6;
  padding: 8px 12px;
  cursor: pointer;
}

.button.primary {
  background: #285083;
  border-color: #3b6ca8;
}

.button:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.result {
  margin-top: 14px;
  color: #b8c6d8;
  word-break: break-word;
}

@media (max-width: 900px) {
  .header, .status-grid, form, .catalog {
    grid-template-columns: 1fr;
  }
}