* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: #f5f7fb;
  font-family: Arial, "Microsoft YaHei", sans-serif;
}

.container {
  max-width: 520px;
  margin: 0 auto;
  padding: 16px;
}

.card {
  background: #fff;
  border-radius: 16px;
  padding: 18px;
  margin-bottom: 16px;
  box-shadow: 0 4px 18px rgba(0, 0, 0, 0.08);
}

h2 {
  margin: 0 0 8px;
}

.hint {
  font-size: 13px;
  color: #666;
}

.row {
  display: grid;
  grid-template-columns: 1fr 1.5fr;
  gap: 10px;
  align-items: center;
  margin: 12px 0;
}

.label {
  font-weight: 600;
}

select {
  width: 100%;
  padding: 10px;
  border-radius: 8px;
  border: 1px solid #ddd;
}

.total {
  font-size: 36px;
  font-weight: bold;
  color: #1677ff;
  margin-top: 10px;
}

button {
  width: 100%;
  margin-top: 14px;
  padding: 12px;
  border: none;
  border-radius: 10px;
  background: #1677ff;
  color: #fff;
  font-size: 16px;
}

@media (max-width: 420px) {
  .row {
    grid-template-columns: 1fr;
  }
}