:root {
  --bg: #f6f7fb;
  --card: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --line: #e5e7eb;
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --shadow: 0 12px 28px rgba(15, 23, 42, 0.08);
}

* { box-sizing: border-box; }
html {
  -webkit-text-size-adjust: 100%;
}
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
}

.app {
  max-width: 980px;
  margin: 0 auto;
  padding: 32px 20px 48px;
}

header {
  margin-bottom: 24px;
}

h1 {
  margin: 0 0 8px;
  font-size: 32px;
  line-height: 1.2;
}

header p, .hint {
  color: var(--muted);
}

.grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 20px;
}

.card {
  background: var(--card);
  border-radius: 18px;
  padding: 24px;
  box-shadow: var(--shadow);
}

.field-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-bottom: 18px;
}

label {
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 14px;
  color: var(--muted);
}

input {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 14px 16px;
  font-size: 16px;
  color: var(--text);
  background: #fff;
}

input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.12);
}

.actions {
  display: flex;
  gap: 12px;
  margin-top: 18px;
}

button {
  border: none;
  border-radius: 12px;
  padding: 14px 18px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  background: var(--primary);
  color: #fff;
}

button:hover {
  background: var(--primary-dark);
}

button.ghost {
  background: #eef2ff;
  color: var(--primary-dark);
}

button.ghost:hover {
  background: #e0e7ff;
}

.advanced {
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 12px 14px 0;
  margin-top: 4px;
}

.advanced summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 14px;
}

.tax-toggle {
  display: flex;
  flex-direction: row;
  align-items: center;
  gap: 10px;
  margin: 6px 2px 14px;
  color: var(--text);
  font-weight: 500;
}

.tax-toggle input {
  width: 18px;
  height: 18px;
  margin: 0;
  accent-color: var(--primary);
}

.result-card h2 {
  margin-top: 0;
  margin-bottom: 18px;
}

.result-list {
  display: grid;
  gap: 14px;
}

.result-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-radius: 14px;
  gap: 16px;
}

.result-item span {
  color: var(--muted);
}

.result-item strong {
  font-size: 18px;
  text-align: right;
}

@media (max-width: 820px) {
  .grid,
  .field-row {
    grid-template-columns: 1fr;
  }

  h1 {
    font-size: 26px;
  }

  .app {
    padding: 20px 14px 32px;
  }
}

@media (max-width: 640px) {
  body {
    background: #eef2f7;
  }

  .app {
    padding: 12px 12px 28px;
  }

  header {
    margin-bottom: 14px;
  }

  h1 {
    font-size: 24px;
  }

  header p {
    margin: 0;
    font-size: 13px;
    line-height: 1.5;
  }

  .card {
    padding: 16px;
    border-radius: 16px;
  }

  .field-row {
    gap: 12px;
    margin-bottom: 14px;
  }

  label {
    gap: 6px;
    font-size: 13px;
  }

  input {
    padding: 15px 14px;
    font-size: 16px;
    min-height: 48px;
  }

  .actions {
    position: sticky;
    bottom: 0;
    margin: 18px -16px -16px;
    padding: 12px 16px calc(12px + env(safe-area-inset-bottom));
    background: rgba(255, 255, 255, 0.96);
    border-top: 1px solid var(--line);
  }

  button {
    flex: 1;
    min-height: 48px;
    font-size: 16px;
  }

  .advanced {
    padding: 10px 12px 0;
  }

  .result-card h2 {
    margin-bottom: 14px;
    font-size: 18px;
  }

  .result-list {
    gap: 10px;
  }

  .result-item {
    flex-direction: column;
    align-items: flex-start;
    gap: 6px;
    padding: 12px 14px;
  }

  .result-item strong {
    font-size: 20px;
    text-align: left;
    word-break: break-word;
  }

  .hint {
    margin-top: 12px;
    font-size: 13px;
    line-height: 1.5;
  }
}