:root {
  --bg: #0f172a;
  --bg-grad-1: #1e293b;
  --bg-grad-2: #0f172a;
  --card: #1e293b;
  --card-2: #243349;
  --border: #334155;
  --text: #e2e8f0;
  --muted: #94a3b8;
  --primary: #38bdf8;
  --primary-strong: #0ea5e9;
  --green: #34d399;
  --red: #f87171;
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.35);
  --radius: 16px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  /* 防止 iOS Safari 自動放大字級導致版面不一致 */
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

/* 統一表單元件外觀（iOS Safari 與 Chrome 一致） */
input, button {
  font-family: inherit;
  font-size: inherit;
}
input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang TC",
    "Microsoft JhengHei", "Noto Sans TC", Roboto, Helvetica, Arial, sans-serif;
  color: var(--text);
  background: radial-gradient(1200px 600px at 80% -10%, #1e3a5f 0%, transparent 50%),
    linear-gradient(160deg, var(--bg-grad-1), var(--bg-grad-2));
  min-height: 100vh;
  line-height: 1.5;
  overflow-x: hidden;
}

input { max-width: 100%; }

.app {
  max-width: 960px;
  margin: 0 auto;
  padding: 32px 20px 48px;
}

.app__header { text-align: center; margin-bottom: 24px; }
.app__title {
  font-size: clamp(26px, 5vw, 36px);
  margin: 0 0 8px;
  background: linear-gradient(90deg, #38bdf8, #818cf8);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  font-weight: 800;
}
.app__subtitle { color: var(--muted); margin: 0; font-size: 15px; }

.tabs {
  display: flex;
  gap: 8px;
  background: var(--card);
  border: 1px solid var(--border);
  padding: 6px;
  border-radius: 999px;
  width: fit-content;
  margin: 0 auto 24px;
}
.tab {
  border: none;
  background: transparent;
  color: var(--muted);
  font-size: 15px;
  font-weight: 600;
  padding: 10px 22px;
  border-radius: 999px;
  cursor: pointer;
  white-space: nowrap;
  flex: 0 0 auto;
  transition: all 0.2s ease;
}
.tab--active {
  background: linear-gradient(90deg, var(--primary-strong), #6366f1);
  color: #fff;
  box-shadow: 0 4px 14px rgba(14, 165, 233, 0.4);
}

.layout {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 20px;
  align-items: start;
}

/* ---------- 平板 / 手機 ---------- */
@media (max-width: 760px) {
  .layout { grid-template-columns: 1fr; gap: 16px; }

  /* 分頁換行排成兩行（不捲動） */
  .tabs {
    width: 100%;
    max-width: 100%;
    flex-wrap: wrap;
    justify-content: center;
    border-radius: 14px;
  }
  .tab {
    flex: 1 1 calc(50% - 4px);
    min-width: 0;
    text-align: center;
    padding: 10px 12px;
    font-size: 14px;
  }
}

/* ---------- 手機 ---------- */
@media (max-width: 480px) {
  .app { padding: 20px 14px 36px; }
  .app__subtitle { font-size: 13px; }
  .card { padding: 16px; }
  .fields { gap: 12px; }
  .summary { grid-template-columns: 1fr 1fr; gap: 10px; }
  .summary__value { font-size: 19px; }
  .actions { position: sticky; bottom: 8px; }
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: var(--shadow);
}
.card__title {
  font-size: 17px;
  margin: 0 0 18px;
  font-weight: 700;
}

.fields {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}
.fields.hidden { display: none; }

.field { display: flex; flex-direction: column; gap: 6px; min-width: 0; }
.field--full { grid-column: 1 / -1; }
.field__label { font-size: 13px; color: var(--muted); }
.field input[type="number"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  margin: 0;
  background: #0b1220;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 11px 12px;
  color: var(--text);
  font-size: 16px;
  line-height: 1.2;
  outline: none;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}
.field input[type="number"]:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(56, 189, 248, 0.15);
}

.rate-input { display: flex; gap: 10px; }
.rate-input input { flex: 1; }
.rate-input .btn { flex: 0 0 auto; padding-inline: 16px; }
.rate-status { font-size: 11px; font-weight: 600; }
.rate-status--ok { color: var(--green); }
.rate-status--err { color: var(--red); }
.rate-status--loading { color: var(--muted); }

.summary__sub { font-size: 12px; color: var(--muted); margin-top: 3px; }

.seg {
  display: flex;
  gap: 6px;
  background: #0b1220;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 5px;
}
.seg__btn {
  flex: 1;
  border: none;
  background: transparent;
  color: var(--muted);
  font-weight: 600;
  font-size: 14px;
  padding: 9px;
  border-radius: 7px;
  cursor: pointer;
  transition: all 0.15s ease;
}
.seg__btn--active {
  background: linear-gradient(90deg, var(--primary-strong), #6366f1);
  color: #fff;
}

.hint {
  font-size: 12px;
  color: var(--muted);
  background: #0b1220;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px 12px;
  margin: 4px 0 0;
  line-height: 1.5;
}

.toggle {
  flex-direction: row;
  align-items: center;
  gap: 10px;
  margin-top: 4px;
}
.toggle input { width: 18px; height: 18px; accent-color: var(--primary-strong); }

.actions { display: flex; gap: 12px; margin-top: 20px; }
.btn {
  flex: 1;
  border: none;
  border-radius: 10px;
  padding: 13px;
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  transition: transform 0.08s ease, opacity 0.15s ease;
}
.btn:active { transform: translateY(1px); }
.btn--primary {
  background: linear-gradient(90deg, var(--primary-strong), #6366f1);
  color: #fff;
}
.btn--ghost {
  background: transparent;
  color: var(--muted);
  border: 1px solid var(--border);
  flex: 0 0 auto;
  padding-inline: 20px;
}

/* 結果 */
.result__empty { color: var(--muted); text-align: center; padding: 30px 0; }

.summary {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-bottom: 18px;
}
.summary__item {
  background: var(--card-2);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px;
}
.summary__item--wide { grid-column: 1 / -1; }
.summary__label { font-size: 12px; color: var(--muted); }
.summary__value { font-size: 22px; font-weight: 800; margin-top: 2px; }
.value--green { color: var(--green); }
.value--red { color: var(--red); }

.breakdown { margin-top: 8px; }
.breakdown__group { margin-bottom: 16px; }
.breakdown__heading {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-size: 14px;
  font-weight: 700;
  padding: 8px 0;
  border-bottom: 1px solid var(--border);
  margin-bottom: 6px;
}
.breakdown__heading .amount { color: var(--primary); }

.fee-row {
  display: flex;
  justify-content: space-between;
  font-size: 13px;
  padding: 5px 0;
  color: var(--muted);
}
.fee-row span:last-child { color: var(--text); font-variant-numeric: tabular-nums; }
.fee-row--total {
  font-weight: 700;
  color: var(--text);
  border-top: 1px dashed var(--border);
  margin-top: 4px;
  padding-top: 8px;
}

.app__footer { text-align: center; margin-top: 32px; }
.app__footer p { color: var(--muted); font-size: 12px; }