/* ── Foundation ─────────────────────────────────────────── */

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

/* ── Palette · Light ────────────────────────────────────── */

:root,
[data-theme="light"] {
  --canvas: #f7f4ef;
  --surface: #fffdf9;
  --inset: #f3efe8;
  --inset-muted: #ebe6dc;
  --ink: #1c1917;
  --ink-soft: #44403c;
  --ink-muted: #78716c;
  --ink-faint: #a8a29e;
  --line: #e7e0d5;
  --line-strong: #d6d0c4;
  --accent: #c45c26;
  --accent-deep: #a34a1c;
  --shadow: rgba(28, 25, 23, 0.06);
  --shadow-lift: rgba(28, 25, 23, 0.1);
  --focus: rgba(196, 92, 38, 0.18);
  --danger: #b91c1c;
  --disabled: #a8a29e;
  --chevron: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%2378716c' d='M2.5 4.5 6 8l3.5-3.5'/%3E%3C/svg%3E");
}

/* ── Palette · Dark ─────────────────────────────────────── */

[data-theme="dark"] {
  --canvas: #141210;
  --surface: #1f1c18;
  --inset: #2a2622;
  --inset-muted: #242019;
  --ink: #f5f0e8;
  --ink-soft: #d6d0c4;
  --ink-muted: #a8a29e;
  --ink-faint: #78716c;
  --line: #3d3830;
  --line-strong: #524a40;
  --accent: #d97744;
  --accent-deep: #c45c26;
  --shadow: rgba(0, 0, 0, 0.32);
  --shadow-lift: rgba(0, 0, 0, 0.42);
  --focus: rgba(217, 119, 68, 0.28);
  --danger: #f87171;
  --disabled: #78716c;
  --chevron: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%23a8a29e' d='M2.5 4.5 6 8l3.5-3.5'/%3E%3C/svg%3E");
}

/* ── Rhythm ─────────────────────────────────────────────── */

:root {
  --ease: 0.2s ease;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
}

/* ── Page ───────────────────────────────────────────────── */

body {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: max(1.5rem, env(safe-area-inset-top))
           max(1.5rem, env(safe-area-inset-right))
           max(1.5rem, env(safe-area-inset-bottom))
           max(1.5rem, env(safe-area-inset-left));
  font-family: "Iowan Old Style", "Palatino Linotype", Palatino, "Noto Serif KR", "Noto Serif JP", serif;
  background: var(--canvas);
  color: var(--ink);
  transition: background-color var(--ease), color var(--ease);
}

/* ── Sheet ──────────────────────────────────────────────── */

.sheet {
  position: relative;
  width: 100%;
  max-width: 480px;
  padding: 2rem;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  box-shadow: 0 8px 32px var(--shadow);
  transition: background-color var(--ease), border-color var(--ease), box-shadow var(--ease);
}

/* ── Toolbar ────────────────────────────────────────────── */

.toolbar {
  position: absolute;
  top: 1.25rem;
  display: flex;
  gap: 2px;
  padding: 3px;
  background: var(--inset);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
}

.toolbar--start { left: 1.25rem; }
.toolbar--end { right: 1.25rem; }

.toolbar__btn {
  padding: 0.35rem 0.62rem;
  font-family: inherit;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--ink-muted);
  background: transparent;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  white-space: nowrap;
  transition: background var(--ease), color var(--ease), box-shadow var(--ease);
}

.toolbar__btn:hover {
  color: var(--ink-soft);
}

.toolbar__btn.is-active {
  color: var(--ink);
  background: var(--surface);
  box-shadow: 0 1px 2px var(--shadow);
}

/* ── Masthead ───────────────────────────────────────────── */

.masthead {
  margin-bottom: 1.75rem;
  text-align: center;
}

.masthead__title {
  margin-bottom: 0.35rem;
  font-size: clamp(1.3rem, 4vw, 1.8rem);
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

/* ── Composer ───────────────────────────────────────────── */

.composer {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
}

.composer__label {
  font-size: 0.78rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-muted);
}

.composer__row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.5rem;
  width: 100%;
  max-width: 380px;
}

/* ── Field ──────────────────────────────────────────────── */

.field {
  width: 100%;
  height: 44px;
  padding: 0 0.85rem;
  font-family: inherit;
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--ink);
  background: var(--inset);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  transition: border-color var(--ease), box-shadow var(--ease), background-color var(--ease);
}

.field:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--focus);
}

.field--select {
  cursor: pointer;
  appearance: none;
  -webkit-appearance: none;
  padding-right: 2rem;
  background-image: var(--chevron);
  background-repeat: no-repeat;
  background-position: right 0.75rem center;
  background-size: 12px;
}

.field--select.is-placeholder {
  color: var(--ink-faint);
}

.field--amount {
  text-align: right;
  font-variant-numeric: tabular-nums;
}

/* ── Rates ──────────────────────────────────────────────── */

.rates {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin-bottom: 1.25rem;
}

.rate-card {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem 1.25rem;
  background: var(--inset);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  transition: border-color var(--ease), box-shadow var(--ease), background-color var(--ease);
  container-type: inline-size;
}

.rate-card__flag {
  flex-shrink: 0;
  width: 2.5rem;
  font-size: 2rem;
  line-height: 1;
  text-align: center;
}

.rate-card__body {
  flex: 1;
  min-width: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, auto);
  grid-template-rows: auto auto;
  column-gap: 1rem;
  align-items: baseline;
}

.rate-card__name {
  grid-column: 1;
  grid-row: 1;
  margin-bottom: 0;
  font-size: 0.78rem;
  font-weight: 500;
  letter-spacing: 0.04em;
  color: var(--ink-muted);
}

.rate-card__value {
  grid-column: 1 / -1;
  grid-row: 2;
  margin-top: 0.2rem;
  font-size: clamp(0.95rem, 2.4vw, 1.35rem);
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  line-height: 1.25;
  color: var(--ink);
  text-align: right;
  white-space: nowrap;
  overflow-x: auto;
  scrollbar-width: none;
}

.rate-card__value::-webkit-scrollbar {
  display: none;
}

@container (max-width: 280px) {
  .rate-card__value {
    font-size: 0.88rem;
  }
}

.rate-card__value.is-loading {
  color: var(--ink-faint);
}

/* ── Status ─────────────────────────────────────────────── */

.status {
  margin-bottom: 1rem;
  font-size: 0.78rem;
  line-height: 1.55;
  text-align: center;
  color: var(--ink-faint);
  word-break: keep-all;
}

.status--error {
  color: var(--danger);
}

.is-hidden {
  display: none;
}

/* ── Action ─────────────────────────────────────────────── */

.action {
  display: block;
  width: 100%;
  min-height: 44px;
  padding: 0.75rem;
  font-family: inherit;
  font-size: 0.82rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: #fff;
  background: var(--accent);
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background var(--ease);
}

.action:hover {
  background: var(--accent-deep);
}

.action.is-busy {
  background: var(--disabled);
  cursor: wait;
}

/* ── Responsive ─────────────────────────────────────────── */

@media (max-width: 359px) {
  body {
    padding: max(1rem, env(safe-area-inset-top))
             max(1rem, env(safe-area-inset-right))
             max(1rem, env(safe-area-inset-bottom))
             max(1rem, env(safe-area-inset-left));
  }

  .sheet {
    padding: 1.25rem;
  }

  .toolbar--start { top: 1rem; left: 1rem; }
  .toolbar--end { top: 1rem; right: 1rem; }

  .masthead__title {
    padding-top: 2.5rem;
  }

  .rate-card__flag {
    font-size: 1.5rem;
  }
}

@media (min-width: 480px) {
  .sheet {
    max-width: 620px;
    padding: 2.5rem;
  }

  .composer__row {
    max-width: 440px;
  }

  .toolbar--start { top: 1.5rem; left: 1.5rem; }
  .toolbar--end { top: 1.5rem; right: 1.5rem; }
}

@media (min-width: 640px) {
  .sheet {
    max-width: 760px;
  }

  .composer__row {
    max-width: 480px;
  }
}

@media (min-width: 768px) {
  .sheet {
    max-width: 900px;
    padding: 2.75rem 3rem;
  }

  .composer__row {
    max-width: 520px;
  }

  .rate-card {
    padding: 1.15rem 1.5rem;
  }

  .rate-card:hover {
    border-color: var(--line-strong);
    box-shadow: 0 4px 16px var(--shadow-lift);
  }
}