/* ── Variables ─────────────────────────────────────────────────────── */
:root {
  --scale: 1;
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --primary-light: #eff6ff;
  --primary-muted: rgba(37,99,235,0.07);
  --bg: #eef2f7;
  --surface: #ffffff;
  --border: #e2e8f0;
  --to-bg: #f0f7ff;
  --to-border: rgba(37,99,235,0.14);
  --text: #0f172a;
  --text-muted: #64748b;
  --text-light: #94a3b8;
  --error: #dc2626;
  --success: #16a34a;
  --radius: 20px;
  --radius-sm: 14px;
  --radius-xs: 10px;
  --shadow: 0 2px 8px rgba(0,0,0,.05), 0 12px 40px rgba(0,0,0,.09);
  --shadow-lg: 0 8px 32px rgba(0,0,0,.14);
  --transition: 170ms ease;
  --fs-xs: calc(0.75rem * var(--scale));
  --fs-sm: calc(0.875rem * var(--scale));
  --fs-base: calc(1rem * var(--scale));
  --fs-md: calc(1.125rem * var(--scale));
  --fs-lg: calc(1.25rem * var(--scale));
  --fs-xl: calc(1.5rem * var(--scale));
  --fs-2xl: calc(1.875rem * var(--scale));
  --fs-3xl: calc(2.25rem * var(--scale));
}

/* ── Reset ─────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; -webkit-text-size-adjust: 100%; }
body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  font-size: var(--fs-base);
  background: var(--bg);
  color: var(--text);
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  line-height: 1.5;
}
button { cursor: pointer; font-family: inherit; border: none; background: none; }
input  { font-family: inherit; }
a      { color: inherit; }

/* ── Header ────────────────────────────────────────────────────────── */
.app-header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 0 1.25rem;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 100;
}
.header-brand { display: flex; align-items: center; gap: 0.625rem; }
.header-icon  { width: 30px; height: 30px; flex-shrink: 0; }
.header-icon svg { display: block; width: 100%; height: 100%; }
.header-title {
  font-size: var(--fs-md);
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.025em;
}

/* ── Main ──────────────────────────────────────────────────────────── */
.main-content {
  flex: 1;
  padding: 1.5rem 1rem;
  max-width: 480px;
  width: 100%;
  margin: 0 auto;
}

/* ── Card ──────────────────────────────────────────────────────────── */
.card {
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
}

/* ── Converter blocks ──────────────────────────────────────────────── */
.conv-block {
  padding: 1.125rem 1.375rem;
}
.to-block {
  background: var(--to-bg);
}
.block-label {
  display: block;
  font-size: calc(0.685rem * var(--scale));
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.09em;
  color: var(--text-light);
  margin-bottom: 0.625rem;
}
.block-row {
  display: flex;
  align-items: center;
}

/* ── Amount input ──────────────────────────────────────────────────── */
.amount-input {
  flex: 1;
  min-width: 0;
  padding: 0;
  border: none;
  background: transparent;
  font-size: calc(2rem * var(--scale));
  font-weight: 600;
  color: var(--text);
  letter-spacing: -0.025em;
  -moz-appearance: textfield;
  line-height: 1.1;
}
.amount-input::-webkit-outer-spin-button,
.amount-input::-webkit-inner-spin-button { -webkit-appearance: none; }
.amount-input:focus { outline: none; }
.amount-input::placeholder { color: var(--text-light); }

/* ── Vertical separator ─────────────────────────────────────────────── */
.v-sep {
  width: 1px;
  height: 2.5rem;
  background: var(--border);
  flex-shrink: 0;
  margin: 0 0.875rem;
}

/* ── Currency picker ───────────────────────────────────────────────── */
.currency-picker {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
  padding: 0.5rem 0.5rem 0.5rem 0.625rem;
  border-radius: var(--radius-xs);
  transition: background var(--transition);
  user-select: none;
  flex-shrink: 0;
  -webkit-tap-highlight-color: transparent;
}
.currency-picker:hover  { background: var(--primary-muted); }
.currency-picker.open   { background: var(--primary-muted); }
.currency-picker:focus  { outline: 2px solid var(--primary); outline-offset: 2px; }
.to-block .currency-picker:hover { background: rgba(37,99,235,0.1); }
.to-block .currency-picker.open  { background: rgba(37,99,235,0.1); }

.picker-flag { font-size: 1.5rem; line-height: 1; flex-shrink: 0; }
.picker-meta { display: flex; flex-direction: column; line-height: 1.25; }
.picker-code {
  font-size: var(--fs-base);
  font-weight: 700;
  color: var(--text);
}
.picker-name {
  font-size: calc(0.7rem * var(--scale));
  color: var(--text-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 72px;
}
.picker-symbol { display: none; }
.picker-arrow {
  width: 14px;
  height: 14px;
  color: var(--text-muted);
  flex-shrink: 0;
  transition: transform var(--transition);
}
.currency-picker.open .picker-arrow { transform: rotate(180deg); }

/* ── Swap row ──────────────────────────────────────────────────────── */
.swap-row {
  display: flex;
  align-items: center;
  padding: 0 1.375rem;
  position: relative;
  z-index: 1;
}
.swap-line {
  flex: 1;
  height: 1px;
  background: var(--border);
}
.swap-btn {
  width: 34px;
  height: 34px;
  border-radius: 50%;
  background: var(--surface);
  border: 1.5px solid var(--border);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  margin: 0 0.75rem;
  box-shadow: 0 1px 4px rgba(0,0,0,.1);
  transition:
    background var(--transition),
    color var(--transition),
    border-color var(--transition),
    transform 300ms cubic-bezier(0.34, 1.56, 0.64, 1);
}
.swap-btn:hover  { background: var(--primary); color: #fff; border-color: var(--primary); }
.swap-btn:active { transform: rotate(180deg); }
.swap-btn svg    { width: 15px; height: 15px; }

/* ── Result area ───────────────────────────────────────────────────── */
.result-area {
  flex: 1;
  min-width: 0;
  display: flex;
  align-items: center;
  min-height: 3rem;
}
#resultLoading { display: flex; align-items: center; }
#resultContent { display: flex; flex-direction: column; }

.result-value {
  font-size: calc(2rem * var(--scale));
  font-weight: 600;
  color: var(--primary-dark);
  letter-spacing: -0.025em;
  line-height: 1.1;
}
.result-curr {
  font-size: var(--fs-xs);
  color: var(--text-muted);
  font-weight: 500;
  margin-top: 3px;
}
.result-error {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.3rem;
  color: var(--error);
  font-size: var(--fs-xs);
}
.result-error svg { width: 18px; height: 18px; }
.retry-btn {
  font-size: var(--fs-xs);
  color: var(--primary);
  text-decoration: underline;
}

/* ── Spinner ───────────────────────────────────────────────────────── */
.spinner {
  width: 24px;
  height: 24px;
  border: 2.5px solid var(--border);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ── Rates row ─────────────────────────────────────────────────────── */
.rates-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  margin-top: 0.875rem;
  padding-top: 0.875rem;
  border-top: 1px solid var(--to-border);
}
.rate-lines { display: flex; flex-direction: column; gap: 2px; }
.result-rate-line {
  font-size: var(--fs-xs);
  color: var(--text-muted);
}

/* ── Copy button ───────────────────────────────────────────────────── */
.copy-btn {
  font-size: var(--fs-xs);
  font-weight: 500;
  color: var(--primary);
  background: var(--primary-light);
  padding: 0.3rem 0.75rem;
  border-radius: 999px;
  display: flex;
  align-items: center;
  gap: 0.3rem;
  transition: background var(--transition);
  flex-shrink: 0;
}
.copy-btn:hover  { background: #dbeafe; }
.copy-btn svg    { width: 12px; height: 12px; }
.copy-btn.copied { color: var(--success); background: #dcfce7; }

/* ── Source info ───────────────────────────────────────────────────── */
.source-info {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem;
  padding: 0.875rem 1.375rem;
  border-top: 1px solid var(--border);
}
.source-updated {
  display: flex;
  align-items: center;
  gap: 0.3rem;
  font-size: var(--fs-xs);
  color: var(--text-muted);
}
.source-updated svg { width: 12px; height: 12px; flex-shrink: 0; }
.source-link {
  display: flex;
  align-items: center;
  gap: 0.3rem;
  font-size: var(--fs-xs);
  font-weight: 500;
  color: var(--primary);
  text-decoration: none;
  transition: opacity var(--transition);
}
.source-link:hover { opacity: 0.7; text-decoration: underline; }
.source-link svg   { width: 11px; height: 11px; }

/* ── Dropdown overlay ──────────────────────────────────────────────── */
.dropdown-overlay {
  position: fixed;
  inset: 0;
  z-index: 200;
}

/* ── Dropdown panel ────────────────────────────────────────────────── */
.dropdown-panel {
  position: fixed;
  z-index: 201;
  background: var(--surface);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-lg);
  width: min(420px, calc(100vw - 2rem));
  max-height: 60vh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}
.dropdown-search {
  padding: 0.75rem;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.dropdown-search svg { width: 16px; height: 16px; color: var(--text-muted); flex-shrink: 0; }
.dropdown-search input {
  flex: 1;
  border: none;
  outline: none;
  font-size: var(--fs-base);
  color: var(--text);
  background: transparent;
}
.clear-btn {
  font-size: var(--fs-xs);
  color: var(--text-muted);
  width: 20px;
  height: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  transition: background var(--transition);
}
.clear-btn:hover { background: var(--border); }
.dropdown-list {
  overflow-y: auto;
  list-style: none;
  flex: 1;
}
.dropdown-item {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  padding: 0.625rem 1rem;
  cursor: pointer;
  transition: background var(--transition);
}
.dropdown-item:hover,
.dropdown-item.focused  { background: var(--bg); }
.dropdown-item.selected { background: var(--primary-light); }
.dropdown-item .di-flag   { font-size: 1.25rem; line-height: 1; flex-shrink: 0; }
.dropdown-item .di-code   { font-size: var(--fs-sm); font-weight: 700; color: var(--text); width: 44px; flex-shrink: 0; }
.dropdown-item .di-name   { font-size: var(--fs-sm); color: var(--text-muted); flex: 1; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.dropdown-item .di-symbol { font-size: var(--fs-xs); font-weight: 600; color: var(--primary); flex-shrink: 0; min-width: 28px; text-align: right; }
.dropdown-empty {
  padding: 2rem 1rem;
  text-align: center;
  font-size: var(--fs-sm);
  color: var(--text-muted);
}

/* ── Settings overlay ──────────────────────────────────────────────── */
.settings-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,.35);
  z-index: 300;
  opacity: 0;
  transition: opacity var(--transition);
}
.settings-overlay.visible { opacity: 1; }

/* ── Settings panel ────────────────────────────────────────────────── */
.settings-panel {
  position: fixed;
  top: 0; right: 0; bottom: 0;
  width: min(320px, 90vw);
  background: var(--surface);
  z-index: 301;
  box-shadow: -4px 0 24px rgba(0,0,0,.12);
  display: flex;
  flex-direction: column;
  transform: translateX(100%);
  transition: transform 280ms cubic-bezier(0.4, 0, 0.2, 1);
  overflow-y: auto;
}
.settings-panel.open { transform: translateX(0); }
.settings-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.25rem 1.25rem 1rem;
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  background: var(--surface);
}
.settings-header h2 {
  font-size: var(--fs-md);
  font-weight: 600;
  color: var(--text);
}
.settings-section {
  padding: 1.25rem;
  border-bottom: 1px solid var(--border);
}
.settings-label {
  font-size: var(--fs-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  margin-bottom: 0.875rem;
}
.size-options {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.5rem;
}
.size-btn {
  padding: 0.5rem;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-xs);
  background: var(--surface);
  color: var(--text-muted);
  font-weight: 600;
  font-family: inherit;
  transition: all var(--transition);
  display: flex;
  align-items: center;
  justify-content: center;
}
.size-btn:hover { border-color: var(--primary); color: var(--primary); }
.size-btn.active { background: var(--primary); border-color: var(--primary); color: #fff; }
.size-btn[data-size="0.85"] { font-size: 0.7rem; }
.size-btn[data-size="1"]    { font-size: 0.875rem; }
.size-btn[data-size="1.15"] { font-size: 1rem; }
.size-btn[data-size="1.3"]  { font-size: 1.125rem; }

.lang-options { display: flex; flex-direction: column; gap: 0.5rem; }
.lang-btn {
  padding: 0.625rem 1rem;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-xs);
  background: var(--surface);
  color: var(--text);
  font-size: var(--fs-sm);
  font-weight: 500;
  text-align: left;
  transition: all var(--transition);
}
.lang-btn:hover { border-color: var(--primary); color: var(--primary); }
.lang-btn.active {
  background: var(--primary-light);
  border-color: var(--primary);
  color: var(--primary);
  font-weight: 600;
}

/* ── Icon button ───────────────────────────────────────────────────── */
.icon-btn {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-xs);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  transition: background var(--transition), color var(--transition);
}
.icon-btn:hover { background: var(--bg); color: var(--text); }
.icon-btn svg   { width: 20px; height: 20px; }

/* ── Footer ────────────────────────────────────────────────────────── */
.app-footer {
  text-align: center;
  padding: 1.25rem 1rem 1.5rem;
  color: var(--text-light);
  font-size: var(--fs-xs);
  line-height: 1.8;
}
.footer-built {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.3rem;
}
.heart-icon { width: 12px; height: 12px; display: inline-block; }

/* ── Hidden util ───────────────────────────────────────────────────── */
[hidden] { display: none !important; }

/* ── Responsive ────────────────────────────────────────────────────── */
@media (max-width: 479px) {
  .picker-name { display: none; }
  .amount-input, .result-value { font-size: calc(1.6rem * var(--scale)); }
  .conv-block { padding: 1rem 1.125rem; }
  .swap-row   { padding: 0 1.125rem; }
  .v-sep      { margin: 0 0.625rem; }
}
@media (min-width: 640px) {
  .main-content { padding: 2.5rem 1.5rem; }
}