/* ---------- Theme engine ----------
   Mode (light/dark) controls surfaces/text.
   Theme controls the accent hue. Combined via CSS variables so
   6 themes x 2 modes need almost no duplicated code. */

:root {
  --radius: 14px;
  --radius-sm: 9px;
  --transition: 180ms ease;
}

[data-mode="light"] {
  --bg: #f5f7fb;
  --bg-grad: linear-gradient(180deg, #f8fafc 0%, #eef1f8 100%);
  --card-bg: #ffffff;
  --card-bg-2: #fafbfe;
  --text: #1a1f2b;
  --muted: #64748b;
  --border: #e2e8f0;
  --shadow: 0 1px 2px rgba(15, 23, 42, 0.04), 0 8px 24px rgba(15, 23, 42, 0.06);
  --track-bg: #e2e8f0;
  --code-bg: #f1f5f9;
}

[data-mode="dark"] {
  --bg: #0b0f1a;
  --bg-grad: linear-gradient(180deg, #0b0f1a 0%, #101627 100%);
  --card-bg: #151b2b;
  --card-bg-2: #1a2236;
  --text: #e8ecf6;
  --muted: #93a0b8;
  --border: #2a3350;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 8px 24px rgba(0, 0, 0, 0.35);
  --track-bg: #2a3350;
  --code-bg: #1c2438;
}

/* Accent hue per theme (hue, saturation) */
[data-theme="indigo"] { --hue: 243; --sat: 75%; --swatch: #4f46e5; }
[data-theme="ocean"]  { --hue: 199; --sat: 85%; --swatch: #0ea5e9; }
[data-theme="sunset"] { --hue: 22;  --sat: 90%; --swatch: #f97316; }
[data-theme="forest"] { --hue: 152; --sat: 55%; --swatch: #16a34a; }
[data-theme="rose"]   { --hue: 340; --sat: 75%; --swatch: #e11d48; }
[data-theme="slate"]  { --hue: 215; --sat: 20%; --swatch: #64748b; }

:root {
  --primary: hsl(var(--hue) var(--sat) 55%);
  --primary-dark: hsl(var(--hue) var(--sat) 45%);
  --primary-soft: hsl(var(--hue) var(--sat) 55% / 0.12);
  --accent2: hsl(calc(var(--hue) + 45) var(--sat) 50%);
  --success: #10b981;
  --danger: #ef4444;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg-grad);
  color: var(--text);
  transition: background var(--transition), color var(--transition);
}

.app {
  max-width: 1080px;
  margin: 0 auto;
  padding: 24px 20px 60px;
}

/* ---------- Header ---------- */

.topbar {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

header h1 {
  font-size: 1.9rem;
  margin: 0 0 4px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.subtitle {
  color: var(--muted);
  margin: 0;
  max-width: 560px;
  font-size: 0.95rem;
}

.controls {
  display: flex;
  align-items: center;
  gap: 8px;
}

.control-item {
  position: relative;
  display: flex;
}

.icon-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--card-bg);
  color: var(--text);
  cursor: pointer;
  transition: transform var(--transition), background var(--transition), border-color var(--transition);
  box-shadow: var(--shadow);
}

.icon-btn:hover { transform: translateY(-1px); border-color: var(--primary); }
.icon-btn svg { width: 19px; height: 19px; }

.currency-btn {
  width: auto;
  padding: 0 14px;
  border-radius: 999px;
  gap: 5px;
  font-size: 0.82rem;
  font-weight: 700;
}

.currency-popover {
  min-width: 220px;
}

.currency-list {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.currency-list button {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 8px 10px;
  border: 1px solid transparent;
  border-radius: 8px;
  background: transparent;
  color: var(--text);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  text-align: left;
  transition: background var(--transition), border-color var(--transition);
}

.currency-list button:hover { background: var(--primary-soft); }
.currency-list button.active { border-color: var(--primary); background: var(--primary-soft); }

.currency-name {
  color: var(--muted);
  font-weight: 400;
  font-size: 0.78rem;
}

.currency-note {
  margin: 10px 0 0 !important;
  font-size: 0.68rem !important;
  text-transform: none !important;
  letter-spacing: 0 !important;
}

#modeToggle .sun-icon, #modeToggle .moon-icon {
  display: none;
}
[data-mode="light"] #modeToggle .sun-icon { display: block; }
[data-mode="dark"] #modeToggle .moon-icon { display: block; }

.theme-popover {
  position: absolute;
  top: 48px;
  right: 0;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow);
  padding: 14px;
  display: none;
  z-index: 20;
  min-width: 210px;
}

.theme-popover.open { display: block; }

.theme-popover p {
  margin: 0 0 10px;
  font-size: 0.78rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.swatch-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
}

.swatch {
  width: 100%;
  aspect-ratio: 1;
  border-radius: 10px;
  border: 2px solid transparent;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 0.9rem;
  transition: transform var(--transition), border-color var(--transition);
}

.swatch:hover { transform: scale(1.06); }
.swatch.active { border-color: var(--text); }

/* ---------- Layout ---------- */

main {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
  margin-top: 24px;
}

.form-card { grid-column: 1; }
.result-card { grid-column: 2; grid-row: 1 / 3; }
.breakdown-card { grid-column: 1; }
.model-card { grid-column: 1; }
.history-card { grid-column: 2; }

@media (max-width: 760px) {
  main { grid-template-columns: 1fr; }
  .form-card, .result-card, .breakdown-card, .model-card, .history-card {
    grid-column: 1;
    grid-row: auto;
  }
}

.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: var(--shadow);
  transition: background var(--transition), border-color var(--transition);
}

.card h2 {
  margin: 0 0 4px;
  font-size: 1.05rem;
  display: flex;
  align-items: center;
  gap: 8px;
}

.card-desc {
  color: var(--muted);
  font-size: 0.8rem;
  margin: 0 0 16px;
}

/* ---------- Form ---------- */

.field {
  margin-bottom: 18px;
}

.field-label {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.85rem;
  color: var(--muted);
  margin-bottom: 8px;
}

.tooltip {
  position: relative;
  display: inline-flex;
  width: 15px;
  height: 15px;
  border-radius: 50%;
  background: var(--track-bg);
  color: var(--muted);
  align-items: center;
  justify-content: center;
  font-size: 0.65rem;
  cursor: help;
}

.tooltip::after {
  content: attr(data-tip);
  position: absolute;
  bottom: 130%;
  left: 50%;
  transform: translateX(-50%);
  background: var(--text);
  color: var(--card-bg);
  padding: 6px 9px;
  border-radius: 6px;
  font-size: 0.72rem;
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition);
  z-index: 10;
}

.tooltip:hover::after, .tooltip:focus::after { opacity: 1; }

.slider-row {
  display: flex;
  align-items: center;
  gap: 12px;
}

input[type="range"] {
  flex: 1;
  -webkit-appearance: none;
  height: 6px;
  border-radius: 999px;
  background: var(--track-bg);
  outline: none;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--primary);
  border: 3px solid var(--card-bg);
  box-shadow: 0 0 0 1px var(--primary);
  cursor: pointer;
}

input[type="range"]::-moz-range-thumb {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--primary);
  border: 3px solid var(--card-bg);
  box-shadow: 0 0 0 1px var(--primary);
  cursor: pointer;
}

.slider-value {
  min-width: 78px;
  text-align: right;
  font-variant-numeric: tabular-nums;
  font-weight: 600;
  font-size: 0.9rem;
}

select, .number-input {
  width: 100%;
  padding: 10px 12px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--code-bg);
  color: var(--text);
  font-size: 0.95rem;
}

.segmented {
  display: flex;
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
}

.segmented button {
  flex: 1;
  padding: 9px 6px;
  border: none;
  background: var(--code-bg);
  color: var(--muted);
  cursor: pointer;
  font-size: 0.82rem;
  transition: background var(--transition), color var(--transition);
}

.segmented button + button { border-left: 1px solid var(--border); }
.segmented button.active { background: var(--primary); color: white; }

.toggle-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
}

.toggle-row .field-label { margin-bottom: 0; }

.switch {
  position: relative;
  display: inline-block;
  width: 42px;
  height: 24px;
  flex-shrink: 0;
}

.switch input { opacity: 0; width: 0; height: 0; }

.switch .slider {
  position: absolute;
  inset: 0;
  background: var(--track-bg);
  border-radius: 999px;
  cursor: pointer;
  transition: background var(--transition);
}

.switch .slider::before {
  content: "";
  position: absolute;
  width: 18px;
  height: 18px;
  left: 3px;
  top: 3px;
  background: white;
  border-radius: 50%;
  transition: transform var(--transition);
}

.switch input:checked + .slider { background: var(--primary); }
.switch input:checked + .slider::before { transform: translateX(18px); }

.primary-btn {
  width: 100%;
  padding: 13px;
  border: none;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--primary), var(--accent2));
  color: white;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: filter var(--transition), transform var(--transition);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.primary-btn:hover { filter: brightness(1.08); }
.primary-btn:active { transform: scale(0.98); }

.ghost-btn {
  padding: 9px 14px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text);
  font-size: 0.82rem;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: border-color var(--transition), background var(--transition);
}

.ghost-btn:hover { border-color: var(--primary); background: var(--primary-soft); }

/* ---------- Result ---------- */

.result-placeholder {
  color: var(--muted);
  font-size: 0.95rem;
  padding: 20px 0;
}

.result-amount {
  font-size: 2.6rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--primary), var(--accent2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  margin: 4px 0 4px;
  font-variant-numeric: tabular-nums;
}

.result-range {
  color: var(--muted);
  font-size: 0.82rem;
  margin-bottom: 16px;
}

.result-actions {
  display: flex;
  gap: 8px;
  margin-bottom: 18px;
  flex-wrap: wrap;
}

.breakdown-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
}

.breakdown-table td {
  padding: 6px 0;
  border-top: 1px solid var(--border);
}

.breakdown-table td:last-child {
  text-align: right;
  font-variant-numeric: tabular-nums;
  font-weight: 600;
}

/* ---------- Model / metrics ---------- */

.metrics {
  display: flex;
  gap: 20px;
  margin: 14px 0;
  flex-wrap: wrap;
}

.metric-label {
  display: block;
  font-size: 0.72rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.metric-value {
  display: block;
  font-size: 1.25rem;
  font-weight: 700;
}

.card-header-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 4px;
}

.spinner {
  width: 14px;
  height: 14px;
  border: 2px solid var(--track-bg);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
  display: inline-block;
}

@keyframes spin { to { transform: rotate(360deg); } }

/* ---------- History ---------- */

.history-list {
  list-style: none;
  margin: 12px 0 0;
  padding: 0;
  max-height: 220px;
  overflow-y: auto;
}

.history-list li {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 0;
  border-top: 1px solid var(--border);
  font-size: 0.82rem;
}

.history-list .hist-amount { font-weight: 700; }
.history-list .hist-meta { color: var(--muted); font-size: 0.75rem; }

.remove-btn {
  border: none;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font-size: 0.95rem;
  padding: 2px 6px;
  border-radius: 6px;
}
.remove-btn:hover { color: var(--danger); background: rgba(239,68,68,0.1); }

.empty-note {
  color: var(--muted);
  font-size: 0.82rem;
  padding: 8px 0;
}

/* ---------- Toasts ---------- */

.toast-container {
  position: fixed;
  bottom: 20px;
  right: 20px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  z-index: 50;
}

.toast {
  background: var(--card-bg);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 10px 16px;
  border-radius: 10px;
  box-shadow: var(--shadow);
  font-size: 0.85rem;
  display: flex;
  align-items: center;
  gap: 8px;
  animation: toast-in 0.2s ease;
}

.toast.fade-out { animation: toast-out 0.25s ease forwards; }

@keyframes toast-in {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes toast-out {
  to { opacity: 0; transform: translateY(8px); }
}

/* ---------- Footer ---------- */

footer {
  margin-top: 40px;
  text-align: center;
  color: var(--muted);
  font-size: 0.8rem;
}

footer a { color: var(--primary); }