:root {
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-card: #1e293b;
  --bg-input: #334155;
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent: #3b82f6;
  --accent-hover: #2563eb;
  --accent-orange: #f97316;
  --accent-green: #22c55e;
  --border: #334155;
  --shadow: 0 4px 6px -1px rgba(0,0,0,0.3);
  --radius: 12px;
  --radius-sm: 8px;
  --success: #22c55e;
  --warning: #eab308;
  --danger: #ef4444;
  --font: 'Inter', system-ui, -apple-system, sans-serif;
  --header-h: 56px;
  --nav-h: 64px;
}

[data-theme="light"] {
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-card: #ffffff;
  --bg-input: #f1f5f9;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  --border: #e2e8f0;
  --shadow: 0 4px 6px -1px rgba(0,0,0,0.08);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font);
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100dvh;
  line-height: 1.5;
  overflow-x: hidden;
}

/* Header */
.app-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-h);
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 12px 0 14px;
  gap: 8px;
  box-shadow: var(--shadow);
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--text-primary);
  text-decoration: none;
}

.logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--accent), var(--accent-orange));
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  color: white;
  font-weight: 800;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

.header-tools {
  display: flex;
  align-items: center;
  gap: 2px;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 3px;
}

.icon-btn {
  width: 36px;
  height: 36px;
  border: none;
  background: transparent;
  color: var(--text-primary);
  border-radius: 9px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.15s ease;
  font-size: 16px;
  line-height: 1;
  padding: 0;
}

.icon-btn:hover, .icon-btn:active {
  background: var(--accent);
  color: white;
}

.logo-text {
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 42vw;
}

@media (max-width: 380px) {
  .logo-text { max-width: 28vw; font-size: 0.95rem; }
  .lang-select { max-width: 88px; font-size: 11px; min-width: 72px; padding: 6px 6px; }
  .icon-btn { width: 34px; height: 34px; font-size: 15px; }
}

/* Search */
.search-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.6);
  z-index: 200;
  padding: 16px;
}

.search-overlay.active {
  display: flex;
  flex-direction: column;
}

.search-box {
  background: var(--bg-card);
  border-radius: var(--radius);
  padding: 16px;
  max-width: 600px;
  width: 100%;
  margin: 60px auto 0;
}

.search-input {
  width: 100%;
  padding: 14px 16px;
  font-size: 1.1rem;
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-input);
  color: var(--text-primary);
  outline: none;
}

.search-input:focus {
  border-color: var(--accent);
}

.search-results {
  margin-top: 12px;
  max-height: 60vh;
  overflow-y: auto;
}

.search-item {
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 12px;
  transition: background 0.15s;
}

.search-item:hover {
  background: var(--bg-input);
}

/* Main Layout */
.app-container {
  display: flex;
  min-height: calc(100dvh - var(--header-h));
}

.sidebar {
  display: none;
  width: 280px;
  background: var(--bg-secondary);
  border-right: 1px solid var(--border);
  padding: 16px 12px;
  overflow-y: auto;
  flex-shrink: 0;
}

.sidebar-section {
  margin-bottom: 20px;
}

.sidebar-title {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  padding: 0 12px 8px;
  font-weight: 600;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 12px;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s;
  border: none;
  background: none;
  width: 100%;
  text-align: left;
}

.nav-item:hover, .nav-item.active {
  background: var(--bg-input);
  color: var(--accent);
}

.nav-item .icon {
  font-size: 1.2rem;
  width: 24px;
  text-align: center;
}

.main-content {
  flex: 1;
  padding: 16px;
  padding-bottom: calc(var(--nav-h) + 24px);
  max-width: 100%;
  overflow-x: hidden;
}

/* Dashboard */
.page {
  display: none;
  animation: fadeIn 0.25s ease;
}

.page.active {
  display: block;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

.page-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.page-subtitle {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 20px;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: 12px;
}

.calc-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 12px;
  text-align: center;
  cursor: pointer;
  transition: all 0.2s;
  box-shadow: var(--shadow);
}

.calc-card:hover, .calc-card:active {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 8px 16px -4px rgba(59,130,246,0.25);
}

.calc-card .card-icon {
  font-size: 1.8rem;
  margin-bottom: 8px;
}

.calc-card .card-title {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
}

.calc-card .card-desc {
  font-size: 0.7rem;
  color: var(--text-muted);
  margin-top: 4px;
}

/* Calculator Form */
.calc-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 20px;
}

.back-btn {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--bg-input);
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 1.2rem;
}

.calc-form {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 16px;
  margin-bottom: 16px;
}

.form-group {
  margin-bottom: 16px;
}

.form-group label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 6px;
}

.form-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.form-row .form-group {
  flex: 1;
  min-width: 120px;
}

input[type="number"],
input[type="text"],
select {
  width: 100%;
  padding: 14px 16px;
  font-size: 1.05rem;
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-input);
  color: var(--text-primary);
  outline: none;
  transition: border-color 0.15s;
  -moz-appearance: textfield;
}

input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button {
  -webkit-appearance: none;
}

input:focus, select:focus {
  border-color: var(--accent);
}

.unit-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 4px;
}

.btn-group {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-top: 8px;
}

.btn {
  padding: 14px 20px;
  font-size: 1rem;
  font-weight: 600;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.15s;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  flex: 1;
  min-width: 100px;
}

.btn-primary {
  background: var(--accent);
  color: white;
}

.btn-primary:hover {
  background: var(--accent-hover);
}

.btn-secondary {
  background: var(--bg-input);
  color: var(--text-primary);
  border: 1px solid var(--border);
}

.btn-orange {
  background: var(--accent-orange);
  color: white;
}

.btn-success {
  background: var(--success);
  color: white;
}

/* Results */
.results-panel {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 16px;
  margin-bottom: 16px;
  display: none;
}

.results-panel.visible {
  display: block;
  animation: fadeIn 0.3s ease;
}

.results-title {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.result-item {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
}

.result-item:last-child {
  border-bottom: none;
}

.result-label {
  font-size: 0.9rem;
  color: var(--text-secondary);
  flex: 1;
}

.result-value {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--accent);
  text-align: right;
}

.result-unit {
  font-size: 0.8rem;
  color: var(--text-muted);
  font-weight: 500;
  margin-left: 4px;
}

.formula-box {
  background: var(--bg-input);
  border-radius: var(--radius-sm);
  padding: 12px 14px;
  margin: 12px 0;
  font-family: 'JetBrains Mono', 'Fira Code', monospace;
  font-size: 0.85rem;
  color: var(--text-secondary);
  overflow-x: auto;
  white-space: pre-wrap;
  border-left: 3px solid var(--accent);
}

.step-box {
  margin-top: 16px;
}

.step {
  padding: 8px 0;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.step strong {
  color: var(--text-primary);
}

/* Action bar for results */
.action-bar {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 16px;
}

.action-bar .btn {
  flex: 1;
  min-width: 80px;
  padding: 12px;
  font-size: 0.9rem;
}

/* Bottom Nav (Mobile) */
.bottom-nav {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: var(--nav-h);
  background: var(--bg-secondary);
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-around;
  align-items: center;
  z-index: 90;
  padding-bottom: env(safe-area-inset-bottom);
}

.bottom-nav-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  color: var(--text-muted);
  font-size: 0.65rem;
  font-weight: 500;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px 12px;
  transition: color 0.15s;
}

.bottom-nav-item.active {
  color: var(--accent);
}

.bottom-nav-item .icon {
  font-size: 1.4rem;
}

/* Favorites badge */
.fav-btn.active {
  color: var(--accent-orange);
}

/* Notes & Library */
.note-card, .formula-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  margin-bottom: 12px;
}

.note-card h3, .formula-card h3 {
  font-size: 1rem;
  margin-bottom: 8px;
}

.note-card p, .formula-card p {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

/* Toast */
.toast {
  position: fixed;
  bottom: calc(var(--nav-h) + 20px);
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: var(--bg-secondary);
  color: var(--text-primary);
  padding: 12px 24px;
  border-radius: 50px;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  z-index: 300;
  opacity: 0;
  transition: all 0.3s;
  font-size: 0.9rem;
  font-weight: 500;
  white-space: nowrap;
}

.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* Desktop */
@media (min-width: 768px) {
  .sidebar {
    display: block;
  }
  .bottom-nav {
    display: none;
  }
  .main-content {
    padding: 24px;
    padding-bottom: 24px;
  }
  .card-grid {
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 16px;
  }
  .calc-form, .results-panel {
    padding: 24px;
  }
}

@media (min-width: 1024px) {
  .main-content {
    max-width: 900px;
  }
}

/* Print / PDF */
@media print {
  .app-header, .sidebar, .bottom-nav, .btn, .action-bar, .back-btn {
    display: none !important;
  }
  .main-content {
    padding: 0;
  }
  body {
    background: white;
    color: black;
  }
}

/* Loading */
.loading {
  display: flex;
  justify-content: center;
  padding: 40px;
}

.spinner {
  width: 40px;
  height: 40px;
  border: 3px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

/* Empty state */
.empty-state {
  text-align: center;
  padding: 40px 20px;
  color: var(--text-muted);
}

.empty-state .icon {
  font-size: 3rem;
  margin-bottom: 12px;
}

.lang-select {
  appearance: none;
  -webkit-appearance: none;
  background: var(--bg-input) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%9494a3' stroke-width='2.5'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E") no-repeat right 8px center;
  color: var(--text-primary);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 0 28px 0 12px;
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  height: 42px;
  min-width: 100px;
  max-width: 130px;
  line-height: 42px;
}
.lang-select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 2px rgba(59,130,246,0.25);
}
.lang-select:hover {
  border-color: var(--accent);
}


/* ===== Header brand (title + tagline) ===== */
.app-header {
  position: sticky;
  top: 0;
  z-index: 100;
  min-height: var(--header-h);
  background: linear-gradient(135deg, #1d4ed8 0%, #1e3a8a 55%, #0f172a 100%);
  border-bottom: none;
  display: flex;
  align-items: center;
  justify-content: flex-start;
  padding: 12px 16px;
  box-shadow: 0 4px 20px rgba(0,0,0,0.25);
}

.logo {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: #fff;
  min-width: 0;
}

.logo-icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  flex-shrink: 0;
  overflow: hidden;
  box-shadow: 0 2px 10px rgba(0,0,0,0.25);
}

.logo-copy {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
}

.logo-title {
  font-weight: 800;
  font-size: 1.15rem;
  letter-spacing: -0.02em;
  color: #fff;
  line-height: 1.2;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.logo-tagline {
  font-size: 0.75rem;
  font-weight: 500;
  color: rgba(255,255,255,0.78);
  letter-spacing: 0.02em;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* ===== Quick action tiles ===== */
.quick-actions {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  padding: 12px 14px 8px;
  background: var(--bg-primary);
}

.qa-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 12px 6px;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: var(--bg-secondary);
  color: var(--text-primary);
  cursor: pointer;
  transition: transform 0.15s ease, background 0.15s ease, border-color 0.15s ease;
  box-shadow: 0 2px 8px rgba(0,0,0,0.12);
  min-height: 72px;
}

.qa-btn:hover, .qa-btn:active {
  border-color: var(--accent);
  background: var(--bg-input);
  transform: translateY(-1px);
}

.qa-icon {
  font-size: 1.35rem;
  line-height: 1;
}

.qa-label {
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--text-muted);
  letter-spacing: 0.01em;
}

.qa-btn:hover .qa-label, .qa-btn:active .qa-label {
  color: var(--text-primary);
}

/* Language bottom sheet */
.lang-sheet[hidden] { display: none !important; }
.lang-sheet {
  position: fixed;
  inset: 0;
  z-index: 300;
  display: flex;
  align-items: flex-end;
  justify-content: center;
}
.lang-sheet-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0,0,0,0.55);
}
.lang-sheet-panel {
  position: relative;
  width: 100%;
  max-width: 420px;
  background: var(--bg-secondary);
  border-radius: 18px 18px 0 0;
  padding: 16px 16px 28px;
  border: 1px solid var(--border);
  box-shadow: 0 -8px 30px rgba(0,0,0,0.35);
}
.lang-sheet-title {
  font-weight: 700;
  font-size: 0.95rem;
  margin-bottom: 12px;
  color: var(--text-primary);
  text-align: center;
}
.lang-option {
  display: block;
  width: 100%;
  text-align: left;
  padding: 14px 16px;
  margin-bottom: 8px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--bg-input);
  color: var(--text-primary);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
}
.lang-option:hover, .lang-option.active {
  border-color: var(--accent);
  background: rgba(59,130,246,0.15);
}

@media (min-width: 768px) {
  .quick-actions {
    max-width: 520px;
    margin: 0 auto;
  }
  .logo-title { font-size: 1.25rem; }
}


/* Compact brand header (screenshot style) */
.app-header {
  position: sticky;
  top: 0;
  z-index: 100;
  min-height: 56px;
  height: auto;
  background: linear-gradient(180deg, #0b1f4a 0%, #0f172a 100%);
  border-bottom: 1px solid rgba(255,255,255,0.06);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 12px 10px 14px;
  gap: 8px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.35);
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: #fff;
  min-width: 0;
  flex: 1;
}

.logo-icon {
  width: 40px;
  height: 40px;
  border-radius: 11px;
  flex-shrink: 0;
  overflow: hidden;
}

.logo-copy {
  display: flex;
  flex-direction: column;
  gap: 1px;
  min-width: 0;
}

.logo-title {
  font-weight: 800;
  font-size: 0.98rem;
  color: #fff;
  line-height: 1.15;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.logo-tagline {
  font-size: 0.68rem;
  font-weight: 500;
  color: rgba(255,255,255,0.72);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 2px;
  flex-shrink: 0;
}

.header-actions .icon-btn {
  width: 38px;
  height: 38px;
  border: none;
  background: transparent;
  color: rgba(255,255,255,0.92);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 17px;
  cursor: pointer;
  padding: 0;
}

.header-actions .icon-btn:hover,
.header-actions .icon-btn:active {
  background: rgba(255,255,255,0.12);
  color: #fff;
}

/* hide old quick-actions if any remnant */
.quick-actions { display: none !important; }

#page-dashboard > .page-title,
#page-dashboard > .page-subtitle {
  display: none !important;
}

.formula-cat {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--accent, #3b82f6);
  margin: 18px 4px 8px;
}
.formula-sketch {
  margin: 10px 0;
  padding: 8px;
  background: var(--bg-elevated, #1e293b);
  border-radius: 12px;
  border: 1px solid var(--border, #334155);
  text-align: center;
}
.formula-vars, .formula-ref {
  font-size: 0.85rem;
  color: var(--text-muted, #94a3b8);
  margin: 8px 0 0;
  line-height: 1.45;
}
.formula-ref {
  color: #93c5fd;
}
.formula-card {
  margin-bottom: 12px;
}

/* Desktop / tablet search in header */
.desktop-search-box {
  display: none;
  flex: 1;
  max-width: 420px;
  margin: 0 16px;
  position: relative;
}
.desktop-search-input {
  width: 100%;
  padding: 10px 14px 10px 36px;
  border-radius: 12px;
  border: 1px solid rgba(255,255,255,0.12);
  background: rgba(15,23,42,0.55) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='%2394a3b8' viewBox='0 0 16 16'%3E%3Cpath d='M11.742 10.344a6.5 6.5 0 1 0-1.397 1.398h-.001l3.85 3.85a1 1 0 0 0 1.415-1.414l-3.85-3.85zm-5.242.656a5 5 0 1 1 0-10 5 5 0 0 1 0 10z'/%3E%3C/svg%3E") no-repeat 12px center;
  color: #fff;
  font-size: 0.9rem;
  outline: none;
}
.desktop-search-input::placeholder { color: rgba(255,255,255,0.45); }
.desktop-search-input:focus {
  border-color: rgba(96,165,250,0.6);
  background-color: rgba(15,23,42,0.85);
}
.desktop-search-results {
  position: absolute;
  top: calc(100% + 6px);
  left: 0;
  right: 0;
  max-height: 360px;
  overflow-y: auto;
  background: var(--bg-secondary, #1e293b);
  border: 1px solid var(--border, #334155);
  border-radius: 12px;
  box-shadow: 0 12px 40px rgba(0,0,0,0.45);
  z-index: 200;
}
.desktop-search-results .search-item {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  padding: 10px 14px;
  cursor: pointer;
  border-bottom: 1px solid var(--border, #334155);
  color: var(--text-primary, #e2e8f0);
}
.desktop-search-results .search-item:hover {
  background: rgba(59,130,246,0.12);
}
.desktop-search-results .search-item:last-child { border-bottom: none; }

@media (min-width: 768px) {
  .desktop-search-box { display: block; }
}
@media (max-width: 767px) {
  .desktop-search-box { display: none !important; }
}

/* Unit picker (Material-style bottom sheet) */
.unit-pick-btn {
  width: 100%;
  text-align: left;
  padding: 14px 16px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--bg-input, var(--bg-secondary));
  color: var(--text-primary);
  font-size: 1.05rem;
  font-weight: 600;
  cursor: pointer;
  min-height: 48px;
}
.unit-pick-btn:hover, .unit-pick-btn:focus {
  border-color: var(--accent);
  outline: none;
}
.unit-picker-sheet[hidden] { display: none !important; }
.unit-picker-sheet {
  position: fixed;
  inset: 0;
  z-index: 400;
  display: flex;
  align-items: flex-end;
  justify-content: center;
}
.unit-picker-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0,0,0,0.5);
}
.unit-picker-panel {
  position: relative;
  width: 100%;
  max-width: 480px;
  max-height: min(78vh, 640px);
  background: var(--bg-secondary, #1e293b);
  border-radius: 20px 20px 0 0;
  border: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  box-shadow: 0 -8px 40px rgba(0,0,0,0.4);
  padding-bottom: env(safe-area-inset-bottom, 8px);
}
.unit-picker-handle {
  width: 40px;
  height: 4px;
  border-radius: 2px;
  background: var(--border);
  margin: 10px auto 6px;
}
.unit-picker-title {
  font-weight: 700;
  font-size: 1rem;
  text-align: center;
  padding: 4px 16px 10px;
  color: var(--text-primary);
}
.unit-picker-search-wrap { padding: 0 14px 10px; }
.unit-picker-search {
  width: 100%;
  padding: 12px 14px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--bg-input, var(--bg-primary));
  color: var(--text-primary);
  font-size: 0.95rem;
}
.unit-picker-search:focus {
  outline: none;
  border-color: var(--accent);
}
.unit-picker-list {
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
  padding: 0 8px 16px;
  flex: 1;
}
.up-cat {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--accent, #3b82f6);
  padding: 14px 12px 6px;
  margin-top: 4px;
  border-top: 1px solid var(--border);
  background: transparent;
}
.up-cat:first-child { border-top: none; margin-top: 0; }
.up-item {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 2px;
  width: 100%;
  text-align: left;
  padding: 12px 14px;
  border: none;
  border-radius: 10px;
  background: transparent;
  color: var(--text-primary);
  cursor: pointer;
  min-height: 48px;
}
.up-item:hover, .up-item:active {
  background: rgba(59,130,246,0.1);
}
.up-item.selected {
  background: rgba(59,130,246,0.18);
}
.up-item.selected .up-item-main {
  color: var(--accent, #60a5fa);
}
.up-item-main {
  font-weight: 600;
  font-size: 0.98rem;
}
.up-item-sub {
  font-size: 0.78rem;
  color: var(--text-muted);
}
.up-empty {
  padding: 24px;
  text-align: center;
  color: var(--text-muted);
}
@media (min-width: 768px) {
  .unit-picker-sheet { align-items: center; }
  .unit-picker-panel {
    border-radius: 16px;
    max-height: 70vh;
  }
  .unit-picker-handle { display: none; }
}


/* ===== Custom MU Select (replaces native <select> UI only) ===== */
select.mu-native-hidden {
  position: absolute !important;
  opacity: 0 !important;
  pointer-events: none !important;
  width: 1px !important;
  height: 1px !important;
  margin: -1px !important;
  padding: 0 !important;
  border: 0 !important;
  clip: rect(0,0,0,0) !important;
}
.mu-select {
  position: relative;
  width: 100%;
  font-family: inherit;
}
.mu-select-trigger {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 14px 16px;
  min-height: 48px;
  border-radius: 14px;
  border: 2px solid var(--border);
  background: var(--bg-input);
  color: var(--text-primary);
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  text-align: left;
  transition: border-color 0.15s, box-shadow 0.15s;
  -webkit-tap-highlight-color: transparent;
}
.mu-select-trigger:hover {
  border-color: color-mix(in srgb, var(--accent) 50%, var(--border));
}
.mu-select.open .mu-select-trigger,
.mu-select-trigger:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(59,130,246,0.2);
}
.mu-select-trigger .mu-select-value {
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.mu-select-chevron {
  flex-shrink: 0;
  width: 18px;
  height: 18px;
  opacity: 0.7;
  transition: transform 0.2s ease;
}
.mu-select.open .mu-select-chevron {
  transform: rotate(180deg);
}
.mu-select-panel {
  position: absolute;
  left: 0;
  right: 0;
  top: calc(100% + 6px);
  z-index: 250;
  max-height: min(320px, 50vh);
  display: flex;
  flex-direction: column;
  background: var(--bg-secondary, #1e293b);
  border: 1px solid var(--border);
  border-radius: 14px;
  box-shadow: 0 12px 40px rgba(0,0,0,0.4);
  opacity: 0;
  transform: translateY(-6px) scale(0.98);
  pointer-events: none;
  transition: opacity 0.2s ease, transform 0.2s ease;
  overflow: hidden;
}
.mu-select.open .mu-select-panel {
  opacity: 1;
  transform: translateY(0) scale(1);
  pointer-events: auto;
}
.mu-select-search {
  margin: 10px 10px 6px;
  padding: 10px 12px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--bg-input);
  color: var(--text-primary);
  font-size: 0.9rem;
  flex-shrink: 0;
}
.mu-select-search:focus {
  outline: none;
  border-color: var(--accent);
}
.mu-select-options {
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
  padding: 4px 6px 10px;
  flex: 1;
}
.mu-select-group {
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--accent, #60a5fa);
  padding: 10px 12px 4px;
  margin-top: 2px;
  border-top: 1px solid var(--border);
}
.mu-select-group:first-child {
  border-top: none;
  margin-top: 0;
}
.mu-select-option {
  display: block;
  width: 100%;
  text-align: left;
  padding: 12px 14px;
  min-height: 44px;
  border: none;
  border-radius: 10px;
  background: transparent;
  color: var(--text-primary);
  font-size: 0.95rem;
  font-weight: 500;
  cursor: pointer;
}
.mu-select-option:hover,
.mu-select-option:focus {
  background: rgba(59,130,246,0.12);
  outline: none;
}
.mu-select-option.selected {
  background: rgba(59,130,246,0.2);
  color: var(--accent, #60a5fa);
  font-weight: 600;
}
.mu-select-option.hidden { display: none; }
.mu-select-empty {
  padding: 16px;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.9rem;
}
/* Unit pick button polish */
.unit-pick-btn {
  width: 100%;
  padding: 14px 16px;
  min-height: 48px;
  border-radius: 14px;
  border: 2px solid var(--border);
  background: var(--bg-input);
  color: var(--text-primary);
  font-size: 1rem;
  font-weight: 600;
  text-align: left;
  cursor: pointer;
  position: relative;
}
.unit-pick-btn::after {
  content: "";
  position: absolute;
  right: 16px;
  top: 50%;
  width: 10px;
  height: 10px;
  border-right: 2px solid var(--text-muted);
  border-bottom: 2px solid var(--text-muted);
  transform: translateY(-60%) rotate(45deg);
}
.unit-pick-btn:hover, .unit-pick-btn:focus {
  border-color: var(--accent);
  outline: none;
}
.up-cat {
  background: color-mix(in srgb, var(--bg-primary) 60%, transparent);
}