/* ==========================================================================
   Formula Visualiser — Stylesheet
   Scientific instrument aesthetic: monospace data, clean borders, no shadows.
   ========================================================================== */

/* --------------------------------------------------------------------------
   Custom properties — light theme (default)
   -------------------------------------------------------------------------- */

:root {
  --bg:           #f4f5f7;
  --surface:      #ffffff;
  --surface-2:    #f0f2f5;
  --border:       #d0d4dc;
  --text:         #1c1e26;
  --text-muted:   #6b7280;
  --accent:       #1d4ed8;
  --accent-hover: #1e40af;
  --canvas-bg:    #eef0f4;
  --status-bg:    rgba(244, 245, 247, 0.92);

  --topbar-height: 52px;
  --sidebar-width: 220px;

  --font-ui:   system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Courier New', monospace;
}

/* --------------------------------------------------------------------------
   Dark theme overrides
   -------------------------------------------------------------------------- */

[data-theme="dark"] {
  --bg:           #0d0f14;
  --surface:      #161921;
  --surface-2:    #1e2230;
  --border:       #252a36;
  --text:         #e2e5ec;
  --text-muted:   #8892a4;
  --accent:       #60a5fa;
  --accent-hover: #93c5fd;
  --canvas-bg:    #080a0f;
  --status-bg:    rgba(13, 15, 20, 0.92);
}

/* --------------------------------------------------------------------------
   Reset / base
   -------------------------------------------------------------------------- */

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

html, body {
  height: 100%;
  overflow: hidden;
}

body {
  font-family: var(--font-ui);
  font-size: 14px;
  color: var(--text);
  background: var(--bg);
  line-height: 1.5;
}

/* --------------------------------------------------------------------------
   Utility
   -------------------------------------------------------------------------- */

.hidden {
  display: none !important;
}

/* --------------------------------------------------------------------------
   Topbar
   -------------------------------------------------------------------------- */

.topbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--topbar-height);
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 0 16px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  z-index: 200;
}

/* --------------------------------------------------------------------------
   Brand
   -------------------------------------------------------------------------- */

.brand {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-shrink: 0;
  user-select: none;
}

.brand-icon {
  font-size: 20px;
  line-height: 1;
  color: var(--accent);
}

.brand-name {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.03em;
  color: var(--text);
  white-space: nowrap;
}

/* --------------------------------------------------------------------------
   Search
   -------------------------------------------------------------------------- */

.search-wrap {
  display: flex;
  align-items: center;
  gap: 8px;
  flex: 1;
  max-width: 480px;
  margin: 0 auto;
}

.formula-input {
  flex: 1;
  height: 32px;
  padding: 0 10px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--text);
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 3px;
  outline: none;
  transition: border-color 0.15s, box-shadow 0.15s;
}

.formula-input::placeholder {
  color: var(--text-muted);
}

.formula-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 2px color-mix(in srgb, var(--accent) 20%, transparent);
}

/* --------------------------------------------------------------------------
   Buttons
   -------------------------------------------------------------------------- */

.btn-primary {
  height: 32px;
  padding: 0 14px;
  font-family: var(--font-ui);
  font-size: 13px;
  font-weight: 500;
  color: #ffffff;
  background: var(--accent);
  border: none;
  border-radius: 3px;
  cursor: pointer;
  white-space: nowrap;
  transition: background 0.15s;
  flex-shrink: 0;
}

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

.btn-primary:active {
  opacity: 0.85;
}

.btn-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 30px;
  height: 30px;
  padding: 0;
  font-size: 18px;
  line-height: 1;
  color: var(--text-muted);
  background: transparent;
  border: none;
  border-radius: 3px;
  cursor: pointer;
  transition: color 0.15s, background 0.15s;
  flex-shrink: 0;
}

.btn-icon:hover {
  color: var(--text);
  background: var(--surface-2);
}

/* --------------------------------------------------------------------------
   Topbar right slot
   -------------------------------------------------------------------------- */

.topbar-right {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: 4px;
  flex-shrink: 0;
}

/* --------------------------------------------------------------------------
   Theme toggle icon visibility
   -------------------------------------------------------------------------- */

[data-theme="light"] .theme-icon-light {
  display: none;
}

[data-theme="dark"] .theme-icon-dark {
  display: none;
}

/* --------------------------------------------------------------------------
   Layout (below topbar)
   -------------------------------------------------------------------------- */

.layout {
  display: flex;
  flex-direction: row;
  height: calc(100vh - var(--topbar-height));
  margin-top: var(--topbar-height);
  overflow: hidden;
}

/* --------------------------------------------------------------------------
   Sidebar
   -------------------------------------------------------------------------- */

.sidebar {
  width: var(--sidebar-width);
  min-width: var(--sidebar-width);
  display: flex;
  flex-direction: column;
  background: var(--surface);
  border-right: 1px solid var(--border);
  overflow: hidden;
  transition: width 0.22s ease, min-width 0.22s ease;
  z-index: 100;
}

.sidebar.collapsed {
  width: 0;
  min-width: 0;
  border-right-color: transparent;
}

.sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
  position: sticky;
  top: 0;
  z-index: 1;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
  white-space: nowrap;
  flex-shrink: 0;
}

.molecule-list {
  flex: 1;
  overflow-y: auto;
  padding: 4px 0;
  /* Thin scrollbar */
  scrollbar-width: thin;
  scrollbar-color: var(--border) transparent;
}

.molecule-list::-webkit-scrollbar {
  width: 4px;
}

.molecule-list::-webkit-scrollbar-track {
  background: transparent;
}

.molecule-list::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 2px;
}

/* --------------------------------------------------------------------------
   Molecule list items
   -------------------------------------------------------------------------- */

.mol-item {
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 8px 12px;
  font-family: var(--font-ui);
  text-align: left;
  color: var(--text);
  background: transparent;
  border: none;
  border-radius: 0;
  cursor: pointer;
  transition: background 0.1s;
  white-space: nowrap;
  overflow: hidden;
}

.mol-item:hover {
  background: var(--surface-2);
}

.mol-item.active {
  background: var(--surface-2);
  border-left: 2px solid var(--accent);
  padding-left: 10px;
}

.mol-name {
  font-size: 13px;
  font-weight: 500;
  overflow: hidden;
  text-overflow: ellipsis;
}

.mol-formula {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-muted);
  overflow: hidden;
  text-overflow: ellipsis;
}

/* --------------------------------------------------------------------------
   Canvas area
   -------------------------------------------------------------------------- */

.canvas-area {
  flex: 1;
  position: relative;
  overflow: hidden;
  background: var(--canvas-bg);
}

#canvas {
  width: 100%;
  height: 100%;
  display: block;
}

/* --------------------------------------------------------------------------
   Formula display bar
   -------------------------------------------------------------------------- */

.formula-display {
  position: absolute;
  top: 12px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  gap: 0;
  background: var(--status-bg);
  border: 1px solid var(--border);
  border-radius: 3px;
  padding: 5px 14px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--text);
  white-space: nowrap;
  pointer-events: none;
  z-index: 10;
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  max-width: calc(100% - 32px);
  overflow: hidden;
  text-overflow: ellipsis;
}

.formula-display:empty {
  display: none;
}

.fd-formula {
  font-weight: 700;
  color: var(--text);
}

.fd-sep {
  margin: 0 8px;
  color: var(--text-muted);
  pointer-events: none;
}

.fd-iupac {
  color: var(--text-muted);
  font-size: 12px;
  font-style: italic;
  font-family: var(--font-ui);
  max-width: 240px;
  overflow: hidden;
  text-overflow: ellipsis;
}

.fd-mw {
  color: var(--text-muted);
  font-size: 12px;
}

.fd-cid {
  color: var(--accent);
  font-size: 11px;
  text-decoration: none;
  pointer-events: all;
}

.fd-cid:hover {
  text-decoration: underline;
  color: var(--accent-hover);
}

/* --------------------------------------------------------------------------
   Status overlays (loading / error)
   -------------------------------------------------------------------------- */

.status-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  background: var(--status-bg);
  color: var(--text-muted);
  font-size: 13px;
  z-index: 50;
  backdrop-filter: blur(2px);
  -webkit-backdrop-filter: blur(2px);
}

.error-overlay {
  color: #ef4444;
  font-family: var(--font-ui);
  font-size: 14px;
  text-align: center;
  padding: 24px;
  line-height: 1.6;
}

/* --------------------------------------------------------------------------
   Loading spinner
   -------------------------------------------------------------------------- */

.loading-spinner {
  width: 40px;
  height: 40px;
  border: 3px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  flex-shrink: 0;
}

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

/* --------------------------------------------------------------------------
   Atom Inspector panel
   -------------------------------------------------------------------------- */

.inspector {
  position: fixed;
  bottom: 20px;
  right: 20px;
  width: 300px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 4px;
  z-index: 300;
  overflow: hidden;
  transition: opacity 0.15s, transform 0.15s;
}

.inspector.hidden {
  display: none;
}

.inspector-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
}

.inspector-title {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
}

.inspector-content {
  padding: 14px;
  overflow-y: auto;
  max-height: calc(100vh - 140px);
  scrollbar-width: thin;
  scrollbar-color: var(--border) transparent;
}

.inspector-content::-webkit-scrollbar {
  width: 4px;
}

.inspector-content::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 2px;
}

/* --------------------------------------------------------------------------
   Inspector: element hero
   -------------------------------------------------------------------------- */

.element-hero {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 12px;
}

.element-symbol-large {
  font-family: var(--font-mono);
  font-size: 52px;
  font-weight: 700;
  line-height: 1;
  /* Color is set inline via JS */
  text-shadow: 0 0 20px currentColor;
  flex-shrink: 0;
}

.element-name {
  font-size: 16px;
  font-weight: 600;
  color: var(--text);
  line-height: 1.3;
}

.element-subtitle {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-muted);
  margin-top: 2px;
}

/* --------------------------------------------------------------------------
   Inspector: divider
   -------------------------------------------------------------------------- */

.inspector-divider {
  border: none;
  border-top: 1px solid var(--border);
  margin: 0 0 12px 0;
}

/* --------------------------------------------------------------------------
   Inspector: stats grid
   -------------------------------------------------------------------------- */

.stats-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
  margin: 0 0 4px 0;
}

.stat-item {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 2px;
  padding: 8px 10px;
}

.stat-label {
  display: block;
  font-size: 10px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
}

.stat-value {
  display: block;
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 700;
  color: var(--text);
  margin-top: 3px;
}

/* --------------------------------------------------------------------------
   Inspector: noble gas badge
   -------------------------------------------------------------------------- */

.noble-badge {
  display: inline-block;
  margin-top: 8px;
  padding: 4px 8px;
  border: 1px solid var(--border);
  border-radius: 2px;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-muted);
  background: var(--surface-2);
}

/* --------------------------------------------------------------------------
   Inspector: color row
   -------------------------------------------------------------------------- */

.color-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: 12px;
  font-size: 12px;
  color: var(--text-muted);
}

.color-row label {
  flex-shrink: 0;
}

.color-row input[type="color"] {
  width: 32px;
  height: 22px;
  padding: 1px 2px;
  border: 1px solid var(--border);
  border-radius: 2px;
  background: var(--surface-2);
  cursor: pointer;
  flex-shrink: 0;
}

.color-symbol-label {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-muted);
}

/* --------------------------------------------------------------------------
   Inspector: position row
   -------------------------------------------------------------------------- */

.position-row {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-muted);
  margin-top: 10px;
  line-height: 1.6;
}

.pos-label {
  font-weight: 600;
  margin-right: 4px;
}

/* ==========================================================================
   Responsive: narrow screens
   ========================================================================== */

@media (max-width: 600px) {
  .sidebar {
    width: 0;
    min-width: 0;
  }

  .brand-name {
    display: none;
  }

  .search-wrap {
    max-width: none;
  }

  .inspector {
    bottom: 0;
    right: 0;
    width: 100%;
    border-radius: 0;
    border-left: none;
    border-right: none;
    border-bottom: none;
  }

  .formula-display {
    font-size: 12px;
    padding: 4px 10px;
  }
}