.app-body {
  height: 100dvh;
  overflow: hidden;
}

.covalent {
  --topbar-height: 50px;
  --tools-width: 52px;
  --inspector-width: 300px;
  display: grid;
  grid-template-rows: var(--topbar-height) minmax(0, 1fr);
  height: 100dvh;
  background: var(--background);
}

.covalent-topbar {
  position: relative;
  z-index: 45;
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: 0 var(--space-3);
  border-bottom: 1px solid var(--border);
  background: color-mix(in srgb, var(--background) 86%, transparent);
  backdrop-filter: blur(14px) saturate(1.4);
}

.covalent-topbar .brand {
  flex: none;
}

.covalent-topbar .crumbs {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: 13.5px;
  font-weight: 500;
  white-space: nowrap;
}

.covalent-topbar .crumbs a {
  color: var(--text-muted);
}

.covalent-topbar .crumbs a:hover {
  color: var(--text);
}

.covalent-topbar .crumbs h1 {
  font-size: 13.5px;
  font-weight: 600;
}

.crumb-separator {
  color: var(--text-subtle);
}

.crumb-separator::before {
  content: "/";
}

.topbar-group {
  display: flex;
  align-items: center;
  gap: 2px;
  margin-left: var(--space-3);
  padding-left: var(--space-3);
  border-left: 1px solid var(--border);
}

.topbar-group .button span {
  font-size: 13px;
}

.view-switch {
  margin-left: var(--space-2);
}

.topbar-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-left: auto;
}

.search-trigger.compact {
  min-width: 0;
  height: 30px;
}

.menu-anchor {
  position: relative;
}

.menu {
  position: absolute;
  top: calc(100% + 6px);
  right: 0;
  z-index: 60;
  display: grid;
  min-width: 240px;
  padding: 4px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-large);
  background: var(--surface);
  box-shadow: var(--shadow-large);
  animation: palette-in 160ms var(--ease-out) both;
}

.menu button {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  height: 34px;
  padding: 0 10px;
  border: 0;
  border-radius: var(--radius);
  background: none;
  color: var(--text);
  font-size: 13.5px;
  text-align: left;
}

.menu button:hover,
.menu button:focus-visible {
  background: var(--surface-hover);
}

.menu button .icon {
  color: var(--text-subtle);
}

.menu button span {
  flex: 1;
}

.menu kbd {
  height: 18px;
  font-size: 10.5px;
}

.menu-separator {
  height: 1px;
  margin: 4px 6px;
  background: var(--border);
}

.menu.settings {
  gap: var(--space-3);
  min-width: 280px;
  padding: var(--space-4);
}

.setting-toggle {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: 13.5px;
  cursor: pointer;
}

.setting-toggle input {
  accent-color: var(--accent);
}

.covalent-body {
  display: grid;
  grid-template-columns: var(--tools-width) minmax(0, 1fr) var(--inspector-width);
  min-height: 0;
}

.covalent-tools {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  padding: var(--space-2) 0;
  overflow-y: auto;
  border-right: 1px solid var(--border);
  background: var(--background-subtle);
}

.tool-button {
  position: relative;
  display: grid;
  place-items: center;
  flex: none;
  width: 38px;
  height: 38px;
  border: 1px solid transparent;
  border-radius: var(--radius);
  background: none;
  color: var(--text-muted);
  transition: background-color 120ms ease, color 120ms ease, border-color 120ms ease;
}

.tool-button:hover {
  background: var(--surface-hover);
  color: var(--text);
}

.tool-button[aria-pressed="true"] {
  border-color: var(--accent-border);
  background: var(--accent-soft);
  color: var(--accent-text);
}

.tool-button .ring-size {
  position: absolute;
  right: 4px;
  bottom: 2px;
  font-size: 9.5px;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
}

.tool-separator {
  flex: none;
  width: 22px;
  height: 1px;
  margin: 6px 0;
  background: var(--border);
}

.covalent-stage {
  position: relative;
  min-width: 0;
  min-height: 0;
  overflow: hidden;
  background-color: var(--background);
  background-image: radial-gradient(var(--grid-line) 1.1px, transparent 1.1px);
  background-size: 22px 22px;
}

.covalent-canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  outline: none;
  touch-action: none;
  user-select: none;
}

.covalent-canvas[data-cursor="crosshair"] {
  cursor: crosshair;
}

.covalent-canvas[data-cursor="pointer"] {
  cursor: pointer;
}

.covalent-canvas[data-cursor="move"] {
  cursor: move;
}

.covalent-canvas[data-cursor="grab"] {
  cursor: grab;
}

.covalent-canvas[data-cursor="erase"] {
  cursor: not-allowed;
}

.covalent-3d {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.overlay .hover-atom {
  fill: var(--accent-soft);
  stroke: var(--accent);
  stroke-width: 1.5;
}

.overlay .hover-bond {
  stroke: var(--accent);
  stroke-width: 9;
  stroke-opacity: 0.22;
  stroke-linecap: round;
}

.overlay .selected-atom {
  fill: color-mix(in srgb, var(--accent) 22%, transparent);
  stroke: var(--accent);
  stroke-width: 1.5;
}

.overlay .selected-bond {
  stroke: var(--accent);
  stroke-width: 11;
  stroke-opacity: 0.28;
  stroke-linecap: round;
}

.overlay .preview-bond {
  stroke: var(--accent);
  stroke-width: 2;
  stroke-linecap: round;
}

.overlay .preview-bond.double {
  stroke-width: 1.6;
}

.overlay .preview-atom {
  fill: var(--accent);
}

.overlay .preview-label {
  fill: var(--accent-text);
  font-family: var(--font-sans);
  font-size: 12px;
  font-weight: 600;
}

.overlay .guide {
  stroke: var(--accent);
  stroke-width: 1;
  stroke-dasharray: 3 4;
  stroke-opacity: 0.6;
}

.overlay .marquee {
  fill: var(--accent-soft);
  stroke: var(--accent);
  stroke-width: 1;
  stroke-dasharray: 4 3;
}

.overlay .selection-frame {
  fill: none;
  stroke: var(--accent);
  stroke-width: 1;
  stroke-dasharray: 4 4;
  stroke-opacity: 0.7;
}

.overlay .rotate-stem {
  stroke: var(--accent);
  stroke-width: 1;
  stroke-opacity: 0.7;
}

.overlay .rotate-handle {
  fill: var(--surface);
  stroke: var(--accent);
  stroke-width: 1.5;
  cursor: grab;
}

.overlay .rotate-handle.active {
  fill: var(--accent);
}

.overlay .rotate-pivot {
  fill: var(--accent);
}

.overlay .arrow-handle {
  fill: var(--surface);
  stroke: var(--accent);
  stroke-width: 1.5;
}

.overlay .arrow-handle.active {
  fill: var(--accent);
}

.overlay .preview-arrow .scheme-arrow {
  stroke: var(--accent);
}

.overlay .preview-arrow .scheme-head {
  fill: var(--accent);
}

.selection-bar {
  position: absolute;
  left: var(--x);
  top: var(--y);
  z-index: 20;
  display: flex;
  gap: 2px;
  padding: 3px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: var(--shadow-medium);
  transform: translateX(-50%);
}

.selection-bar[hidden] {
  display: none;
}

.overlay .problem {
  fill: none;
  stroke: var(--danger);
  stroke-width: 1.5;
  stroke-dasharray: 3 3;
}

.structure.monochrome .atom {
  fill: var(--ink);
}

.stage-empty {
  position: absolute;
  inset: 50% auto auto 50%;
  display: grid;
  gap: var(--space-4);
  justify-items: center;
  width: min(420px, calc(100% - 48px));
  transform: translate(-50%, -50%);
  text-align: center;
  pointer-events: none;
}

.stage-empty p {
  display: grid;
  gap: 6px;
}

.stage-empty strong {
  font-size: 16px;
  font-weight: 600;
}

.stage-empty span {
  color: var(--text-muted);
  font-size: 13.5px;
  line-height: 1.55;
}

.stage-empty .examples {
  justify-content: center;
  pointer-events: auto;
}

.element-bar {
  position: absolute;
  left: 50%;
  bottom: 44px;
  display: flex;
  gap: 2px;
  padding: 4px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: color-mix(in srgb, var(--surface) 92%, transparent);
  box-shadow: var(--shadow-medium);
  backdrop-filter: blur(10px);
  transform: translateX(-50%);
}

.element-button {
  display: grid;
  place-items: center;
  min-width: 32px;
  height: 30px;
  padding: 0 6px;
  border: 1px solid transparent;
  border-radius: 8px;
  background: none;
  color: var(--ink);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 14px;
  font-weight: 600;
}

.element-button:hover {
  background: var(--surface-hover);
}

.element-button[aria-pressed="true"] {
  border-color: var(--accent-border);
  background: var(--accent-soft);
}

.element-button.e-n { color: var(--element-n); }
.element-button.e-o { color: var(--element-o); }
.element-button.e-s { color: var(--element-s); }
.element-button.e-p { color: var(--element-p); }
.element-button.e-f,
.element-button.e-cl { color: var(--element-f); }
.element-button.e-br { color: var(--element-br); }
.element-button.e-i { color: var(--element-i); }
.element-button.more { color: var(--text-muted); }

.view3d-bar {
  position: absolute;
  left: 50%;
  bottom: 44px;
  display: none;
  gap: var(--space-3);
  align-items: center;
  padding: 4px 12px 4px 4px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: color-mix(in srgb, var(--surface) 92%, transparent);
  box-shadow: var(--shadow-medium);
  backdrop-filter: blur(10px);
  transform: translateX(-50%);
  white-space: nowrap;
}

.view3d-bar .segmented {
  border: 0;
  background: none;
}

.covalent[data-view="3d"] .view3d-bar {
  display: flex;
}

.covalent[data-view="3d"] .element-bar,
.covalent[data-view="3d"] .zoom-controls,
.covalent[data-view="3d"] .stage-empty,
.covalent[data-view="3d"] .topbar-group,
.covalent[data-view="3d"] .covalent-tools > * {
  visibility: hidden;
}

.stage-footer {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  height: 36px;
  padding: 0 var(--space-2) 0 var(--space-4);
  pointer-events: none;
}

.stage-hint {
  overflow: hidden;
  color: var(--text-subtle);
  font-size: 12.5px;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.stage-hint.warning {
  color: var(--danger);
}

.zoom-controls {
  display: flex;
  align-items: center;
  gap: 2px;
  pointer-events: auto;
}

.zoom-value {
  min-width: 52px;
  height: 28px;
  border: 0;
  border-radius: var(--radius-small);
  background: none;
  color: var(--text-muted);
  font-size: 12px;
  font-variant-numeric: tabular-nums;
}

.zoom-value:hover {
  background: var(--surface-hover);
  color: var(--text);
}

.covalent-inspector {
  min-height: 0;
  overflow-y: auto;
  border-left: 1px solid var(--border);
  background: var(--background);
}

.inspector-section {
  padding: var(--space-4) var(--space-5);
  border-bottom: 1px solid var(--border);
}

.inspector-section h2 {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  margin-bottom: var(--space-3);
  color: var(--text-subtle);
  font-size: 11.5px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.compound-name {
  display: grid;
  gap: 2px;
  margin-bottom: var(--space-3);
}

.compound-name strong {
  font-size: 16px;
  font-weight: 650;
  letter-spacing: -0.015em;
  overflow-wrap: anywhere;
}

.compound-name a {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  width: fit-content;
  color: var(--accent-text);
  font-size: 12.5px;
}

.compound-name small {
  color: var(--text-muted);
  font-size: 12px;
  line-height: 1.4;
}

.inspector-section .facts > div {
  grid-template-columns: minmax(96px, 44%) minmax(0, 1fr);
  padding: 7px 0;
  font-size: 13px;
}

.inspector-section details summary {
  cursor: pointer;
  color: var(--text-muted);
  font-size: 13px;
  font-weight: 500;
}

.inspector-section details[open] summary {
  margin-bottom: var(--space-3);
}

.inspector-section .copy-field code {
  font-size: 11.5px;
}

.inspector-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  margin-top: var(--space-3);
  font-size: 13px;
}

.inspector-row > span {
  color: var(--text-muted);
}

.stepper {
  display: inline-flex;
  align-items: center;
  gap: 2px;
}

.stepper output {
  min-width: 28px;
  text-align: center;
  font-variant-numeric: tabular-nums;
}

.inspector-empty {
  color: var(--text-subtle);
  font-size: 13px;
}

.periodic-popover {
  position: absolute;
  left: 50%;
  bottom: 88px;
  z-index: 40;
  display: grid;
  grid-template-columns: repeat(18, 26px);
  gap: 2px;
  padding: 8px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-large);
  background: var(--surface);
  box-shadow: var(--shadow-large);
  transform: translateX(-50%);
}

.periodic-popover button {
  height: 24px;
  padding: 0;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--background-subtle);
  color: var(--text);
  font-size: 11px;
  font-weight: 600;
}

.groups-popover {
  grid-template-columns: repeat(10, minmax(44px, auto));
}

.groups-popover button {
  height: 26px;
  padding: 0 6px;
  font-family: Arial, Helvetica, sans-serif;
  font-size: 12px;
}

.element-button.groups {
  color: var(--text-muted);
  font-family: inherit;
  font-size: 12.5px;
  font-weight: 500;
}

.atom-label {
  position: absolute;
  left: var(--x);
  top: var(--y);
  z-index: 30;
  width: 96px;
  height: 30px;
  font-family: Arial, Helvetica, sans-serif;
  font-weight: 600;
  transform: translate(-50%, -50%);
}

.conditions-editor {
  position: absolute;
  left: var(--x);
  top: var(--y);
  z-index: 30;
  display: grid;
  gap: 22px;
  width: 240px;
  transform: translate(-50%, -50%);
  pointer-events: none;
}

.conditions-editor .input {
  height: 30px;
  pointer-events: auto;
  font-family: Arial, Helvetica, sans-serif;
  font-size: 13px;
}

.inspector-field {
  display: grid;
  gap: 4px;
  margin-top: var(--space-3);
  font-size: 13px;
}

.inspector-field > span {
  color: var(--text-muted);
}

.inspector-field .input {
  height: 30px;
  font-family: Arial, Helvetica, sans-serif;
  font-size: 13px;
}

.role-heading {
  margin: var(--space-3) 0 var(--space-1);
  color: var(--text-muted);
  font-size: 12.5px;
  font-weight: 500;
}

.reaction-section .role-heading:first-of-type {
  margin-top: 0;
}

.species-list {
  display: grid;
  margin: 0;
  padding: 0;
  list-style: none;
}

.species-list li {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  column-gap: var(--space-3);
  align-items: baseline;
  padding: 7px 0;
  border-bottom: 1px solid var(--border);
  font-size: 13px;
}

.species-list li:last-child {
  border-bottom: 0;
}

.species-mass {
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
}

.species-list small {
  grid-column: 1 / -1;
  color: var(--text-muted);
  font-size: 12px;
  overflow-wrap: anywhere;
}

.species-list small:empty {
  display: none;
}

.reaction-section .callout {
  margin-top: var(--space-3);
  font-size: 13px;
  line-height: 1.45;
}

.reaction-section details.more {
  margin-top: var(--space-3);
}

.periodic-popover button:hover {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.noscript {
  padding: var(--space-10);
}

@media (max-width: 1100px) {
  .covalent {
    --inspector-width: 260px;
  }

  .topbar-group .button span,
  .search-trigger.compact span,
  .search-trigger.compact .kbd-group {
    display: none;
  }
}

@media (max-width: 820px) {
  .covalent-body {
    grid-template-columns: minmax(0, 1fr);
    grid-template-rows: minmax(0, 1fr) auto;
  }

  .covalent-tools {
    grid-row: 2;
    flex-direction: row;
    justify-content: flex-start;
    padding: 4px var(--space-2);
    overflow-x: auto;
    overflow-y: hidden;
    border-top: 1px solid var(--border);
    border-right: 0;
  }

  .tool-separator {
    width: 1px;
    height: 22px;
    margin: 0 4px;
  }

  .covalent-inspector {
    display: none;
  }

  .covalent-topbar .crumbs a,
  .covalent-topbar .crumbs .crumb-separator {
    display: none;
  }

  .topbar-group {
    margin-left: 0;
    padding-left: 0;
    border-left: 0;
  }

  .element-bar,
  .view3d-bar {
    bottom: 40px;
    max-width: calc(100% - 16px);
    overflow-x: auto;
  }

  .periodic-popover {
    grid-template-columns: repeat(9, 30px);
    max-height: 50vh;
    overflow-y: auto;
  }
}

@media (max-width: 560px) {
  .covalent-topbar {
    gap: var(--space-1);
    padding: 0 var(--space-2);
  }

  .covalent-topbar .crumbs h1 {
    position: absolute;
    width: 1px;
    height: 1px;
    overflow: hidden;
    clip-path: inset(50%);
  }

  .topbar-actions {
    gap: 2px;
  }

  .export-button span,
  .export-button .icon + span + .icon {
    display: none;
  }

  .view-switch {
    margin-left: 0;
  }

  .view-switch button,
  .view3d-bar .segmented button {
    padding: 0 7px;
  }

  .view3d-bar {
    gap: 4px;
    padding-right: 8px;
  }

  .view3d-bar .segmented button,
  .view3d-bar .setting-toggle {
    gap: 5px;
    font-size: 12.5px;
  }

  .view3d-bar .segmented button {
    padding: 0 6px;
  }
}