:root {
  color-scheme: light;
  --bg: #f3f4f6;
  --panel: #ffffff;
  --border: #d8dee7;
  --text: #111827;
  --muted: #6b7280;
  --accent: #2563eb;
  --accent-deep: #1d4ed8;
  --green: #16a34a;
  --amber: #d97706;
  --red: #dc2626;
  --shadow-soft: 0 1px 2px rgba(15, 23, 42, 0.04), 0 10px 24px rgba(15, 23, 42, 0.04);
  --radius-xl: 20px;
  --body-font: "Avenir Next", "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  --heading-font: var(--body-font);
}

* {
  box-sizing: border-box;
}

html {
  min-height: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--text);
  font-family: var(--body-font);
  background: var(--bg);
}

button,
input,
select {
  font: inherit;
}

button {
  cursor: pointer;
}

.page-shell {
  width: min(1600px, calc(100vw - 32px));
  margin: 14px auto 28px;
}

.eyebrow {
  margin: 0 0 4px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 700;
}

.panel-header h2 {
  margin: 0;
  font-family: var(--heading-font);
  font-size: 1.08rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.workspace {
  display: grid;
  grid-template-columns: 320px minmax(0, 1fr);
  gap: 16px;
  margin-top: 8px;
}

.panel,
.stage-panel {
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  background: var(--panel);
  box-shadow: var(--shadow-soft);
}

.sidebar,
.stage-panel {
  padding: 18px;
}

.sidebar {
  align-self: start;
  position: sticky;
  top: 16px;
  max-height: calc(100vh - 32px);
  overflow: auto;
}

.panel-header,
.section-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
}

.panel-header {
  margin-bottom: 18px;
}

.panel-header > div:first-child {
  min-width: 0;
}

.control-section + .control-section {
  margin-top: 22px;
}

.control-section--tight + .control-section--tight {
  margin-top: 18px;
}

.section-heading h3 {
  margin: 0;
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.brand-mark {
  width: 60px;
  height: 60px;
  display: block;
  flex: 0 0 auto;
  border-radius: 18px;
  filter: drop-shadow(0 6px 14px rgba(37, 99, 235, 0.12));
  overflow: visible;
  transform-origin: center;
  transition: transform 140ms ease, filter 140ms ease;
}

.brand-mark--active {
  filter: drop-shadow(0 8px 18px rgba(37, 99, 235, 0.26));
  transform: scale(1.05);
}

.mode-toggle-grid,
.field-grid {
  display: grid;
  gap: 12px;
}

.mode-toggle-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.field-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.field-grid.field-grid--single {
  grid-template-columns: 1fr;
}

.toggle-card,
.tool-button,
.primary-button,
.ghost-button {
  border: 0;
  border-radius: 12px;
  transition:
    transform 180ms ease,
    background-color 180ms ease,
    color 180ms ease,
    border-color 180ms ease;
}

.toggle-card,
.tool-button,
.ghost-button {
  border: 1px solid var(--border);
  background: #ffffff;
  color: var(--text);
}

.toggle-card:hover,
.tool-button:hover,
.primary-button:hover,
.ghost-button:hover {
  background: #f8fafc;
}

.toggle-card {
  text-align: left;
  padding: 14px;
}

.toggle-card span {
  display: block;
  margin-bottom: 6px;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.toggle-card strong {
  font-size: 0.96rem;
}

.toggle-card.is-active,
.tool-button.is-active {
  border-color: #bfdbfe;
  background: #eff6ff;
  color: var(--accent-deep);
}

.tool-grid,
.action-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.action-grid.action-grid--single {
  grid-template-columns: 1fr;
}

.action-grid--edit {
  margin-top: 10px;
}

.mini-metrics {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 12px;
  color: var(--muted);
  font-size: 0.84rem;
}

.mini-metrics strong {
  color: var(--text);
}

.tool-button,
.primary-button,
.ghost-button {
  min-height: 42px;
  padding: 11px 13px;
  font-size: 0.92rem;
  font-weight: 700;
  line-height: 1.2;
}

.primary-button {
  width: 100%;
  border: 1px solid var(--accent);
  background: var(--accent);
  color: white;
}

.primary-button--play {
  width: 100%;
  min-width: 0;
}

.ghost-button[disabled],
.primary-button[disabled] {
  opacity: 0.45;
  cursor: not-allowed;
  transform: none;
}

.field {
  display: grid;
  gap: 8px;
}

.field span {
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.field input,
.field select {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: #ffffff;
  color: var(--text);
  outline: none;
}

.field input:focus,
.field select:focus {
  border-color: #93c5fd;
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.12);
}

.field input[type="range"] {
  padding: 0;
  accent-color: var(--accent);
  box-shadow: none;
}

.microcopy {
  color: var(--muted);
  font-size: 0.84rem;
  line-height: 1.55;
}

.inspector-card {
  padding: 16px;
  border-radius: 14px;
}

.inspector-card {
  border: 1px solid var(--border);
  background: #ffffff;
}

.inspector-title {
  margin: 0 0 14px;
  font-weight: 700;
  font-size: 0.98rem;
}

.control-disclosure {
  margin-top: 20px;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: #ffffff;
}

.control-disclosure summary {
  cursor: pointer;
  list-style: none;
}

.control-disclosure summary::-webkit-details-marker {
  display: none;
}

.control-disclosure summary {
  padding: 13px 16px;
  color: var(--text);
  font-size: 0.95rem;
  font-weight: 700;
  line-height: 1.3;
}

.control-disclosure--subtle {
  margin-top: 12px;
}

.control-disclosure[open] summary {
  border-bottom: 1px solid var(--border);
}

.disclosure-body {
  padding: 14px 16px 16px;
}

.stage-shell {
  min-width: 0;
}

.stage-panel {
  display: grid;
  gap: 14px;
}

.graph-stage {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--border);
  border-radius: 16px;
  background: #ffffff;
  min-height: 600px;
}

.graph-stage::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(148, 163, 184, 0.14) 1px, transparent 1px),
    linear-gradient(90deg, rgba(148, 163, 184, 0.14) 1px, transparent 1px);
  background-size: 40px 40px, 40px 40px;
  pointer-events: none;
}

#graph-svg {
  position: relative;
  z-index: 1;
  width: 100%;
  height: auto;
  display: block;
  aspect-ratio: 1200 / 760;
}

.edge-popover {
  position: absolute;
  z-index: 3;
  width: min(216px, calc(100% - 24px));
  padding: 12px;
  border: 1px solid rgba(37, 99, 235, 0.18);
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.98);
  box-shadow: 0 10px 30px rgba(15, 23, 42, 0.12);
  transform: translateX(-50%);
}

.edge-popover__title {
  margin-bottom: 10px;
  font-size: 0.88rem;
  font-weight: 700;
  line-height: 1.35;
}

.edge-popover__field {
  display: grid;
  gap: 6px;
}

.edge-popover__field span {
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.edge-popover__field input {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: #ffffff;
  color: var(--text);
}

.edge-popover__field input:focus {
  border-color: #93c5fd;
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.12);
  outline: none;
}

.edge-popover__delete {
  width: 100%;
  margin-top: 10px;
}

.issue-modal-backdrop {
  position: absolute;
  inset: 0;
  z-index: 4;
  display: grid;
  place-items: center;
  padding: 20px;
  background: rgba(15, 23, 42, 0.22);
}

.issue-modal {
  width: min(440px, calc(100% - 8px));
  padding: 22px;
  border: 1px solid rgba(37, 99, 235, 0.16);
  border-radius: 18px;
  background: #ffffff;
  box-shadow: 0 18px 48px rgba(15, 23, 42, 0.18);
}

.issue-modal__eyebrow {
  margin-bottom: 8px;
  color: #b91c1c;
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.issue-modal__title {
  margin: 0;
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1.2;
}

.issue-modal__message {
  margin: 12px 0 0;
  color: var(--text);
  font-size: 0.96rem;
  line-height: 1.55;
}

.issue-modal__details {
  margin: 14px 0 0;
  padding-left: 18px;
  color: var(--muted);
  font-size: 0.9rem;
  line-height: 1.55;
}

.issue-modal__details li + li {
  margin-top: 8px;
}

.issue-modal__actions {
  margin-top: 18px;
}

.issue-modal__button {
  width: 100%;
}

.transport-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.transport-row--sidebar {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.playback-card {
  padding: 14px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: #ffffff;
}

.playback-card strong {
  display: block;
  margin-bottom: 6px;
  font-size: 0.94rem;
  font-weight: 700;
}

.playback-card p {
  margin: 0;
  color: var(--muted);
  font-size: 0.84rem;
  line-height: 1.5;
}

.empty-state {
  padding: 18px;
  border-radius: 14px;
  border: 1px dashed var(--border);
  color: var(--muted);
  background: #f8fafc;
  line-height: 1.6;
}

.edge-hitbox {
  fill: none;
  stroke: transparent;
  stroke-width: 16;
  cursor: pointer;
}

.edge-line,
.preview-edge {
  fill: none;
  stroke-linecap: round;
  stroke-linejoin: round;
  transition:
    stroke 180ms ease,
    stroke-width 180ms ease,
    opacity 180ms ease;
}

.edge-line {
  stroke-width: 3.25;
}

.preview-edge {
  stroke: rgba(37, 99, 235, 0.66);
  stroke-width: 3.25;
  stroke-dasharray: 10 10;
}

.edge-label {
  font-size: 13px;
  font-weight: 800;
  fill: #334155;
  paint-order: stroke;
  stroke: rgba(255, 255, 255, 0.95);
  stroke-width: 5;
  stroke-linejoin: round;
  text-anchor: middle;
  pointer-events: none;
}

.edge--idle .edge-line {
  stroke: rgba(100, 116, 139, 0.42);
}

.edge--active .edge-line {
  stroke: var(--amber);
  stroke-width: 4.4;
}

.edge--tree .edge-line,
.edge--selected .edge-line,
.edge--relaxed .edge-line {
  stroke: var(--green);
}

.edge--back .edge-line,
.edge--rejected .edge-line {
  stroke: var(--red);
}

.edge--forward .edge-line {
  stroke: var(--amber);
}

.edge--cross .edge-line {
  stroke: #0891b2;
}

.edge--candidate .edge-line {
  stroke: #eab308;
  stroke-dasharray: 12 10;
}

.edge--path .edge-line {
  stroke: var(--accent);
  stroke-width: 4.8;
}

.edge--muted .edge-line {
  stroke: rgba(148, 163, 184, 0.34);
}

.edge.is-selected .edge-line {
  stroke-width: 5.2;
  filter: drop-shadow(0 0 6px rgba(37, 99, 235, 0.16));
}

.vertex {
  cursor: pointer;
  transition: transform 180ms ease;
}

.vertex-circle,
.vertex-badge rect {
  transition:
    fill 180ms ease,
    stroke 180ms ease,
    stroke-width 180ms ease,
    transform 180ms ease;
}

.vertex-circle {
  fill: rgba(255, 255, 255, 0.95);
  stroke: rgba(100, 116, 139, 0.26);
  stroke-width: 2.6;
}

.vertex-title {
  font-size: 22px;
  font-weight: 900;
  fill: #26323f;
  pointer-events: none;
}

.vertex-badge rect {
  fill: rgba(255, 255, 255, 0.9);
  stroke: rgba(15, 23, 42, 0.12);
}

.vertex-badge text {
  fill: #4b5563;
  font-size: 10px;
  font-weight: 800;
  pointer-events: none;
}

.vertex--idle .vertex-circle {
  fill: rgba(255, 255, 255, 0.9);
}

.vertex--source .vertex-circle {
  fill: rgba(37, 99, 235, 0.14);
  stroke: rgba(37, 99, 235, 0.64);
}

.vertex--target .vertex-circle {
  fill: rgba(251, 113, 133, 0.18);
  stroke: rgba(225, 29, 72, 0.6);
}

.vertex--frontier .vertex-circle {
  fill: rgba(2, 132, 199, 0.18);
  stroke: rgba(2, 132, 199, 0.52);
}

.vertex--active .vertex-circle {
  fill: rgba(217, 119, 6, 0.2);
  stroke: rgba(217, 119, 6, 0.66);
}

.vertex--visited .vertex-circle,
.vertex--settled .vertex-circle {
  fill: rgba(22, 163, 74, 0.16);
  stroke: rgba(22, 163, 74, 0.54);
}

.vertex--muted .vertex-circle {
  fill: rgba(226, 232, 240, 0.72);
  stroke: rgba(148, 163, 184, 0.28);
}

.vertex--component .vertex-circle {
  fill: color-mix(in srgb, var(--component-color) 14%, white);
  stroke: color-mix(in srgb, var(--component-color) 78%, black 4%);
}

.vertex.is-selected .vertex-circle {
  stroke: #111827;
  stroke-width: 3.6;
}

.vertex.is-pending .vertex-circle {
  animation: pulse-ring 1400ms ease-in-out infinite;
}

@keyframes pulse-ring {
  0%,
  100% {
    stroke-width: 2.6;
    transform: scale(1);
  }

  50% {
    stroke-width: 4.4;
    transform: scale(1.04);
  }
}

@media (max-width: 1480px) {
  .workspace {
    grid-template-columns: 300px minmax(0, 1fr);
  }
}

@media (max-width: 1120px) {
  .page-shell {
    width: min(100vw - 20px, 1800px);
    margin: 10px auto 24px;
  }

  .workspace {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: static;
    max-height: none;
    overflow: visible;
  }

  .graph-stage {
    min-height: 460px;
  }
}

@media (max-width: 720px) {
  .page-shell {
    width: calc(100vw - 12px);
  }

  .sidebar,
  .stage-panel {
    padding: 16px;
  }

  .mode-toggle-grid,
  .field-grid,
  .tool-grid,
  .action-grid {
    grid-template-columns: 1fr;
  }

  .primary-button--play {
    width: 100%;
  }

  .transport-row--sidebar {
    grid-template-columns: 1fr;
  }
}