/* === CSS Variables (academic palette) === */
:root {
  --color-room: #E69F00;
  --color-door: #009E73;
  --color-corridor: #CC79A7;
  --color-outside: #56B4E9;
  --color-transition: #D55E00;

  --bg-primary: #f8f9fa;
  --bg-card: #ffffff;
  --bg-sidebar: #ffffff;
  --border-color: #dee2e6;
  --text-primary: #212529;
  --text-secondary: #6c757d;
  --accent: #0d6efd;
  --accent-hover: #0b5ed7;

  --sidebar-width: 320px;
}

/* === Reset / Base === */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto,
    'Helvetica Neue', Arial, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.5;
}

/* === App layout === */
.app {
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}

/* === Header === */
.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 24px;
  background: var(--bg-card);
  border-bottom: 1px solid var(--border-color);
  flex-shrink: 0;
}

.header h1 {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.header h1 span {
  color: var(--accent);
}

.header-subtitle {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

/* === Main content area === */
.main-content {
  flex: 1;
  display: flex;
  overflow: hidden;
}

/* === Results layout: sidebar + canvas === */
.results-layout {
  display: flex;
  width: 100%;
  height: 100%;
}

.graph-area {
  flex: 1;
  position: relative;
  background: #fff;
  overflow: hidden;
}

.sidebar {
  width: var(--sidebar-width);
  min-width: var(--sidebar-width);
  background: var(--bg-sidebar);
  overflow-y: auto;
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.sidebar-left {
  border-right: 1px solid var(--border-color);
}

.sidebar-right {
  border-left: 1px solid var(--border-color);
}

/* === Cards / panels === */
.panel {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 16px;
}

.panel h3 {
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-secondary);
  margin-bottom: 12px;
}

/* === Upload area (idle state) === */
.upload-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-start;
  width: 100%;
  height: 100%;
  padding: 48px 40px;
  overflow-y: auto;
}

/* === Intro / landing === */
.intro {
  text-align: center;
  max-width: 680px;
  margin-bottom: 28px;
}

.intro-title {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 14px;
}

.intro-title span {
  color: var(--accent);
}

.intro-abstract {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.intro-footer {
  margin-top: 36px;
  padding-bottom: 8px;
  font-size: 0.8rem;
  color: var(--text-secondary);
  text-align: center;
}

.intro-footer a {
  color: var(--accent);
  text-decoration: none;
}

.intro-footer a:hover {
  text-decoration: underline;
}

.dropzone {
  width: 100%;
  max-width: 600px;
  border: 2px dashed var(--border-color);
  border-radius: 12px;
  padding: 48px 32px;
  text-align: center;
  cursor: pointer;
  transition: border-color 0.2s, background 0.2s;
}

.dropzone:hover,
.dropzone.drag-over {
  border-color: var(--accent);
  background: rgba(13, 110, 253, 0.04);
}

.dropzone-icon {
  display: block;
  margin: 0 auto 14px;
  color: var(--accent);
  opacity: 0.85;
  transition: transform 0.2s, opacity 0.2s;
}

.dropzone:hover .dropzone-icon,
.dropzone.drag-over .dropzone-icon {
  opacity: 1;
  transform: translateY(-2px);
}

.dropzone-text {
  font-size: 1rem;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

.dropzone-sub {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

/* === Example cards === */
.examples-section {
  margin-top: 32px;
  width: 100%;
  max-width: 600px;
}

.examples-section h2 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 16px;
  color: var(--text-primary);
}

.example-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

.example-card {
  position: relative;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  overflow: hidden;
  cursor: pointer;
  transition: box-shadow 0.2s, border-color 0.2s;
  background: var(--bg-card);
}

.example-card:hover {
  border-color: var(--accent);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
}

.example-card img {
  width: 100%;
  height: 100px;
  object-fit: cover;
  display: block;
}

.example-card-info {
  padding: 8px 10px;
}

.example-card-name {
  font-size: 0.78rem;
  font-weight: 500;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.example-card-meta {
  font-size: 0.7rem;
  color: var(--text-secondary);
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 4px;
}

.cached-badge {
  background: #d4edda;
  color: #155724;
  font-size: 0.65rem;
  font-weight: 600;
  padding: 1px 6px;
  border-radius: 4px;
}

/* === Processing overlay === */
.processing-overlay {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100%;
  gap: 16px;
}

.spinner {
  width: 48px;
  height: 48px;
  border: 4px solid var(--border-color);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

.processing-text {
  font-size: 1rem;
  color: var(--text-secondary);
}

.processing-stage {
  font-size: 0.85rem;
  color: var(--accent);
  font-weight: 500;
}

/* === Error state === */
.error-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100%;
  gap: 12px;
}

.error-message {
  color: #dc3545;
  font-size: 0.95rem;
  max-width: 400px;
  text-align: center;
}

/* === Graph controls === */
.type-toggle {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 4px 0;
}

.type-toggle label {
  font-size: 0.82rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 6px;
}

.type-swatch {
  display: inline-block;
  width: 12px;
  height: 12px;
  border-radius: 3px;
}

/* === Node type control group (checkbox + slider) === */
.type-control-group {
  padding: 2px 0;
}

.size-slider {
  display: flex;
  align-items: center;
  gap: 6px;
  padding-left: 24px;
}

.size-slider input[type="range"] {
  flex: 1;
  height: 4px;
  -webkit-appearance: none;
  appearance: none;
  background: var(--border-color);
  border-radius: 2px;
  outline: none;
}

.size-slider input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
}

.size-slider input[type="range"]::-moz-range-thumb {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
  border: none;
}

.size-value {
  font-size: 0.72rem;
  color: var(--text-secondary);
  min-width: 20px;
  text-align: right;
}

/* === Stats panel === */
.stat-row {
  display: flex;
  justify-content: space-between;
  padding: 4px 0;
  font-size: 0.82rem;
}

.stat-row .label {
  color: var(--text-secondary);
}

.stat-row .value {
  font-weight: 600;
}

.stat-divider {
  border: none;
  border-top: 1px solid var(--border-color);
  margin: 8px 0;
}

/* === Export panel === */
.export-buttons {
  display: flex;
  gap: 8px;
}

.btn {
  padding: 8px 16px;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  background: var(--bg-card);
  cursor: pointer;
  font-size: 0.82rem;
  font-weight: 500;
  transition: background 0.15s, border-color 0.15s;
}

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

.btn-primary {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

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

.btn-block {
  width: 100%;
}

/* === Tooltip === */
.node-tooltip {
  position: absolute;
  z-index: 1000;
  background: rgba(33, 37, 41, 0.95);
  color: #fff;
  padding: 8px 12px;
  border-radius: 6px;
  font-size: 0.75rem;
  line-height: 1.5;
  pointer-events: none;
  max-width: 220px;
  white-space: nowrap;
}

.tooltip-type {
  font-weight: 600;
  text-transform: capitalize;
}

/* === Graph stage toggle === */
.stage-label {
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--text-secondary);
  display: block;
  margin-bottom: 6px;
}

.stage-toggle {
  display: flex;
  gap: 0;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  overflow: hidden;
}

.stage-btn {
  flex: 1;
  padding: 6px 12px;
  font-size: 0.78rem;
  font-weight: 500;
  border: none;
  background: var(--bg-card);
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
  color: var(--text-secondary);
}

.stage-btn:not(:last-child) {
  border-right: 1px solid var(--border-color);
}

.stage-btn.active {
  background: var(--accent);
  color: #fff;
}

.stage-btn:hover:not(.active) {
  background: var(--bg-primary);
}

/* === Back button === */
.back-btn-row {
  padding: 8px 0;
}

/* === Navigation / routing panel === */
.route-hint {
  font-size: 0.72rem;
  color: var(--text-secondary);
  margin-bottom: 12px;
  line-height: 1.4;
}

.route-field {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.78rem;
  font-weight: 500;
  margin-bottom: 8px;
}

.route-dot {
  display: inline-block;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  flex-shrink: 0;
}

.route-select {
  flex: 1;
  min-width: 0;
  padding: 5px 8px;
  font-size: 0.78rem;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  background: var(--bg-card);
  color: var(--text-primary);
  cursor: pointer;
}

.route-select:focus {
  outline: none;
  border-color: var(--accent);
}

.route-buttons {
  display: flex;
  gap: 8px;
  margin-top: 4px;
}

.route-buttons .btn {
  flex: 1;
}

.route-buttons .btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.route-result {
  margin-top: 12px;
  padding: 10px 12px;
  border: 1px solid var(--border-color);
  border-left: 3px solid var(--accent);
  border-radius: 6px;
  background: var(--bg-primary);
}

.route-result-fail {
  border-left-color: #dc3545;
  font-size: 0.78rem;
  color: #dc3545;
}

.route-result-row {
  display: flex;
  justify-content: space-between;
  font-size: 0.8rem;
  padding: 2px 0;
}

.route-result-row .label {
  color: var(--text-secondary);
}

.route-result-row .value {
  font-weight: 600;
}

.route-badge {
  display: inline-block;
  margin-top: 6px;
  background: #fde2d4;
  color: #8a3b12;
  font-size: 0.68rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 4px;
}

/* === Header back button === */
.header-left {
  display: flex;
  align-items: center;
  gap: 14px;
}

.back-btn {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 6px 12px;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  background: var(--bg-card);
  cursor: pointer;
  font-size: 0.82rem;
  font-weight: 500;
  transition: background 0.15s, border-color 0.15s;
}

.back-btn:hover {
  background: var(--bg-primary);
  border-color: var(--accent);
}

.back-arrow {
  font-size: 1.1rem;
  line-height: 1;
}

/* === Collapsible panel header === */
.panel-collapse-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  background: none;
  border: none;
  padding: 0;
  margin: 0;
  cursor: pointer;
}

.panel-collapse-header h3 {
  margin-bottom: 0;
}

.panel-collapse-header .chevron {
  color: var(--text-secondary);
  transition: transform 0.18s;
  font-size: 1rem;
}

.panel-collapse-header .chevron.open {
  transform: rotate(90deg);
}

.panel-collapse-body {
  margin-top: 12px;
}

.stat-image {
  max-width: 150px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* === Opacity slider === */
.opacity-slider {
  padding-left: 0;
  margin-top: 6px;
}

.opacity-label {
  font-size: 0.72rem;
  color: var(--text-secondary);
  min-width: 48px;
}

/* === Floating canvas toolbar (zoom + fit) === */
.canvas-toolbar {
  position: absolute;
  right: 14px;
  bottom: 14px;
  display: flex;
  align-items: center;
  gap: 4px;
  background: rgba(255, 255, 255, 0.95);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 4px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.12);
  z-index: 50;
}

.zoom-btn {
  min-width: 30px;
  height: 30px;
  padding: 0 8px;
  border: none;
  border-radius: 6px;
  background: transparent;
  cursor: pointer;
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

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

.zoom-btn.fit-btn {
  font-size: 0.8rem;
  font-weight: 600;
  border-left: 1px solid var(--border-color);
  margin-left: 2px;
}

.zoom-readout {
  font-size: 0.74rem;
  color: var(--text-secondary);
  min-width: 42px;
  text-align: center;
}

/* === Mode banner (overlay hint) === */
.mode-banner {
  position: absolute;
  top: 14px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--accent);
  color: #fff;
  padding: 7px 16px;
  border-radius: 999px;
  font-size: 0.8rem;
  font-weight: 500;
  box-shadow: 0 2px 8px rgba(13, 110, 253, 0.3);
  z-index: 50;
  pointer-events: none;
}

/* === Navigation start/end pickers === */
.route-pick {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 8px;
}

.route-pick-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  flex: 0 0 auto;
  min-width: 130px;
}

.route-pick-btn.arming {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.route-current {
  font-size: 0.78rem;
  color: var(--text-secondary);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.route-advanced {
  margin-top: 10px;
}

.route-advanced summary {
  font-size: 0.74rem;
  color: var(--text-secondary);
  cursor: pointer;
  margin-bottom: 8px;
}

/* === Edit toolkit === */
.edit-tools {
  display: flex;
  gap: 6px;
  margin-bottom: 6px;
}

.edit-tool {
  flex: 1;
  padding: 7px 6px;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  background: var(--bg-card);
  cursor: pointer;
  font-size: 0.78rem;
  font-weight: 500;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
}

.edit-tool:hover {
  border-color: var(--accent);
}

.edit-tool.active {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.edit-nodetype {
  margin-top: 10px;
}

.nodetype-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
  margin-top: 6px;
}

.nodetype-chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 8px;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  background: var(--bg-card);
  cursor: pointer;
  font-size: 0.74rem;
  transition: border-color 0.15s, background 0.15s;
}

.nodetype-chip.active {
  border-color: var(--accent);
  background: rgba(13, 110, 253, 0.06);
  font-weight: 600;
}

.edit-hint {
  margin-top: 10px;
  padding: 8px 10px;
  background: var(--bg-primary);
  border-left: 3px solid var(--accent);
  border-radius: 6px;
  font-size: 0.76rem;
  color: var(--text-primary);
}

.edit-undo-note {
  margin-top: 10px;
  font-size: 0.7rem;
  color: var(--text-secondary);
  line-height: 1.4;
}

/* === Connectivity (stats panel) === */
.conn-ok {
  color: #1a7f37;
  font-weight: 700;
  margin-left: 4px;
}

.conn-warn {
  border: none;
  background: none;
  cursor: pointer;
  color: #d39e00;
  font-size: 0.95rem;
  margin-left: 4px;
  padding: 0 2px;
  line-height: 1;
}

.conn-warn:hover {
  color: #b8860b;
}

.conn-list {
  margin: 6px 0 4px;
  padding: 8px;
  background: #fff8e6;
  border: 1px solid #f0d98c;
  border-radius: 6px;
}

.conn-list-title {
  font-size: 0.72rem;
  color: #7a5b00;
  margin-bottom: 6px;
  line-height: 1.4;
}

.conn-node {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  width: 100%;
  text-align: left;
  border: none;
  background: none;
  cursor: pointer;
  font-size: 0.74rem;
  color: var(--text-primary);
  padding: 3px 4px;
  border-radius: 4px;
}

.conn-node:hover {
  background: rgba(0, 0, 0, 0.05);
}

.conn-more {
  font-size: 0.7rem;
  color: var(--text-secondary);
  margin-top: 4px;
  padding-left: 4px;
}

.conn-flag {
  color: #b02a37;
  font-weight: 700;
}

.conn-locate {
  margin-top: 4px;
  font-style: italic;
}

.conn-node-id {
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.conn-reason {
  font-size: 0.64rem;
  font-weight: 600;
  padding: 1px 6px;
  border-radius: 4px;
  flex-shrink: 0;
}

.conn-reason-isolated {
  background: #f8d7da;
  color: #842029;
}

.conn-reason-room {
  background: #fff3cd;
  color: #664d03;
}

.conn-reason-exit {
  background: #cfe2ff;
  color: #084298;
}