/* Electric blue × acid lime. Shared drawing tokens also drive layer swatches. */
:root {
  --primary: #3156ff;
  --primary-hover: #2143db;
  --primary-soft: #e9eeff;
  --accent: #d8ff36;
  --accent-ink: #172800;
  --ink: #161c35;
  --muted: #53617e;
  --line: #d6ddee;
  --panel: #ffffff;
  --surface: #f4f6ff;
  --canvas: #101529;
  --canvas-panel: #1b2443;
  --canvas-hover: #29375e;
  --canvas-text: #edf2ff;
  --canvas-muted: #b4c2e7;
  --canvas-border: #52688f;
  --target-boundary: #d8ff36;
  --skeleton: #43e6ff;
  --auxiliary: #b69aff;
  --mountain: #ff79be;
  --valley: #43e6ff;
  --success: #176644;
  --error: #b4233a;
  --orange: var(--primary);
  --orange-soft: var(--primary-soft);
  --teal: var(--skeleton);
}

body, .ribbon, .workflow { background: var(--surface); }
button:hover { background: var(--primary-soft); }
button:focus-visible, a:focus-visible, input:focus-visible,
select:focus-visible { outline: 2px solid var(--primary); outline-offset: 2px; }
.button.secondary, .menubar, .left-panel, .right-panel, .command-line,
.menu-popover, dialog, .format-choices label, .example-card {
  background: var(--panel); color: var(--ink); border-color: var(--line);
}
.divider, .status-divider { background: var(--line); }
.ribbon, .ribbon-group, .left-panel, .right-panel, .workflow,
.layer-row, .role-field, .validation-note, .check-item,
.shortcut-row, .property-grid input, .fixed-value,
.form-row input[type=text], .form-row select { border-color: var(--line); }

/* Header and primary actions. */
.topbar { background: var(--primary); color: #ffffff; border-color: var(--primary); }
.brand, .brand strong span, .studio-label, .save-state { color: #ffffff; }
.brand-mark { color: var(--accent); }
.topbar .divider { background: #ffffff66; }
.topbar .button.ghost:hover { background: #ffffff22; }
.topbar button:focus-visible, .topbar a:focus-visible { outline-color: var(--accent); }
.prototype-pill { color: #ffffff; background: #ffffff22; }
.save-state i { background: var(--accent); }
.avatar { background: var(--accent); color: var(--accent-ink); }
.export-button, .export-button:hover { background: var(--accent); color: var(--accent-ink); }
.export-button:hover { box-shadow: inset 0 0 0 2px var(--accent-ink); }
.primary, .tool.active { background: var(--primary); color: #ffffff; }
.primary:hover, .tool.active:hover { background: var(--primary-hover); }
.menu-tabs button, .example-link, .group-label, .tool kbd,
.project-card p, .section-heading, .section-heading>span,
.object-row .object-vertices, .add-object, .layer-row,
.layer-row .layer-number, .left-bottom p, .eyebrow, .version,
.right-tabs button, .selected-heading>div>span, .section-label>span,
.property-grid label, .property-stat, .small-note,
.snap-options label, .snap-options kbd, .snap-symbol,
.fixed-value small, .panel-footer, .menu-popover kbd,
.modal-heading button, .modal-body>p, .shortcut-row,
.example-card p, .check-intro>p, .validation-note p {
  color: var(--muted);
}
.menu-tabs button.active, .right-tabs button.active,
.section-label, .property-stat b, .selected-heading b { color: var(--ink); }
.menu-tabs button.active:after, .right-tabs button.active:after { background: var(--primary); }
.project-icon, .object-glyph { background: var(--primary-soft); color: var(--primary); border-color: var(--line); }
.object-row .icon, .layer-row .eye-button, .selected-heading>button { color: var(--muted); }
.object-row.selected { background: var(--primary-soft); color: var(--ink); box-shadow: inset 3px 0 var(--primary); }
.object-row.selected .icon, .left-bottom .text-button, .example-card .icon { color: var(--primary); }
.little-dot, .ready-dot { background: var(--success); }

/* A dark outline keeps bright layer chips legible on the white panel.
   Their fills are the exact tokens used by the canvas and its legend. */
.layer-key { border-color: var(--canvas-border); }
.layer-key.boundary { background: var(--target-boundary); border-color: var(--canvas); }
.layer-key.skeleton { background: var(--skeleton); border-color: var(--canvas); }
.layer-key.aux { background: var(--auxiliary); border-color: var(--canvas); }
.layer-key.paper { background: transparent; border-color: var(--canvas-border); }
.layer-row.off { opacity: .65; }

/* Canvas chrome. */
.drawing-area, .drawing-tab, #canvasBg { background: var(--canvas); fill: var(--canvas); }
.drawing-tabbar { background: var(--canvas-panel); border-color: var(--canvas-border); }
.drawing-tab { color: var(--canvas-text); border-top-color: var(--accent); }
.tab-square { border-color: var(--accent); }
.tab-format, .new-tab, .view-caption, .view-caption span,
.canvas-heading, .dim, .canvas-badge, .badge-divider,
.canvas-legend { color: var(--canvas-muted); }
.new-tab:hover { background: var(--canvas-hover); }
.view-tag { border-color: var(--canvas-border); color: var(--canvas-text); }
.canvas-badge>span:first-child { background: var(--accent); }
.floating-tools, .zoom-controls { background: var(--canvas-panel); border-color: var(--canvas-border); }
.floating-tools button, .zoom-controls button { color: var(--canvas-text); }
.floating-tools button:hover, .zoom-controls button:hover { background: var(--canvas-hover); }
.floating-tools button.active { background: var(--accent); color: var(--accent-ink); }
.floating-tools>span { background: var(--canvas-border); }
#zoomValue { border-color: var(--canvas-border); }
.drawing-area button:focus-visible { outline-color: var(--accent); }
.axis-widget { border-left-color: var(--skeleton); border-bottom-color: var(--accent); color: var(--skeleton); }
.axis-x { color: var(--accent); }
.axis-widget i { background: var(--canvas); border-color: var(--canvas-text); }
.legend-line { border-top-width: 2px; }
.legend-line.outline { border-color: var(--target-boundary); }
.legend-line.skeleton { border-color: var(--skeleton); }
.legend-line.auxiliary { border-color: var(--auxiliary); }
.legend-line.mountain { border-color: var(--mountain); border-top-style: dashed; }
.legend-line.valley { border-color: var(--valley); border-top-style: dashed; }

/* The same boundary color applies to both selected and unselected polygons.
   Handles, line weight and the selection box communicate selection. */
#grid circle { fill: #53668d; opacity: .62; }
#majorGrid path { stroke: #3c4b70; opacity: .6; }
#paperLayer rect { fill: var(--canvas-text); fill-opacity: .012; stroke: var(--canvas-border); }
#paperLayer path { stroke: var(--canvas-muted); }
.polygon-edge { stroke: var(--target-boundary); fill: var(--target-boundary); fill-opacity: .025; stroke-width: 1.5; }
.selected-polygon { stroke: var(--target-boundary); fill: var(--target-boundary); fill-opacity: .065; stroke-width: 2; }
.selection-box { stroke: var(--canvas-text); stroke-width: 1; }
.handle { fill: var(--canvas); stroke: var(--target-boundary); stroke-width: 1.4; }
.handle.vertex-selected { fill: var(--target-boundary); stroke: var(--canvas-text); }
.paper-label, .shape-label, .dimension-text { fill: var(--canvas-muted); font-size: 8px; }
.dimension-line { stroke: var(--canvas-muted); stroke-width: .8; }
.crease-line { stroke: var(--skeleton); stroke-width: 1.5; }
.crease-line.aux, .crease-line.U { stroke: var(--auxiliary); opacity: 1; }
.crease-line.M { stroke: var(--mountain); }
.crease-line.V { stroke: var(--valley); }
.crease-line.selected { stroke-width: 3; }
.skeleton-node { fill: var(--skeleton); stroke: var(--canvas); }
.snap-mark { stroke: var(--accent); stroke-width: 2; }
.snap-text { fill: var(--accent); font-size: 8px; }
.draft-line { fill: var(--target-boundary); stroke: var(--target-boundary); stroke-width: 1.7; }
#draftLayer circle { fill: var(--target-boundary); }

/* Property controls, workflow and status. */
.workflow-caption small, .step b, .step span, .command-line,
.command-prompt, .command-line>kbd { color: var(--muted); }
.step span { border-color: var(--line); background: var(--panel); }
.step.active span { background: var(--accent); color: var(--accent-ink); border-color: var(--accent); box-shadow: 0 0 0 3px #d8ff3633; }
.step.active b { color: var(--ink); }
.step.completed span { background: var(--primary-soft); color: var(--primary); border-color: var(--line); }
.workflow-steps>i { border-color: var(--line); }
.stage-next { background: var(--panel); color: var(--primary); border-color: var(--line); }
.property-grid input, .fixed-value, .form-row input[type=text], .form-row select { background: var(--panel); color: var(--ink); }
.property-grid input:focus { border-color: var(--primary); outline: 2px solid var(--primary); outline-offset: 1px; }
.property-grid input:disabled, .fixed-value { background: var(--surface); color: var(--muted); }
.role-field { background: var(--surface); color: var(--ink); }
.role-field .icon { color: var(--muted); }
.orange-dot { background: var(--target-boundary); box-shadow: 0 0 0 1px var(--canvas); }
.switch { background: #8693b1; }
.switch.on { background: var(--primary); }
.switch.on:hover { background: var(--primary-hover); }
.snap-options input { border-color: #7888ae; }
.snap-options input:checked { background: var(--primary); border-color: var(--primary); }
.statusbar { background: var(--surface); color: var(--muted); border-color: var(--line); }
.status-right button { color: var(--muted); }
.status-right button.active { background: var(--primary); color: #ffffff; }
.check-intro, .check-item { color: var(--success); }
.check-item.error { color: var(--error); }
.check-item.warning { color: #895000; }
.check-summary { padding: 10px 0; margin: 10px 0 0; font-size: 11px; font-weight: 600; line-height: 1.8; color: var(--success); }
.check-summary.error { color: var(--error); }
.check-summary.warning { color: #895000; }
.validation-note { color: var(--muted); }
.validation-note>span { background: var(--primary-soft); color: #394b90; }
.segmented button { border-color: var(--line); }
.segmented button.active { background: var(--primary); color: #ffffff; border-color: var(--primary); }

/* Menus and dialogs. */
.toast { background: var(--panel); color: var(--ink); border-color: var(--primary); box-shadow: 0 4px 24px #10152930; }
.toast.error { color: var(--error); border-color: var(--error); }
dialog { box-shadow: 0 24px 100px #10152966; }
dialog::backdrop { background: #101529cc; }
.format-choices label:has(input:checked) { background: var(--primary-soft); border-color: var(--primary); }
.shortcut-row kbd { background: var(--primary-soft); color: var(--ink); }
.redo-button { white-space: nowrap; font-size: 11px; }
#redoCount { font-family: var(--mono); font-size: 10px; padding: 2px 4px; border-radius: 3px; background: var(--primary-soft); color: var(--ink); }

/* Group selection and model-space transforms; handles retain screen-space strokes. */
.selection-box { pointer-events: none; }
.scale-handle {
  fill: var(--accent); stroke: var(--canvas); stroke-width: 1.6;
  vector-effect: non-scaling-stroke; pointer-events: all;
}
.scale-hit { fill: transparent; stroke: none; pointer-events: all; }
.scale-handle.nw, .scale-handle.se, .scale-hit.nw, .scale-hit.se,
[data-scale="nw"], [data-scale="se"] { cursor: nwse-resize; }
.scale-handle.ne, .scale-handle.sw, .scale-hit.ne, .scale-hit.sw,
[data-scale="ne"], [data-scale="sw"] { cursor: nesw-resize; }
.vertex-handle {
  fill: var(--canvas); stroke: var(--skeleton); stroke-width: 1.6;
  vector-effect: non-scaling-stroke; cursor: crosshair; pointer-events: all;
}
.vertex-handle.vertex-selected { fill: var(--skeleton); stroke: var(--canvas-text); }
.selected-edge { stroke: var(--skeleton); stroke-width: 3; vector-effect: non-scaling-stroke; pointer-events: none; }
.selection-marquee {
  fill: var(--primary); fill-opacity: .18; stroke: var(--accent);
  stroke-width: 1.2; stroke-dasharray: 5 3;
  vector-effect: non-scaling-stroke; pointer-events: none;
}
.selection-caption {
  fill: var(--canvas-text); stroke: var(--canvas); stroke-width: 3;
  paint-order: stroke fill; stroke-linejoin: round;
  font-family: var(--mono); font-size: 8px; pointer-events: none;
}
.skeleton-section { background: var(--primary-soft); }
.auto-skeleton { display: flex; gap: 4px; align-items: center; font-size: 10px; color: var(--ink); letter-spacing: 0; }
.auto-skeleton input { accent-color: var(--primary); }
.skeleton-state { font-size: 11px; line-height: 1.7; color: var(--ink); overflow-wrap: anywhere; margin: 0; }
.skeleton-state[data-phase="computing"], .skeleton-state[data-phase="waiting"] { color: var(--primary); }
.skeleton-state[data-phase="error"], .skeleton-state[data-phase="offline"] { color: var(--error); }
.skeleton-state[data-phase="ready"] { color: var(--success); }
.skeleton-actions { display: flex; align-items: center; gap: 12px; margin-top: 12px; }
.skeleton-actions .button { font-size: 10px; padding: 0 9px; }
.assignment-section { background: #faf9ff; }
.completion-section { background: #f3f0ff; }
.completion-section>.button { margin-top: 12px; }
.clear-canvas-button { color: var(--error); }
.drag-skeleton-preview { opacity: .58; stroke-dasharray: 3 2; }
.crease-selection-halo { stroke: #fff; stroke-width: 7; stroke-opacity: .42; vector-effect: non-scaling-stroke; stroke-linecap: round; }
.crease-selection-summary { color: var(--primary); font-family: var(--mono); font-size: 11px; margin: 10px 0; line-height: 1.7; }
#projectTabs { display: flex; min-width: 0; overflow-x: auto; flex: 1; scrollbar-width: thin; align-self: stretch; }
#projectTabs .drawing-tab { display: flex; align-items: center; gap: 8px; flex: 0 0 auto; max-width: 220px; color: var(--muted); background: transparent; border: 0; border-right: 1px solid var(--line); border-top: 3px solid transparent; border-radius: 0; padding: 0 14px; cursor: pointer; }
#projectTabs .drawing-tab.active { color: var(--ink); background: var(--panel); border-top-color: var(--primary); }
#projectTabs .drawing-tab:focus-visible { outline: 2px solid var(--primary); outline-offset: -3px; }
.project-tab-name { max-width: 140px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.drawing-tabbar .new-tab { flex-shrink: 0; }
#projectSessionHint { font-size: 9px; white-space: nowrap; }
.example-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 10px; margin-top: 10px; font-size: 11px; }
.example-actions .button { padding: 6px 10px; font-size: 11px; }
#modal:has(.classic-grid) { width: min(900px, calc(100vw - 32px)); max-width: none; }
.classic-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px; margin: 22px 0; }
.classic-card { min-width: 0; overflow: hidden; border: 1px solid var(--line); border-radius: 10px; background: var(--panel); }
.classic-preview { display: block; width: 100%; aspect-ratio: 420 / 297; background: var(--canvas); color: var(--target-boundary); }
.classic-preview-crease { stroke: var(--auxiliary); stroke-width: 1.2; stroke-dasharray: 3 2; }
.classic-preview-crease.M { stroke: var(--mountain); stroke-dasharray: 5 2 1 2; }
.classic-preview-crease.V { stroke: var(--valley); }
.classic-card-body { padding: 16px; }
.classic-card .classic-meta { color: var(--primary); font-size: 10px; margin: 0 0 6px; }
.classic-card h3 { font-size: 16px; margin: 0 0 9px; }
.classic-card .classic-description { font-size: 12px; line-height: 1.7; margin: 0; }
.classic-card .classic-source { color: var(--muted); font-size: 10px; line-height: 1.6; margin: 10px 0 14px; }
.classic-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 14px; font-size: 11px; }
.classic-actions .button { font-size: 11px; padding: 7px 12px; }
.classic-actions a:focus-visible { outline: 2px solid var(--primary); outline-offset: 4px; }
.classic-practice-heading { margin-top: 26px; font-size: 13px; }
@media(max-width:580px) { .classic-grid { grid-template-columns: 1fr; } }
.assignment-settings label { display: grid; gap: 6px; margin: 8px 0; font-size: 11px; }
.assignment-settings select,.assignment-settings input { min-width: 0; width: 100%; padding: 7px; border: 1px solid var(--line); border-radius: 4px; background: var(--panel); color: var(--ink); }
@media(max-width:950px) { #projectSessionHint { display: none; } }
@media(max-width:540px) { #projectTabs .drawing-tab { max-width: 160px; padding: 0 8px; } .project-tab-name { max-width: 95px; } }
.assignment-section>.text-button { margin-top: 12px; }
.algorithm-report { max-height: 48vh; overflow: auto; white-space: pre-wrap; overflow-wrap: anywhere; font-family: var(--mono); font-size: 11px; line-height: 1.65; padding: 14px; background: var(--surface); border-radius: 6px; }
#completionState { margin-top: 12px; }
.skeleton-section a, .modal-body a { color: var(--primary); }
.form-row input[type=url] { width: 250px; min-width: 0; padding: 8px; border: 1px solid var(--line); border-radius: 4px; background: var(--panel); color: var(--ink); }

@media (max-width: 950px) {
  .canvas-legend { gap: 8px; }
}