:root {
  --bg: #f7f8fa; --panel: #ffffff; --text: #1d2330; --muted: #5d6675; --line: #dfe3ea;
  --accent: #4b5ef0; --accent-text: #ffffff; --error: #b42318; --ok: #1a7f37; --viewer-bg: #eef0f4;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14171c; --panel: #1c2027; --text: #e6e9ef; --muted: #9aa3b2; --line: #2e343e;
    --accent: #7b8bff; --accent-text: #0e1116; --error: #ff8a80; --ok: #6fdc8c; --viewer-bg: #22262e;
  }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--text);
       font: 15px/1.5 system-ui, -apple-system, "Segoe UI", sans-serif; }
a { color: var(--accent); }
.top { padding: 20px 24px 8px; }
.top h1 { margin: 0; font-size: 22px; }
.sub { margin: 4px 0 0; color: var(--muted); }
.layout { display: grid; grid-template-columns: minmax(0, 1fr) 340px; gap: 20px; padding: 16px 24px; }
@media (max-width: 860px) { .layout { grid-template-columns: minmax(0, 1fr); padding: 12px 16px; } }
.viewer { position: relative; height: min(70vh, 640px); min-height: 320px; border: 1px solid var(--line);
          border-radius: 10px; overflow: hidden; background: var(--viewer-bg); }
.viewer canvas { position: absolute; inset: 0; width: 100%; height: 100%; display: block; }
.viewer.dragging { outline: 3px dashed var(--accent); outline-offset: -8px; }
.drop, .busy { position: absolute; inset: 0; display: flex; flex-direction: column; align-items: center;
               justify-content: center; gap: 8px; text-align: center; padding: 16px; background: var(--viewer-bg); }
/* Above the canvas, which is absolutely positioned too and comes later in the DOM:
   without this the canvas swallows the clicks on "Choose file". */
.drop, .busy { z-index: 2; }
.drop[hidden], .busy[hidden], [hidden] { display: none !important; }
.no-webgl { position: absolute; left: 16px; right: 16px; bottom: 12px; margin: 0; z-index: 1;
            color: var(--muted); font-size: 13px; text-align: center; }
.view-toggle { display: flex; margin: 10px 0 2px; border: 1px solid var(--line); border-radius: 8px; overflow: hidden; }
.view-toggle button { flex: 1; padding: 7px 10px; border: 0; background: var(--panel); color: var(--text);
                      font: inherit; cursor: pointer; }
.view-toggle button + button { border-left: 1px solid var(--line); }
.view-toggle button.active { background: var(--accent); color: var(--accent-text); font-weight: 600; }
.face-pick { display: flex; flex-direction: column; gap: 4px; margin-top: 8px; font-weight: 600; }
.face-list { max-height: 180px; overflow-y: auto; border: 1px solid var(--line); border-radius: 6px;
             background: var(--bg); padding: 4px 0; font-weight: 400; font-size: 14px; }
.face-list label { display: flex; gap: 8px; align-items: center; padding: 3px 10px; cursor: pointer; }
.face-list label:hover { background: var(--panel); }
.face-pick p { margin: 2px 0 0; font-weight: 400; }
.busy { flex-direction: row; background: color-mix(in srgb, var(--viewer-bg) 85%, transparent); }
.panel { display: flex; flex-direction: column; gap: 14px; }
.box { background: var(--panel); border: 1px solid var(--line); border-radius: 10px; padding: 14px 16px; margin: 0; }
.box h2 { margin: 0 0 10px; font-size: 16px; }
.box p { margin: 6px 0; }
.muted, .hint { color: var(--muted); font-size: 13px; }
.field { display: flex; justify-content: space-between; align-items: center; gap: 10px; margin: 10px 0; }
.field input, .field select { width: 130px; padding: 6px 8px; border: 1px solid var(--line); border-radius: 6px;
               background: var(--bg); color: var(--text); font: inherit; }
.check { display: flex; gap: 8px; align-items: center; margin: 10px 0; }
.seg { display: flex; gap: 16px; border: 0; padding: 0; margin: 0 0 6px; }
.estimate { margin: 12px 0; padding: 10px 12px; border-radius: 8px; background: var(--bg); font-size: 14px; }
dl { display: grid; grid-template-columns: auto 1fr; gap: 3px 12px; margin: 0; }
dt { color: var(--muted); }
dd { margin: 0; text-align: right; }
.button { display: inline-block; padding: 9px 16px; border-radius: 8px; border: 1px solid var(--line);
          background: var(--panel); color: var(--text); font: inherit; cursor: pointer; text-decoration: none; }
.button.primary { background: var(--accent); border-color: var(--accent); color: var(--accent-text);
                  font-weight: 600; width: 100%; text-align: center; margin-top: 8px; }
.button:disabled { opacity: 0.5; cursor: not-allowed; }
.link { background: none; border: 0; color: var(--accent); cursor: pointer; font: inherit; padding: 0; margin-top: 8px; }
.error { color: var(--error); }
.ok { color: var(--ok); font-weight: 600; }
.notes ul { padding-left: 18px; margin: 8px 0 0; color: var(--muted); font-size: 13px; }
.notes summary { cursor: pointer; font-weight: 600; }
.foot { padding: 8px 24px 24px; color: var(--muted); font-size: 12px; }
.spinner { display: inline-block; width: 14px; height: 14px; border: 2px solid var(--line);
           border-top-color: var(--accent); border-radius: 50%; animation: spin 0.8s linear infinite;
           vertical-align: -2px; margin-right: 6px; }
@keyframes spin { to { transform: rotate(360deg); } }

/* ── boundary + sketch editor ─────────────────────────────────────────────── */
:root { --sk-add: #4b5ef0; --sk-sub: #c2410c; --sk-grid: rgba(120, 130, 150, 0.18); --sk-grid-major: rgba(120, 130, 150, 0.35); }
@media (prefers-color-scheme: dark) { :root { --sk-add: #7b8bff; --sk-sub: #fb923c; } }
.boundary { margin: 12px 0 4px; }
.boundary > span { font-weight: 600; }
.boundary p { margin: 2px 0 6px; font-size: 14px; }
.boundary-acts { display: flex; gap: 12px; align-items: center; }
.boundary-acts .link { margin-top: 0; }
.sketch-modal { position: fixed; inset: 0; z-index: 50; background: rgba(10, 12, 18, 0.55);
                display: flex; align-items: center; justify-content: center; padding: 16px; }
.sketch-dialog { background: var(--panel); color: var(--text); border-radius: 12px; width: min(1400px, 100%);
                 height: min(900px, 100%); display: flex; flex-direction: column; overflow: hidden;
                 border: 1px solid var(--line); }
.sketch-head { padding: 12px 16px 4px; }
.sketch-head h2 { margin: 0; font-size: 17px; }
.sketch-head p { margin: 4px 0 0; }
.sketch-root { flex: 1; display: flex; flex-direction: column; min-height: 0; }
.sk-bar { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; padding: 8px 16px;
          border-bottom: 1px solid var(--line); }
.sk-bar button, .sk-op button, .sk-pt button { padding: 6px 10px; border: 1px solid var(--line); border-radius: 6px;
          background: var(--panel); color: var(--text); font: inherit; font-size: 14px; cursor: pointer; }
.sk-bar button.active, .sk-op button.active { background: var(--accent); border-color: var(--accent); color: var(--accent-text); }
.sk-sep { width: 1px; align-self: stretch; background: var(--line); margin: 0 4px; }
.sk-snap { display: flex; gap: 4px; align-items: center; font-size: 14px; margin-left: auto; }
.sk-snap select { font: inherit; font-size: 13px; padding: 3px; background: var(--bg); color: var(--text);
                  border: 1px solid var(--line); border-radius: 5px; }
.sk-body { flex: 1; display: grid; grid-template-columns: minmax(0, 1fr) 300px; min-height: 0; }
.sk-canvas { width: 100%; height: 100%; display: block; background: var(--viewer-bg); touch-action: none;
             cursor: crosshair; user-select: none; }
.sk-side { border-left: 1px solid var(--line); padding: 12px 14px; overflow-y: auto; display: flex;
           flex-direction: column; gap: 8px; font-size: 14px; }
.sk-side h3 { margin: 6px 0 4px; font-size: 15px; }
.sk-help, .sk-note { margin: 0; color: var(--muted); font-size: 13px; }
.sk-note:empty { display: none; }
.sk-note { color: var(--sk-sub); }
.sk-op { display: flex; }
.sk-op button { flex: 1; border-radius: 0; }
.sk-op button:first-child { border-radius: 6px 0 0 6px; }
.sk-op button:last-child { border-radius: 0 6px 6px 0; border-left: 0; }
.sk-field { display: flex; justify-content: space-between; align-items: center; gap: 8px; }
.sk-field input, .sk-pt input { width: 96px; padding: 5px 7px; border: 1px solid var(--line); border-radius: 6px;
                                background: var(--bg); color: var(--text); font: inherit; font-size: 14px; }
.sk-pt { display: flex; gap: 6px; align-items: center; }
.sk-pt input { width: 80px; }
.sk-acts { display: flex; gap: 8px; margin-top: 4px; }
.sk-acts .button { padding: 6px 12px; font-size: 14px; }
.sk-list { display: flex; flex-direction: column; gap: 4px; }
.sk-item { text-align: left; padding: 5px 8px; border: 1px solid var(--line); border-radius: 6px; background: var(--bg);
           color: var(--text); font: inherit; font-size: 13px; cursor: pointer; border-left-width: 4px; }
.sk-item.add { border-left-color: var(--sk-add); }
.sk-item.subtract { border-left-color: var(--sk-sub); }
.sk-item.active { outline: 2px solid var(--accent); }
.sk-foot { margin-top: auto; display: flex; gap: 8px; padding-top: 10px; border-top: 1px solid var(--line); }
.sk-foot .button { padding: 8px 12px; font-size: 14px; width: auto; margin-top: 0; }
.sk-foot .button.primary { flex: 1; }
.sk-grid { stroke: var(--sk-grid); }
.sk-grid.major { stroke: var(--sk-grid-major); }
.sk-face { fill: var(--panel); stroke: var(--text); }
.sk-seam { stroke: var(--muted); fill: none; }
.sk-label { fill: var(--muted); }
.sk-knurl path { fill: none; stroke: var(--muted); opacity: 0.35; }
.sk-shape { cursor: move; }
.sk-shape.add { fill: color-mix(in srgb, var(--sk-add) 22%, transparent); stroke: var(--sk-add); }
.sk-shape.subtract { fill: url(#sk-hatch); stroke: var(--sk-sub); }
.sk-shape.ghost { opacity: 0.35; pointer-events: none; }
.sk-shape.selected { stroke-dasharray: none; filter: drop-shadow(0 0 2px var(--accent)); }
.sk-shape.draft { fill-opacity: 0.4; }
.sk-hatch-line { stroke: var(--sk-sub); stroke-width: 1; vector-effect: non-scaling-stroke; }
.sk-rubber { stroke: var(--sk-add); stroke-dasharray: 3 3; }
.sk-handle { fill: var(--panel); stroke: var(--accent); stroke-width: 0.15; cursor: pointer; vector-effect: non-scaling-stroke; }
.sk-handle.rot { fill: var(--accent); }
@media (max-width: 860px) {
  .sk-body { grid-template-columns: 1fr; grid-template-rows: minmax(260px, 1fr) auto; }
  .sk-side { border-left: 0; border-top: 1px solid var(--line); max-height: 45vh; }
  .sketch-modal { padding: 0; }
  .sketch-dialog { border-radius: 0; height: 100%; }
}

/* split sketch dialog: editor left, the live 3D view right */
.sketch-split { flex: 1; display: grid; grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr); min-height: 0; }
.sketch-3d-pane { display: flex; flex-direction: column; border-left: 1px solid var(--line); min-height: 0; }
.sketch-3d { position: relative; flex: 1; min-height: 0; background: var(--viewer-bg); }
.sketch-3d canvas { position: absolute; inset: 0; width: 100%; height: 100%; display: block; }
.sketch-3d-pane p { margin: 0; padding: 6px 12px; font-size: 12px; border-top: 1px solid var(--line); }
.sketch-split .sk-body { grid-template-columns: minmax(0, 1fr) 260px; }
@media (max-width: 860px) {
  .sketch-split { grid-template-columns: 1fr; grid-template-rows: 34vh minmax(0, 1fr); }
  .sketch-3d-pane { order: -1; border-left: 0; border-bottom: 1px solid var(--line); }
  .sketch-split .sk-body { grid-template-columns: 1fr; }
}