:root {
  --bg: #fafafa;
  --surface: #ffffff;
  --surface-2: #f4f4f5;
  --border: #d4d4d8;
  --text: #18181b;
  --text-muted: #71717a;
  --accent: #1971c2;
  --danger: #e03131;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.06), 0 2px 8px rgba(0, 0, 0, 0.04);
  --radius: 4px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font: 14px/1.4 ui-sans-serif, system-ui, -apple-system, "Segoe UI", Helvetica, Arial, sans-serif;
}

body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

/* ---------- topbar ---------- */

.topbar {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 8px 16px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}

.brand {
  font-weight: 600;
  font-size: 15px;
}

.project-picker {
  display: flex;
  align-items: center;
  gap: 6px;
}

.topbar-spacer { flex: 1; }

/* ---------- layout ---------- */

.layout {
  display: grid;
  grid-template-columns: 220px 1fr 280px;
  flex: 1;
  min-height: 0;
}

.sidebar,
.inspector {
  background: var(--surface);
  padding: 12px;
  overflow-y: auto;
}

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

.sidebar-heading {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-muted);
  margin: 0 0 8px 0;
}

.tool-list,
.legend-list {
  list-style: none;
  padding: 0;
  margin: 0 0 8px 0;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.legend-row {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 4px 6px;
  border-radius: var(--radius);
  cursor: pointer;
}
.legend-row:hover { background: var(--surface-2); }
.legend-row[aria-current="true"] {
  background: var(--surface-2);
  outline: 1px solid var(--accent);
}
.legend-swatch {
  width: 14px;
  height: 14px;
  border-radius: 3px;
  border: 1px solid rgba(0, 0, 0, 0.15);
  flex-shrink: 0;
}
.legend-name { flex: 1; }
.legend-edit {
  background: transparent;
  border: 0;
  cursor: pointer;
  color: var(--text-muted);
  padding: 2px 4px;
  border-radius: 2px;
  font-size: 12px;
}
.legend-edit:hover { color: var(--text); background: var(--surface-2); }

/* ---------- canvas ---------- */

.canvas-wrap {
  position: relative;
  overflow: hidden;
  background: #f7f7f7;
  background-image:
    linear-gradient(to right, rgba(0,0,0,0.04) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(0,0,0,0.04) 1px, transparent 1px);
  background-size: 50px 50px;
}

#canvas {
  width: 100%;
  height: 100%;
  display: block;
}

.empty-hint {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  color: var(--text-muted);
  font-size: 14px;
  pointer-events: none;
  background: rgba(255, 255, 255, 0.85);
  padding: 8px 14px;
  border-radius: var(--radius);
}

.muted { color: var(--text-muted); }

/* ---------- canvas elements ---------- */

.frame-rect {
  fill: rgba(25, 113, 194, 0.04);
  stroke: var(--accent);
  stroke-width: 1.5;
  stroke-dasharray: 6 4;
}
.frame-rect.selected,
.frame-rect:hover { stroke-width: 2.5; }

.frame-label {
  fill: var(--accent);
  font-size: 13px;
  font-weight: 600;
  cursor: grab;
}

/* Stroke + fill come from the device's user-set colour, written as
   inline style in renderCanvas — leaving them out of .device-rect so
   the author CSS doesn't override the inline style. */
.device-rect {
  stroke-width: 1.5;
}
.device-rect.selected { stroke-width: 3; }
.device-rect:hover { filter: drop-shadow(0 1px 2px rgba(0, 0, 0, 0.15)); }

/* Bottom-right resize affordance per device. Subtle grey by default,
   stronger on hover so m can find it without it dominating the rect. */
.device-resize-handle {
  fill: rgba(120, 120, 120, 0.35);
  stroke: rgba(60, 60, 60, 0.45);
  stroke-width: 1;
  cursor: nwse-resize;
}
.device-resize-handle:hover {
  fill: rgba(60, 60, 60, 0.65);
}

.device-label {
  fill: var(--text);
  font-size: 12px;
  text-anchor: middle;
  dominant-baseline: central;
  pointer-events: none;
  user-select: none;
}

.svg-draggable { cursor: grab; }
.svg-draggable.dragging { cursor: grabbing; }

/* Tool cursor while a tool is armed. The `* { ... !important }` descendant
   rule is the load-bearing part: without it, the `.svg-draggable` rules
   on individual frame/device rects win by element specificity and
   override the SVG-root cursor — so hovering a frame with +Dev armed
   shows `grab`, which lies about what a click will do. */
.canvas-wrap.tool-frame  #canvas,
.canvas-wrap.tool-frame  #canvas *,
.canvas-wrap.tool-device #canvas,
.canvas-wrap.tool-device #canvas *,
.canvas-wrap.tool-io     #canvas,
.canvas-wrap.tool-io     #canvas *,
.canvas-wrap.tool-clamp  #canvas,
.canvas-wrap.tool-clamp  #canvas *,
.canvas-wrap.tool-cable  #canvas,
.canvas-wrap.tool-cable  #canvas * { cursor: crosshair !important; }

/* Clamps — small grey rounded squares (v5 §11). Cables route through
   them in `ord` sequence. */
.clamp {
  fill: rgba(120, 120, 120, 0.85);
  stroke: rgba(40, 40, 40, 0.85);
  stroke-width: 1.5;
  cursor: grab;
}
.clamp.selected {
  stroke-width: 3;
  filter: drop-shadow(0 0 4px var(--accent));
}
.clamp-label {
  fill: var(--text-muted);
  font-size: 10px;
  pointer-events: none;
}
/* Shared-segment count badge — m sees ×N next to clamps that route
   ≥ 2 cables. */
.clamp-badge {
  fill: var(--text);
  font-size: 10px;
  font-weight: 700;
  pointer-events: none;
}
/* Bundle overlay — thick striped polyline drawn on top of individual
   cables along shared segments. v5 §11.3. */
.bundle-line {
  fill: none;
  pointer-events: none;
  opacity: 0.85;
}

.btn-link {
  background: transparent;
  border: 0;
  color: var(--text-muted);
  cursor: pointer;
  font: inherit;
  padding: 0 4px;
  line-height: 1;
}
.btn-link:hover { color: var(--danger); }

/* Highlight a port that's been picked as the cable-draw source. */
.port-circle.cable-from {
  stroke-width: 3;
  filter: drop-shadow(0 0 4px var(--accent));
}

/* Zoom cluster — % + Fit button next to Admin. */
.zoom-cluster {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-left: 8px;
  padding-left: 12px;
  border-left: 1px solid var(--border);
}
#zoom-pct {
  font-size: 12px;
  color: var(--text-muted);
  min-width: 38px;
  text-align: right;
  font-variant-numeric: tabular-nums;
}
.canvas-wrap.panning #canvas,
.canvas-wrap.panning #canvas * { cursor: grabbing !important; }
.canvas-wrap.space-pan-ready #canvas,
.canvas-wrap.space-pan-ready #canvas * { cursor: grab !important; }

/* Header toast — slice 8 export feedback */
.toast {
  display: inline-block;
  margin-left: 12px;
  font-size: 13px;
  padding: 4px 10px;
  border-radius: var(--radius);
  background: var(--surface-2);
  color: var(--text);
  max-width: 420px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.toast.ok    { background: #e8f5e9; color: #1b5e20; }
.toast.error { background: #fdecea; color: #911313; }
.toast a { color: inherit; text-decoration: underline; }

/* IO markers — diamonds. Power-by-convention, so the default fill is
   the Power cable_type colour (#e03131). Rotated 45° rect is the
   easiest way to draw a diamond that still hit-tests at the rotated
   bounds (a <polygon> would also work; rect-with-rotate keeps the
   same DOM shape as device/frame so the drag helpers reuse). */
.io-marker {
  fill: var(--danger);
  fill-opacity: 0.18;
  stroke: var(--danger);
  stroke-width: 1.5;
}
.io-marker.selected,
.io-marker:hover { stroke-width: 2.5; }
.io-marker-label {
  fill: var(--danger);
  font-size: 11px;
  font-weight: 600;
  text-anchor: middle;
  dominant-baseline: central;
  pointer-events: none;
  user-select: none;
}

/* Ports — small circles laid out along the device edge. Both fill and
   stroke come from the cable_type the port carries (set inline in JS)
   so the port reads clearly as a coloured anchor on the device. */
.port-circle {
  stroke-width: 2;
  cursor: crosshair;
}
.port-circle.selected {
  stroke-width: 3;
  filter: drop-shadow(0 0 4px var(--accent));
}

.port-row {
  display: grid;
  grid-template-columns: 14px 1fr auto;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  padding: 2px 4px;
  border-radius: 4px;
  cursor: pointer;
}
.port-row:hover { background: var(--surface-2); }
.port-row .swatch,
.swatch {
  display: inline-block;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  border: 1px solid rgba(0, 0, 0, 0.15);
  margin-right: 6px;
  vertical-align: middle;
}
.port-row .label { color: var(--text); }
.port-row .conn  { color: var(--text-muted); font-size: 11px; }

/* Requirements sidebar list */
.requirement-list {
  list-style: none;
  padding: 0;
  margin: 0 0 8px 0;
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.requirement-row {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  padding: 3px 6px;
  border-radius: var(--radius);
  cursor: pointer;
}
.requirement-row:hover { background: var(--surface-2); }
.requirement-row[aria-current="true"] {
  background: var(--surface-2);
  outline: 1px solid var(--accent);
}
.requirement-row .pair { color: var(--text); }
.requirement-row .pair .type { color: var(--text-muted); font-size: 11px; }
.requirement-row .badge {
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding: 2px 6px;
  border-radius: 10px;
  color: #fff;
}
.requirement-row .badge.must { background: var(--danger); }
.requirement-row .badge.nice { background: var(--text-muted); }

/* Tool-armed: drag-req tool cursor */
.canvas-wrap.tool-req     #canvas,
.canvas-wrap.tool-req     #canvas * { cursor: crosshair !important; }

/* Drag-line preview while dragging from device A toward device B. */
.req-drag-line {
  stroke: var(--accent);
  stroke-width: 2;
  stroke-dasharray: 6 4;
  fill: none;
  pointer-events: none;
}

/* Cables on the canvas. Stroke colour comes from the cable_type;
   solver-owned cables (auto=1) render with a slightly dashed pattern
   so m can tell at a glance which the solver placed. */
.cable-line {
  fill: none;
  stroke-width: 2;
  cursor: pointer;
}
.cable-line.auto { stroke-dasharray: 8 3; }
.cable-line:hover { stroke-width: 4; }
.cable-line.selected { stroke-width: 4; }

/* Endpoint handles — only rendered for the currently-selected cable.
   Grab cursor on idle, grabbing while dragging (.replugging on root). */
.cable-handle {
  cursor: grab;
  stroke-width: 2;
  filter: drop-shadow(0 0 2px rgba(0, 0, 0, 0.35));
}
.cable-handle:hover { stroke-width: 3; }
.canvas-wrap.replugging .cable-handle,
.canvas-wrap.replugging #canvas * { cursor: grabbing !important; }

/* Solve preview-diff modal */
.modal-wide { width: 560px; }

/* Admin modal — wider, tabbed */
.modal-wide.admin-shell-host { width: 760px; }
#modal-admin { width: 760px; max-width: 90vw; }
.admin-shell { padding: 16px; min-height: 460px; }
.admin-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
}
.admin-header h2 { margin: 0; }
.admin-close { font-size: 16px; padding: 4px 8px; }
.admin-tabs {
  display: flex;
  gap: 2px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 12px;
}
.admin-tab {
  background: transparent;
  border: 0;
  border-bottom: 2px solid transparent;
  padding: 8px 12px;
  font: inherit;
  color: var(--text-muted);
  cursor: pointer;
}
.admin-tab:hover { color: var(--text); }
.admin-tab[aria-selected="true"] {
  color: var(--text);
  border-bottom-color: var(--accent);
}
.admin-body {
  font-size: 13px;
  max-height: 60vh;
  overflow-y: auto;
}
.admin-row {
  display: grid;
  gap: 6px 12px;
  padding: 8px 0;
  border-bottom: 1px solid var(--border);
}
.admin-row:last-child { border-bottom: 0; }
.admin-row .field { display: grid; grid-template-columns: 110px 1fr; align-items: center; }
.admin-row .field span { color: var(--text-muted); font-size: 12px; }
.admin-row .field input,
.admin-row .field textarea,
.admin-row .field select {
  width: 100%;
  font: inherit;
  padding: 4px 6px;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--bg);
  color: var(--text);
}
.admin-row .actions { display: flex; gap: 6px; justify-content: flex-end; }
.admin-row.locked { opacity: 0.85; }
.admin-row .locked-badge {
  display: inline-block;
  font-size: 11px;
  padding: 1px 6px;
  border-radius: 3px;
  background: var(--surface-2);
  color: var(--text-muted);
}
.admin-row-title {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-weight: 600;
  margin-bottom: 4px;
}
.admin-row-title .swatch { display: inline-block; }
.admin-empty { color: var(--text-muted); padding: 16px 0; }
.admin-add-row {
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px solid var(--border);
}
.port-profile-list {
  margin: 4px 0 0 0;
  padding: 0;
  list-style: none;
  font-size: 12px;
  color: var(--text-muted);
}
.port-profile-list li {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 2px 0;
}
.tmpl-detail {
  margin: 4px 0 0 0;
  font-size: 12px;
  color: var(--text-muted);
}
.tmpl-detail ul { margin: 4px 0 0 16px; padding: 0; }

.sv-body { font-size: 13px; }
.sv-body h3 {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-muted);
  margin: 12px 0 4px;
}
.sv-body ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.sv-body li {
  padding: 4px 8px;
  border-radius: var(--radius);
  background: var(--surface-2);
}
.sv-body li.added   { border-left: 3px solid #2f9e44; }
.sv-body li.removed { border-left: 3px solid var(--danger); text-decoration: line-through; }
.sv-body li.unmet   { border-left: 3px solid #f59f00; }
.sv-body li.unmet .quickfix {
  display: inline-block;
  margin-left: 8px;
  font-size: 11px;
  padding: 1px 6px;
  background: var(--accent);
  color: #fff;
  border-radius: 10px;
  cursor: pointer;
}

.tp-preview {
  font-size: 13px;
  background: var(--surface-2);
  border-radius: var(--radius);
  padding: 8px 12px;
  margin: 8px 0;
}
.tp-preview h4 {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-muted);
  margin: 6px 0 4px;
}
.tp-preview ul { list-style: none; padding: 0; margin: 0; }
.tp-preview li { padding: 2px 0; }
.tp-preview .skip {
  margin-right: 6px;
  font-size: 11px;
}

.rubber-band {
  fill: rgba(25, 113, 194, 0.08);
  stroke: var(--accent);
  stroke-width: 1;
  stroke-dasharray: 4 4;
  pointer-events: none;
}

/* tool buttons toggle armed-state */
.btn[data-tool].armed {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

/* ---------- inspector ---------- */

.inspector dl {
  margin: 0;
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: 4px 8px;
  font-size: 12px;
}
.inspector dt { color: var(--text-muted); }
.inspector dd { margin: 0; }

.inspector .inline-input {
  font: inherit;
  width: 100%;
  padding: 4px 6px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: #fff;
}
.inspector .inline-input:focus {
  outline: 2px solid var(--accent);
  outline-offset: -1px;
  border-color: var(--accent);
}
.inspector .section-title {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-muted);
  margin: 12px 0 6px 0;
}
.inspector .inspector-actions {
  display: flex;
  gap: 6px;
  margin-top: 12px;
}

/* foreignObject used to inline-name a freshly-placed frame/device */
.inline-namer {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100%;
}
.inline-namer input {
  font: inherit;
  font-size: 12px;
  padding: 2px 4px;
  border: 2px solid var(--accent);
  border-radius: var(--radius);
  background: #fff;
  width: calc(100% - 8px);
  max-width: 200px;
  text-align: center;
}

/* ---------- buttons ---------- */

.btn {
  font: inherit;
  background: var(--surface);
  color: var(--text);
  border: 1px solid var(--border);
  padding: 4px 10px;
  border-radius: var(--radius);
  cursor: pointer;
  box-shadow: var(--shadow);
}
.btn:hover { background: var(--surface-2); }
.btn:disabled { opacity: 0.45; cursor: not-allowed; box-shadow: none; }

.btn-tiny { padding: 2px 8px; font-size: 12px; }
.btn-primary { background: var(--accent); color: #fff; border-color: var(--accent); }
.btn-primary:hover { background: #155da3; }
.btn-danger { background: var(--danger); color: #fff; border-color: var(--danger); }
.btn-danger:hover { background: #b02828; }

/* ---------- dialog ---------- */

.modal {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0;
  width: 380px;
  max-width: calc(100vw - 32px);
  background: var(--surface);
  box-shadow: 0 10px 30px rgba(0,0,0,0.18);
}
.modal::backdrop { background: rgba(0,0,0,0.3); }
.modal form { padding: 16px; }
.modal h2 { margin: 0 0 12px 0; font-size: 16px; }
.modal .banner {
  background: #fff8e1;
  border: 1px solid #f5d76e;
  color: #5b4500;
  padding: 8px 10px;
  border-radius: var(--radius);
  font-size: 13px;
  margin: 0 0 12px 0;
}
.modal .actions {
  display: flex;
  justify-content: flex-end;
  gap: 8px;
  margin-top: 12px;
}
.modal .form-error {
  color: var(--danger);
  font-size: 13px;
  margin: 6px 0 0 0;
}

.field {
  display: flex;
  flex-direction: column;
  gap: 4px;
  margin: 0 0 10px 0;
}
.field span {
  font-size: 12px;
  color: var(--text-muted);
}
.field input,
.field textarea {
  font: inherit;
  padding: 6px 8px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: #fff;
  width: 100%;
}
.field input:focus,
.field textarea:focus {
  outline: 2px solid var(--accent);
  outline-offset: -1px;
  border-color: var(--accent);
}