: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;
  pointer-events: none;
}

.device-rect {
  fill: #fff;
  stroke: var(--text);
  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)); }

.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 * { cursor: crosshair !important; }

.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);
}