:root {
  --bg: #f4f6f9;
  --panel-bg: #ffffff;
  --border: #d7dce3;
  --text: #1c2430;
  --muted: #6b7684;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --danger: #dc2626;
  --danger-hover: #b91c1c;
  --grid-line: #e3e8ef;
  --component: #1c2430;
  --component-selected: #2563eb;
  --wire: #334155;
  --wire-selected: #2563eb;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #12161c;
    --panel-bg: #1a2029;
    --border: #2b3340;
    --text: #e6eaf0;
    --muted: #93a0b0;
    --accent: #4d8dff;
    --accent-hover: #6ea0ff;
    --danger: #f16565;
    --danger-hover: #ff8080;
    --grid-line: #232b36;
    --component: #e6eaf0;
    --component-selected: #4d8dff;
    --wire: #b7c1cd;
    --wire-selected: #4d8dff;
  }
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: "Segoe UI", "Malgun Gothic", -apple-system, BlinkMacSystemFont, sans-serif;
}

.app {
  display: flex;
  flex-direction: column;
  height: 100vh;
}

.app-header {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 16px;
  background: var(--panel-bg);
  border-bottom: 1px solid var(--border);
}

.app-header h1 {
  font-size: 1.15rem;
  margin: 0;
  white-space: nowrap;
}

.home-link {
  text-decoration: none;
  margin-right: 4px;
}

.header-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
}

.field-inline {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.85rem;
  color: var(--muted);
}

select, input[type="number"], input[type="text"] {
  background: var(--panel-bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 5px 8px;
  font-size: 0.85rem;
}

button {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 6px;
  padding: 6px 12px;
  font-size: 0.85rem;
  cursor: pointer;
  transition: background 0.15s ease;
}

button:hover { background: var(--accent-hover); }

button.danger { background: var(--danger); }
button.danger:hover { background: var(--danger-hover); }

button.secondary {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
}
button.secondary:hover { background: var(--grid-line); }

.app-main {
  flex: 1;
  display: flex;
  min-height: 0;
}

.palette {
  width: 220px;
  flex: none;
  background: var(--panel-bg);
  border-right: 1px solid var(--border);
  padding: 12px;
  overflow-y: auto;
}

.palette h2, .side-panel h2 {
  font-size: 0.95rem;
  margin: 0 0 8px;
}

.hint {
  font-size: 0.75rem;
  color: var(--muted);
  line-height: 1.4;
  margin: 0 0 10px;
}

.palette-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}

.palette-grid button {
  background: var(--panel-bg);
  color: var(--text);
  border: 1px solid var(--border);
  padding: 10px 6px;
  font-size: 0.8rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}

.palette-grid button:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--grid-line);
}

.palette-grid .sym {
  font-size: 1.1rem;
}

.canvas-wrap {
  flex: 1;
  overflow: auto;
  background: var(--bg);
}

#canvas {
  display: block;
  width: 1400px;
  height: 900px;
  color: var(--component);
}

.component .value-label, .pin-label {
  fill: var(--muted);
  font-size: 11px;
}

.sym-text {
  fill: var(--component);
  font-size: 12px;
  font-weight: 600;
}

.component path, .component line, .component circle, .component rect {
  stroke: currentColor;
  fill: none;
  stroke-width: 2;
}

.component.selected {
  color: var(--component-selected);
}
.component.selected rect, .component.selected circle {
  filter: drop-shadow(0 0 2px var(--component-selected));
}

.terminal {
  fill: var(--panel-bg);
  stroke: var(--wire);
  stroke-width: 1.5;
  cursor: crosshair;
}
.terminal:hover {
  fill: var(--accent);
  stroke: var(--accent);
}
.terminal.pending {
  fill: var(--danger);
  stroke: var(--danger);
}

.wire {
  stroke: var(--wire);
  stroke-width: 2;
  fill: none;
  cursor: pointer;
}
.wire:hover {
  stroke: var(--accent);
}
.wire.selected {
  stroke: var(--wire-selected);
  stroke-dasharray: 5 3;
}

.component-body {
  cursor: grab;
}
.component-body:active {
  cursor: grabbing;
}

.side-panel {
  width: 280px;
  flex: none;
  background: var(--panel-bg);
  border-left: 1px solid var(--border);
  padding: 12px;
  overflow-y: auto;
}

#properties-panel {
  border-bottom: 1px solid var(--border);
  padding-bottom: 12px;
  margin-bottom: 12px;
}

.prop-row {
  display: flex;
  flex-direction: column;
  gap: 3px;
  margin-bottom: 10px;
  font-size: 0.8rem;
  color: var(--muted);
}

.prop-row input {
  font-size: 0.9rem;
}

details {
  border: 1px solid var(--border);
  border-radius: 6px;
  margin-bottom: 10px;
  padding: 6px 10px;
}

summary {
  cursor: pointer;
  font-size: 0.85rem;
  font-weight: 600;
  padding: 4px 0;
}

.calc-body {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding-top: 8px;
  font-size: 0.8rem;
}

.calc-body label {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 8px;
}

.calc-body input, .calc-body select {
  width: 110px;
}

.calc-result {
  background: var(--grid-line);
  border-radius: 6px;
  padding: 8px;
  font-size: 0.8rem;
  white-space: pre-line;
  min-height: 1.2em;
}

#circuit-summary {
  font-size: 0.8rem;
  line-height: 1.6;
  color: var(--text);
}

@media (max-width: 900px) {
  .app-main { flex-direction: column; }
  .palette, .side-panel { width: 100%; border: none; border-bottom: 1px solid var(--border); }
  .palette-grid { grid-template-columns: repeat(4, 1fr); }
}