:root {
  --panel-bg: #121f30;
  --card-bg: rgba(26, 43, 66, 0.98);
  --card-border: rgba(71, 158, 199, 0.45);
  --title: #e6f7ff;
  --subtitle: #94c8e6;
  --body: #c7e6f5;
  --hint: #80adc7;
  --edge-default: rgba(82, 184, 224, 0.85);
  --edge-weak: rgba(235, 122, 97, 0.88);
  --edge-strong: rgba(97, 224, 184, 0.92);
  --select-outline: #3deb6b;
  --master-glow: rgba(97, 224, 184, 0.35);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: #0a1118;
  color: var(--body);
}

.ble-panel {
  position: relative;
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  background: var(--panel-bg);
  overflow: hidden;
}

.panel-bg {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(ellipse 80% 60% at 50% 40%, rgba(56, 120, 150, 0.12), transparent 70%),
    repeating-linear-gradient(0deg, transparent, transparent 39px, rgba(89, 173, 209, 0.04) 40px),
    repeating-linear-gradient(90deg, transparent, transparent 39px, rgba(89, 173, 209, 0.04) 40px);
}

.panel-header {
  position: relative;
  z-index: 2;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 20px 10px;
  border-bottom: 1px solid rgba(71, 158, 199, 0.2);
}

.title {
  font-size: 20px;
  font-weight: 600;
  color: var(--title);
  letter-spacing: 0.02em;
}

.subtitle {
  margin-top: 4px;
  font-size: 13px;
  color: var(--subtitle);
}

.header-right {
  display: flex;
  align-items: center;
  gap: 12px;
}

.stats {
  font-size: 13px;
  color: var(--subtitle);
  white-space: nowrap;
}

.btn-icon {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  border: 1px solid var(--card-border);
  background: rgba(255, 255, 255, 0.06);
  color: var(--title);
  font-size: 18px;
  cursor: pointer;
}

.btn-icon:hover {
  background: rgba(255, 255, 255, 0.12);
}

.connect-bar {
  position: relative;
  z-index: 2;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  padding: 8px 20px 10px;
  font-size: 13px;
  color: var(--subtitle);
  border-bottom: 1px solid rgba(71, 158, 199, 0.12);
}

.connect-advanced {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
}

.connect-advanced.hidden {
  display: none;
}

.connect-bar label {
  display: flex;
  align-items: center;
  gap: 6px;
}

.connect-bar input[type="text"] {
  width: min(280px, 50vw);
  padding: 6px 10px;
  border-radius: 6px;
  border: 1px solid var(--card-border);
  background: rgba(0, 0, 0, 0.25);
  color: var(--body);
}

.connect-bar input#tcp-host {
  width: min(140px, 28vw);
}

.connect-bar input#device-name {
  width: min(130px, 24vw);
}

.connect-bar input.tcp-port {
  width: 72px;
}

.btn {
  padding: 6px 14px;
  border-radius: 6px;
  border: 1px solid var(--card-border);
  background: rgba(82, 184, 224, 0.18);
  color: var(--title);
  cursor: pointer;
  font-size: 13px;
}

.btn:hover {
  background: rgba(82, 184, 224, 0.32);
}

.conn-status {
  padding: 4px 10px;
  border-radius: 999px;
  font-size: 12px;
}

.conn-status.online {
  background: rgba(61, 235, 107, 0.15);
  color: #3deb6b;
}

.conn-status.offline {
  background: rgba(255, 255, 255, 0.06);
  color: var(--hint);
}

.demo-toggle {
  margin-left: auto;
  cursor: pointer;
}

.topo-view {
  position: relative;
  flex: 1;
  min-height: 0;
  z-index: 1;
}

.topo-viewport {
  position: relative;
  width: 100%;
  height: 100%;
  overflow: hidden;
  touch-action: none;
  cursor: grab;
}

.topo-viewport.dragging {
  cursor: grabbing;
}

.topo-content {
  position: absolute;
  left: 50%;
  top: 50%;
  width: 0;
  height: 0;
  transform-origin: 0 0;
  will-change: transform;
}

.topo-edges {
  position: absolute;
  overflow: visible;
  pointer-events: none;
}

.topo-nodes {
  position: absolute;
  overflow: visible;
  z-index: 3;
}

.topo-node {
  position: absolute;
  width: 136px;
  height: 136px;
  margin-left: -68px;
  margin-top: -68px;
  display: flex;
  flex-direction: column;
  align-items: center;
  cursor: pointer;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
}

.topo-node .icon-wrap {
  position: relative;
  width: 96px;
  height: 96px;
}

.topo-node .selection-ring {
  position: absolute;
  inset: -8px;
  border-radius: 50%;
  border: 3px solid transparent;
  pointer-events: none;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.topo-node.selected .selection-ring {
  border-color: var(--select-outline);
  box-shadow: 0 0 16px rgba(61, 235, 107, 0.45);
}

.topo-node .icon {
  width: 96px;
  height: 96px;
  object-fit: contain;
  background: transparent;
  filter: drop-shadow(0 4px 12px rgba(0, 0, 0, 0.35));
}

.topo-node.is-master .icon-wrap::after {
  content: "";
  position: absolute;
  inset: -6px;
  border-radius: 50%;
  box-shadow: 0 0 20px var(--master-glow);
  pointer-events: none;
}

.topo-node .label {
  margin-top: 4px;
  font-size: 13px;
  font-weight: 600;
  color: var(--title);
  text-shadow: 0 1px 3px rgba(0, 0, 0, 0.6);
}

.topo-node .rssi {
  font-size: 11px;
  color: var(--subtitle);
}

.edge-line {
  stroke-linecap: round;
}

.edge-arrow {
  fill: currentColor;
}

.edge-label {
  font-size: 11px;
  fill: var(--title);
  text-anchor: middle;
  paint-order: stroke;
  stroke: rgba(5, 18, 31, 0.85);
  stroke-width: 3px;
}

.node-panel {
  position: absolute;
  left: 0;
  top: 0;
  width: min(420px, 88vw);
  max-height: min(520px, 70vh);
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 16px;
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.45);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  z-index: 20;
  pointer-events: auto;
}

.node-panel.hidden {
  display: none;
}

.panel-scroll {
  overflow-y: auto;
  padding: 12px;
  flex: 1;
}

.device-header {
  padding-bottom: 12px;
  border-bottom: 1px solid rgba(71, 158, 199, 0.15);
  margin-bottom: 10px;
}

.device-name-row {
  display: flex;
  align-items: center;
  gap: 8px;
}

.device-title {
  font-size: 18px;
  font-weight: 600;
  color: var(--title);
}

.device-old-name {
  font-size: 12px;
  color: var(--hint);
  margin-top: 4px;
}

.btn-edit, .btn-small {
  padding: 4px 10px;
  font-size: 12px;
  border-radius: 6px;
  border: 1px solid var(--card-border);
  background: rgba(255, 255, 255, 0.06);
  color: var(--body);
  cursor: pointer;
}

.rename-row {
  display: none;
  gap: 8px;
  margin-top: 8px;
}

.rename-row.active {
  display: flex;
}

.rename-row input {
  flex: 1;
  padding: 6px 10px;
  border-radius: 6px;
  border: 1px solid var(--card-border);
  background: rgba(0, 0, 0, 0.2);
  color: var(--body);
}

.fold-item {
  margin-bottom: 10px;
  border: 1px solid rgba(71, 158, 199, 0.2);
  border-radius: 12px;
  background: rgba(0, 0, 0, 0.15);
  overflow: hidden;
}

.fold-header {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 12px;
  cursor: pointer;
}

.fold-title-block {
  flex: 1;
  min-width: 0;
}

.fold-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--title);
}

.fold-old-name {
  font-size: 11px;
  color: var(--hint);
}

.fold-expand {
  width: 28px;
  height: 28px;
  border: none;
  background: transparent;
  color: var(--subtitle);
  cursor: pointer;
  font-size: 12px;
}

.fold-body {
  display: none;
  padding: 0 12px 12px;
}

.fold-item.expanded .fold-body {
  display: block;
}

.fold-item.expanded .fold-expand {
  transform: rotate(0deg);
}

.pwm-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 8px;
}

.pwm-row input[type="range"] {
  flex: 1;
  accent-color: #52b8e0;
}

.pwm-value {
  width: 44px;
  text-align: right;
  font-size: 13px;
  color: var(--subtitle);
}

.rename-channel-row {
  display: none;
  gap: 8px;
  padding: 8px 12px 0;
}

.rename-channel-row.active {
  display: flex;
}

.rename-channel-row input {
  flex: 1;
  padding: 5px 8px;
  border-radius: 6px;
  border: 1px solid var(--card-border);
  background: rgba(0, 0, 0, 0.2);
  color: var(--body);
  font-size: 13px;
}

.oval-switch {
  position: relative;
  width: 52px;
  height: 28px;
  flex-shrink: 0;
}

.oval-switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.oval-switch .slider {
  position: absolute;
  inset: 0;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.12);
  border: 1px solid rgba(255, 255, 255, 0.15);
  cursor: pointer;
  transition: background 0.2s;
}

.oval-switch .slider::before {
  content: "";
  position: absolute;
  width: 22px;
  height: 22px;
  left: 3px;
  top: 2px;
  border-radius: 50%;
  background: #fff;
  transition: transform 0.2s;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.3);
}

.oval-switch input:checked + .slider {
  background: rgba(61, 235, 107, 0.35);
  border-color: rgba(61, 235, 107, 0.6);
}

.oval-switch input:checked + .slider::before {
  transform: translateX(24px);
}

.panel-footer {
  position: relative;
  z-index: 2;
  padding: 10px 20px 14px;
  border-top: 1px solid rgba(71, 158, 199, 0.15);
}

.zoom-hint {
  font-size: 12px;
  color: var(--hint);
}

.toast {
  position: fixed;
  left: 50%;
  bottom: 80px;
  transform: translateX(-50%);
  padding: 10px 20px;
  border-radius: 8px;
  background: rgba(20, 35, 50, 0.95);
  border: 1px solid var(--card-border);
  color: var(--title);
  font-size: 14px;
  z-index: 100;
  pointer-events: none;
  transition: opacity 0.3s;
}

.toast.hidden {
  opacity: 0;
}

@media (max-width: 600px) {
  .title { font-size: 17px; }
  .connect-bar { padding: 8px 12px; }
  .panel-header { padding: 12px; }
}