:root {
  --bg: #eef1f6;
  --bg-stage: #fbfcfe;
  --panel: #ffffff;
  --panel-2: #eef1f6;
  --line: #d5dce5;
  --line-soft: #e7ebf1;
  --text: #1f2733;
  --text-dim: #66707e;
  --accent: #2f6fed;
  --accent-soft: #dbe6fb;
  --accent-2: #2ea043;
  --danger: #e5484d;
  --brick: #b5563a;
  --robot: #2f6fed;
  --radius: 10px;
  --rail-w: 60px;
  --panel-w: 320px;
  font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, system-ui, sans-serif;
}

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

html,
body {
  height: 100%;
  background: var(--bg);
  color: var(--text);
  overflow: hidden;
  -webkit-font-smoothing: antialiased;
}

#app {
  display: grid;
  grid-template-columns: var(--rail-w) 1fr var(--panel-w);
  height: 100vh;
}

/* ---------- Tool rail ---------- */
.rail {
  background: var(--panel);
  border-right: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  padding: 12px 0;
}

.brand {
  font-size: 26px;
  margin-bottom: 10px;
  filter: saturate(1.1);
}

.rail-spacer {
  flex: 1;
}

.tool {
  position: relative;
  width: 42px;
  height: 42px;
  border: 1px solid transparent;
  border-radius: var(--radius);
  background: transparent;
  color: var(--text-dim);
  cursor: pointer;
  display: grid;
  place-items: center;
  transition: all 0.14s ease;
}

.tool .ico {
  font-size: 20px;
  line-height: 1;
}

.tool .kbd {
  position: absolute;
  bottom: 3px;
  right: 4px;
  font-size: 8px;
  opacity: 0.5;
  font-weight: 600;
}

.tool:hover {
  background: var(--panel-2);
  color: var(--text);
}

.tool.active {
  background: color-mix(in srgb, var(--accent) 18%, transparent);
  border-color: color-mix(in srgb, var(--accent) 45%, transparent);
  color: var(--accent);
}

.tool.ghost {
  color: var(--text-dim);
}

/* ---------- Stage ---------- */
.stage {
  position: relative;
  background: var(--bg-stage);
  overflow: hidden;
}

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

.readout {
  position: absolute;
  left: 12px;
  bottom: 12px;
  padding: 6px 10px;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.85);
  border: 1px solid var(--line);
  box-shadow: 0 2px 8px rgba(31, 39, 51, 0.08);
  font-size: 12px;
  font-variant-numeric: tabular-nums;
  color: var(--text-dim);
  pointer-events: none;
  backdrop-filter: blur(6px);
}

.hint {
  position: absolute;
  right: 12px;
  bottom: 12px;
  padding: 6px 10px;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.85);
  border: 1px solid var(--line);
  box-shadow: 0 2px 8px rgba(31, 39, 51, 0.08);
  font-size: 12px;
  color: var(--text-dim);
  pointer-events: none;
  backdrop-filter: blur(6px);
  max-width: 320px;
}

/* ---------- Inspector panel ---------- */
.panel {
  background: var(--panel);
  border-left: 1px solid var(--line);
  overflow-y: auto;
  display: flex;
  flex-direction: column;
}

.panel-head {
  padding: 18px 18px 12px;
  border-bottom: 1px solid var(--line-soft);
}

.panel-head h1 {
  font-size: 16px;
  font-weight: 650;
  letter-spacing: -0.01em;
}

.panel-head .sub {
  font-size: 12px;
  color: var(--text-dim);
  margin-top: 2px;
}

.group {
  padding: 16px 18px;
  border-bottom: 1px solid var(--line-soft);
}

.group h2 {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-dim);
  margin-bottom: 12px;
  font-weight: 650;
}

.field {
  display: flex;
  flex-direction: column;
  gap: 5px;
  margin-bottom: 10px;
  flex: 1;
}

.field span {
  font-size: 11px;
  color: var(--text-dim);
}

.row {
  display: flex;
  gap: 8px;
}

input[type="number"],
select {
  background: var(--bg);
  border: 1px solid var(--line);
  color: var(--text);
  border-radius: 8px;
  padding: 8px 9px;
  font-size: 13px;
  width: 100%;
  font-variant-numeric: tabular-nums;
  transition: border-color 0.14s ease;
}

input[type="number"]:focus,
select:focus {
  outline: none;
  border-color: var(--accent);
}

.check {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--text);
  margin: 4px 0 10px;
  cursor: pointer;
}

.check input {
  accent-color: var(--accent);
  width: 15px;
  height: 15px;
}

.note {
  font-size: 11px;
  color: var(--text-dim);
  margin: -2px 0 12px;
  font-variant-numeric: tabular-nums;
}

.btn {
  flex: 1;
  padding: 9px 12px;
  border-radius: 8px;
  border: 1px solid var(--line);
  background: var(--panel-2);
  color: var(--text);
  font-size: 13px;
  font-weight: 550;
  cursor: pointer;
  transition: all 0.14s ease;
  margin-top: 8px;
  width: 100%;
}

.btn:hover {
  border-color: var(--accent);
}

.btn.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.btn.primary:hover {
  filter: brightness(1.08);
}

.btn.danger {
  color: var(--danger);
  border-color: color-mix(in srgb, var(--danger) 40%, transparent);
}

.btn.danger:hover {
  background: color-mix(in srgb, var(--danger) 14%, transparent);
}

.btn.ghost {
  background: transparent;
  color: var(--text-dim);
}

.panel-foot {
  margin-top: auto;
  padding: 12px 18px;
  font-size: 12px;
  color: var(--text-dim);
  display: flex;
  gap: 8px;
  align-items: center;
  font-variant-numeric: tabular-nums;
}

.dot {
  opacity: 0.5;
}

/* Scrollbar */
.panel::-webkit-scrollbar {
  width: 10px;
}
.panel::-webkit-scrollbar-thumb {
  background: var(--line);
  border-radius: 8px;
  border: 3px solid var(--panel);
}