:root {
  --bg: #14171c;
  --panel: #1b2028;
  --panel2: #20262f;
  --line: #2c343f;
  --ink: #e8ecf2;
  --muted: #8a94a3;
  --amber: #ffb454;
  --amber-dim: rgba(255, 180, 84, .14);
  --plus: #ff6b5e;
  --minus: #5ec8ff;
  --nickel: #b9c2cd;
  --nickel-dim: #5c6672;
  --ok: #7dd88f;
  --mono: ui-monospace, "Cascadia Mono", "JetBrains Mono", Consolas, monospace;
  --sans: system-ui, "Segoe UI", Roboto, sans-serif;
}

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

html, body { height: 100%; }

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 14px;
}

.app {
  display: grid;
  grid-template-columns: 300px 1fr;
  height: 100vh;
}

/* ---------- sidebar ---------- */

.sidebar {
  background: var(--panel);
  border-right: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.brand {
  padding: 16px 16px 12px;
  border-bottom: 1px solid var(--line);
}
.brand-title {
  font-family: var(--mono);
  font-size: 16px;
  letter-spacing: .35em;
  color: var(--amber);
}
.brand-sub {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--muted);
  margin-top: 3px;
  letter-spacing: .08em;
}

.config { padding: 12px 16px; border-bottom: 1px solid var(--line); }

.config label {
  display: block;
  font-family: var(--mono);
  font-size: 11px;
  color: var(--muted);
  letter-spacing: .05em;
}
.cfg-row { display: flex; gap: 10px; margin-bottom: 10px; align-items: flex-end; }
.cfg-row label { flex: 1; }
.cfg-wide { margin-bottom: 10px; }

.config input, .config select {
  display: block;
  width: 100%;
  margin-top: 4px;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 6px;
  color: var(--ink);
  font-family: var(--mono);
  font-size: 14px;
  padding: 7px 9px;
  outline: none;
}
.config input:focus, .config select:focus { border-color: var(--amber); }

.hint { display: block; margin-top: 4px; font-size: 10px; color: var(--muted); font-family: var(--sans); letter-spacing: 0; }
.hint code { color: var(--amber); font-family: var(--mono); }

button {
  cursor: pointer;
  font-family: var(--mono);
  border-radius: 6px;
  border: 1px solid var(--line);
  background: var(--panel2);
  color: var(--ink);
  padding: 8px 12px;
  font-size: 12px;
}
button:hover { border-color: var(--amber); }
button.ghost { background: transparent; color: var(--muted); }
button.ghost:hover { color: var(--ink); }
button.ghost.danger:hover { color: var(--plus); border-color: var(--plus); }

.cfg-error {
  background: rgba(255, 107, 94, .12);
  border: 1px solid rgba(255, 107, 94, .4);
  color: #ffb0a8;
  border-radius: 6px;
  padding: 8px 10px;
  font-size: 12px;
  margin-bottom: 8px;
}
.cfg-stats { font-family: var(--mono); font-size: 11px; color: var(--muted); }
.cfg-stats b { color: var(--ink); font-weight: 600; }
.hidden { display: none !important; }

.mode-switch {
  display: flex;
  gap: 6px;
  padding: 10px 16px;
  border-bottom: 1px solid var(--line);
}
.mode-btn { flex: 1; padding: 7px 4px; font-size: 11px; letter-spacing: .04em; color: var(--muted); }
.mode-btn.active { background: var(--amber-dim); border-color: var(--amber); color: var(--amber); }

/* step list */

.step-list {
  flex: 1;
  overflow-y: auto;
  list-style: none;
  padding: 8px 0;
}
.step-list .group-head {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: .25em;
  color: var(--muted);
  padding: 10px 16px 4px;
  text-transform: uppercase;
}
.step-list .step-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 5px 16px;
  font-size: 12px;
  color: var(--muted);
  cursor: pointer;
  border-left: 2px solid transparent;
}
.step-item:hover { color: var(--ink); background: var(--panel2); }
.step-item.done .tick { color: var(--ok); }
.step-item.current {
  color: var(--amber);
  border-left-color: var(--amber);
  background: var(--amber-dim);
}
.step-item .tick { font-family: var(--mono); width: 14px; flex-shrink: 0; text-align: center; color: var(--line); }

.side-foot { padding: 10px 16px; border-top: 1px solid var(--line); }

/* ---------- main ---------- */

.main {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.canvas-wrap {
  flex: 1;
  overflow: auto;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}
#svg { max-width: 100%; max-height: 100%; }

/* step bar */

.step-bar {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 12px 20px;
  background: var(--panel);
  border-top: 1px solid var(--line);
}
.nav-btn {
  font-size: 15px;
  padding: 12px 18px;
  flex-shrink: 0;
}
.nav-btn.primary {
  background: var(--amber);
  border-color: var(--amber);
  color: #1a1408;
  font-weight: 700;
  letter-spacing: .03em;
}
.nav-btn.primary:hover { filter: brightness(1.1); }
.nav-btn:disabled { opacity: .3; cursor: default; }

.step-info { flex: 1; min-width: 0; }
.step-meta { display: flex; align-items: center; gap: 10px; margin-bottom: 2px; }
.step-counter {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--amber);
  letter-spacing: .1em;
}
.side-badge {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: .15em;
  padding: 2px 8px;
  border-radius: 10px;
  border: 1px solid var(--nickel-dim);
  color: var(--nickel);
  text-transform: uppercase;
}
.side-badge.bottom { border-style: dashed; }
.step-title { font-size: 16px; font-weight: 600; }
.step-desc { font-size: 12.5px; color: var(--muted); margin-top: 2px; line-height: 1.45; }
.step-desc b { color: var(--ink); }
.step-desc .warn { color: var(--plus); }

/* legend */

.legend {
  display: flex;
  gap: 18px;
  flex-wrap: wrap;
  padding: 8px 20px 10px;
  background: var(--panel);
  font-size: 11px;
  color: var(--muted);
  font-family: var(--mono);
}
.lg { display: inline-flex; align-items: center; gap: 6px; }
.lgl { stroke: var(--nickel); stroke-width: 5; stroke-linecap: round; }
.lgl.dash { stroke-dasharray: 7 6; }
.pol-plus { color: var(--plus); }
.pol-minus { color: var(--minus); }
.lg b { font-size: 14px; }
.lgc.active-dot {
  width: 10px; height: 10px; border-radius: 50%;
  background: var(--amber); display: inline-block;
}

/* ---------- svg elements ---------- */

.cell-body { fill: var(--panel2); stroke-width: 2; }
.cell-num { font-family: var(--mono); font-size: 9px; fill: var(--muted); }
.cell-pol { font-family: var(--mono); font-size: 20px; font-weight: 700; }
.cell-pol.plus { fill: var(--plus); }
.cell-pol.minus { fill: var(--minus); }
.cell-grp { font-family: var(--mono); font-size: 8px; fill: var(--muted); letter-spacing: .05em; }

.strip { stroke-linecap: round; fill: none; }
.strip.side-bottom { stroke-dasharray: 10 8; }
.strip.done { stroke: var(--nickel-dim); }
.strip.active { stroke: var(--amber); }

.wire { fill: none; stroke-width: 2.5; }
.wire.done { opacity: .75; }

.solder-pt { fill: none; stroke-width: 2; }
.solder-pt.active { stroke: var(--amber); }
.strip.future, .wire.future, .solder-pt.future { display: none; }

.dim { opacity: .18; }

/* свободный режим: слоты и перетаскивание */
.slot {
  fill: none;
  stroke: var(--line);
  stroke-width: 1.5;
  stroke-dasharray: 5 5;
}
.cell.grab { cursor: grab; }
.cell.dragging { opacity: .35; }
.drag-ghost {
  fill: var(--amber-dim);
  stroke: var(--amber);
  stroke-width: 2;
  stroke-dasharray: 6 4;
  pointer-events: none;
}
.free-hint { margin-bottom: 8px; }
.cell-ring { fill: none; stroke: var(--amber); stroke-width: 2.5; }

.strip.active, .wire.active, .solder-pt.active, .cell-ring, .lgc.active-dot {
  animation: pulse 1.2s ease-in-out infinite;
}

.bms-box { fill: var(--panel2); stroke: var(--line); stroke-width: 1.5; }
.bms-label { font-family: var(--mono); font-size: 12px; letter-spacing: .2em; fill: var(--muted); }
.bms-pad { fill: var(--bg); stroke: var(--nickel-dim); stroke-width: 1.5; }
.bms-pad-label { font-family: var(--mono); font-size: 9px; fill: var(--ink); }
.term-label { font-family: var(--mono); font-size: 13px; font-weight: 700; }

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: .35; }
}

@media (prefers-reduced-motion: reduce) {
  .strip.active, .wire.active, .solder-pt.active, .cell-ring, .lgc.active-dot { animation: none; }
}

/* ---------- mobile ---------- */

@media (max-width: 860px) {
  .app { grid-template-columns: 1fr; height: auto; }
  .sidebar { border-right: none; border-bottom: 1px solid var(--line); }
  .step-list { max-height: 200px; }
  .canvas-wrap { min-height: 320px; }
  .step-bar { flex-wrap: wrap; }
  .step-info { order: -1; flex-basis: 100%; }
}