.bg-board-wrapper{display:flex;justify-content:center;align-items:center;padding:.25rem}.bg-board{position:relative;border:2px solid var(--color-border);border-radius:6px;background:#fdfaf2;box-shadow:0 2px 12px #0000001f;-webkit-user-select:none;user-select:none;touch-action:none;overflow:hidden}.bg-board svg{display:block;width:100%;height:100%}.bg-grid-line{stroke:#0000000f;stroke-width:1;fill:none;pointer-events:none}.bg-bridge{stroke:#475569;stroke-width:3;stroke-linecap:round;fill:none;pointer-events:none}.bg-bridge.bg-bridge--conflict{stroke:#e53935;stroke-width:4}.bg-bridge.bg-bridge--ghost{stroke:#ff8f00;stroke-width:4;stroke-dasharray:8 6;stroke-opacity:.65;pointer-events:none}.bg-island{fill:#fff;stroke:#1f2937;stroke-width:2;cursor:pointer;transition:filter .15s,fill .15s,stroke .15s}.bg-island:hover{filter:brightness(.96)}.bg-island-text{font-size:18px;font-weight:700;text-anchor:middle;dominant-baseline:central;pointer-events:none;fill:#1f2937;-webkit-user-select:none;user-select:none;font-family:var(--font-family-base, system-ui, sans-serif)}.bg-island.bg-island--selected{stroke:#ff6f00;stroke-width:4;fill:#fff3e0}.bg-island.bg-island--done{fill:#c8e6c9;stroke:#2e7d32}.bg-island.bg-island--conflict{fill:#ffcdd2;stroke:#c62828;stroke-width:3}.bg-island.bg-hint-source{stroke:#ff8f00;stroke-width:4;filter:drop-shadow(0 0 4px rgba(255,143,0,.5))}.bg-bridge.bg-hint-target{stroke:#1565c0;stroke-width:5;stroke-dasharray:8 4;animation:bg-hint-target-pulse 1.3s ease-in-out infinite}.bg-bridge.bg-hint-wrong{stroke:#c62828;stroke-width:5;stroke-dasharray:4 4;animation:bg-hint-wrong-pulse 1s ease-in-out infinite}@keyframes bg-hint-target-pulse{0%,to{stroke-opacity:1}50%{stroke-opacity:.5}}@keyframes bg-hint-wrong-pulse{0%,to{stroke-opacity:1}50%{stroke-opacity:.4}}.bg-board.bg-solved{border-color:#2e7d32;border-width:3px;box-shadow:0 0 0 3px #2e7d32,0 2px 12px #0000001f;animation:bg-win-border .4s ease-out}@keyframes bg-win-border{0%{box-shadow:0 0 #2e7d32}60%{box-shadow:0 0 0 6px #2e7d3255}to{box-shadow:0 0 0 3px #2e7d32,0 2px 12px #0000001f}}.bg-example{margin-top:1rem;padding-top:.85rem;border-top:1px solid rgba(0,0,0,.08)}.bg-slide{flex:0 0 100%;scroll-snap-align:start;display:flex;flex-direction:column;align-items:center;gap:.55rem;padding:.25rem .5rem;box-sizing:border-box}.bg-example-grid{display:grid;grid-template-columns:repeat(4,36px);grid-template-rows:repeat(3,36px);gap:0;background:#fdfaf2;padding:4px;border:2px solid rgba(0,0,0,.18);border-radius:6px;width:max-content}.bg-ex-cell{display:flex;align-items:center;justify-content:center;font-size:14px;line-height:1;background-color:transparent;color:#222;-webkit-user-select:none;user-select:none;position:relative}.bg-ex-cell.bg-ex-island{font-weight:700;font-size:14px;background-color:#fff;color:#1f2937;border-radius:50%;border:2px solid #1f2937;width:28px;height:28px;margin:auto}.bg-ex-cell.bg-ex-done{background-color:#c8e6c9;border-color:#2e7d32;color:#1b5e20}.bg-ex-cell.bg-ex-bridge-h-single{background-image:linear-gradient(to bottom,transparent 47%,#475569 47%,#475569 53%,transparent 53%)}.bg-ex-cell.bg-ex-bridge-h-double{background-image:linear-gradient(to bottom,transparent 32%,#475569 32%,#475569 40%,transparent 40%,transparent 60%,#475569 60%,#475569 68%,transparent 68%)}.bg-ex-cell.bg-ex-bridge-v-single{background-image:linear-gradient(to right,transparent 47%,#475569 47%,#475569 53%,transparent 53%)}.bg-ex-cell.bg-ex-bridge-v-double{background-image:linear-gradient(to right,transparent 32%,#475569 32%,#475569 40%,transparent 40%,transparent 60%,#475569 60%,#475569 68%,transparent 68%)}.bg-example-caption{font-size:.78rem;color:var(--color-text-muted);margin:0;max-width:300px;text-align:center;min-height:2.4em}.bg-slide-nav{position:absolute;top:58px;transform:translateY(-50%);width:28px;height:28px;border-radius:50%;background:#0000008c;color:#fff;border:none;cursor:pointer;font-size:20px;line-height:1;padding:0 0 2px;display:flex;align-items:center;justify-content:center;z-index:2}.bg-slide-dots{display:flex;justify-content:center;gap:.4rem;margin-top:.45rem}.bg-hint-panel{max-width:480px;margin:.5rem auto 0;background:var(--color-surface);border-radius:var(--radius-md);box-shadow:var(--shadow-md);padding:.75rem 2rem .75rem 1rem;font-size:.85rem;line-height:1.45;color:var(--color-text);position:relative;display:none}.bg-hint-panel.active{display:block;animation:bg-hint-panel-in .2s ease-out}.bg-hint-title{font-weight:700;font-size:.8rem;text-transform:uppercase;letter-spacing:.04em;color:#e65100;margin-bottom:.25rem}.bg-hint-body{color:var(--color-text)}.bg-hint-close{position:absolute;top:.25rem;right:.4rem;background:none;border:none;font-size:1.25rem;line-height:1;color:var(--color-text-muted);cursor:pointer;padding:.25rem .4rem;border-radius:4px}.bg-hint-close:hover{background:#0000000f;color:var(--color-text)}@keyframes bg-hint-panel-in{0%{opacity:0;transform:translateY(-4px)}to{opacity:1;transform:translateY(0)}}@media(prefers-reduced-motion:reduce){.bg-bridge.bg-hint-target,.bg-bridge.bg-hint-wrong,.bg-board.bg-solved,.bg-hint-panel.active{animation:none}}