:root{--bg: #f2f4f7;--panel: rgba(255, 255, 255, .72);--panel-solid: #ffffff;--border: rgba(15, 23, 42, .1);--text: #1d2733;--text-soft: #6b7686;--accent: #0071e3;--accent-soft: rgba(0, 113, 227, .12);--shadow: 0 6px 24px rgba(15, 23, 42, .1);--radius: 14px}*{box-sizing:border-box}html,body{margin:0;height:100%;overflow:hidden;background:var(--bg);color:var(--text);font-family:-apple-system,BlinkMacSystemFont,SF Pro Text,Segoe UI,Roboto,Helvetica,Arial,sans-serif;-webkit-font-smoothing:antialiased}#app{height:100vh;display:flex;flex-direction:column}#topbar{display:flex;align-items:center;gap:18px;flex-wrap:wrap;padding:12px 18px;background:var(--panel);backdrop-filter:saturate(180%) blur(20px);-webkit-backdrop-filter:saturate(180%) blur(20px);border-bottom:1px solid var(--border);z-index:10}.brand{display:flex;flex-direction:column;line-height:1.15;margin-right:6px}.brand-title{font-weight:600;font-size:17px;letter-spacing:-.01em}.brand-sub{font-size:12px;color:var(--text-soft)}.segment{display:inline-flex;background:#7882911f;border-radius:12px;padding:3px;gap:2px}.seg-btn{border:0;background:transparent;color:var(--text);font-size:14px;font-weight:550;padding:8px 18px;border-radius:9px;cursor:pointer;transition:background .18s ease,box-shadow .18s ease,color .18s ease;white-space:nowrap}.seg-btn:hover{color:#000}.seg-btn.active{background:var(--panel-solid);box-shadow:0 1px 3px #0f172a29;color:#000}.tools{display:inline-flex;align-items:center;gap:6px;flex-wrap:wrap;margin-left:auto}.tool-btn{border:1px solid var(--border);background:var(--panel-solid);color:var(--text);font-size:13px;font-weight:500;padding:7px 13px;border-radius:10px;cursor:pointer;transition:background .15s ease,border-color .15s ease,color .15s ease;white-space:nowrap}.tool-btn:hover{border-color:#0f172a38}.tool-btn.active{background:var(--accent);border-color:var(--accent);color:#fff}.divider{width:1px;height:22px;background:var(--border);margin:0 4px}#canvas-wrap{position:relative;flex:1;min-height:0}#scene{display:block;width:100%;height:100%;touch-action:none}#loading{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;color:var(--text-soft);font-size:15px;background:var(--bg);transition:opacity .5s ease}#loading.hidden{opacity:0;pointer-events:none}#legend{position:absolute;left:50%;bottom:16px;transform:translate(-50%);background:var(--panel);backdrop-filter:blur(14px);-webkit-backdrop-filter:blur(14px);border:1px solid var(--border);border-radius:999px;padding:7px 16px;box-shadow:var(--shadow);pointer-events:none}.hint{font-size:12px;color:var(--text-soft)}@media (max-width: 720px){#topbar{gap:10px;padding:10px 12px}.brand{width:100%;margin:0}.tools{margin-left:0}.seg-btn{padding:8px 12px;font-size:13px}.hint{font-size:11px}}