:root{--bg:#0f1826;--bg-panel:#142236;--bg-panel-raised:#182940;--grid-line:#94b0d60f;--border:#24354d;--accent:#e8a33d;--accent-soft:#e8a33d24;--blue:#6c93c7;--text:#e7edf5;--text-muted:#8ca0b8;--text-faint:#5b6d85;--danger:#d9705a;--font-display:"Space Grotesk", sans-serif;--font-body:"IBM Plex Sans", sans-serif;--font-mono:"IBM Plex Mono", monospace}*{box-sizing:border-box}html,body,#root{height:100%;margin:0}body{background:var(--bg);color:var(--text);font-family:var(--font-body);background-image:linear-gradient(var(--grid-line) 1px, transparent 1px), linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);background-size:28px 28px}button{cursor:pointer;font-family:inherit}.shell{grid-template-columns:240px minmax(340px,1fr) minmax(360px,1.3fr);height:100vh;display:grid}.rail{background:var(--bg-panel);border-right:1px solid var(--border);flex-direction:column;gap:18px;padding:20px 16px;display:flex;overflow:hidden}.rail-head{align-items:center;gap:10px;display:flex}.mark{border:1.5px solid var(--accent);width:34px;height:34px;font-family:var(--font-mono);color:var(--accent);border-radius:6px;flex-shrink:0;justify-content:center;align-items:center;font-size:12px;display:flex}.rail-head h1{font-family:var(--font-display);letter-spacing:-.01em;margin:0;font-size:16px;font-weight:600}.rail-head p{color:var(--text-faint);margin:2px 0 0;font-size:11.5px}.new-btn{background:var(--accent-soft);border:1px solid var(--accent);color:var(--accent);text-align:left;border-radius:6px;padding:9px 12px;font-size:13px;font-weight:500;transition:background .15s}.new-btn:hover{background:#e8a33d3d}.rail-list{flex-direction:column;gap:2px;display:flex;overflow-y:auto}.rail-empty{color:var(--text-faint);padding:8px 2px;font-size:12.5px;line-height:1.5}.rail-item{color:var(--text-muted);text-align:left;background:0 0;border:1px solid #0000;border-radius:6px;align-items:center;gap:9px;width:100%;padding:8px;font-size:13px;display:flex}.rail-item:hover{background:var(--bg-panel-raised)}.rail-item.active{background:var(--bg-panel-raised);border-color:var(--border);color:var(--text)}.sheet-no{font-family:var(--font-mono);color:var(--text-faint);flex-shrink:0;font-size:10.5px}.rail-item-title{text-overflow:ellipsis;white-space:nowrap;flex:1;overflow:hidden}.rail-item-del{opacity:0;color:var(--text-faint);padding:2px 4px;font-size:11px}.rail-item:hover .rail-item-del{opacity:1}.rail-item-del:hover{color:var(--danger)}.spec{background:var(--bg);border-right:1px solid var(--border);flex-direction:column;min-width:0;display:flex}.spec-scroll{flex-direction:column;flex:1;gap:14px;padding:24px;display:flex;overflow-y:auto}.spec-intro p{color:var(--text-muted);margin:0 0 16px;font-size:14px;line-height:1.6}.spec-examples{flex-direction:column;gap:8px;display:flex}.spec-examples span{color:var(--text-faint);border-left:2px solid var(--border);padding-left:10px;font-size:12.5px;font-style:italic}.bubble{border-radius:8px;max-width:90%;padding:10px 13px}.bubble p{white-space:pre-wrap;margin:4px 0 0;font-size:13.5px;line-height:1.55}.bubble-role{color:var(--text-faint);font-size:10.5px;font-family:var(--font-mono)}.bubble.user{background:var(--bg-panel);border:1px solid var(--border);align-self:flex-end}.bubble.assistant{border:1px solid var(--border);background:0 0;align-self:flex-start}.pending-text{color:var(--accent)}.error-banner{border:1px solid var(--danger);color:#f0a996;background:#d9705a1f;border-radius:6px;margin:0 24px 12px;padding:10px 12px;font-size:12.5px}.composer{border-top:1px solid var(--border);flex-direction:column;gap:10px;padding:16px 24px 20px;display:flex}.composer textarea{resize:none;background:var(--bg-panel);border:1px solid var(--border);width:100%;color:var(--text);font-family:var(--font-body);border-radius:8px;padding:11px 13px;font-size:13.5px;line-height:1.5}.composer textarea:focus{border-color:var(--accent);outline:none}.composer button{background:var(--accent);color:#1a1305;border:none;border-radius:6px;align-self:flex-end;padding:9px 18px;font-size:13px;font-weight:600}.composer button:disabled{background:var(--border);color:var(--text-faint);cursor:default}.preview{flex-direction:column;min-width:0;display:flex}.preview-head{border-bottom:1px solid var(--border);justify-content:space-between;align-items:center;padding:14px 20px;display:flex}.preview-label{color:var(--text-muted);text-overflow:ellipsis;white-space:nowrap;font-size:12.5px;overflow:hidden}.export-btn{border:1px solid var(--border);color:var(--blue);background:0 0;border-radius:6px;flex-shrink:0;margin-left:12px;padding:6px 12px;font-size:12px}.export-btn:hover:not(:disabled){border-color:var(--blue)}.export-btn:disabled{color:var(--text-faint);cursor:default}.preview-frame-wrap{flex:1;min-height:0;padding:16px}.preview-frame-wrap iframe{border:1px solid var(--border);background:#fff;border-radius:8px;width:100%;height:100%}.preview-empty{border:1px dashed var(--border);border-radius:8px;justify-content:center;align-items:center;height:100%;display:flex}.preview-empty p{color:var(--text-faint);font-size:13px}@media (width<=980px){.shell{grid-template-rows:auto auto 1fr;grid-template-columns:1fr;height:auto}.rail{border-right:none;border-bottom:1px solid var(--border)}.rail-list{max-height:160px}}