:root{--bg:#1e1e1e;--bg-panel:#252526;--bg-elevated:#2d2d30;--bg-input:#3c3c3c;--border:#3c3c3c;--border-strong:#4a4a4f;--text:#d4d4d4;--text-dim:#9d9d9d;--text-faint:#6f6f6f;--accent:#007acc;--accent-hover:#1b8ad6;--ok:#4ec9b0;--warn:#dcdcaa;--bad:#f14c4c;--font-mono:"SF Mono","JetBrains Mono",Menlo,Consolas,"Liberation Mono",monospace;--font-ui:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif;--safe-b:env(safe-area-inset-bottom,0px)}*{box-sizing:border-box}#__next,body,html{height:100%;margin:0}body{background:var(--bg);color:var(--text);font-family:var(--font-ui);font-size:14px;-webkit-font-smoothing:antialiased;-webkit-text-size-adjust:100%;overscroll-behavior:none}button{font-family:inherit;font-size:inherit;cursor:pointer}.app{display:flex;flex-direction:column;height:100vh;height:100dvh}.app-header{display:flex;align-items:center;gap:12px;flex:none;padding:11px 14px;background:var(--bg-elevated);border-bottom:1px solid var(--border)}.app-brand{display:flex;align-items:baseline;gap:10px;min-width:0}.app-title{font-weight:600;font-size:13px;letter-spacing:.2px;white-space:nowrap}.app-subtitle{display:none}.app-account{display:flex;align-items:center;gap:10px;margin-left:auto;flex:none}.app-login{max-width:120px;overflow:hidden;text-overflow:ellipsis}.app-login,.auth-button{color:var(--text);font-size:12px;font-weight:500;white-space:nowrap}.auth-button{flex:none;padding:7px 14px;border-radius:4px;border:1px solid var(--border-strong);background:var(--bg-input)}.auth-button:hover{background:#4a4a4f;border-color:#5a5a60}.auth-button.is-primary{background:var(--accent);border-color:var(--accent);color:#ffffff;font-weight:600}.auth-button.is-primary:hover{background:var(--accent-hover);border-color:var(--accent-hover)}.app-warning{color:var(--warn);font-size:11px;border:1px solid rgba(220,220,170,.35);border-radius:3px;padding:1px 5px}.app-title{overflow:hidden;text-overflow:ellipsis;color:inherit;text-decoration:none}.app-title:hover{color:var(--accent-hover)}.app-main{position:relative;flex:1 1;min-height:0}.panel{display:flex;flex-direction:column;min-height:0;background:var(--bg-panel)}.app-main>[data-tab-panel]{display:none;height:100%}.app[data-tab=diagram] [data-tab-panel=diagram],.app[data-tab=feedback] [data-tab-panel=feedback],.app[data-tab=problem] [data-tab-panel=problem]{display:flex}.panel-center{background:var(--bg)}.panel-header{display:flex;align-items:center;justify-content:space-between;gap:8px;height:36px;padding:0 14px;flex:none;font-size:11px;font-weight:600;letter-spacing:.9px;text-transform:uppercase;color:var(--text-dim);border-bottom:1px solid var(--border)}.panel-hint{margin:12px 14px 4px;color:var(--text-faint);font-size:12px;line-height:1.5}.hint-desktop{display:none}.link-button{background:none;border:none;padding:4px 0;color:var(--text-faint);font-size:11px;letter-spacing:.4px;text-transform:none}.link-button:hover:not(:disabled){color:var(--accent-hover)}.link-button:disabled{opacity:.4;cursor:default}.app-footer{flex:none;display:flex;justify-content:center;padding:7px 14px;background:var(--bg-panel);border-top:1px solid var(--border)}.app-footer-link{color:var(--text-faint);font-size:11.5px;text-decoration:none}.app-footer-link:hover{color:var(--accent-hover);text-decoration:underline}.tab-bar{display:flex;flex:none;border-top:1px solid var(--border);background:var(--bg-elevated);padding-bottom:var(--safe-b)}.tab-button{position:relative;flex:1 1;padding:12px 4px;background:none;border:none;border-top:2px solid transparent;color:var(--text-faint);font-size:13px}.tab-button.is-active{border-top-color:var(--accent);color:#ffffff}.tab-dot{display:inline-block;width:6px;height:6px;margin-left:6px;border-radius:50%;background:var(--text-faint);vertical-align:middle}.tab-dot-loading{background:var(--accent)}.tab-dot-done{background:var(--ok)}.tab-dot-error{background:var(--bad)}.panel-left{overflow-y:auto;-webkit-overflow-scrolling:touch}.task-list{list-style:none;margin:0;padding:4px 0;border-bottom:1px solid var(--border);flex:none}.task-item{display:flex;align-items:center;justify-content:space-between;gap:8px;width:100%;text-align:left;padding:12px 14px;background:none;border:none;border-left:2px solid transparent;color:var(--text-dim)}.task-item:hover{background:var(--bg-elevated);color:var(--text)}.task-item.is-active{background:#37373d;border-left-color:var(--accent);color:#ffffff}.task-item-title{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.task-solved{flex:none;color:var(--ok);font-size:12px}.solved-bar{display:flex;align-items:center;justify-content:space-between;gap:10px;flex:none;padding:7px 14px;background:rgba(78,201,176,.08);border-bottom:1px solid var(--border)}.solved-mark{color:var(--ok);font-size:12px;font-weight:600}.panel-header-title{overflow:hidden;text-overflow:ellipsis;white-space:nowrap;text-transform:none;letter-spacing:.3px;font-size:12px;color:var(--text)}.task-row{display:flex;align-items:stretch}.task-row .task-item{flex:1 1;min-width:0}.task-remove{flex:none;width:30px;background:none;border:none;color:var(--text-faint);font-size:16px;line-height:1}.task-remove:hover{color:var(--bad)}.task-group{border-bottom:1px solid var(--border);padding-bottom:6px;flex:none}.task-group-header{display:flex;align-items:center;justify-content:space-between;padding:10px 14px 4px;font-size:11px;font-weight:600;letter-spacing:.9px;text-transform:uppercase;color:var(--text-faint)}.task-add{background:none;border:1px solid var(--border-strong);border-radius:3px;color:var(--text-dim);font-size:11px;letter-spacing:.3px;text-transform:none;padding:3px 8px}.task-add:hover{color:#ffffff;border-color:var(--accent);background:rgba(0,122,204,.2)}.task-group-empty{margin:2px 14px 6px;color:var(--text-faint);font-size:11.5px;line-height:1.5}.task-badge{display:inline-block;margin-bottom:10px;padding:2px 7px;border:1px solid var(--border-strong);border-radius:3px;color:var(--text-faint);font-size:10.5px;letter-spacing:.4px;text-transform:uppercase}.dialog{position:fixed;z-index:50;left:0;right:0;bottom:0;display:flex;flex-direction:column;max-height:88dvh;background:var(--bg-panel);border-top:1px solid var(--border-strong);border-radius:12px 12px 0 0;box-shadow:0 -12px 32px rgba(0,0,0,.55);transform:translateY(102%);transition:transform .22s ease;padding-bottom:var(--safe-b)}.dialog.is-open{transform:translateY(0)}.dialog-body{flex:1 1;min-height:0;overflow-y:auto;padding:0 14px 12px}.dialog-hint{margin-left:0;margin-right:0}.dialog-body{display:flex;flex-direction:column}.dialog-textarea{width:100%;height:32dvh;min-height:116px;max-height:300px;flex:1 1 auto;resize:vertical;background:var(--bg);border:1px solid var(--border-strong);border-radius:4px;padding:10px;color:var(--text);font-family:var(--font-mono);font-size:16px;line-height:1.5;outline:none}.dialog-textarea:focus{border-color:var(--accent)}.dialog-textarea:disabled{opacity:.6}.dialog-error{margin:10px 0 0;padding:9px 11px;border:1px solid rgba(241,76,76,.4);border-left:3px solid var(--bad);border-radius:4px;background:rgba(241,76,76,.08);color:var(--text);line-height:1.55}.dialog-footer{flex:none;display:flex;gap:10px;padding:12px 14px;border-top:1px solid var(--border)}.task-detail{padding:14px}.task-title{margin:0 0 8px;font-size:16px;font-weight:600}.task-description{margin:0 0 16px;color:var(--text-dim);line-height:1.6}.task-examples-header{font-size:11px;font-weight:600;letter-spacing:.8px;text-transform:uppercase;color:var(--text-faint);margin-bottom:8px}.task-example{background:var(--bg);border:1px solid var(--border);border-radius:4px;padding:8px 10px;margin-bottom:8px}.example-row{display:flex;gap:8px;align-items:baseline;padding:2px 0}.example-key{flex:none;width:48px;color:var(--text-faint);font-size:11px}.example-value{font-family:var(--font-mono);font-size:12px;color:var(--ok);word-break:break-word}.dialog-backdrop,.sheet-backdrop{position:fixed;inset:0;z-index:30;background:rgba(0,0,0,.55);opacity:0;pointer-events:none;transition:opacity .18s ease}.dialog-backdrop.is-open,.sheet-backdrop.is-open{opacity:1;pointer-events:auto}.panel-right{position:fixed;left:0;right:0;bottom:0;z-index:40;max-height:78dvh;border-top:1px solid var(--border-strong);border-radius:12px 12px 0 0;box-shadow:0 -12px 32px rgba(0,0,0,.5);transform:translateY(102%);transition:transform .22s ease;padding-bottom:var(--safe-b)}.panel-right.is-open{transform:translateY(0)}.dialog-close,.sheet-close{background:none;border:none;padding:0 4px;color:var(--text-dim);font-size:22px;line-height:1}.palette-list{display:flex;flex-direction:column;gap:8px;padding:10px 14px 20px;overflow-y:auto;-webkit-overflow-scrolling:touch}.palette-item{display:block;width:100%;text-align:left;background:var(--bg-elevated);border:1px solid var(--border);border-left:3px solid var(--accent);border-radius:4px;padding:13px 12px;-webkit-user-select:none;-moz-user-select:none;user-select:none;touch-action:manipulation}.palette-item:hover{border-color:var(--border-strong);background:#333336}.palette-item.is-dragging{opacity:.35}.palette-item.is-overlay{width:260px;cursor:-webkit-grabbing;cursor:grabbing;box-shadow:0 8px 20px rgba(0,0,0,.5)}.palette-label{font-family:var(--font-mono);font-size:12.5px;color:var(--text);line-height:1.4}.canvas-scroll{flex:1 1;min-height:0;overflow:auto;-webkit-overflow-scrolling:touch;background-image:radial-gradient(#2a2a2a 1px,transparent 0);background-size:20px 20px}.canvas-surface{position:relative}.canvas-edges,.canvas-labels{position:absolute;inset:0;pointer-events:none}.edge-path{fill:none;stroke:#5a6470;stroke-width:1.5}.edge-label{font-family:var(--font-mono);font-size:10px;fill:var(--text-faint);text-anchor:middle}.edge-label-rail{text-anchor:start}.edge-label-yes{fill:var(--ok)}.edge-label-no{fill:#d19a66}.block-slot{position:absolute;touch-action:manipulation}.block-slot.is-active-drag{opacity:.3}.block-card{position:relative;display:flex;align-items:center;height:100%;background:var(--bg-elevated);border:1px solid var(--border-strong);border-left:3px solid var(--accent);border-radius:4px;padding:0 24px 0 10px;box-shadow:0 1px 3px rgba(0,0,0,.35)}.block-card.is-overlay{width:260px;height:72px;cursor:-webkit-grabbing;cursor:grabbing;box-shadow:0 10px 24px rgba(0,0,0,.55)}.block-body{display:flex;align-items:center;flex-wrap:wrap;gap:6px 6px;width:100%}.block-keyword{font-size:12px;font-weight:600;color:#c8c8c8;white-space:nowrap}.block-field,.block-keyword{font-family:var(--font-mono)}.block-field{flex:1 1;min-width:76px;background:var(--bg-input);border:1px solid transparent;border-radius:3px;padding:6px;color:#9cdcfe;font-size:16px;outline:none}.block-field::placeholder{color:var(--text-faint);font-style:italic}.block-field:focus{border-color:var(--accent);background:#1e1e1e}.block-remove{position:absolute;top:2px;right:2px;width:22px;height:22px;line-height:20px;padding:0;background:none;border:none;border-radius:3px;color:var(--text-faint);font-size:16px}.block-remove:hover{background:var(--bad);color:#ffffff}.zone{position:absolute;display:flex;align-items:center;justify-content:center;padding:0;border-radius:4px;background:none;color:var(--text-faint);border:1px dashed var(--border-strong);touch-action:manipulation}.zone-insert{border-color:#3a4048;background:var(--bg)}.zone-placeholder{border-color:var(--border-strong);background:var(--bg)}.zone.is-over,.zone.is-selected{border-color:var(--accent);border-style:solid;background:rgba(0,122,204,.22);color:var(--text)}.zone-label{font-family:var(--font-mono);font-size:11px;white-space:nowrap;overflow:hidden}.canvas-footer{flex:none;display:flex;gap:10px;padding:10px 14px;border-top:1px solid var(--border);background:var(--bg-panel)}.add-button,.dialog-cancel{flex:1 1;background:var(--bg-elevated);border:1px solid var(--border-strong);border-radius:4px;color:var(--text);padding:12px 14px;font-weight:500}.add-button:hover,.dialog-cancel:hover{background:#333336}.check-button{flex:1 1;background:var(--accent);border:none;border-radius:4px;color:#ffffff;font-weight:600;padding:12px 18px}.check-button:hover:not(:disabled){background:var(--accent-hover)}.check-button:disabled{opacity:.45;cursor:default}.feedback-body{flex:1 1;min-height:0;overflow-y:auto;-webkit-overflow-scrolling:touch;padding:14px}.feedback-idle{margin:0;color:var(--text-faint);line-height:1.6}.feedback-loading{display:flex;align-items:center;gap:10px;color:var(--text-dim)}.spinner{width:14px;height:14px;border:2px solid var(--border-strong);border-top-color:var(--accent);border-radius:50%;animation:spin .7s linear infinite}@keyframes spin{to{transform:rotate(1turn)}}.feedback-card{border:1px solid var(--border);border-left:3px solid var(--text-faint);border-radius:4px;background:var(--bg-elevated);padding:12px 14px}.feedback-title{font-weight:600;margin-bottom:6px}.feedback-text{margin:0 0 8px;color:var(--text-dim);line-height:1.65;white-space:pre-wrap}.feedback-text:last-child{margin-bottom:0}.feedback-note{margin:10px 0 0;color:var(--text-faint);font-size:11.5px}.tone-ok{border-left-color:var(--ok);background:rgba(78,201,176,.08)}.tone-ok .feedback-title{color:var(--ok)}.tone-warn{border-left-color:var(--warn);background:rgba(220,220,170,.08)}.tone-warn .feedback-title{color:var(--warn)}.tone-bad{border-left-color:var(--bad);background:rgba(241,76,76,.08)}.tone-bad .feedback-title{color:var(--bad)}.tone-neutral .feedback-title{color:var(--text)}@media (prefers-reduced-motion:reduce){.dialog,.dialog-backdrop,.panel-right,.sheet-backdrop{transition:none}}@media (min-width:640px){.panel-right{left:auto;width:340px;max-height:100dvh;top:0;border-radius:0;border-left:1px solid var(--border-strong);transform:translateX(102%)}.panel-right.is-open{transform:translateX(0)}.app-subtitle{display:inline;color:var(--text-faint);font-size:12px}}@media (min-width:1024px){body{font-size:13px}.app-header{padding:10px 16px}.app-main{display:grid;grid-template-columns:300px minmax(0,1fr) 300px;grid-template-rows:minmax(0,1fr) 220px;grid-template-areas:"left center right" "bottom bottom bottom"}.app-main>.panel-right,.app-main>[data-tab-panel]{display:flex;height:auto;min-height:0}[data-tab-panel=problem]{grid-area:left;border-right:1px solid var(--border)}[data-tab-panel=diagram]{grid-area:center}[data-tab-panel=feedback]{grid-area:bottom;border-top:1px solid var(--border)}.panel-right{position:static;grid-area:right;width:auto;max-height:none;transform:none;border-radius:0;border-top:none;border-left:1px solid var(--border);box-shadow:none;padding-bottom:0;z-index:auto}.add-button,.hint-mobile,.sheet-backdrop,.sheet-close,.tab-bar{display:none}.hint-desktop{display:inline}.task-item{padding:7px 14px}.palette-item{padding:9px 10px;cursor:-webkit-grab;cursor:grab;touch-action:none}.palette-label{font-size:11.5px}.block-slot{cursor:-webkit-grab;cursor:grab;touch-action:none}.block-field{min-width:34px;padding:3px 5px}.block-field,.block-keyword{font-size:11.5px}.block-remove{top:3px;right:3px;width:16px;height:16px;line-height:14px;font-size:14px}.block-card{padding:0 22px 0 10px}.zone-insert{opacity:0;transition:opacity .12s ease}.canvas-surface.is-dragging .zone-insert,.zone-insert:hover{opacity:1}.canvas-footer{justify-content:flex-end;padding:10px 16px}.check-button{flex:none;padding:8px 18px}.feedback-body{padding:14px 16px}.dialog{top:50%;left:50%;right:auto;bottom:auto;width:620px;max-width:calc(100vw - 48px);max-height:80vh;border:1px solid var(--border-strong);border-radius:6px;transform:translate(-50%,-46%);opacity:0;pointer-events:none;transition:opacity .16s ease,transform .16s ease}.dialog.is-open{transform:translate(-50%,-50%);opacity:1;pointer-events:auto}.dialog-footer{justify-content:flex-end}.dialog-footer .check-button,.dialog-footer .dialog-cancel{flex:none}.dialog-textarea{height:240px;max-height:44vh;font-size:13px}}