.app{max-width:980px;margin:0 auto;padding:24px 20px 64px}.app-header{text-align:center;margin-bottom:8px}.app-header h1{margin:0;font-size:1.8rem}.app-header p{margin:4px 0 0;color:var(--muted)}.more{display:grid;grid-template-columns:repeat(auto-fit,minmax(210px,1fr));gap:10px;margin:20px 0 8px}.more-card{display:flex;gap:12px;align-items:center;padding:12px 14px;background:var(--panel);border:1px solid var(--border);border-radius:var(--radius);color:var(--ink);text-decoration:none;min-height:48px}.more-card:hover,.more-card:focus-visible{border-color:var(--brand);background:var(--brand-light)}.more-icon{font-size:1.8rem;line-height:1}.more-card strong{display:block}.more-card small{display:block;color:var(--muted);font-size:.85rem}.tabs{display:flex;flex-wrap:wrap;gap:8px;justify-content:center;margin:20px 0 24px}.tab{padding:10px 16px;border:1px solid var(--border);background:var(--panel);border-radius:20px;color:var(--muted);font-size:.92rem;font-weight:500}.tab.active{background:var(--brand);border-color:var(--brand);color:#fff}.panel{background:var(--panel);border:1px solid var(--border);border-radius:var(--radius);padding:20px 22px}.panel h2{margin-top:0;font-size:1.25rem}.panel .lead{color:var(--muted);margin-top:-4px}.field{margin:14px 0}.field label{display:block;font-weight:600;margin-bottom:6px;font-size:.9rem}.field input[type=text],.field textarea{width:100%;padding:10px 12px;border:1px solid var(--border);border-radius:8px}.row{display:flex;gap:12px;flex-wrap:wrap}.row .field{flex:1;min-width:140px}.btn{padding:10px 16px;border:1px solid var(--brand);background:var(--brand);color:#fff;border-radius:8px;font-weight:600}.btn.ghost{background:#fff;color:var(--brand)}.output{margin-top:16px;padding:14px 16px;background:var(--brand-light);border-radius:8px;overflow-x:auto}.mono{font-family:ui-monospace,SF Mono,Menlo,monospace;font-size:.9rem}.error{color:var(--bad);font-size:.9rem}.hint{color:var(--muted);font-size:.85rem}.board{width:100%;aspect-ratio:1;border-radius:8px}.graph-target{width:100%}.graph-target .line{stroke-width:3px}.jxgbox{position:relative;overflow:hidden;background-color:#fff;border:1px solid #356aa0;border-radius:10px;margin:0;touch-action:none}.jxgbox svg text{cursor:default}.JXGtext{background-color:transparent;padding:0;margin:0}.JXGinfobox{border:none}.how-to{max-width:640px;margin:16px auto 0;padding:12px 16px 12px 36px;background:var(--panel);border:1px solid var(--border);border-radius:var(--radius);line-height:1.7}.challenge{margin:16px 0;padding:14px 16px;background:var(--brand-light);border:2px solid #b9cfe0;border-radius:var(--radius)}.challenge.solved{background:#e8f6ee;border-color:var(--ok)}.challenge-top{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:8px}.challenge-count{font-size:.85rem;font-weight:700;color:var(--muted);text-transform:uppercase;letter-spacing:.04em}.challenge-dots{display:flex;gap:6px}.dot{width:16px;height:16px;padding:0;border-radius:50%;border:2px solid var(--brand);background:#fff}.dot.done{background:var(--ok);border-color:var(--ok)}.dot.current{outline:3px solid #f2b705;outline-offset:1px}.challenge-task{margin:10px 0 6px;font-size:1.2rem;font-weight:600}.challenge-status{min-height:1.5em}.challenge-hint{margin:8px 0 0;padding:8px 10px;background:#fff8e1;border-radius:8px}.challenge-actions{display:flex;flex-wrap:wrap;align-items:center;gap:8px;margin-top:10px}.ok{color:var(--ok)}.muted{color:var(--muted)}.all-done{font-weight:700}.link-btn{margin-top:8px;padding:0;border:0;background:none;color:var(--muted);font-size:.85rem;text-decoration:underline}.btn:disabled{opacity:.5;cursor:default}.mode-switch{display:inline-flex;border:1px solid var(--brand);border-radius:8px;overflow:hidden;margin-bottom:4px}.mode-switch button{padding:8px 14px;border:0;background:#fff;color:var(--brand);font-weight:600}.mode-switch button.active{background:var(--brand);color:#fff}.equation-readout{margin:8px 0;text-align:center;font-size:1.8rem;font-weight:700;font-family:Times New Roman,Georgia,serif;font-style:italic}.sliders{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:12px 24px;margin-bottom:12px}.slider label{display:flex;justify-content:space-between;font-weight:600;margin-bottom:4px}.slider-value{min-width:3ch;text-align:right;font-size:1.2rem;color:var(--brand)}.slider-row{display:flex;align-items:center;gap:8px}.slider-row input[type=range]{flex:1;accent-color:var(--brand)}.step-btn{width:40px;height:40px;border:1px solid var(--brand);border-radius:8px;background:#fff;color:var(--brand);font-size:1.3rem;font-weight:700}.presets{display:flex;flex-wrap:wrap;gap:8px;margin:8px 0}.chip{padding:6px 12px;border:1px solid var(--border);border-radius:16px;background:#fff}.shape-layout{display:grid;grid-template-columns:minmax(0,3fr) minmax(200px,2fr);gap:16px;align-items:start}.readout{display:grid;grid-template-columns:1fr 1fr;gap:8px;margin:0}.readout div{padding:8px 10px;background:var(--brand-light);border-radius:8px}.readout .readout-wide{grid-column:1 / -1;background:#fff8e1}.readout dt{font-size:.8rem;color:var(--muted);font-weight:600}.readout dd{margin:2px 0 0;font-size:1.15rem;font-weight:700}@media(max-width:640px){.app{padding:16px 16px 48px}.panel{padding:16px}.shape-layout{grid-template-columns:1fr}.equation-readout{font-size:1.5rem}}:root{--bg: #f5f7fa;--panel: #ffffff;--ink: #1f2d3d;--muted: #5b6b7b;--brand: #2d5a7b;--brand-light: #eef4f9;--border: #d5dee6;--ok: #1f8a4c;--bad: #c0392b;--radius: 10px;font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;color:var(--ink)}*{box-sizing:border-box}body{margin:0;background:var(--bg)}button{font-family:inherit;cursor:pointer}input,textarea,select{font-family:inherit;font-size:1rem}h1,h2,h3{color:var(--ink)}