:root{--bg: #0e1418;--panel: #18222a;--line: #2a3a44;--ink: #eef6fa;--dim: #92a9b5;--accent: #3aa0b3;--accent2: #59c7da;--box: #1f3d44;--bad: #5a1f26}*{box-sizing:border-box}html,body{margin:0;height:100%}body{background:radial-gradient(900px 560px at 50% -8%,#16242c,var(--bg));color:var(--ink);font-family:system-ui,-apple-system,Segoe UI,sans-serif;display:flex;justify-content:center;-webkit-user-select:none;user-select:none}#app{width:100%;max-width:540px;padding:12px 12px 26px}header{text-align:center;margin-bottom:6px}h1{margin:0;font-size:28px;letter-spacing:5px;font-weight:800;color:var(--accent2)}.sub{margin:3px 0 0;color:var(--dim);font-size:13px}.bar{display:flex;gap:8px;justify-content:center;flex-wrap:wrap;align-items:center;margin:10px 0}.seg{display:inline-flex;background:var(--panel);border:1px solid var(--line);border-radius:999px;overflow:hidden}.seg button{background:none;border:none;color:var(--dim);padding:6px 13px;font:600 13px system-ui;cursor:pointer}.seg button.active{background:var(--accent);color:#04181c}.btn{background:var(--panel);border:1px solid var(--line);color:var(--ink);padding:7px 16px;border-radius:999px;font:700 13px system-ui;cursor:pointer}.btn:hover{border-color:var(--accent2)}.btn.primary{background:var(--accent);color:#04181c;border-color:var(--accent)}.scoreboard{display:flex;gap:10px;justify-content:center;margin:8px 0}.readout{background:#0a0f13;border:1px solid var(--line);border-radius:8px;padding:5px 16px;font:800 18px ui-monospace,monospace;color:var(--accent2);min-width:80px;text-align:center}.readout span{color:var(--dim);font-size:11px;display:block;font-weight:600;letter-spacing:.5px}.stage{position:relative;margin:6px 0}.balance{position:relative;display:grid;grid-template-columns:1fr auto 1fr;align-items:center;gap:6px;padding:18px 8px 10px;background:linear-gradient(180deg,#11191f,#0c1216);border:1px solid var(--line);border-radius:14px}.pan{min-height:88px;display:flex;align-items:center;justify-content:center;background:#0b1115;border:2px solid var(--line);border-radius:12px;padding:10px;position:relative;transition:transform .25s ease}.balance .pan.left{transform:translateY(6px)}.balance .pan.right{transform:translateY(-6px)}.balance.level .pan.left,.balance.level .pan.right{transform:translateY(0)}.balance.level .pan{border-color:var(--accent);box-shadow:0 0 0 1px var(--accent) inset}.pivot{width:18px;height:18px;border-radius:50%;background:var(--accent);box-shadow:0 0 14px var(--accent)}.term{font:800 clamp(20px,7vw,34px) ui-monospace,"Cascadia Code",monospace;color:var(--ink);letter-spacing:1px;text-align:center}.term.box{color:var(--accent2);background:var(--box);border:2px dashed var(--accent);border-radius:10px;padding:6px 16px}.eqline{text-align:center;color:var(--dim);font:700 16px ui-monospace,monospace;margin:8px 0 4px;min-height:20px}.builder{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:10px;margin:8px 0}.ops{display:grid;grid-template-columns:repeat(3,1fr);gap:6px}.op{background:#0c1216;border:1px solid var(--line);color:var(--ink);padding:10px 4px;border-radius:8px;font:700 13px system-ui;cursor:pointer}.op:hover:not(:disabled){border-color:var(--accent2)}.op.sel{background:var(--accent);color:#04181c;border-color:var(--accent)}.op:disabled{opacity:.35;cursor:default}.operand{margin-top:10px;min-height:40px}.operand .prompt{margin:0 0 6px;color:var(--dim);font-size:13px;text-align:center}.numgrid{display:grid;grid-template-columns:repeat(10,1fr);gap:4px}.numgrid button{background:#0c1216;border:1px solid var(--line);color:var(--ink);padding:8px 0;border-radius:6px;font:800 14px ui-monospace,monospace;cursor:pointer}.numgrid button:hover:not(:disabled){border-color:var(--accent2);background:#14202a}.numgrid button:disabled{opacity:.25;cursor:default}.hintsreadout{text-align:center;color:var(--dim);font-size:12px;margin:2px 0}.overlay{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;background:#080c10d1;border-radius:14px;backdrop-filter:blur(3px)}.overlay.hidden{display:none}.card{background:var(--panel);border:1px solid var(--line);border-radius:16px;padding:22px 26px;text-align:center;max-width:340px}.card h2{margin:0 0 6px;font-size:24px;color:var(--accent2)}.card p{margin:6px 0;color:var(--dim);font-size:14px}.card .row{display:flex;gap:8px;justify-content:center;margin-top:14px}.hint{text-align:center;color:var(--dim);font-size:12px;margin-top:12px;line-height:1.5}.hint em{color:var(--accent2);font-style:normal;font-weight:700}