:root{--bg:#0e2436;--bg2:#123049;--panel:#16324a;--paper:#f2eedf;--paper2:#e9e3ce;--ink:#16324a;--cream:#ede8d8;--orange:#d4622b;--orange-dim:#8c4520;--cyan:#8fc1de;--green:#3f7a5d;--green-dim:#2a5240;--red:#b23a2e;--muted:#6f8ca3;--line:#2a4a63}*{box-sizing:border-box}html,body,#root{height:100%;margin:0}body{background:var(--bg);color:var(--cream);font-family:Georgia,Times New Roman,serif}.mono{font-family:Courier New,Courier,monospace}.display{letter-spacing:.06em;text-transform:uppercase;font-family:Arial,Helvetica,sans-serif;font-weight:800}#sidebar{background:var(--bg2);border-right:1px solid var(--line);box-sizing:border-box;flex-direction:column;flex-shrink:0;width:220px;height:100%;padding:18px 12px 14px;display:flex;overflow:hidden}#sidebar h1{color:var(--orange);margin:0 0 2px;font-size:14.5px}#sidebar .sub{color:var(--muted);margin-bottom:18px;font-family:Courier New,monospace;font-size:11.5px}#stack{flex-direction:column;flex:1;gap:4px;min-height:0;padding-right:2px;display:flex;overflow-y:auto}.stage{border:1px solid var(--line);cursor:pointer;background:var(--panel);border-radius:5px;padding:7px 10px;transition:transform .15s,background .2s;position:relative}.stage:hover{transform:translate(2px)}.stage .num{color:var(--muted);font-family:Courier New,monospace;font-size:10.5px}.stage .name{margin-top:2px;font-size:13px;line-height:1.3}.stage.locked{opacity:.4;cursor:not-allowed}.stage.locked:hover{transform:none}.stage.mastered{background:var(--green-dim);border-color:var(--green)}.stage.active{border-color:var(--orange);box-shadow:0 0 0 1px var(--orange) inset}.stage .check{color:#bfe6d3;font-size:12px;position:absolute;top:8px;right:8px}.stage .lockicon{color:var(--muted);font-size:11px;position:absolute;top:9px;right:8px}#nose{text-align:center;color:var(--cyan);opacity:.8;padding-bottom:6px;font-size:20px}#progress-foot{color:var(--muted);border-top:1px solid var(--line);margin-top:10px;padding-top:10px;font-family:Courier New,monospace;font-size:11px}#reset-btn{border:1px solid var(--line);color:var(--muted);cursor:pointer;background:0 0;border-radius:4px;width:100%;margin-top:8px;padding:5px 8px;font-family:Courier New,monospace;font-size:10.5px}#reset-btn:hover{border-color:var(--red);color:var(--red)}#main{box-sizing:border-box;flex:1;height:100%;padding:28px 40px 60px;overflow-y:auto}#topbar{flex-wrap:wrap;justify-content:space-between;align-items:center;gap:16px;max-width:820px;margin:0 auto 22px;display:flex}#content{max-width:820px;margin:0 auto}#tabs{gap:6px;display:flex}.tabbtn{border:1px solid var(--line);color:var(--muted);cursor:pointer;background:0 0;border-radius:20px;padding:6px 14px;font-family:Arial,sans-serif;font-size:11.5px}.tabbtn.on{background:var(--orange);border-color:var(--orange);color:#1a1005}.steplabel{letter-spacing:.1em;text-transform:uppercase;color:#8a8360;border-top:1px solid #ddd6bc;margin:16px 0 6px;padding-top:12px;font-family:Courier New,monospace;font-size:10.5px}.worked{border-left:3px solid var(--cyan);background:#eae5d1;border-radius:0 6px 6px 0;margin:14px 0;padding:12px 14px}.worked .lbl{text-transform:uppercase;color:var(--ink);opacity:.6;margin-bottom:4px;font-family:Arial,sans-serif;font-size:11px;font-weight:700}.locknotice{color:var(--ink);opacity:.75;font-family:Arial,sans-serif;font-size:14px}.card{background:var(--paper);color:var(--ink);border-radius:8px;margin-bottom:18px;padding:26px 28px;box-shadow:0 2px #00000040}.card h2{margin:0 0 4px;font-family:Arial,sans-serif;font-size:22px;font-weight:800}.eyebrow{letter-spacing:.12em;text-transform:uppercase;color:var(--orange-dim);margin-bottom:6px;font-family:Courier New,monospace;font-size:10.5px}.card p{font-size:15px;line-height:1.55}.drill{border:1px dashed #b8b092;border-radius:8px;margin-top:14px;padding:16px 18px}.drill .q{margin-bottom:10px;font-family:Arial,sans-serif;font-size:14.5px;font-weight:700}.choices{flex-direction:column;gap:7px;margin-bottom:10px;display:flex}.choice{text-align:left;cursor:pointer;color:var(--ink);background:#fbfaf3;border:1px solid #b8b092;border-radius:6px;padding:9px 12px;font-family:Arial,sans-serif;font-size:13.5px}.choice:hover{border-color:var(--orange)}.choice.correct{border-color:var(--green);background:#dcefe3;font-weight:700}.choice.wrong{border-color:var(--red);background:#f5dcd8}.btn{background:var(--orange);color:#1a1005;cursor:pointer;border:none;border-radius:6px;padding:8px 16px;font-family:Arial,sans-serif;font-size:13px;font-weight:700}.feedback{border-radius:5px;margin-top:8px;padding:8px 10px;font-family:Arial,sans-serif;font-size:13.5px}.feedback.ok{color:#1e4d34;background:#dcefe3}.feedback.no{color:#7a2a20;background:#f5dcd8}.retryRow{flex-wrap:wrap;gap:8px;margin-top:10px;display:flex}.explainBit{opacity:.9;margin-top:6px;font-family:Arial,sans-serif;font-size:12.5px;line-height:1.5}.progressbar{background:#ded7bd;border-radius:3px;height:6px;margin:6px 0 14px;overflow:hidden}.progressbar>div{background:var(--orange);height:100%}.mastery-banner{background:var(--ink);color:var(--cream);border-radius:8px;justify-content:space-between;align-items:center;margin-top:16px;padding:14px 18px;font-family:Arial,sans-serif;display:flex}.mastery-banner .score{color:var(--cyan);font-family:Courier New,monospace;font-size:20px}.breakdown{border:1px solid #ded7bd;border-radius:8px;margin-top:12px;overflow:hidden}.breakItem{border-bottom:1px solid #ded7bd;gap:8px;padding:8px 12px;font-family:Arial,sans-serif;font-size:13px;display:flex}.breakItem:last-child{border-bottom:none}.breakItem .mark{flex-shrink:0;width:14px;font-weight:700}.breakItem.ok{color:#1e4d34;background:#f2f8f4}.breakItem.ok .mark{color:#2f7a52}.breakItem.no{color:#7a2a20;background:#fbf3f1}.breakItem.no .mark{color:#b23a2e}.scoreLockNote{opacity:.75;margin-top:8px;font-family:Arial,sans-serif;font-size:11px;font-style:italic}.btn.ghost{border:1px solid var(--ink);color:var(--ink);background:0 0}#sidebarToggle{border:1px solid var(--line);color:var(--cream);cursor:pointer;background:0 0;border-radius:6px;margin-right:8px;padding:4px 10px;font-size:18px;display:none}#sidebarOverlay{display:none}@media (width<=640px){#sidebar{z-index:50;width:min(80vw,280px);height:100vh;transition:transform .2s;position:fixed;top:0;left:0;transform:translate(-100%);box-shadow:2px 0 16px #00000080}#sidebar.open{transform:translate(0)}#sidebarOverlay.open{z-index:40;background:#00000073;display:block;position:fixed;inset:0}#sidebarToggle{display:inline-block}#main{width:100%}#topbar{gap:8px}.card{padding:18px 16px}}