.hub-section{margin-top:32px}.hub-section h2{margin:0 0 16px}.hub-box{background:var(--sunken);border:1px solid var(--hairline);border-radius:16px;padding:28px}.hub-box h2{margin:0}.hub-box .hub-box-sub{margin:4px 0 20px}@media (width<=767px){.hub-box{padding:20px}}.mode-card{background:var(--surface);border:1px solid var(--hairline);color:var(--ink);box-sizing:border-box;border-radius:12px;flex-direction:column;gap:6px;height:100%;padding:20px;text-decoration:none;transition:border-color .15s ease-out;display:flex}.mode-card:hover{border-color:var(--accent)}.mode-card .row{justify-content:space-between;align-items:center;gap:8px;display:flex}.mode-card h3{margin:0}.mode-card p{color:var(--ink-muted);margin:0;font-size:14px;line-height:21px}.diff-dot{border-radius:50%;flex:none;width:9px;height:9px}.diff-beginner{background:var(--success)}.diff-intermediate{background:var(--brass)}.diff-advanced{background:var(--accent)}.app-only-note{background:var(--sunken);border:1px solid var(--hairline);color:var(--ink-muted);border-radius:12px;padding:20px 24px;font-size:15px}.exercise-wrap{max-width:1200px;margin:0 auto;padding:0 32px 64px}.exercise-panel{background:var(--surface);border:1px solid var(--hairline);border-radius:16px;margin-top:32px;overflow:hidden}.ex-head{border-bottom:1px solid var(--hairline);align-items:center;gap:20px;height:56px;padding:0 24px;display:flex}.ex-head .mode-name{font-family:var(--font-display);white-space:nowrap;font-size:17px;font-weight:700}.ex-head .crumb{color:var(--ink-muted);text-overflow:ellipsis;white-space:nowrap;font-size:13px;overflow:hidden}.ex-head .spacer{flex:1}.ex-dots{gap:6px;display:flex}.ex-dots i{background:var(--pressed);border-radius:50%;width:8px;height:8px}.ex-dots i.ok{background:var(--success)}.ex-dots i.bad{background:var(--error)}.ex-exit{color:var(--ink-placeholder);border-radius:6px;padding:8px;font-size:18px;line-height:1;text-decoration:none}.ex-exit:hover{color:var(--ink);background:var(--accent-wash)}.ex-body{grid-template-columns:minmax(0,1fr) 320px;display:grid}@media (width<=1119px){.ex-body{grid-template-columns:1fr}}.ex-stage{border-right:1px solid var(--hairline);min-height:480px;padding:48px 56px}@media (width<=1119px){.ex-stage{border-right:none;border-bottom:1px solid var(--hairline);padding:32px 24px}}.ex-prompt{font-family:var(--font-body);margin:0 0 32px;font-size:20px;font-weight:600}.ex-playrow{flex-wrap:wrap;align-items:center;gap:20px;margin-bottom:40px;display:flex}.ex-playrow .play-btn{width:72px;height:72px}.ex-playrow .play-btn[data-playing=true]{background:var(--accent-hover)}.ex-replay-hint{color:var(--ink-muted);font-size:14px}.ex-replay-hint b{font-family:var(--font-mono);font-weight:400}.ex-segment{font-family:var(--font-mono);font-size:13px}.answer-surface{grid-template-columns:repeat(auto-fill,minmax(130px,1fr));gap:12px;max-width:640px;display:grid}.ans-tile{font-family:var(--font-mono);color:var(--ink);background:var(--surface);border:1px solid var(--border);cursor:pointer;text-align:center;border-radius:10px;padding:18px 8px 22px;font-size:16px;transition:border-color .15s ease-out,color .15s ease-out,background-color .15s ease-out;position:relative}.ans-tile:hover:not(:disabled){border-color:var(--accent);color:var(--accent)}.ans-tile:disabled{cursor:default}.ans-tile .kbd{color:var(--ink-muted);font-size:10px;position:absolute;bottom:6px;left:0;right:0}.ans-tile.is-right{border-color:var(--success);background:var(--success-wash);color:var(--success)}.ans-tile.is-wrong{border-color:var(--error);background:var(--accent-wash);color:var(--error)}.ans-tile.is-dim{opacity:.45}.reveal{border-top:1px solid var(--hairline);margin-top:40px;padding-top:28px;animation:.25s ease-out reveal-rise}@keyframes reveal-rise{0%{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}.reveal-staff{width:100%;max-width:640px;height:auto;margin-top:8px;display:block}.reveal-row{flex-wrap:wrap;justify-content:space-between;align-items:baseline;gap:16px;max-width:640px;margin-top:12px;display:flex}.reveal-actions{flex-wrap:wrap;gap:10px;margin-top:20px;display:flex}.ex-rail{background:var(--sunken);flex-direction:column;gap:32px;padding:32px 24px;display:flex}.rail-panel h4{font-family:var(--font-mono);letter-spacing:.08em;text-transform:uppercase;color:var(--ink-muted);margin:0 0 12px;font-size:12px}.stat-row{border-bottom:1px solid var(--hairline);justify-content:space-between;padding:7px 0;font-size:15px;display:flex}.stat-row:last-child{border-bottom:none}.stat-row b{font-family:var(--font-mono);font-weight:400}.rail-panel .desc{color:var(--ink-muted);margin:0;font-size:14px;line-height:22px}.rail-select{width:100%;font-family:var(--font-body);color:var(--ink);background:var(--surface);border:1px solid var(--border);border-radius:8px;margin-top:6px;padding:9px 12px;font-size:15px}.hint-box{color:var(--ink-muted);font-size:14px;line-height:22px}