:root{--bg: #0f1115;--panel: #1a1d24;--panel-2: #232733;--text: #e9ecf2;--muted: #9aa3b2;--accent: #3d8bfd;--left: #f59f00;--ok: #51cf66;--bad: #e03131;color-scheme:dark;font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif}*{box-sizing:border-box}[hidden]{display:none!important}html,body{margin:0;height:100%;background:var(--bg);color:var(--text);overscroll-behavior:none}body{display:flex;flex-direction:column;height:100dvh;padding:env(safe-area-inset-top) env(safe-area-inset-right) 0 env(safe-area-inset-left)}button,input,select{font:inherit;color:inherit}button{background:var(--panel-2);border:1px solid #333a48;border-radius:8px;padding:6px 12px;cursor:pointer;touch-action:manipulation}button:hover{border-color:#4a5366}button.primary{background:var(--accent);border-color:var(--accent);color:#fff;min-width:44px}button.link{background:none;border:none;color:var(--accent);padding:4px 0}.topbar{display:flex;align-items:center;gap:12px;padding:8px 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.meta{color:var(--muted);font-size:13px}.badge{font-size:12px;padding:2px 8px;border-radius:999px;background:var(--panel-2);color:var(--muted);white-space:nowrap}.section-head{display:flex;align-items:baseline;justify-content:space-between;gap:12px;margin-top:28px}.section-head h2{margin:0 0 4px}.course-continue{display:grid;gap:4px;width:100%;text-align:left;padding:16px 18px;margin:8px 0 12px;border:none;border-radius:14px;background:linear-gradient(135deg,#2f6fd8,#6a4fd8);color:#fff}.course-continue .kicker{font-size:12px;text-transform:uppercase;letter-spacing:.08em;opacity:.85}.course-continue strong{font-size:19px}.course-continue .tip{font-size:14px;opacity:.9;line-height:1.4}.course-units{display:grid;gap:8px;margin-bottom:14px}.unit{background:var(--panel);border-radius:12px}.unit summary{display:flex;justify-content:space-between;align-items:center;padding:12px 14px;cursor:pointer;list-style:none;font-weight:600}.unit summary::-webkit-details-marker{display:none}.unit summary:before{content:"▸";color:var(--muted);margin-right:8px;transition:transform .15s}.unit[open] summary:before{transform:rotate(90deg)}.unit-title{flex:1}.unit-count{font-size:13px;color:var(--muted);font-weight:400}.unit summary.complete .unit-count{color:var(--ok)}.lessons{list-style:none;margin:0;padding:0 8px 8px;display:grid;gap:6px}.lesson{width:100%;display:flex;gap:12px;align-items:flex-start;text-align:left;padding:10px 12px;background:var(--panel-2);border-color:transparent}.lesson .num{flex:none;width:28px;height:28px;border-radius:50%;display:grid;place-items:center;font-size:13px;font-weight:600;background:var(--bg);color:var(--muted)}.lesson.done .num{background:var(--ok);color:#0f1115}.lesson.next{border-color:var(--accent)}.lesson.next .num{background:var(--accent);color:#fff}.lesson .body{display:grid;gap:2px;min-width:0}.lesson .name{font-weight:600}.lesson 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.actions{display:flex;gap:8px;justify-content:center;margin-top:12px}.progress{height:10px;background:#20242e;position:relative;cursor:pointer;flex-shrink:0}#progress-section{position:absolute;top:0;bottom:0;background:#3d8bfd40}#progress-fill{position:absolute;top:0;bottom:0;left:0;background:var(--accent);width:0}.controls{display:flex;flex-wrap:wrap;align-items:center;gap:8px 12px;padding:8px 12px calc(8px + env(safe-area-inset-bottom));background:var(--panel)}.segmented{display:inline-flex}.segmented button{border-radius:0;margin-left:-1px}.segmented button:first-child{border-radius:8px 0 0 8px}.segmented button:last-child{border-radius:0 8px 8px 0}.segmented button.active{background:var(--accent);border-color:var(--accent);color:#fff}.toggle,.tempo{display:inline-flex;align-items:center;gap:6px;font-size:14px;white-space:nowrap}.tempo input{width:110px}.tempo output{min-width:3.2em}.more{position:relative}.more summary{list-style:none;cursor:pointer;padding:6px 10px;border-radius:8px;background:var(--panel-2);border:1px solid #333a48}.more summary::-webkit-details-marker{display:none}.more-panel{position:absolute;bottom:calc(100% + 8px);right:0;background:var(--panel);border:1px solid #333a48;border-radius:10px;padding:12px;display:grid;gap:10px;z-index:5;min-width:240px}.lesson-btn{margin-left:auto}.lesson-panel{position:absolute;top:0;right:0;bottom:0;width:min(340px,90vw);background:var(--panel);border-left:1px solid #262b36;padding:12px 16px;overflow-y:auto;z-index:10;box-shadow:-8px 0 24px #0006}.lesson-head{display:flex;justify-content:space-between;align-items:center}.lesson-head h3{margin:0}#lesson-steps{padding-left:0;list-style:none;display:grid;gap:6px}#lesson-steps button{width:100%;text-align:left;display:flex;justify-content:space-between;gap:8px}#lesson-steps button.active{border-color:var(--accent)}#lesson-steps .done{color:var(--ok)}@media(max-width:640px){.controls{gap:6px 8px;padding:6px 8px calc(6px + 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