:root{--bg:#f6f7f9;--card:#fff;--ink:#1c2430;--mute:#5d6877;--line:#e1e5ea;--acc:#1f5eff;--ok:#1a7f4b;--err:#b3261e}
@media (prefers-color-scheme:dark){:root{--bg:#10141a;--card:#181e27;--ink:#e8ecf1;--mute:#98a3b3;--line:#2a3340;--acc:#6b95ff;--ok:#4cc38a;--err:#ff8a80}}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.55 system-ui,-apple-system,"Segoe UI",Roboto,Arial,sans-serif}
.wrap{max-width:760px;margin:0 auto;padding:16px}
.top{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:8px 0 16px}
.top a{color:var(--ink);text-decoration:none;font-weight:600}
.top form{margin:0}
.card{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:20px;margin:0 0 16px}
h1{font-size:26px;line-height:1.25;margin:0 0 12px}
h2{font-size:19px;margin:0 0 8px}
p{margin:0 0 12px}
.mute{color:var(--mute);font-size:14px}
label{display:block;font-weight:600;margin:0 0 6px}
input[type=email],input[type=text],input[type=password],textarea{width:100%;padding:12px;border:1px solid var(--line);border-radius:10px;background:var(--bg);color:var(--ink);font:inherit}
textarea{min-height:130px;resize:vertical}
.btn{display:inline-block;border:0;border-radius:10px;background:var(--acc);color:#fff;font:inherit;font-weight:600;padding:12px 20px;cursor:pointer;text-decoration:none}
.btn.ghost{background:transparent;color:var(--ink);border:1px solid var(--line);padding:8px 14px}
.row{display:flex;gap:12px;flex-wrap:wrap;align-items:center;margin-top:12px}
.err{color:var(--err);font-weight:600}
.ok{color:var(--ok);font-weight:600}
.lesson{display:flex;gap:14px;align-items:flex-start;text-decoration:none;color:inherit}
.lesson .n{flex:0 0 36px;height:36px;border-radius:50%;background:var(--bg);border:1px solid var(--line);display:flex;align-items:center;justify-content:center;font-weight:700}
.lesson .n.done{background:var(--ok);color:#fff;border-color:var(--ok)}
.video{position:relative;aspect-ratio:16/9;background:#000;border-radius:12px;overflow:hidden;margin:0 0 16px}
.video iframe{position:absolute;inset:0;width:100%;height:100%;border:0}
ul.files{padding-left:20px;margin:0}
ul.files a{color:var(--acc)}
.chk{display:flex;gap:10px;align-items:center;margin:0 0 12px;font-weight:600}
.chk input{width:20px;height:20px}
.vplayer{position:absolute;inset:0}
.vplayer iframe{width:100%;height:100%;border:0}
ul.chapters{list-style:none;padding:0;margin:0}
.chap{display:block;width:100%;text-align:left;background:transparent;border:0;border-bottom:1px solid var(--line);color:var(--ink);font:inherit;padding:10px 4px;cursor:pointer;min-height:44px}
.chap b{color:var(--acc);margin-right:8px}
.pr{margin:0 0 16px}
.pr pre{white-space:pre-wrap;word-break:break-word;background:var(--bg);border:1px solid var(--line);border-radius:10px;padding:14px;font:14px/1.5 ui-monospace,Menlo,Consolas,monospace;margin:8px 0 0}