:root{
  --bg:#F5F7F8; --surface:#FFFFFF; --surface-2:#EEF2F3; --ink:#15222B; --muted:#576670; --line:#DCE3E6;
  --brand:#0F766E; --brand-ink:#FFFFFF; --brand-soft:#D9F0ED; --sun:#F5A524; --danger:#B42318; --ok:#177245;
  --shadow:0 1px 2px rgba(21,34,43,.06),0 6px 20px rgba(21,34,43,.06);
  --r-lg:18px; --r-md:12px; --r-sm:8px;
  --font:Inter,"Segoe UI",system-ui,-apple-system,Roboto,"Helvetica Neue",Arial,sans-serif;
  --mono:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}
[data-theme="dark"]{
  --bg:#0E1518; --surface:#162026; --surface-2:#1C2A31; --ink:#E8EEF0; --muted:#9AAAB3; --line:#26363E;
  --brand:#2DD4BF; --brand-ink:#06201C; --brand-soft:#12332F; --sun:#FBBF24; --danger:#F97066; --ok:#4ADE80;
  --shadow:0 1px 2px rgba(0,0,0,.4),0 6px 20px rgba(0,0,0,.25);
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{font-family:var(--font);background:var(--bg);color:var(--ink);line-height:1.55;min-height:100vh;display:flex;flex-direction:column;-webkit-font-smoothing:antialiased}
img,svg{display:block;max-width:100%}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer;background:none;border:0}
a{color:var(--brand)}
:focus-visible{outline:3px solid var(--sun);outline-offset:2px;border-radius:6px}
.sr{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
.wrap{width:min(1160px,100% - 32px);margin-inline:auto}

/* Header */
header.top{position:sticky;top:0;z-index:30;background:color-mix(in srgb,var(--bg) 88%,transparent);backdrop-filter:saturate(1.4) blur(10px);border-bottom:1px solid var(--line)}
.top .wrap{display:flex;align-items:center;gap:12px;height:64px}
.logo{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--ink);font-weight:800;letter-spacing:.02em}
.logo-mark{width:36px;height:36px;border-radius:10px;background:var(--brand);display:grid;place-items:center}
.logo b{font-weight:800}
.logo small{display:block;font-size:.68rem;font-weight:600;color:var(--muted);letter-spacing:.04em;margin-top:-2px}
.spacer{flex:1}
.nav{display:flex;gap:4px}
.nav a{padding:8px 12px;border-radius:var(--r-sm);text-decoration:none;color:var(--muted);font-weight:600;font-size:.95rem}
.nav a:hover{background:var(--surface-2);color:var(--ink)}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:10px 16px;border-radius:var(--r-md);font-weight:700;border:1px solid var(--line);background:var(--surface);transition:background .15s,transform .15s}
.btn:hover{background:var(--surface-2)}
.btn:active{transform:translateY(1px)}
.btn.primary{background:var(--brand);color:var(--brand-ink);border-color:transparent}
.btn.primary:hover{filter:brightness(1.08);background:var(--brand)}
.btn.danger{color:var(--danger)}
.icon-btn{width:40px;height:40px;border-radius:50%;display:grid;place-items:center;border:1px solid var(--line);background:var(--surface)}
.icon-btn:hover{background:var(--surface-2)}

/* Hero */
.hero{padding:56px 0 28px}
.hero-grid{display:grid;grid-template-columns:1.15fr .85fr;gap:40px;align-items:center}
.hero h1{font-size:clamp(2.1rem,5.2vw,3.6rem);line-height:1.08;font-weight:800;letter-spacing:-.025em;max-width:16ch}
.hero p.lead{margin-top:18px;color:var(--muted);font-size:1.1rem;max-width:52ch}
.search{margin-top:26px;display:flex;gap:8px;max-width:520px;background:var(--surface);border:1px solid var(--line);border-radius:var(--r-md);padding:6px 6px 6px 14px;box-shadow:var(--shadow)}
.search svg{flex:none;align-self:center;color:var(--muted)}
.search input{flex:1;min-width:0;border:0;background:transparent;outline:0;padding:8px 4px}
.hero-card{background:var(--surface);border:1px solid var(--line);border-radius:var(--r-lg);padding:22px;box-shadow:var(--shadow)}
.hero-card h2{font-size:1rem;margin-bottom:14px}
.path{display:grid;gap:10px}
.path button{display:flex;align-items:center;gap:12px;text-align:left;padding:12px;border-radius:var(--r-md);border:1px solid var(--line);background:var(--bg);width:100%;transition:border-color .15s,background .15s}
.path button:hover{border-color:var(--brand);background:var(--brand-soft)}
.path .dot{width:38px;height:38px;border-radius:10px;display:grid;place-items:center;font-weight:800;font-size:.85rem;color:#fff;flex:none}
.path strong{display:block;font-size:.97rem}
.path span.s{font-size:.84rem;color:var(--muted)}

/* Topics */
.section{padding:28px 0 12px}
.section-head{display:flex;align-items:end;justify-content:space-between;gap:12px;flex-wrap:wrap;margin-bottom:16px}
.section-head h2{font-size:1.5rem;letter-spacing:-.01em}
.section-head p{color:var(--muted);font-size:.95rem}
.chips{display:flex;gap:8px;flex-wrap:wrap}
.chip{padding:8px 14px;border-radius:999px;border:1px solid var(--line);background:var(--surface);font-weight:600;font-size:.92rem;color:var(--muted)}
.chip:hover{color:var(--ink);border-color:var(--muted)}
.chip[aria-pressed="true"]{background:var(--brand);color:var(--brand-ink);border-color:transparent}

/* Cards */
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:16px;margin-top:18px}
.card{display:flex;flex-direction:column;text-align:left;background:var(--surface);border:1px solid var(--line);border-radius:var(--r-lg);overflow:hidden;box-shadow:var(--shadow);transition:transform .18s,border-color .18s;content-visibility:auto;contain-intrinsic-size:260px}
.card:hover{transform:translateY(-3px);border-color:var(--brand)}
.card .cover{height:116px;display:flex;align-items:flex-end;padding:14px;color:#fff;position:relative}
.card .cover .ini{font-size:2rem;font-weight:800;letter-spacing:-.02em}
.card .cover .play{position:absolute;right:14px;top:14px;width:36px;height:36px;border-radius:50%;background:rgba(255,255,255,.22);display:grid;place-items:center}
.card .body{padding:14px 16px 16px;display:flex;flex-direction:column;gap:8px;flex:1}
.card h3{font-size:1.05rem}
.card p{font-size:.9rem;color:var(--muted);flex:1}
.tags{display:flex;gap:6px;flex-wrap:wrap}
.tag{font-size:.74rem;font-weight:700;padding:3px 9px;border-radius:999px;background:var(--surface-2);color:var(--muted)}
.empty{grid-column:1/-1;text-align:center;padding:40px 16px;color:var(--muted);border:1px dashed var(--line);border-radius:var(--r-lg)}

/* About */
.about{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin:12px 0 48px}
.about div{padding:20px;background:var(--surface);border:1px solid var(--line);border-radius:var(--r-lg)}
.about h3{font-size:1.02rem;margin-bottom:6px}
.about p{color:var(--muted);font-size:.93rem}

/* Watch view */
#watch{display:none;padding:22px 0 60px}
body.watching #home{display:none}
body.watching #watch{display:block}
.back{margin-bottom:14px}
.watch-grid{display:grid;grid-template-columns:minmax(0,1fr) 320px;gap:24px;align-items:start}
.player{position:relative;aspect-ratio:16/9;background:#0b1114;border-radius:var(--r-lg);overflow:hidden;box-shadow:var(--shadow)}
.player iframe{position:absolute;inset:0;width:100%;height:100%;border:0}
.poster{position:absolute;inset:0;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:14px;color:#fff;text-align:center;padding:20px}
.poster .big{width:76px;height:76px;border-radius:50%;background:rgba(255,255,255,.95);display:grid;place-items:center;transition:transform .15s}
.poster:hover .big{transform:scale(1.06)}
.poster strong{font-size:1.15rem}
.poster span{font-size:.9rem;opacity:.85;max-width:40ch}
.watch-info h1{font-size:1.6rem;margin:18px 0 6px;letter-spacing:-.01em}
.watch-info p{color:var(--muted);max-width:70ch}
.side{background:var(--surface);border:1px solid var(--line);border-radius:var(--r-lg);padding:18px}
.side h2{font-size:1rem;margin-bottom:10px}
.side ul{list-style:none;display:grid;gap:8px}
.side li button{width:100%;text-align:left;padding:10px 12px;border-radius:var(--r-md);border:1px solid var(--line);background:var(--bg);font-weight:600;font-size:.92rem}
.side li button:hover,.side li button[aria-current="true"]{border-color:var(--brand);background:var(--brand-soft)}
.side .ask{margin-top:14px;width:100%}
.tip{margin-top:14px;font-size:.85rem;color:var(--muted)}
.lesson-bar{display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap;margin-top:12px;padding:10px 12px;background:var(--surface);border:1px solid var(--line);border-radius:var(--r-md);font-weight:600}
.lesson-bar[hidden],#lessonsBox[hidden]{display:none}
.side li button .ck{display:inline-block;width:18px;margin-right:6px;color:var(--ok);font-weight:800}
.prog{height:6px;border-radius:99px;background:var(--surface-2);overflow:hidden;margin-top:6px}
.prog i{display:block;height:100%;background:var(--brand)}

/* Footer */
footer{margin-top:auto;border-top:1px solid var(--line);background:var(--surface)}
footer .wrap{display:flex;flex-wrap:wrap;gap:10px 24px;justify-content:space-between;align-items:center;padding:20px 0;font-size:.9rem;color:var(--muted)}
footer button{color:var(--muted);text-decoration:underline;font-size:.85rem}

/* Chat */
.fab{position:fixed;right:18px;bottom:calc(18px + env(safe-area-inset-bottom));z-index:40;display:flex;align-items:center;gap:10px;padding:13px 18px;border-radius:999px;background:var(--brand);color:var(--brand-ink);font-weight:800;box-shadow:0 8px 24px rgba(15,118,110,.35)}
.fab:hover{filter:brightness(1.08)}
.chat{position:fixed;right:18px;bottom:calc(18px + env(safe-area-inset-bottom));z-index:50;width:min(410px,100vw - 24px);height:min(600px,100dvh - 36px);background:var(--surface);border:1px solid var(--line);border-radius:var(--r-lg);box-shadow:0 18px 50px rgba(0,0,0,.28);display:none;flex-direction:column;overflow:hidden}
.chat.open{display:flex;animation:pop .18s ease-out}
@keyframes pop{from{opacity:0;transform:translateY(10px) scale(.98)}to{opacity:1;transform:none}}
.chat-head{display:flex;align-items:center;gap:10px;padding:12px 14px;background:var(--brand);color:var(--brand-ink)}
.chat-head .av{width:34px;height:34px;border-radius:50%;background:rgba(255,255,255,.22);display:grid;place-items:center;font-weight:800}
.chat-head div b{display:block;line-height:1.1}
.chat-head div small{opacity:.85;font-size:.76rem}
.chat-head .spacer{flex:1}
.chat-head button{color:inherit;width:34px;height:34px;border-radius:50%}
.chat-head button:hover{background:rgba(255,255,255,.18)}
.msgs{flex:1;overflow-y:auto;padding:14px;display:flex;flex-direction:column;gap:10px;background:var(--bg);overscroll-behavior:contain}
.m{max-width:88%;padding:10px 13px;border-radius:14px;font-size:.94rem;word-wrap:break-word;overflow-wrap:anywhere}
.m.bot{align-self:flex-start;background:var(--surface);border:1px solid var(--line);border-bottom-left-radius:4px}
.m.me{align-self:flex-end;background:var(--brand);color:var(--brand-ink);border-bottom-right-radius:4px;white-space:pre-wrap}
.m p+p,.m ul+p,.m p+ul,.m pre+p,.m p+pre{margin-top:8px}
.m ul{padding-left:20px}
.m code{font-family:var(--mono);font-size:.86em;background:var(--surface-2);padding:1px 5px;border-radius:5px}
.m pre{background:#0f1a1f;color:#e6edf0;padding:10px 12px;border-radius:10px;overflow-x:auto;font-size:.83rem}
.m pre code{background:none;padding:0;color:inherit}
.m.err{border-color:var(--danger);color:var(--danger)}
.dots{display:inline-flex;gap:4px;padding:4px 0}
.dots i{width:7px;height:7px;border-radius:50%;background:var(--muted);animation:b 1s infinite}
.dots i:nth-child(2){animation-delay:.15s}.dots i:nth-child(3){animation-delay:.3s}
@keyframes b{0%,80%,100%{opacity:.3;transform:none}40%{opacity:1;transform:translateY(-3px)}}
.sugg{display:flex;gap:6px;flex-wrap:wrap;padding:0 14px 10px;background:var(--bg)}
.sugg button{font-size:.8rem;padding:6px 11px;border-radius:999px;border:1px solid var(--line);background:var(--surface);color:var(--muted)}
.sugg button:hover{color:var(--ink);border-color:var(--brand)}
.composer{display:flex;gap:8px;padding:10px;border-top:1px solid var(--line);background:var(--surface);align-items:flex-end}
.composer textarea{flex:1;resize:none;max-height:120px;border:1px solid var(--line);border-radius:var(--r-md);padding:10px 12px;background:var(--bg);outline:0;line-height:1.4}
.composer textarea:focus{border-color:var(--brand)}
.composer .btn{padding:10px 14px}

/* Admin modal */
dialog{border:0;border-radius:var(--r-lg);background:var(--surface);color:var(--ink);width:min(560px,100% - 24px);max-height:calc(100dvh - 24px);padding:0;box-shadow:0 24px 70px rgba(0,0,0,.4);overflow:auto}
dialog::backdrop{background:rgba(8,14,17,.62)}
.dlg{padding:22px}
.dlg h2{font-size:1.25rem;margin-bottom:4px}
.dlg .sub{color:var(--muted);font-size:.92rem;margin-bottom:16px}
.field{display:grid;gap:6px;margin-bottom:14px}
.field label{font-weight:700;font-size:.9rem}
.field input,.field select{border:1px solid var(--line);border-radius:var(--r-md);padding:11px 12px;background:var(--bg);outline:0;width:100%}
.field input:focus,.field select:focus{border-color:var(--brand)}
.row{display:flex;gap:8px;flex-wrap:wrap}
.row>.field{flex:1;min-width:180px}
.note{font-size:.85rem;min-height:1.3em;margin:4px 0 10px}
.note.bad{color:var(--danger)}.note.good{color:var(--ok)}
.sep{border:0;border-top:1px solid var(--line);margin:18px 0}
.custom-list{list-style:none;display:grid;gap:8px;margin-top:8px}
.custom-list li{display:flex;align-items:center;gap:10px;justify-content:space-between;padding:9px 12px;border:1px solid var(--line);border-radius:var(--r-md);font-size:.92rem}
.dlg-actions{display:flex;gap:8px;flex-wrap:wrap;justify-content:space-between;margin-top:6px}
.pw{position:relative}
.pw button{position:absolute;right:6px;top:50%;transform:translateY(-50%);padding:6px 10px;font-size:.82rem;font-weight:700;color:var(--muted)}

@media (max-width:900px){
  .hero-grid{grid-template-columns:1fr}
  .watch-grid{grid-template-columns:1fr}
  .about{grid-template-columns:1fr}
  .nav{display:none}
}
@media (max-width:560px){
  .hero{padding-top:32px}
  .chat{right:0;bottom:0;width:100vw;height:100dvh;border-radius:0;border:0}
  .fab span{display:none}
  .fab{padding:15px}
  .logo small{display:none}
}
@media (prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important;scroll-behavior:auto!important}}