:root{color-scheme:dark;--bg:#101522;--card:#1a2233;--line:#303a50;--text:#f3f5fc;--muted:#a3aec6;--accent:#c5f36b}*{box-sizing:border-box}body{margin:0;background:var(--bg);font:16px/1.6 system-ui,sans-serif;color:var(--text)}.shell{max-width:900px;margin:auto;padding:24px 22px 120px}header{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-bottom:32px}a{color:inherit;text-decoration:none}#brand{font-size:27px;font-weight:900}#brand span{color:var(--accent)}#brand small{font-size:11px;letter-spacing:2px;margin-left:9px}.pill,.tag{font-size:10px;font-weight:700;letter-spacing:1.5px;color:var(--accent);border:1px solid var(--line);border-radius:30px;padding:7px 10px}h1{font-size:clamp(32px,6vw,51px);line-height:1.12;letter-spacing:-1.7px;margin:16px 0}h2{line-height:1.3;font-size:25px}h3{line-height:1.35;margin:10px 0}.muted,small{color:var(--muted)}p{margin:12px 0}.hero{padding:30px;border:1px solid #455439;border-radius:22px;background:radial-gradient(ellipse at top right,#314633 0,transparent 65%),var(--card)}.hero p{max-width:550px}.eyebrow{color:var(--accent);font-size:11px;letter-spacing:2px}.grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;margin:20px 0}.card{background:var(--card);border:1px solid var(--line);padding:22px;border-radius:18px}.card.action{cursor:pointer}.card.action:hover{border-color:var(--accent)}button{font:inherit;cursor:pointer;color:var(--text);background:var(--card);border:1px solid var(--line);border-radius:12px;padding:12px 18px}button:hover{border-color:var(--accent)}button:focus-visible,a:focus-visible{outline:3px solid var(--accent);outline-offset:3px}button:disabled{cursor:default;opacity:.6}.primary{background:var(--accent);color:#152111;font-weight:750;border:0}.row{display:flex;gap:10px;align-items:center;flex-wrap:wrap}.lesson{display:flex;align-items:center;gap:15px;width:100%;text-align:left;margin:9px 0}.number{font-size:13px;color:var(--accent)}.lesson div{flex:1}.lesson small{display:block}.body{font-size:18px;line-height:1.85;white-space:pre-line}.choice{display:block;text-align:left;width:100%;margin:10px 0}.correct{border-color:var(--accent);background:#263c2c}.incorrect{border-color:#f59494;background:#442d39}.feedback{border-left:3px solid var(--accent);padding:16px;background:var(--card);margin:18px 0}.feedback.bad{border-color:#f59494}nav{position:fixed;bottom:0;left:50%;transform:translateX(-50%);width:min(900px,100%);display:flex;background:#101522f5;border-top:1px solid var(--line);padding:9px 10px calc(9px + env(safe-area-inset-bottom));z-index:10}nav button{flex:1;border:0;background:none;padding:5px;font-size:24px;color:var(--muted)}nav small{display:block;font-size:11px}nav button.active,nav button.active small{color:var(--accent)}svg{width:100%;height:auto;background:#121b2b;border-radius:12px;display:block;margin:15px 0}textarea,input{width:100%;border:1px solid var(--line);border-radius:10px;background:var(--bg);color:var(--text);padding:12px;font:inherit;margin:5px 0}textarea{height:190px;resize:vertical}.stat{font-size:34px;color:var(--accent);font-weight:800}.bar{height:7px;background:var(--line);border-radius:9px;overflow:hidden;margin:14px 0}.bar span{display:block;height:100%;background:var(--accent)}#toast{position:fixed;bottom:100px;left:50%;transform:translateX(-50%);background:#e3f3c7;color:#182117;border-radius:12px;padding:10px 18px;display:none;max-width:90%;z-index:20}details{border:1px solid var(--line);padding:15px;border-radius:12px;margin:15px 0}summary{cursor:pointer}.danger{color:#ffb2b2}.hint{font-size:13px;color:var(--muted)}@media(max-width:520px){.shell{padding:18px 16px 120px}.hero{padding:23px}.grid{gap:10px}.card{padding:17px}.pill{font-size:8px}#brand small{font-size:9px;letter-spacing:1px}}
.resource{display:block;width:100%;text-align:left;margin:14px 0}#libFilters{margin:18px 0}#libList .card{margin:12px 0}#resourceActions{margin-top:18px}#tracks{margin:16px 0}nav button{min-width:0}nav small{font-size:10px}ol li,ul li{margin-bottom:10px}

#start{display:flex;gap:10px;flex-wrap:wrap;margin-top:20px}.update-note{margin-top:18px;border-color:#657944}
.procard{border-color:#c5f36b}.price{font-size:38px;font-weight:800;margin:16px 0;color:var(--accent)}.price small{font-size:14px}.accept{display:flex;align-items:flex-start;gap:12px;margin:20px 0}.accept input{width:auto;margin-top:8px}#buyActions{margin-top:18px}#proHeader{white-space:nowrap}
.chatBubble{background:var(--card);border:1px solid var(--line);padding:18px;border-radius:16px;margin:15px 0}.chatBubble.mine{border-color:#657944;background:#202b27}.chatText{white-space:pre-wrap;overflow-wrap:anywhere;margin-top:8px}#chatInput{height:130px}#chatModes{margin:20px 0}
#languageSelect{width:auto;max-width:130px;color:var(--text);background:var(--card);border:1px solid var(--line);border-radius:12px;padding:8px;font:inherit;font-size:12px}header{flex-wrap:wrap}.learningPicture{margin:16px 0}.learningPicture img{width:100%;border-radius:16px;display:block}.learningPicture figcaption{font-size:11px;color:var(--muted);margin-top:5px}#academyVideo{width:100%;min-height:220px;border-radius:18px;background:#080c13}.guideSteps{padding-left:24px}.guideSteps li{background:var(--card);border:1px solid var(--line);padding:16px;border-radius:12px;margin:14px 0;line-height:1.7}.resource .learningPicture{margin:0 0 14px}.resource .learningPicture figcaption{display:none}

/* Version 1.1: responsive, readable study interface. */
:root{--bg:#0b1220;--card:#142238;--line:#293a53;--text:#eef5fb;--muted:#a8b9cb;--accent:#c5f374}
body{background:radial-gradient(ellipse at 90% -10%,#18392f 0,transparent 32rem),var(--bg);font-family:system-ui,-apple-system,"Segoe UI",sans-serif}
.shell{max-width:900px;padding-top:clamp(16px,4vw,30px)}header{margin-bottom:22px;gap:12px}#brand{letter-spacing:-1px}#brand small{color:#bed0d7}
.hero{position:relative;overflow:hidden;padding:clamp(24px,4vw,38px);background:radial-gradient(circle at 85% 18%,#49754a77,transparent 34%),linear-gradient(135deg,#1d3442,#142333 62%,#182f2d);border:1px solid #426052;box-shadow:0 22px 55px #0003}
.hero:after{content:"";position:absolute;right:-25px;top:48px;width:220px;height:220px;border:1px solid #a9e47522;border-radius:50%;box-shadow:0 0 0 34px #a9e4750c,0 0 0 70px #a9e47508;pointer-events:none}.hero h1,.hero p,.hero #start,.hero .eyebrow{position:relative;z-index:1}
h1{font-size:clamp(31px,6vw,48px);letter-spacing:-1.5px}h2{font-size:clamp(22px,4.5vw,27px)}.eyebrow{font-weight:800;letter-spacing:1.6px}
.card{background:linear-gradient(145deg,#17273c,#132135);border-color:#2d4055;border-radius:20px;box-shadow:0 10px 28px #030a1329}.card.action{transition:transform .15s ease,border-color .15s ease,background .15s ease}.card.action:hover{transform:translateY(-2px);border-color:#b7ed78}
button{min-height:44px;border-radius:13px;transition:border-color .15s,background .15s}.primary{color:#102013;background:linear-gradient(135deg,#d9ff93,#a9e965);box-shadow:0 6px 20px #a8f15c22}.choice{background:#17283d;padding:16px 18px}.choice:focus-visible{outline-color:#d8ff9d}.correct{background:#244235}.incorrect{background:#482a39}
nav{background:#0c1727f2;backdrop-filter:blur(18px);border-color:#2b3a4a;padding-top:10px}nav button{min-height:49px;font-size:21px}nav small{font-size:10px;line-height:1.1}.stat{color:#d0f886}.bar span{background:linear-gradient(90deg,#64ddc9,#c5f374)}
#academyVideo{box-shadow:0 12px 34px #0007;border:1px solid #31455a}textarea:focus,input:focus{outline:2px solid #b5ea77;outline-offset:1px}.feedback{border-radius:12px}.hint{line-height:1.55}
@media(max-width:520px){.shell{padding:15px 15px 125px}.hero{padding:24px 20px}.hero:after{opacity:.45;right:-100px}.grid{gap:10px}.card{padding:17px}nav{gap:2px}nav button{padding:4px 1px}nav small{font-size:9px}.body{font-size:17px;line-height:1.7}}
@media(prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}}

.owner-tools{margin-top:16px}.owner-tools button{width:100%;text-align:left;padding:19px}.card code{display:inline-block;color:#c5f374;background:#0b1727;border-radius:6px;padding:2px 5px;overflow-wrap:anywhere}

.source-link { display:inline-flex; align-items:center; min-height:44px; color:#c5f36b; text-decoration:underline; }
.source-address { margin-top:14px; }
.source-address textarea { height:72px; resize:none; font-size:13px; }