:root{--bg:#050b07;--panel:#0b1710;--panel2:#102319;--line:#1e3928;--text:#edf7ef;--muted:#94a99a;--accent:#a9d96b;--accent2:#d9f5b2;--red:#ff7777;--yellow:#ffd477}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:radial-gradient(circle at 15% 0,#173a21 0,#071008 34%,#040805 100%);color:var(--text);font:15px Inter,system-ui,-apple-system,Segoe UI,sans-serif;min-height:100vh}.wrap{max-width:1180px;margin:auto;padding:0 20px}
header{position:sticky;top:0;z-index:20;background:#050b07dd;backdrop-filter:blur(18px);border-bottom:1px solid var(--line)}.nav{min-height:70px;display:flex;align-items:center;justify-content:space-between;gap:20px}.logo{font-size:19px;font-weight:900;letter-spacing:-.5px}.logo span{color:var(--accent)}.logo small{color:#66806c;font-size:10px;margin-left:4px}
nav{display:flex;gap:5px;flex-wrap:wrap}.navbtn,button{font:inherit;font-weight:700;color:var(--text);background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:10px 14px;cursor:pointer;transition:.18s}.navbtn:hover,button:hover{border-color:#557b48;transform:translateY(-1px)}.navbtn.active,.primary{background:var(--accent);color:#081008;border-color:var(--accent)}
main{padding-bottom:60px}.page{padding:34px 0}.hidden{display:none!important}.hero{padding:55px 0 35px;max-width:850px}.eyebrow,.unit{color:var(--accent);font-size:11px;font-weight:900;letter-spacing:1.5px}.hero h1{font-size:clamp(42px,7vw,76px);line-height:.95;letter-spacing:-3px;margin:12px 0 18px}.hero h1 em{font-style:normal;color:var(--accent)}.hero p,.pagehead p{color:var(--muted);font-size:17px;line-height:1.6;max-width:760px}.actions{display:flex;gap:10px;margin-top:25px}.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:15px;margin-top:22px}.card{background:linear-gradient(145deg,#102219ee,#09150dee);border:1px solid var(--line);border-radius:20px;padding:21px;box-shadow:0 15px 50px #0005}.card h3{margin:8px 0}.card p{color:var(--muted);line-height:1.55}.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:10px}.stats div{border:1px solid var(--line);background:#09140d;border-radius:15px;padding:16px}.stats b{display:block;font-size:26px;color:var(--accent)}.stats span{font-size:12px;color:var(--muted)}
.pagehead{display:flex;align-items:end;justify-content:space-between;gap:20px;margin-bottom:20px}.pagehead h2{font-size:38px;margin:5px 0}.selectrow{display:flex;gap:8px}select,input{background:#08130c;color:var(--text);border:1px solid var(--line);border-radius:11px;padding:11px 12px}.syllabusGrid{display:grid;gap:12px}.syllabusItem{border:1px solid var(--line);border-radius:16px;background:#09150d;padding:18px}.syllabusItem h3{margin:0 0 10px;color:var(--accent2)}.syllabusItem ul{margin:0;padding-left:20px;color:var(--muted);line-height:1.7}
.studyCard{max-width:850px;min-height:310px;margin:35px auto 15px;border:1px solid var(--line);border-radius:24px;background:linear-gradient(145deg,#12291aeF,#08130c);padding:35px;display:flex;flex-direction:column;justify-content:center}.studyCard .label{color:var(--accent);font-size:11px;font-weight:900;letter-spacing:1.3px}.studyCard h3{font-size:30px;margin:12px 0}.studyCard p{color:var(--muted);font-size:18px;line-height:1.65}.studyControls{display:flex;justify-content:center;align-items:center;gap:30px}.studyControls button{font-size:20px;border-radius:50%;width:48px;height:48px;padding:0}
.quizSetup{max-width:850px;margin:30px auto}.modegrid{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin:22px 0}.mode{padding:22px;text-align:left}.mode b{display:block;font-size:28px;color:var(--accent)}.mode span{color:var(--muted)}.mode.featured{border-color:#5d873f;background:#142719}.settings{display:grid;grid-template-columns:1fr 1fr;gap:12px}.settings label{font-size:12px;color:var(--muted);display:grid;gap:6px}.quiztop{display:flex;justify-content:space-between;color:var(--accent);font-weight:800}.progress{height:7px;background:#142218;border-radius:99px;overflow:hidden;margin:12px 0}.progress i{height:100%;display:block;background:var(--accent);width:0;transition:.2s}.qtype{font-size:11px;letter-spacing:1.4px;color:var(--accent)}#qBox h2{font-size:28px;line-height:1.3}.options{display:grid;gap:9px;margin-top:20px}.option{text-align:left;width:100%;background:#09150d}.option.selected{border-color:var(--accent);background:#172d1b}.option.correct{border-color:#72d66d;background:#113019}.option.wrong{border-color:var(--red);background:#301517}.feedback{padding:13px;border-radius:12px;margin-top:15px;background:#0d1d13;color:var(--muted);line-height:1.5}.quiznav{display:flex;justify-content:space-between;margin-top:12px}.result{max-width:850px;margin:30px auto;text-align:center}.bigscore{font-size:70px;font-weight:950;color:var(--accent)}.result .card{text-align:left;margin-top:15px}.wrongitem{padding:14px;border-bottom:1px solid var(--line)}.wrongitem:last-child{border:0}.wrongitem b{color:var(--red)}
.mistake{margin:10px 0}.mistake h3{margin:5px 0}.mistake p{color:var(--muted)}.empty{text-align:center;padding:45px;color:var(--muted)}
footer{text-align:center;color:#64796a;padding:30px 20px;border-top:1px solid var(--line);font-size:12px}
@media(max-width:800px){.grid,.stats{grid-template-columns:1fr 1fr}.nav{align-items:flex-start;padding-top:12px;padding-bottom:12px;flex-direction:column}.hero h1{letter-spacing:-2px}.pagehead{align-items:flex-start;flex-direction:column}}@media(max-width:550px){.wrap{padding:0 13px}.grid,.stats,.modegrid,.settings{grid-template-columns:1fr}.hero{padding-top:30px}.hero h1{font-size:43px}.pagehead h2{font-size:31px}nav{width:100%;overflow:auto;flex-wrap:nowrap}.navbtn{white-space:nowrap}.studyCard{min-height:360px;padding:24px}}
.aiPanel{margin-top:18px;padding:16px;border:1px solid rgba(255,255,255,.1);border-radius:18px;background:rgba(255,255,255,.035);display:flex;justify-content:space-between;gap:20px;align-items:center}.aiPanel p{margin:5px 0 8px;opacity:.7}.aiActions{display:flex;align-items:center;gap:10px;flex-wrap:wrap}.check{display:flex;align-items:center;gap:7px;white-space:nowrap}.dot{display:inline-block;width:8px;height:8px;border-radius:50%;background:#777;margin-right:6px}.dot.on{background:#6ee7a1;box-shadow:0 0 10px #6ee7a1}.tiny{padding:3px 7px;font-size:11px;margin-left:7px}.aiTag{display:inline-block;font-size:10px;padding:3px 7px;border-radius:99px;background:rgba(110,231,161,.13);color:#8ff0b8;margin-left:8px}.generating{text-align:center;padding:55px 20px}.spinner{width:32px;height:32px;border:3px solid rgba(255,255,255,.15);border-top-color:#8ff0b8;border-radius:50%;margin:0 auto 18px;animation:spin .8s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}
@media(max-width:700px){.aiPanel{flex-direction:column;align-items:flex-start}.aiActions{width:100%}}

/* V4 AI difficulty/key indicators */
.keyHint{font-size:.78rem;opacity:.78;align-self:center}.keyHint code{font-family:ui-monospace,monospace}.difficulty{display:inline-block;margin-left:.35rem;padding:.18rem .45rem;border-radius:999px;font-size:.68rem;font-weight:800;letter-spacing:.05em;border:1px solid rgba(255,255,255,.12)}.difficulty.easy{background:rgba(90,180,110,.12)}.difficulty.medium{background:rgba(220,180,70,.12)}.difficulty.hard{background:rgba(220,80,80,.12)}@media(max-width:720px){.keyHint{width:100%;margin-top:.5rem}}