/* QuestLearn — clean multi-subject study app */
:root{
  --bg:#0b0d12; --bg2:#11141b; --card:#161a23; --card2:#1c212c;
  --line:rgba(255,255,255,.08); --line2:rgba(255,255,255,.14);
  --text:#eef1f6; --muted:#9aa4b5; --faint:#6b7488;
  --accent:#6c8cff;            /* overridden per-subject via inline style */
  --accent-soft:rgba(108,140,255,.14);
  --good:#39d98a; --bad:#ff6b6b; --warn:#ffcf5c;
  --radius:16px; --radius-sm:11px;
  --shadow:0 10px 40px rgba(0,0,0,.45);
  --font:'Inter',system-ui,-apple-system,Segoe UI,Roboto,sans-serif;
}
*{box-sizing:border-box}
html,body{margin:0;padding:0}
body{background:var(--bg);color:var(--text);font-family:var(--font);line-height:1.55;-webkit-font-smoothing:antialiased}
a{color:inherit}
button{font-family:inherit;cursor:pointer;border:none;background:none;color:inherit}
h1,h2,h3,h4{margin:0;line-height:1.2;font-weight:700}
p{margin:0}
::selection{background:var(--accent-soft)}
.hidden{display:none!important}

/* ---- app frame ---- */
.appShell{min-height:100vh;display:flex;flex-direction:column}
.container{width:100%;max-width:1180px;margin:0 auto;padding:0 22px}

/* ---- top bar ---- */
.topbar{position:sticky;top:0;z-index:30;background:rgba(11,13,18,.82);backdrop-filter:blur(14px);border-bottom:1px solid var(--line)}
.topbar .container{display:flex;align-items:center;gap:16px;height:64px}
.brand{display:flex;align-items:center;gap:10px;font-weight:800;font-size:19px;letter-spacing:-.02em}
.brand .mark{width:32px;height:32px;border-radius:9px;display:grid;place-items:center;background:linear-gradient(135deg,var(--accent),#a06bff);color:#fff;font-weight:900}
.brand em{font-style:normal;color:var(--accent)}
.topbar .spacer{flex:1}
.stat{display:flex;align-items:center;gap:7px;padding:7px 12px;background:var(--card);border:1px solid var(--line);border-radius:999px;font-size:13px;font-weight:600}
.stat b{font-size:14px}
.stat em{font-style:normal;color:var(--muted);font-weight:500}
.backBtn{display:flex;align-items:center;gap:7px;padding:8px 14px;background:var(--card);border:1px solid var(--line);border-radius:999px;font-weight:600;font-size:14px;transition:.15s}
.backBtn:hover{border-color:var(--line2);background:var(--card2)}

/* ---- subject nav (within a subject) ---- */
.subnav{display:flex;gap:6px;overflow-x:auto;padding:14px 0 0}
.subnav button{padding:9px 16px;border-radius:999px;font-weight:600;font-size:14px;color:var(--muted);white-space:nowrap;transition:.15s}
.subnav button:hover{color:var(--text)}
.subnav button.active{background:var(--accent);color:#fff}

/* ---- home / subject picker ---- */
.home{padding:46px 0 60px}
.home .hero{text-align:center;max-width:640px;margin:0 auto 46px}
.home .hero .kicker{display:inline-block;padding:6px 14px;border-radius:999px;background:var(--accent-soft);color:var(--accent);font-weight:700;font-size:12px;letter-spacing:.08em;text-transform:uppercase;margin-bottom:18px}
.home .hero h1{font-size:40px;letter-spacing:-.03em;margin-bottom:14px}
.home .hero p{color:var(--muted);font-size:17px}
.subjectGrid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:18px}
.subjectCard{position:relative;text-align:left;padding:24px;border-radius:var(--radius);background:var(--card);border:1px solid var(--line);transition:.18s;overflow:hidden}
.subjectCard:hover{transform:translateY(-3px);border-color:var(--accent);box-shadow:var(--shadow)}
.subjectCard .glow{position:absolute;inset:-40% 40% 60% -20%;background:radial-gradient(circle,var(--sc) 0%,transparent 70%);opacity:.16;pointer-events:none}
.subjectCard .ico{width:54px;height:54px;border-radius:14px;display:grid;place-items:center;font-size:28px;background:var(--card2);border:1px solid var(--line);margin-bottom:16px}
.subjectCard h3{font-size:20px;margin-bottom:5px;letter-spacing:-.02em}
.subjectCard .code{font-size:12px;font-weight:700;color:var(--sc);letter-spacing:.06em}
.subjectCard p{color:var(--muted);font-size:14px;margin:10px 0 16px}
.subjectCard .foot{display:flex;align-items:center;justify-content:space-between;font-size:13px;color:var(--faint)}
.subjectCard .prog{height:6px;border-radius:999px;background:var(--card2);overflow:hidden;margin-top:12px}
.subjectCard .prog span{display:block;height:100%;background:var(--sc);border-radius:999px}

/* ---- page shells ---- */
.page{padding:26px 0 70px;animation:fade .3s ease}
@keyframes fade{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}
.pageHead{margin-bottom:24px}
.pageHead .kicker{color:var(--accent);font-weight:700;font-size:12px;letter-spacing:.09em;text-transform:uppercase}
.pageHead h1{font-size:30px;letter-spacing:-.03em;margin:6px 0 8px}
.pageHead p{color:var(--muted);max-width:640px}

/* ---- chapter path ---- */
.pathGrid{display:flex;flex-direction:column;gap:14px}
.chapCard{display:flex;gap:18px;padding:20px;border-radius:var(--radius);background:var(--card);border:1px solid var(--line);transition:.16s}
.chapCard:hover{border-color:var(--line2)}
.chapCard .node{flex:none;width:56px;height:56px;border-radius:16px;display:grid;place-items:center;font-size:26px;background:var(--card2);border:1px solid var(--line)}
.chapCard.done .node{background:var(--accent);color:#fff;border-color:transparent}
.chapCard .body{flex:1;min-width:0}
.chapCard .body small{color:var(--faint);font-weight:700;font-size:11px;letter-spacing:.08em}
.chapCard .body h3{font-size:18px;margin:3px 0 4px}
.chapCard .body>p{color:var(--muted);font-size:14px;margin-bottom:12px}
.chapCard .acts{display:flex;gap:10px;flex-wrap:wrap}
.btn{padding:9px 16px;border-radius:10px;font-weight:600;font-size:14px;border:1px solid var(--line);background:var(--card2);transition:.15s}
.btn:hover{border-color:var(--line2)}
.btn.primary{background:var(--accent);border-color:transparent;color:#fff}
.btn.primary:hover{filter:brightness(1.08)}
.btn.ghost{background:transparent}
.bossCard{border-color:var(--accent);background:linear-gradient(120deg,var(--accent-soft),transparent)}

/* ---- study reader ---- */
.studyWrap{display:grid;grid-template-columns:230px 1fr;gap:24px;align-items:start}
.chapIndex{position:sticky;top:80px;background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:12px;max-height:calc(100vh - 100px);overflow:auto}
.chapIndex .lbl{font-size:11px;font-weight:700;letter-spacing:.08em;color:var(--faint);padding:8px 10px}
.chapIndex button{display:flex;gap:10px;align-items:center;width:100%;text-align:left;padding:10px;border-radius:10px;font-size:13px;transition:.13s}
.chapIndex button:hover{background:var(--card2)}
.chapIndex button.active{background:var(--accent-soft);color:var(--accent)}
.chapIndex button b{font-weight:600;color:var(--text)}
.chapIndex button.active b{color:var(--accent)}
.chapIndex .num{flex:none;width:24px;height:24px;border-radius:7px;display:grid;place-items:center;background:var(--card2);font-size:12px;font-weight:700}

.reader{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:30px}
.reader>header{border-bottom:1px solid var(--line);padding-bottom:20px;margin-bottom:8px}
.reader>header .kicker{color:var(--faint);font-weight:700;font-size:11px;letter-spacing:.08em}
.reader>header h1{font-size:26px;letter-spacing:-.02em;margin:6px 0 8px}
.reader>header p{color:var(--muted)}
.section{padding:26px 0;border-bottom:1px solid var(--line)}
.section:last-child{border-bottom:none}
.section .sTitle{display:flex;gap:12px;align-items:baseline;margin-bottom:12px}
.section .sTitle .n{flex:none;width:26px;height:26px;border-radius:8px;display:grid;place-items:center;background:var(--accent);color:#fff;font-size:13px;font-weight:800}
.section .sTitle h2{font-size:20px;letter-spacing:-.02em}
.section .intro{color:#d3d9e4;margin-bottom:16px}
.box{border-radius:var(--radius-sm);padding:16px 18px;margin:14px 0;border:1px solid var(--line)}
.box .bh{display:flex;align-items:center;gap:8px;font-weight:700;font-size:14px;margin-bottom:10px}
.keyBox{background:var(--card2)}
.keyBox ul{margin:0;padding-left:20px}
.keyBox li{margin:5px 0;color:#d3d9e4}
.exBox{background:rgba(108,140,255,.07);border-color:var(--accent-soft)}
.exBox .scenario{font-style:italic;color:#cfd6e2;margin-bottom:10px}
.exBox ol{margin:0;padding-left:22px}
.exBox li{margin:6px 0}
.exBox+.exBox{margin-top:10px}
.missBox{background:rgba(255,107,107,.07);border-color:rgba(255,107,107,.25)}
.missBox ul{margin:0;padding-left:20px}
.missBox li{margin:5px 0;color:#f0c9c9}
.memBox{background:rgba(57,217,138,.07);border-color:rgba(57,217,138,.22);display:flex;gap:12px;align-items:flex-start}
.memBox .mtext strong{display:block;margin-bottom:2px}
.memBox .mtext p{color:#c4e6d3}

/* practice inline */
.practice{background:var(--bg2);border:1px solid var(--line);border-radius:var(--radius-sm);padding:16px 18px;margin-top:14px}
.practice .ph{display:flex;gap:8px;align-items:center;font-weight:700;margin-bottom:6px}
.practice .prompt{margin-bottom:12px;color:#d3d9e4}
.opts{display:flex;flex-direction:column;gap:8px}
.opt{display:flex;gap:12px;align-items:center;text-align:left;padding:12px 14px;border-radius:10px;border:1px solid var(--line);background:var(--card);transition:.13s}
.opt:hover:not(:disabled){border-color:var(--line2)}
.opt .k{flex:none;width:26px;height:26px;border-radius:7px;display:grid;place-items:center;background:var(--card2);font-weight:700;font-size:13px}
.opt.correct{border-color:var(--good);background:rgba(57,217,138,.12)}
.opt.wrong{border-color:var(--bad);background:rgba(255,107,107,.12)}
.opt.dim{opacity:.5}
.opt .mark{margin-left:auto;font-weight:800}
.feedback{margin-top:12px;padding:12px 14px;border-radius:10px;font-size:14px}
.feedback.ok{background:rgba(57,217,138,.1);border:1px solid rgba(57,217,138,.3)}
.feedback.no{background:rgba(255,107,107,.1);border:1px solid rgba(255,107,107,.3)}
.feedback strong{display:block;margin-bottom:3px}
.feedback button{margin-top:8px;font-size:13px;color:var(--accent);font-weight:600}
.reader>footer{display:flex;justify-content:space-between;gap:12px;padding-top:20px}

/* ---- quiz modal ---- */
.modalLayer{position:fixed;inset:0;z-index:60;background:rgba(6,8,12,.72);backdrop-filter:blur(6px);display:grid;place-items:center;padding:20px;animation:fade .2s}
.quizWin{width:100%;max-width:600px;background:var(--card);border:1px solid var(--line2);border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow)}
.quizWin header{display:flex;align-items:center;gap:14px;padding:16px 20px;border-bottom:1px solid var(--line)}
.quizWin header .close{font-size:22px;color:var(--muted);width:32px;height:32px;border-radius:8px}
.quizWin header .close:hover{background:var(--card2)}
.qbar{flex:1;height:8px;border-radius:999px;background:var(--card2);overflow:hidden}
.qbar span{display:block;height:100%;background:var(--accent);transition:.3s}
.qstats{display:flex;gap:12px;font-size:13px;font-weight:600}
.quizStage{padding:24px 22px}
.quizStage .meta{display:flex;justify-content:space-between;font-size:12px;color:var(--faint);font-weight:700;margin-bottom:12px}
.quizStage h1{font-size:20px;letter-spacing:-.01em;margin-bottom:18px}
.quizWin footer{padding:16px 22px;border-top:1px solid var(--line);display:flex;align-items:center;gap:14px;justify-content:space-between}
.quizWin footer .fb{display:flex;gap:10px;align-items:flex-start;font-size:14px}
.quizWin footer.ok{background:rgba(57,217,138,.06)}
.quizWin footer.no{background:rgba(255,107,107,.06)}

/* ---- exam ---- */
.examGrid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:18px}
.examCard{padding:22px;border-radius:var(--radius);background:var(--card);border:1px solid var(--line);transition:.16s}
.examCard:hover{border-color:var(--accent);transform:translateY(-2px)}
.examCard .banner{display:flex;justify-content:space-between;align-items:center;margin-bottom:14px}
.examCard .banner .big{font-size:30px}
.examCard .tag{font-size:11px;font-weight:700;letter-spacing:.06em;color:var(--accent);background:var(--accent-soft);padding:5px 10px;border-radius:999px}
.examCard h2{font-size:19px;margin-bottom:10px}
.examCard .facts{display:flex;flex-wrap:wrap;gap:12px;color:var(--muted);font-size:13px;margin-bottom:16px}
.examModalWin{width:100%;max-width:900px;max-height:92vh;overflow:auto;background:var(--card);border:1px solid var(--line2);border-radius:var(--radius);box-shadow:var(--shadow)}
.examModalWin header{position:sticky;top:0;background:var(--card);display:flex;align-items:center;gap:14px;padding:16px 22px;border-bottom:1px solid var(--line);z-index:2}
.examTimer{margin-left:auto;font-weight:800;padding:7px 14px;border-radius:999px;background:var(--card2);border:1px solid var(--line)}
.examTimer.danger{color:var(--bad);border-color:var(--bad)}
.examBody{padding:22px}
.qmeta{display:flex;justify-content:space-between;font-size:13px;color:var(--faint);font-weight:700;margin-bottom:8px}
.examBody h1{font-size:20px;margin-bottom:16px;letter-spacing:-.01em}
.written label{display:block;font-size:13px;color:var(--muted);margin-bottom:6px;font-weight:600}
.written textarea{width:100%;min-height:130px;background:var(--bg2);border:1px solid var(--line);border-radius:10px;color:var(--text);padding:12px 14px;font-family:var(--font);font-size:14px;resize:vertical}
.written .wc{font-size:12px;color:var(--faint);margin-top:6px}
.tableBlock .tTitle{display:flex;justify-content:space-between;align-items:baseline;margin-bottom:10px}
.tableBlock .tTitle strong{font-size:15px}
.tableBlock .tTitle span{font-size:12px;color:var(--faint)}
.tableScroll{overflow-x:auto;border:1px solid var(--line);border-radius:10px}
table.acct{width:100%;border-collapse:collapse;min-width:520px}
table.acct th,table.acct td{border:1px solid var(--line);padding:0}
table.acct thead th{background:var(--card2);padding:10px 12px;font-size:13px;text-align:left}
table.acct tbody th{background:var(--bg2);padding:10px 12px;font-size:13px;text-align:left;font-weight:600}
table.acct td input{width:100%;background:transparent;border:none;color:var(--text);padding:10px 12px;font-family:var(--font);font-size:14px}
table.acct td input:focus{outline:2px solid var(--accent);outline-offset:-2px;background:var(--accent-soft)}
.paperCtrls{display:flex;justify-content:space-between;gap:12px;margin-top:22px}
.qmap{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:20px}
.qmap button{width:40px;height:40px;border-radius:9px;border:1px solid var(--line);background:var(--card2);font-weight:700;font-size:13px;display:flex;flex-direction:column;align-items:center;justify-content:center;line-height:1}
.qmap button small{font-size:9px;color:var(--faint);font-weight:600}
.qmap button.active{border-color:var(--accent);color:var(--accent)}
.qmap button.answered{background:var(--accent-soft)}
.examResults{text-align:center;padding:30px 22px}
.examResults .medal{font-size:46px}
.examResults h1{font-size:40px;margin:8px 0}
.markScheme{text-align:left;margin-top:20px}
.markScheme details{border:1px solid var(--line);border-radius:10px;padding:12px 14px;margin-bottom:8px}
.markScheme summary{cursor:pointer;font-weight:600}
.markScheme ul{margin:10px 0 0;padding-left:20px;color:var(--muted)}
.markScheme li{margin:4px 0}

/* ---- toast ---- */
.toast{position:fixed;bottom:22px;left:50%;transform:translateX(-50%);z-index:80;background:var(--card2);border:1px solid var(--line2);border-radius:999px;padding:12px 20px;display:flex;gap:10px;align-items:center;font-weight:600;box-shadow:var(--shadow);animation:fade .25s}

/* ---- right rail on path page ---- */
.pathLayout{display:grid;grid-template-columns:1fr 300px;gap:24px;align-items:start}
.rail{position:sticky;top:80px;display:flex;flex-direction:column;gap:16px}
.railCard{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:18px}
.railCard .rh{display:flex;justify-content:space-between;align-items:center;margin-bottom:14px}
.railCard .rh small{font-size:11px;letter-spacing:.08em;color:var(--faint);font-weight:700;display:block}
.railCard .rh strong{font-size:15px}
.levelBar{height:9px;border-radius:999px;background:var(--card2);overflow:hidden;margin-top:10px}
.levelBar span{display:block;height:100%;background:var(--accent);border-radius:999px;transition:.4s}
.xpLine{display:flex;justify-content:space-between;font-size:13px;color:var(--muted)}
.miniChap{display:flex;gap:10px;align-items:center;padding:7px 0;font-size:13px}
.miniChap .mc{flex:none;width:22px;height:22px;border-radius:6px;display:grid;place-items:center;background:var(--card2);font-size:11px;font-weight:700}
.miniChap.done .mc{background:var(--accent);color:#fff}
.tip{display:flex;gap:12px;align-items:flex-start}
.tip p{color:var(--muted);font-size:13px}

@media(max-width:900px){
  .studyWrap{grid-template-columns:1fr}
  .chapIndex{position:static;max-height:none;display:flex;gap:6px;overflow-x:auto}
  .chapIndex .lbl{display:none}
  .chapIndex button{white-space:nowrap}
  .pathLayout{grid-template-columns:1fr}
  .rail{position:static}
  .home .hero h1{font-size:30px}
}