:root{
 --bg:#f5eede;--surface:#fffdf8;--soft:#f6efe0;--ink:#1d2b3a;--muted:#4c5d70;--faint:#84909e;
 --line:#e3d8c1;--line2:#efe6d2;--accent:#a06a2f;--accent-d:#7c521f;--accent-l:#f3e8d4;
 --amber:#c9a253;--amber-d:#95682a;--amber-l:#f7edd6;--mint:#2e8b57;--deva:'Noto Serif Devanagari',serif;
 --navy:#1c3a5e;--navy-deep:#142a44;
 --shadow:0 1px 2px rgba(20,42,68,.05),0 16px 40px -22px rgba(20,42,68,.28);
}
*{box-sizing:border-box;margin:0;-webkit-print-color-adjust:exact;print-color-adjust:exact}
html{scroll-behavior:smooth}
body{color:var(--ink);background:
 radial-gradient(820px 460px at 90% -8%,rgba(28,58,94,.10),transparent 60%),
 radial-gradient(640px 420px at 2% 4%,rgba(201,162,83,.14),transparent 56%),var(--bg);
 font-family:'Inter',system-ui,sans-serif;font-size:16px;line-height:1.64;-webkit-font-smoothing:antialiased}
.reveal{opacity:0;transform:translateY(22px);transition:opacity .7s cubic-bezier(.2,.7,.2,1),transform .7s cubic-bezier(.2,.7,.2,1)}
.reveal.in{opacity:1;transform:none}
@media(prefers-reduced-motion:reduce){.reveal{opacity:1;transform:none;transition:none}}
#bar{position:fixed;top:0;left:0;height:3px;width:0;z-index:60;background:linear-gradient(90deg,var(--accent),var(--amber))}
.topbar{position:sticky;top:0;z-index:50;display:flex;align-items:center;justify-content:space-between;gap:14px;flex-wrap:wrap;
 padding:9px 26px;background:rgba(20,42,68,.97);backdrop-filter:blur(12px);border-bottom:1px solid rgba(201,162,83,.30)}
.brand{display:flex;align-items:center;gap:11px}
.brand img{height:34px;width:auto;display:block}
.brand .bt{display:flex;flex-direction:column;line-height:1.08;font-family:'Plus Jakarta Sans';font-weight:800;font-size:21px;color:#fff}
.brand b{color:var(--amber)}
.brand small{font-weight:600;font-size:9.5px;letter-spacing:.2em;text-transform:uppercase;color:#93a3b7;margin-top:1px}
.tools{display:flex;gap:8px;align-items:center}
.btn{font-family:'Plus Jakarta Sans';font-weight:600;font-size:13px;color:#f3ece0;background:rgba(255,255,255,.08);
 border:1px solid rgba(201,162,83,.45);border-radius:10px;padding:8px 15px;cursor:pointer;transition:.16s}
.btn:hover{border-color:var(--amber);color:var(--amber)}
.langtoggle{display:inline-flex;border:1px solid rgba(201,162,83,.45);border-radius:10px;overflow:hidden;background:rgba(255,255,255,.06)}
.langtoggle button{font:inherit;font-weight:700;font-size:12.5px;padding:8px 12px;border:none;background:transparent;color:#c9d4e2;cursor:pointer}
.langtoggle button.on{background:var(--amber);color:var(--navy-deep)}
.wrap{max-width:880px;margin:0 auto;padding:0 26px 90px}
/* bilingual */
.en,.hi{display:block}
.hi{font-family:var(--deva);color:#4a4230;font-size:.98em;line-height:1.75;margin-top:4px}
body.lang-en .hi{display:none}
body.lang-hi .en{display:none}
body.lang-en .en,body.lang-hi .hi{margin-top:0}
.hero .hi{color:#ece2cf}
.key .hi{color:#3a3320}.key.amber .hi{color:#5a4620}
.quiz .hi,.opt .hi,.exp .hi{color:#e7ddc9}
.st-q .hi{color:#4a4230}.st-o .hi{color:#5a6172}.st-a .hi{color:#1a3327}
.hero{position:relative;overflow:hidden;border-radius:26px;color:#fff;padding:42px 42px 36px;margin:20px 0 26px;
 background:linear-gradient(135deg,#142a44,#1c3a5e 60%,#264c75)}
.hero:before{content:"";position:absolute;inset:0;background:radial-gradient(440px 240px at 88% 130%,rgba(201,162,83,.48),transparent 62%)}
.hero .kic{position:relative;font-family:'DM Mono';font-size:12px;letter-spacing:.16em;text-transform:uppercase;color:#d9c39a}
.hero h1{position:relative;font-family:'Plus Jakarta Sans';font-weight:800;font-size:clamp(38px,7vw,58px);line-height:1.0;margin:12px 0 12px;letter-spacing:-.02em}
.hero .lede{position:relative;max-width:600px;font-size:15px}
.hero .chips{position:relative;display:flex;gap:10px;margin-top:20px;flex-wrap:wrap}
.hero .chips span{background:rgba(255,255,255,.12);border:1px solid rgba(255,255,255,.18);border-radius:11px;padding:8px 13px;font-size:13px;color:#eaf0ff;font-weight:600}
.hero .emoji{position:absolute;right:32px;top:26px;font-size:78px;line-height:1;filter:drop-shadow(0 8px 18px rgba(0,0,0,.3))}
@media(max-width:740px){.hero .emoji{display:none}}
.sec{position:relative;background:var(--surface);border:1px solid var(--line);border-radius:20px;margin:0 0 18px;box-shadow:var(--shadow);padding:6px 26px;overflow:hidden;scroll-margin-top:74px;transition:border-color .2s,box-shadow .2s}
.sec:hover{border-color:#e0cfa8}
.sec>.head,.sec>.body{position:relative;z-index:1}
.sdiv{display:flex;align-items:center;gap:12px;max-width:230px;margin:-4px auto 14px}
.sdiv i{flex:1;height:2px;border-radius:2px;background:linear-gradient(90deg,transparent,var(--line2),var(--line))}
.sdiv i:last-child{background:linear-gradient(90deg,var(--line),var(--line2),transparent)}
.sdiv b{width:8px;height:8px;border-radius:2px;background:var(--accent);transform:rotate(45deg);flex:none}
.sec>.head{display:flex;align-items:center;gap:16px;padding:16px 0;cursor:pointer;user-select:none}
.badge{width:54px;height:54px;border-radius:16px;display:grid;place-items:center;font-size:27px;flex:none;
 background:linear-gradient(150deg,var(--accent-l),#e8d7b4);box-shadow:inset 0 0 0 1px #e5d3ab}
.badge.b-amber{background:linear-gradient(150deg,var(--amber-l),#f6e6c2);box-shadow:inset 0 0 0 1px #ecdcb0}
.head .t{flex:1}.head .nx{font-family:'DM Mono';font-size:12px;color:var(--accent);font-weight:500}
.head h2{font-family:'Plus Jakarta Sans';font-weight:700;font-size:24px;margin:2px 0 0;letter-spacing:-.01em;line-height:1.15}
.head h2 .hi{font-size:16px;font-weight:500;color:var(--muted);margin-top:1px}
.head .chev{width:24px;height:24px;flex:none;color:var(--faint);transition:transform .25s;align-self:flex-start;margin-top:18px}
.sec.collapsed .chev{transform:rotate(-90deg)}
.sec .body{padding:0 0 22px;border-top:1px solid var(--line2);margin-top:-2px}
.sec.collapsed .body{display:none}
.lead{color:var(--muted);font-size:15.5px;margin:16px 0 6px;max-width:74ch}
.lead.hi{margin:2px 0 14px}
ul.pts{list-style:none;margin:6px 0 14px;padding:0;display:grid;gap:9px}
ul.pts li{position:relative;padding:11px 16px 11px 40px;background:var(--soft);border:1px solid var(--line2);border-radius:13px;font-size:15px}
ul.pts li:before{content:"\203A";position:absolute;left:16px;top:9px;color:var(--accent);font-weight:800;font-size:18px}
strong{color:var(--accent-d);font-weight:700}
.kw{color:var(--ink);font-weight:600}.hi .kw{color:#2a2416}
.hl{background:rgba(231,200,119,.42);padding:.04em .2em;border-radius:4px;font-weight:700;color:#26303c;-webkit-box-decoration-break:clone;box-decoration-break:clone}
.hi .hl{color:#2a2416}
.hero .hl,.quiz .hl,.opt .hl,.formula .hl{color:#fff;background:rgba(243,201,138,.30)}
.chip{font-family:'DM Mono';font-weight:500;font-size:13px;background:var(--accent-l);color:var(--accent-d);border:1px solid #e3d3ad;border-radius:8px;padding:1px 8px;white-space:nowrap}
.key{display:flex;gap:14px;align-items:flex-start;background:linear-gradient(120deg,#f7efdd,#fffdf8);
 border:1px solid #ecdcb8;border-left:5px solid var(--accent);border-radius:15px;padding:16px 18px;margin:16px 0}
.key .ic{font-size:25px;flex:none;line-height:1.1}
.key .kl{font-weight:800;font-size:11px;letter-spacing:.12em;text-transform:uppercase;color:var(--accent);margin-bottom:5px}
.key .kt{font-size:15.5px}
.key.amber{background:linear-gradient(120deg,#fdf4e3,#fffaf0);border-color:#f0dcb0;border-left-color:var(--amber)}
.key.amber .kl{color:var(--amber-d)}
.formula{background:#142a44;color:#eaf0ff;border-radius:13px;padding:14px 17px;margin:15px 0;font-family:'DM Mono',monospace;font-size:13.5px;line-height:1.9;overflow:auto}
.formula .fl{font-family:'Plus Jakarta Sans';font-weight:800;font-size:10.5px;letter-spacing:.12em;text-transform:uppercase;color:#f3c98a;margin-bottom:6px}
.formula b{color:#f3c98a}.formula .hi{color:#cdd7ea;font-size:13px}
.cap{font-weight:800;font-size:12px;letter-spacing:.06em;text-transform:uppercase;color:var(--amber-d);margin:22px 0 9px;display:flex;align-items:center;gap:8px}
.cap:before{content:"";width:16px;height:3px;background:var(--amber);border-radius:3px}
.tw{overflow:auto;margin:6px 0 14px;border:1px solid var(--line);border-radius:14px}
table{border-collapse:collapse;width:100%;font-size:14px;background:var(--surface)}
th,td{text-align:left;padding:11px 14px;border-bottom:1px solid var(--line2);vertical-align:top}
th{background:#1c3a5e;color:#fff;font-weight:600;font-size:12.5px}
th .hi{color:#cfd7ee;font-weight:500;font-size:11.5px}
td .hi{color:#5a6172;font-size:12.5px}
tr:last-child td{border-bottom:none}tbody tr:nth-child(even) td{background:var(--soft)}
.eg{background:linear-gradient(180deg,#fffdf8,#fbf5e6);border:1px solid #ecdcb8;border-radius:15px;padding:15px 17px;margin:15px 0}
.eg .egh{font-family:'DM Mono';font-weight:500;font-size:12px;letter-spacing:.08em;text-transform:uppercase;color:var(--accent);margin-bottom:7px}
.eg p{font-size:14.5px;color:var(--ink);margin:4px 0;line-height:1.6}
.eg p.hi{color:#4a4230}
.eg .ans{font-weight:700;color:var(--mint)}
.quiz{background:linear-gradient(150deg,#142a44,#264c75);color:#fff;border-radius:22px;padding:30px 28px;margin:26px 0 10px}
.quiz h2{font-family:'Plus Jakarta Sans';font-weight:800;font-size:27px;margin:0 0 4px}
.quiz p.sub{color:#cfd7ee;margin:0 0 4px;font-size:14px}
.quiz p.sub.hi{color:#c7bfae;margin:0 0 18px}
.q{background:rgba(255,255,255,.07);border:1px solid rgba(255,255,255,.15);border-radius:14px;padding:16px 18px;margin:0 0 13px}
.q .qh{font-weight:600;font-size:15px;margin-bottom:11px}.q .qh .qn{font-family:'DM Mono';color:#f3c98a;font-weight:500;font-size:12px;letter-spacing:.06em}
.opt{display:block;width:100%;text-align:left;font:inherit;font-weight:500;font-size:14px;color:#eef2ff;
 background:rgba(255,255,255,.06);border:1px solid rgba(255,255,255,.15);border-radius:11px;padding:11px 14px;margin:7px 0;cursor:pointer;transition:.15s}
.opt:hover{border-color:#f3c98a;background:rgba(255,255,255,.12)}
.opt.right{background:rgba(46,139,87,.32);border-color:#37d6a0;color:#fff}
.opt.wrong{background:rgba(178,59,59,.30);border-color:#f09a9a}
.opt.lock{cursor:default;opacity:.6}.opt.lock.right,.opt.lock.wrong{opacity:1}
.exp{font-size:13px;color:#d7deef;margin-top:8px;display:none}.exp.show{display:block}
.exp b{color:#f3c98a}
.score{font-family:'Plus Jakarta Sans';font-weight:700;font-size:18px;margin-top:6px}
.round-head{display:flex;align-items:center;gap:10px;flex-wrap:wrap;margin:0 0 14px}
.round-badge{font-family:'DM Mono';font-weight:500;font-size:12.5px;letter-spacing:.04em;color:#142a44;
 background:#f3c98a;border-radius:999px;padding:4px 12px}
.round-sub{font-size:12.5px;color:#cfd7ee}
.retest{margin:18px 0 4px;padding:22px 20px;text-align:center;background:rgba(255,255,255,.08);
 border:1px solid rgba(243,201,138,.45);border-radius:16px}
.retest .rt-emoji{font-size:34px;line-height:1}
.retest .rt-title{font-family:'Plus Jakarta Sans';font-weight:800;font-size:22px;margin:6px 0 4px}
.retest .rt-score{font-size:14px;color:#cfd7ee;margin-bottom:8px}.retest .rt-score b{color:#fff}
.retest .rt-msg{font-size:14px;color:#e7ecfb;line-height:1.55;max-width:470px;margin:0 auto}
.retest .rt-done{font-size:14.5px;color:#37d6a0;font-weight:600;margin:12px auto 0;max-width:470px}
.retest .rt-actions{margin-top:16px}
.retest .rt-btn{font:inherit;font-weight:700;font-size:14.5px;color:#142a44;background:#f3c98a;
 border:none;border-radius:12px;padding:13px 22px;cursor:pointer;transition:.15s}
.retest .rt-btn:hover{background:#f7d6a0;transform:translateY(-1px)}
footer{max-width:880px;margin:0 auto;padding:26px;color:var(--faint);font-size:13px;text-align:center;border-top:1px solid var(--line)}
footer b{color:var(--ink)}footer b em{color:var(--accent);font-style:normal}
@media print{#bar,.topbar,.btn,.langtoggle,.quiz,.sdiv{display:none!important}.wrap{padding:0}.sec.collapsed .body{display:block!important}
 .hi{display:block!important}.sec{box-shadow:none;margin:0 0 10px}.hero{margin:0 0 12px}.key,ul.pts li,tr,.cap,.head,.eg,.formula{break-inside:avoid}
 thead{display:table-header-group}body{background:#fff}}
.selftest{margin:16px 0 4px;background:linear-gradient(150deg,#fbf5e6,#f7efdd);border:1px solid var(--line);
 border-left:4px solid var(--accent);border-radius:14px;padding:14px 16px 8px}
.selftest .st-h{font-family:'Plus Jakarta Sans',serif;font-weight:800;font-size:15px;color:var(--accent-d);margin-bottom:10px;display:flex;align-items:center;gap:8px;flex-wrap:wrap}
.selftest .st-h span{font-family:'Plus Jakarta Sans';font-weight:700;font-size:10px;letter-spacing:.08em;text-transform:uppercase;color:var(--faint)}
.st-item{background:#fff;border:1px solid var(--line);border-radius:11px;padding:11px 13px;margin-bottom:9px}
.st-q{font-weight:600;font-size:14.5px;color:var(--ink);margin:0 0 8px;line-height:1.55}
.pyqtag{display:inline-block;font-family:'Plus Jakarta Sans';font-weight:800;font-size:9.5px;letter-spacing:.06em;text-transform:uppercase;color:var(--amber-d);background:var(--amber-l);border:1px solid #ecdcb0;border-radius:5px;padding:1px 6px;margin-right:6px;vertical-align:middle;white-space:nowrap}
.hi .pyqtag{color:var(--amber-d)}
.st-o{margin:0 0 8px;padding-left:22px}
.st-o li{font-size:14px;color:var(--muted);margin:5px 0}
.st-o li.st-click{cursor:pointer;border-radius:8px;padding:3px 9px;transition:.14s;border:1px solid transparent}
.st-o li.st-click:hover:not(.st-lock){background:var(--accent-l);border-color:var(--line)}
.st-o li.st-lock{cursor:default}
.st-o li.st-right{background:#e7f7ef;border-color:#bfe6d0;color:#177a4d;font-weight:600}
.st-o li.st-wrong{background:#fbeaea;border-color:#f0c9c9;color:#b23b3b;font-weight:600}
.st-blank{display:inline-block;min-width:70px;border-bottom:2px dotted var(--accent);margin:0 3px}
.st-btn{font-family:'Plus Jakarta Sans';font-weight:600;font-size:12.5px;color:var(--accent);background:var(--accent-l);
 border:1px solid transparent;border-radius:8px;padding:5px 12px;cursor:pointer;transition:.15s}
.st-btn:hover:not(:disabled){background:var(--accent);color:#fff}
.st-btn:disabled{color:var(--mint);background:#e7f7f0;cursor:default}
.st-a{display:none;margin-top:8px;font-size:13.5px;line-height:1.6;color:var(--ink);
 background:#f0fbf6;border:1px solid #c9ecdc;border-radius:8px;padding:8px 11px}
.st-item.st-open .st-a{display:block}
@media print{.st-a{display:block!important}.st-btn{display:none}}