:root{--bg:#f4f6fb;--card:#fff;--ink:#1b2236;--mute:#6a7390;--line:#e2e6f0;--brand:#1f4fd8;--brand2:#e8eefc;--ok:#15803d;--okbg:#e6f6ec;--bad:#c62828;--badbg:#fdeaea;--saffron:#ff9933}
@media(prefers-color-scheme:dark){:root{--bg:#10141f;--card:#1a2030;--ink:#eef1fa;--mute:#98a2c3;--line:#2a3350;--brand:#6b93ff;--brand2:#212a45;--ok:#4ade80;--okbg:#14301f;--bad:#ff7b7b;--badbg:#3a1b1b}}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.5 system-ui,-apple-system,"Segoe UI",Roboto,sans-serif}
.wrap{max-width:860px;margin:0 auto;padding:0 16px}
.top{background:var(--card);border-bottom:3px solid var(--saffron);position:sticky;top:0;z-index:5}
.bar{display:flex;justify-content:space-between;align-items:center;height:56px}
.brand{font-weight:700;color:var(--ink);text-decoration:none;display:flex;gap:8px;align-items:center}
.logo{background:var(--brand);color:#fff;border-radius:6px;padding:2px 8px;font-size:14px}
nav a{margin-left:18px;color:var(--mute);text-decoration:none;font-weight:600}
nav a:hover{color:var(--brand)}
main{padding-top:20px;padding-bottom:40px;min-height:70vh}
h1{font-size:28px;line-height:1.2;margin:8px 0}
h2{font-size:20px;margin:24px 0 12px}
.lead{color:var(--mute);margin:0 0 16px}
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:12px}
.card{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:16px}
.tile{cursor:pointer;text-align:left;font:inherit;color:inherit;transition:.15s}
.tile:hover{border-color:var(--brand);transform:translateY(-2px)}
.tile b{display:block;font-size:17px}
.tile span{color:var(--mute);font-size:14px}
.tile.main{background:var(--brand);color:#fff;border-color:var(--brand)}
.tile.main span{color:#dbe5ff}
.pill{display:inline-block;background:var(--brand2);color:var(--brand);border-radius:99px;padding:2px 10px;font-size:13px;font-weight:600}
.stats{display:flex;gap:12px;flex-wrap:wrap;margin:12px 0}
.stats .card{flex:1;min-width:120px;text-align:center}
.stats strong{font-size:24px;display:block}
.ad{margin:20px 0;min-height:90px;display:flex;align-items:center;justify-content:center;border:1px dashed var(--line);border-radius:8px;color:var(--mute);font-size:12px;text-align:center;overflow:hidden}
.ad small{display:block}
/* quiz */
.qhead{display:flex;justify-content:space-between;align-items:center;gap:12px;font-weight:600;margin-bottom:8px}
.timer{background:var(--brand2);color:var(--brand);padding:2px 12px;border-radius:99px;font-variant-numeric:tabular-nums}
.timer.low{background:var(--badbg);color:var(--bad)}
.prog{height:6px;background:var(--line);border-radius:3px;overflow:hidden;margin-bottom:16px}
.prog i{display:block;height:100%;background:var(--brand);transition:width .25s}
.qtext{font-size:20px;font-weight:600;margin:0 0 14px}
.sign{width:120px;height:120px;display:block;margin:0 auto 14px}
.opt{display:flex;gap:12px;align-items:flex-start;width:100%;text-align:left;font:inherit;color:inherit;background:var(--card);border:2px solid var(--line);border-radius:10px;padding:12px 14px;margin-bottom:10px;cursor:pointer}
.opt:hover:not(:disabled){border-color:var(--brand)}
.opt .k{flex:none;width:26px;height:26px;border-radius:50%;background:var(--brand2);color:var(--brand);display:grid;place-items:center;font-weight:700;font-size:13px}
.opt.ok{border-color:var(--ok);background:var(--okbg)}
.opt.bad{border-color:var(--bad);background:var(--badbg)}
.opt:disabled{cursor:default}
.expl{background:var(--brand2);border-radius:10px;padding:12px 14px;margin:6px 0 14px}
.btn{font:inherit;font-weight:600;border:0;border-radius:10px;padding:12px 22px;background:var(--brand);color:#fff;cursor:pointer}
.btn.ghost{background:var(--brand2);color:var(--brand)}
.row{display:flex;gap:10px;flex-wrap:wrap}
/* result */
.score{text-align:center;padding:24px}
.score .big{font-size:56px;font-weight:800;line-height:1}
.pass{color:var(--ok)}.fail{color:var(--bad)}
.rev{border-left:4px solid var(--line);padding:8px 12px;margin:10px 0;background:var(--card);border-radius:0 8px 8px 0}
.rev.r{border-color:var(--ok)}.rev.w{border-color:var(--bad)}
.rev .sign{width:56px;height:56px;margin:0 0 6px}
.signgrid{display:grid;grid-template-columns:repeat(auto-fill,minmax(130px,1fr));gap:12px}
.signgrid .card{text-align:center;font-size:14px}
.signgrid .sign{width:80px;height:80px;margin:0 auto 8px}
.foot{border-top:1px solid var(--line);color:var(--mute);font-size:13px;padding:16px 0}
.foot a{color:var(--brand)}
@media(max-width:520px){h1{font-size:24px}.qtext{font-size:18px}}
/* v2 additions */
.opt.sel{border-color:var(--brand);background:var(--brand2)}
.tip{margin-top:8px;font-size:14px;color:var(--brand);font-weight:600}
.pill+.pill{margin-left:6px}
h2 .pill{vertical-align:middle;margin-left:8px;font-size:12px}
.sets{display:grid;grid-template-columns:repeat(auto-fill,minmax(110px,1fr));gap:10px}
.tile.set{text-align:center;padding:12px}
.tile.set.done{border-color:var(--ok);background:var(--okbg)}
.tile:disabled{opacity:.5;cursor:not-allowed;transform:none}
.rev .ans{color:var(--ok);font-weight:600}
.rev .yours{color:var(--bad)}
.rev .why{margin:6px 0 2px;font-size:14px;color:var(--mute)}
.signgrid .card small{display:block;color:var(--mute);margin-top:4px}
/* v3 additions */
.src{margin-top:6px;font-size:12px;color:var(--mute)}
.tile.hardtile{border-color:#e08a00}
.tile.hardtile:hover{border-color:#ff9933}
.tile.banktile{border-color:var(--brand)}
/* v4: Hindi toggle */
body{font-family:system-ui,-apple-system,"Segoe UI","Nirmala UI","Noto Sans Devanagari",Roboto,sans-serif}
nav{display:flex;align-items:center}
.lang{margin-left:18px;font:inherit;font-weight:700;font-size:14px;border:1.5px solid var(--brand);background:var(--brand2);color:var(--brand);border-radius:99px;padding:3px 14px;cursor:pointer}
.lang:disabled{opacity:.45;cursor:not-allowed}
/* v5: SEO pages */
.seo .crumbs{font-size:13px;color:var(--mute);margin-bottom:6px}.seo .crumbs a{color:var(--brand)}
.seo h1{font-size:26px}.seo h2{margin-top:28px}
.qa{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:14px 16px;margin:14px 0}
.qa h3{margin:0 0 8px;font-size:17px}.qa .sign{width:84px;height:84px;margin:4px 0 8px}
.qa .opts{margin:6px 0 8px;padding-left:24px}.qa .opts li.correct{font-weight:700;color:var(--ok)}
.qa p{margin:6px 0}.qa .tip{color:var(--brand);font-weight:600;font-size:14px}.qa .src{font-size:12px;color:var(--mute)}
.studylinks{columns:2;padding-left:18px}.ctabox{margin:28px 0;text-align:center}.ctabox .btn{display:inline-block;text-decoration:none}
.seo nav .lang{text-decoration:none}.studyrow{line-height:2}
.foot a{color:var(--brand)}
@media(max-width:520px){.studylinks{columns:1}}

/* ===== v6: landing page redesign ===== */
:root{--brand:#2563eb;--brand2:#e8f0ff;--line:#dfe7f4;--bg:#f6f9ff;--hero1:#e6f0ff;--hero2:#f6f9ff;--shadow:0 1px 2px rgba(20,40,90,.05),0 6px 18px rgba(20,40,90,.06);--hardbg:#fff4e4;--hardline:#f3c47f;--hardink:#d97706}
@media(prefers-color-scheme:dark){:root:not([data-theme="light"]){--brand:#6b9bff;--brand2:#1f2a47;--line:#2a3555;--bg:#0f1424;--hero1:#16213d;--hero2:#0f1424;--shadow:0 1px 2px rgba(0,0,0,.3);--hardbg:#33250f;--hardline:#7a5a22;--hardink:#fbbf6a}}
.ic{width:22px;height:22px;flex:none}
body{background:var(--bg)}
.top{border-bottom:1px solid var(--line);box-shadow:none}
.bar{height:64px}
.brand{font-size:18px}
.logo{border-radius:9px;padding:6px 10px;font-size:15px;letter-spacing:.3px}
nav{gap:6px}
nav a{margin-left:14px;font-weight:500;color:var(--ink);opacity:.8}
nav a:hover{color:var(--brand);opacity:1}
.lang{display:inline-flex;align-items:center;gap:6px;margin-left:16px;border:1.5px solid var(--brand);background:transparent;color:var(--brand);border-radius:999px;padding:7px 14px;font-weight:600;font-size:14px;line-height:1}
.lang .ic{width:16px;height:16px}
.lang:hover:not(:disabled){background:var(--brand2)}
main{padding-top:0}
.wrap{max-width:1000px}

/* hero */
.hero{display:grid;grid-template-columns:1.05fr .95fr;gap:8px;align-items:center;margin:0 -16px;padding:34px 16px 26px;background:linear-gradient(180deg,var(--hero1),var(--hero2));border-radius:0 0 22px 22px}
.hero h1{font-size:40px;line-height:1.12;margin:6px 0 14px;letter-spacing:-.5px}
.eyebrow{font-size:13px;font-weight:700;letter-spacing:1.5px;color:var(--brand)}
.hero .lead{font-size:16px;line-height:1.6;color:var(--ink);opacity:.8;margin:0 0 20px;max-width:520px}
.journey{display:inline-flex;align-items:center;gap:8px;background:rgba(37,99,235,.1);color:var(--brand);padding:11px 16px;border-radius:12px;font-weight:600;font-size:15px}
.hero-art svg{width:100%;height:auto;display:block;filter:drop-shadow(0 8px 18px rgba(37,99,235,.12))}

/* section headings */
h2.sect{font-size:24px;margin:38px 0 4px;display:flex;align-items:center;gap:10px;flex-wrap:wrap;letter-spacing:-.2px}
.sect-sub{margin:0 0 16px;color:var(--mute);font-size:15px}
.chip{background:var(--brand2);color:var(--brand);font-size:13px;font-weight:600;padding:4px 12px;border-radius:8px}

/* mode cards */
.cards3{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.mode,.pcard{display:flex;align-items:center;gap:14px;text-align:left;font:inherit;color:inherit;background:var(--card);border:1.5px solid var(--line);border-radius:16px;padding:18px;cursor:pointer;box-shadow:var(--shadow);transition:transform .15s,border-color .15s,box-shadow .15s}
.mode:hover,.pcard:hover:not(:disabled){transform:translateY(-2px);border-color:var(--brand)}
.mode .ico,.pcard .ico{flex:none;width:48px;height:48px;border-radius:13px;display:grid;place-items:center;background:var(--brand2);color:var(--brand)}
.mode .ico .ic{width:25px;height:25px}
.mtxt{flex:1;min-width:0;display:flex;flex-direction:column;gap:3px}
.mtxt b{font-size:17px;font-weight:700}
.mtxt span{font-size:13.5px;color:var(--mute);line-height:1.4}
.chev{width:20px;height:20px;color:var(--mute);opacity:.7}
.mode.main{background:var(--brand);border-color:var(--brand);color:#fff;box-shadow:0 8px 22px rgba(37,99,235,.28)}
.mode.main .ico{background:rgba(255,255,255,.2);color:#fff}
.mode.main .mtxt span,.mode.main .chev{color:rgba(255,255,255,.85);opacity:1}
.mode.hard{background:var(--hardbg);border-color:var(--hardline)}
.mode.hard .ico{background:rgba(245,158,11,.18);color:var(--hardink)}
.mode.hard .chev{color:var(--hardink)}

/* test sets */
.setgrid{display:grid;grid-template-columns:repeat(6,1fr);gap:12px}
.setcard{font:inherit;color:inherit;background:var(--card);border:1.5px solid var(--line);border-radius:14px;padding:16px 8px;text-align:center;cursor:pointer;box-shadow:var(--shadow);display:flex;flex-direction:column;gap:4px;transition:.15s}
.setcard b{font-size:15px}.setcard span{font-size:13px;color:var(--mute)}
.setcard:hover{border-color:var(--brand);transform:translateY(-2px)}
.setcard.done{border-color:#22a45d;background:var(--okbg)}.setcard.done span{color:var(--ok);font-weight:600}

/* practice cards */
.pract .pcard{align-items:flex-start;padding:16px}
.pcard .ico.plain{background:transparent;color:var(--brand);width:40px;height:40px;padding-top:2px}
.pcard .ico.plain .ic{width:30px;height:30px}
.pcard .chev{align-self:center}
.pcard .count{align-self:flex-start;margin-top:6px;background:var(--brand2);color:var(--brand)!important;font-size:12.5px!important;font-weight:600;padding:3px 10px;border-radius:7px}
.pcard.hl{border-color:var(--brand);box-shadow:0 0 0 1px var(--brand),var(--shadow)}
.pcard:disabled{opacity:.55;cursor:not-allowed}

/* progress + about */
.stats3{display:grid;grid-template-columns:repeat(3,1fr);background:var(--card);border:1.5px solid var(--line);border-radius:16px;box-shadow:var(--shadow)}
.st{display:flex;align-items:center;justify-content:center;gap:14px;padding:20px 10px}
.st+.st{border-left:1px solid var(--line)}
.st strong{display:block;font-size:26px;line-height:1.1}.st small{color:var(--mute);font-size:13.5px}
.sico{flex:none;width:42px;height:42px;border-radius:50%;background:var(--brand2);color:var(--brand);display:grid;place-items:center}
.about{display:flex;gap:16px;align-items:flex-start;margin-top:18px;padding:20px;background:var(--brand2);border-radius:16px}
.about h3{margin:2px 0 6px;font-size:17px}.about p{margin:0;font-size:14.5px;line-height:1.6;color:var(--ink);opacity:.85}
.about .sico{background:var(--card)}
.foot{margin-top:40px;font-size:12.5px}
.studyrow a{white-space:nowrap}

/* responsive */
@media(max-width:900px){
  .cards3{grid-template-columns:repeat(2,1fr)}
  .setgrid{grid-template-columns:repeat(5,1fr)}
}
@media(max-width:720px){
  .hero{grid-template-columns:1fr;padding-top:24px}
  .hero h1{font-size:32px}
  .hero-art{max-width:420px;margin:6px auto 0}
  nav a{margin-left:10px;font-size:14px}.lang{margin-left:10px;padding:6px 11px}
  .brand{font-size:16px}
}
@media(max-width:560px){
  .cards3{grid-template-columns:1fr}
  .setgrid{grid-template-columns:repeat(3,1fr)}
  .stats3{grid-template-columns:1fr}.st+.st{border-left:0;border-top:1px solid var(--line)}
  h2.sect{font-size:21px}
  .brand span:not(.logo){display:none}
}
@media(max-width:560px){
  nav a[data-go="home"]{display:none}
  .brand,nav a{white-space:nowrap}
  .bar{gap:8px}
}