/* ===== Mridul's CAT Mocks — shared theory-page styles =====
   One source of truth for every /learn topic page. Edit here → all pages update. */
:root{--navy:#0c1f3d;--navy2:#0a1830;--navy3:#132a52;--card:#14284b;--card2:#0f2143;--line:rgba(255,255,255,.10);--gold:#ffc534;--gold2:#ffb01e;--ink:#eaf0fa;--mut:#9db0cf;--green:#3fd18b;--red:#ff6b6b;--blue:#6fb1ff;--violet:#b79cff}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
/* backstop: the page itself must never scroll sideways */
html,body{overflow-x:hidden;max-width:100%}
body{font-family:'Poppins',system-ui,Arial,sans-serif;background:var(--navy2);color:var(--ink);line-height:1.65;-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}
.wrap{max-width:1080px;margin:0 auto;padding:0 20px}
.gold{color:var(--gold)}.green{color:var(--green)}.blue{color:var(--blue)}.red{color:var(--red)}.violet{color:var(--violet)}

/* nav */
.nav{position:sticky;top:0;z-index:60;background:rgba(10,24,48,.9);backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}
.nav .wrap{display:flex;align-items:center;gap:16px;height:58px}
.brand{display:flex;align-items:center;gap:10px;font-weight:800;font-size:15px}
.brand .m{width:32px;height:32px;border-radius:9px;background:#fff;color:var(--navy);display:grid;place-items:center;font-weight:900;font-size:19px}
.brand small{display:block;font-size:9.5px;letter-spacing:2px;color:var(--gold);font-weight:700;line-height:1}
.nav .links{margin-left:auto;display:flex;gap:20px;font-size:13.5px;color:var(--mut);font-weight:600;align-items:center}
.nav .links a:hover{color:#fff}
.btn{display:inline-flex;align-items:center;gap:8px;background:var(--gold);color:#0c1f3d;font-weight:800;padding:9px 16px;border-radius:30px;font-size:13.5px;border:0;cursor:pointer;white-space:nowrap}
.btn:hover{background:var(--gold2)}
.btn.ghost{background:transparent;border:1.5px solid var(--gold);color:var(--gold)}
@media(max-width:860px){.nav .links a.hidem{display:none}}

/* hero */
.hero{background:radial-gradient(1200px 500px at 80% -10%,rgba(46,120,210,.22),transparent),linear-gradient(180deg,var(--navy) 0,var(--navy2) 100%);padding:40px 0 34px;border-bottom:1px solid var(--line)}
.crumb{font-size:12.5px;color:var(--mut);font-weight:600;margin-bottom:14px}
.crumb a:hover{color:var(--gold)}
.badges{display:flex;gap:9px;flex-wrap:wrap;margin-bottom:14px}
.badge{display:inline-block;padding:5px 12px;border-radius:30px;font-size:11.5px;font-weight:700;letter-spacing:.3px}
.badge.sec{background:rgba(111,177,255,.16);color:var(--blue);border:1px solid rgba(111,177,255,.32)}
.badge.wt{background:rgba(255,197,52,.14);color:var(--gold);border:1px solid rgba(255,197,52,.32)}
.badge.diff{background:rgba(63,209,139,.14);color:var(--green);border:1px solid rgba(63,209,139,.30)}
.hero h1{font-size:clamp(28px,5.4vw,46px);font-weight:900;line-height:1.08;margin:4px 0 12px;letter-spacing:-.02em}
.hero p.sub{font-size:clamp(15px,2.2vw,18px);color:var(--mut);max-width:760px}
.herostats{margin-top:22px;display:flex;gap:26px;flex-wrap:wrap}
.herostats div b{color:#fff;font-size:20px;font-weight:800;display:block;line-height:1.1}
.herostats div span{color:var(--mut);font-size:12px}
.herocta{margin-top:24px;display:flex;gap:12px;flex-wrap:wrap;align-items:center}

/* layout with sticky TOC — minmax(0,..) + min-width:0 lets the content track shrink below its widest child (KaTeX) */
.shell{display:grid;grid-template-columns:230px minmax(0,1fr);gap:34px;align-items:start;padding:34px 0 10px}
@media(max-width:900px){.shell{grid-template-columns:minmax(0,1fr)}.toc{display:none}}
.toc{position:sticky;top:74px;font-size:13.5px;min-width:0}
.toc .lbl{color:var(--gold);font-weight:800;font-size:11px;letter-spacing:1.5px;text-transform:uppercase;margin-bottom:10px}
.toc a{display:block;color:var(--mut);padding:6px 0 6px 12px;border-left:2px solid var(--line);font-weight:500}
.toc a:hover{color:#fff;border-color:var(--mut)}
.toc a.on{color:var(--gold);border-color:var(--gold);font-weight:700}
.progwrap{margin-top:18px;background:var(--card);border:1px solid var(--line);border-radius:12px;padding:14px}
.progwrap .pb{height:8px;background:rgba(255,255,255,.08);border-radius:5px;overflow:hidden;margin:8px 0}
.progwrap .pf{height:100%;background:linear-gradient(90deg,var(--gold),var(--gold2));width:0;transition:width .4s}
.progwrap small{color:var(--mut);font-size:11.5px}

/* content — min-width:0 is the key fix so nothing forces the column wider than the viewport */
.content{min-width:0;overflow-wrap:break-word}
.content h2{font-size:clamp(21px,3.4vw,29px);font-weight:800;margin:6px 0 6px;letter-spacing:-.01em;scroll-margin-top:70px}
.content h2 .num{color:var(--gold);font-weight:900;margin-right:10px}
.content h3{font-size:17.5px;font-weight:700;margin:24px 0 6px;color:#fff}
.content p{margin:10px 0;color:#d6e2f4;font-size:15px}
.content section{padding:22px 0 8px;border-bottom:1px solid var(--line);min-width:0}
.content section:last-child{border-bottom:0}
.lead{color:var(--mut);font-size:15.5px;max-width:720px}
ul.clean{list-style:none;margin:12px 0}
ul.clean li{padding-left:22px;position:relative;margin:8px 0;color:#d6e2f4;font-size:14.5px}
ul.clean li:before{content:"";position:absolute;left:0;top:9px;width:8px;height:8px;border-radius:3px;background:var(--gold)}

/* formula box */
.formula{background:linear-gradient(180deg,rgba(255,197,52,.09),rgba(255,197,52,.02));border:1px solid rgba(255,197,52,.28);border-radius:14px;padding:18px 20px;margin:18px 0;min-width:0}
.formula .cap{color:var(--gold);font-weight:800;font-size:12px;letter-spacing:1px;text-transform:uppercase;margin-bottom:10px}
.formula .big{text-align:center;font-size:19px;padding:6px 0;overflow-x:auto;overflow-y:hidden}
.note{background:var(--card2);border-left:3px solid var(--blue);border-radius:0 10px 10px 0;padding:12px 16px;margin:16px 0;font-size:14px;color:#cfe0f6;min-width:0;overflow-x:auto}
.trap{background:rgba(255,107,107,.07);border-left:3px solid var(--red);border-radius:0 10px 10px 0;padding:12px 16px;margin:14px 0;font-size:14px;color:#ffd9d9;min-width:0;overflow-x:auto}
.trap b,.note b{color:#fff}

/* concept cards */
.ccards{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin:18px 0}
@media(max-width:640px){.ccards{grid-template-columns:1fr}}
.ccard{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:18px;min-width:0}
.ccard h4{font-size:15.5px;font-weight:800;margin-bottom:4px}
.ccard p{font-size:13.5px;color:var(--mut);margin:6px 0}

/* tables */
.tbl{width:100%;border-collapse:collapse;margin:18px 0;font-size:13.5px;border-radius:12px;overflow:hidden}
.tbl th,.tbl td{padding:11px 13px;text-align:left;border-bottom:1px solid var(--line);vertical-align:top}
.tbl th{background:var(--navy3);color:#cfe;font-size:11.5px;text-transform:uppercase;letter-spacing:.4px}
.tbl td:first-child{font-weight:700;color:var(--gold);white-space:nowrap}
.tblwrap{overflow-x:auto;min-width:0}

/* worked example */
.wex{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:0;margin:18px 0;overflow:hidden;min-width:0}
.wex .whead{padding:16px 20px;display:flex;gap:12px;align-items:flex-start}
.wex .tagx{flex:0 0 auto;background:rgba(255,197,52,.16);color:var(--gold);font-weight:800;font-size:11px;padding:4px 10px;border-radius:20px;letter-spacing:.3px;margin-top:2px}
.wex .q{font-size:15px;color:#eef4ff;font-weight:500;min-width:0}
.wex .q .src{color:var(--mut);font-size:12px;font-weight:600;display:block;margin-top:4px}
.wex .reveal{width:100%;text-align:left;background:var(--navy3);color:var(--gold);border:0;border-top:1px solid var(--line);padding:13px 20px;font-family:inherit;font-weight:700;font-size:13.5px;cursor:pointer;display:flex;justify-content:space-between;align-items:center;gap:12px}
.wex .reveal:hover{background:#183262}
.wex .sol{display:none;padding:4px 20px 20px;border-top:1px solid var(--line);background:var(--card2)}
.wex .sol.show{display:block}
.wex .sol ol{margin:12px 0 0 18px}
.wex .sol li{margin:9px 0;font-size:14px;color:#d6e2f4;overflow-x:auto}
.wex .ans{margin-top:14px;background:rgba(63,209,139,.12);border:1px solid rgba(63,209,139,.3);border-radius:10px;padding:10px 14px;font-weight:700;color:var(--green);font-size:14.5px}

/* self-check quiz */
.quiz{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:20px;margin:16px 0;min-width:0}
.quiz .qh{font-weight:600;font-size:15px;margin-bottom:12px}
.quiz .qh .n{color:var(--gold);font-weight:800;margin-right:8px}
.opt{display:block;width:100%;text-align:left;background:var(--card2);border:1px solid var(--line);color:#e6eefb;border-radius:10px;padding:11px 14px;margin:8px 0;font-family:inherit;font-size:14px;cursor:pointer;transition:.15s}
.opt:hover{border-color:var(--mut)}
.opt.correct{background:rgba(63,209,139,.16);border-color:var(--green);color:#c9f7e0}
.opt.wrong{background:rgba(255,107,107,.14);border-color:var(--red);color:#ffd9d9}
.opt.dim{opacity:.5}
.qfb{display:none;margin-top:10px;font-size:13.5px;padding:11px 14px;border-radius:10px;background:var(--navy3);color:#cfe0f6;overflow-x:auto}
.qfb.show{display:block}
.qfb b{color:var(--gold)}

/* CTA band */
.ctaband{background:linear-gradient(120deg,var(--navy3),var(--card));border:1px solid var(--line);border-radius:18px;padding:26px;margin:26px 0;text-align:center}
.ctaband h3{font-size:20px;font-weight:800;margin-bottom:6px}
.ctaband p{color:var(--mut);font-size:14px;margin-bottom:16px}
.markbtn{background:transparent;border:1.5px solid var(--green);color:var(--green);font-weight:800;padding:9px 18px;border-radius:30px;font-size:13.5px;cursor:pointer;font-family:inherit}
.markbtn.done{background:var(--green);color:#06251a}

.pillrow{display:flex;gap:8px;flex-wrap:wrap;margin:10px 0}
.pillrow span{background:var(--card2);border:1px solid var(--line);border-radius:8px;padding:6px 11px;font-size:12.5px;color:#cfe0f6}
kbd{background:var(--navy3);border:1px solid var(--line);border-radius:5px;padding:1px 6px;font-family:inherit;font-size:.92em;color:#fff}
footer{padding:34px 0;text-align:center;color:var(--mut);font-size:13px}

/* KaTeX sizing + the critical mobile rule: long display equations scroll INSIDE their box */
.katex{font-size:1.04em}
.formula .katex{font-size:1.18em}
.tbl .katex{font-size:.96em}
.katex-display{overflow-x:auto;overflow-y:hidden;max-width:100%;padding:3px 0;margin:.5em 0}
.katex-display>.katex{white-space:nowrap}
.katex-display::-webkit-scrollbar{height:5px}
.katex-display::-webkit-scrollbar-thumb{background:rgba(255,255,255,.22);border-radius:3px}
@media(max-width:600px){
  .formula .big{font-size:15.5px}
  .formula .katex{font-size:1.02em}
  .content section{padding:20px 0 8px}
  .wex .whead{padding:14px 15px}
  .wex .reveal{padding:12px 15px}
  .wex .sol{padding:4px 15px 16px}
  .wex .sol ol{margin-left:14px}
  .quiz{padding:16px}
  .herostats{gap:18px}
}