:root{
  --ink:#1B2A4A; --ink-soft:#3A4A6B; --paper:#EDEEF2; --paper-card:#FFFFFF;
  --highlight:#FFC845; --redpen:#C0392B; --green-ok:#2F7D5C; --line:#D3D6DE;
  --shadow: 0 1px 0 rgba(27,42,74,0.06);
}
*{box-sizing:border-box;}
html{scroll-behavior:smooth;}
body{margin:0; background:var(--paper); color:var(--ink); font-family:'Inter',sans-serif; line-height:1.55;}
@media (prefers-reduced-motion: reduce){ *{animation:none !important; transition:none !important;} }
.wrap{max-width:1040px; margin:0 auto; padding:0 20px;}
a{color:inherit;}
.mono{font-family:'IBM Plex Mono',monospace;}

.topline{background:var(--ink); color:#fff; font-family:'IBM Plex Mono',monospace; font-size:12px; letter-spacing:0.04em; padding:9px 0; text-align:center;}
.topline .dot{color:var(--highlight); margin:0 6px;}

.sitenav{padding:16px 0; display:flex; justify-content:space-between; align-items:center; flex-wrap:wrap; gap:10px;}
.sitenav .logo{font-family:'Space Grotesk',sans-serif; font-weight:700; font-size:15px; text-decoration:none;}
.sitenav .links{display:flex; gap:18px; font-size:14px; font-weight:600;}
.sitenav .links a{text-decoration:none;}
.sitenav .links a:hover{text-decoration:underline;}

.breadcrumb{font-family:'IBM Plex Mono',monospace; font-size:12px; color:var(--ink-soft); padding:0 0 18px; display:flex; gap:6px; flex-wrap:wrap;}
.breadcrumb a{text-decoration:underline;}
.breadcrumb .sep{color:var(--line);}

.ticket{
  background:var(--paper-card); border:1.5px solid var(--ink); border-radius:10px;
  padding:24px 26px; box-shadow:0 4px 0 var(--ink); margin-bottom:26px;
}
.section-tag{display:inline-block; font-family:'Space Grotesk',sans-serif; font-weight:700; font-size:12px; background:var(--ink); color:#fff; padding:4px 10px; border-radius:5px; letter-spacing:0.03em; margin-bottom:10px;}
.page-title{font-family:'Space Grotesk',sans-serif; font-weight:700; font-size:clamp(24px,4vw,34px); margin:0 0 10px; line-height:1.15;}
.page-sub{color:var(--ink-soft); font-size:15px; margin:0 0 18px; max-width:560px;}

.btn{font-family:'Inter',sans-serif; font-weight:600; font-size:14.5px; padding:12px 20px; border-radius:7px; border:1.5px solid var(--ink); cursor:pointer; text-decoration:none; display:inline-flex; align-items:center; gap:8px;}
.btn-primary{background:var(--ink); color:#fff;} .btn-primary:hover{background:var(--ink-soft);}
.btn-ghost{background:transparent; color:var(--ink);} .btn-ghost:hover{background:rgba(27,42,74,0.06);}

.trust-strip{display:flex; flex-wrap:wrap; gap:10px 24px; padding-top:18px; margin-top:18px; border-top:1px solid var(--line);}
.trust-item{display:flex; align-items:center; gap:7px; font-size:12.5px; color:var(--ink-soft);}
.trust-item .check{width:15px; height:15px; border-radius:50%; background:var(--green-ok); color:#fff; font-size:9px; display:flex; align-items:center; justify-content:center; flex-shrink:0;}

.section-block{padding:34px 0;}
.section-head{display:flex; align-items:baseline; gap:14px; margin-bottom:6px;}
.section-title{font-family:'Space Grotesk',sans-serif; font-weight:600; font-size:22px; margin:0;}
.section-sub{color:var(--ink-soft); font-size:14.5px; margin:0 0 20px;}

.cards{display:grid; grid-template-columns:1fr 1fr; gap:12px;}
@media (max-width:640px){ .cards{grid-template-columns:1fr;} }
.card{
  background:var(--paper-card); border:1px solid var(--line); border-radius:8px;
  padding:16px 18px; display:flex; align-items:center; gap:14px; box-shadow:var(--shadow);
  text-decoration:none; transition:border-color .15s ease, transform .15s ease;
}
.card:hover{border-color:var(--ink); transform:translateY(-1px);}
.bubble{width:22px; height:22px; border-radius:50%; border:2px solid var(--ink); flex-shrink:0; position:relative;}
.bubble::after{content:""; position:absolute; inset:4px; border-radius:50%; background:var(--highlight); opacity:0;}
.card:hover .bubble::after{opacity:1;}
.card-text{flex:1; min-width:0;}
.card-name{font-weight:600; font-size:15px; margin:0 0 2px;}
.card-meta{font-family:'IBM Plex Mono',monospace; font-size:11.5px; color:var(--ink-soft); margin:0;}
.card-arrow{font-family:'IBM Plex Mono',monospace; font-size:13px; color:var(--ink-soft);}

/* ---------- Reading progress bar ---------- */
.progress-bar{
  position:fixed; top:0; left:0; height:3px; width:0%;
  background:var(--highlight); z-index:50; transition:width .1s linear;
}

/* ---------- Two-column page layout: content + sticky sidebar TOC ---------- */
.page-layout{display:block;}
@media (min-width:960px){
  .page-layout{
    display:grid;
    grid-template-columns: minmax(0,700px) 260px;
    gap:48px;
    align-items:start;
  }
}

/* ---------- Long-form content (cheat sheets, blog posts) ---------- */
.content{
  max-width:700px;
  font-size:16.5px;
  line-height:1.75;
  color:var(--ink);
  background:var(--paper-card);
  border:1px solid var(--line);
  border-radius:12px;
  padding:36px 40px;
  box-shadow:var(--shadow);
}
@media (max-width:640px){
  .content{padding:24px 20px; border-radius:10px;}
}
.content > *:first-child{margin-top:0;}
.content h2{
  font-family:'Space Grotesk',sans-serif;
  font-weight:700;
  font-size:23px;
  margin:44px 0 16px;
  scroll-margin-top:24px;
}
.content h3{
  font-family:'Space Grotesk',sans-serif;
  font-weight:600;
  font-size:18px;
  margin:30px 0 12px;
  scroll-margin-top:24px;
}
.content p{color:var(--ink-soft); font-size:16.5px; margin:0 0 18px;}
.content ul, .content ol{color:var(--ink-soft); font-size:16px; padding-left:22px; margin:0 0 20px;}
.content li{margin-bottom:9px; line-height:1.65;}
.content li > ul, .content li > ol{margin-top:9px;}
.content strong{color:var(--ink); font-weight:600;}
.content a{color:var(--ink); text-decoration-color:var(--line); text-underline-offset:3px;}
.content a:hover{text-decoration-color:var(--ink);}

/* Inline code */
.content :not(pre) > code{
  font-family:'IBM Plex Mono',monospace; font-size:0.88em; background:#F1F1F5;
  border:1px solid var(--line); border-radius:4px; padding:1.5px 6px; color:var(--ink);
}

/* Code blocks — dark, distinct from prose, horizontally scrollable, with copy button */
.content pre{
  position:relative;
  background:#152036;
  color:#E8ECF6;
  border-radius:8px;
  padding:18px 20px;
  margin:8px 0 22px;
  overflow-x:auto;
  -webkit-overflow-scrolling:touch;
  font-size:13.5px;
  line-height:1.6;
}
.content pre code{
  font-family:'IBM Plex Mono',monospace;
  background:none; border:none; padding:0; color:inherit;
  white-space:pre;
}
.code-copy-btn{
  position:absolute; top:10px; right:10px;
  background:rgba(255,255,255,0.08); color:#C7CEDD;
  border:1px solid rgba(255,255,255,0.15); border-radius:5px;
  font-family:'IBM Plex Mono',monospace; font-size:11px;
  padding:5px 9px; cursor:pointer;
}
.code-copy-btn:hover{background:rgba(255,255,255,0.16); color:#fff;}
.code-copy-btn.copied{background:var(--green-ok); color:#fff; border-color:var(--green-ok);}

/* Tables — docs style: horizontal rules only, no vertical grid, header underline stronger */
.content table{width:100%; border-collapse:collapse; margin:6px 0; font-size:14.5px;}
.content th, .content td{
  padding:12px 14px; text-align:left; vertical-align:top;
  border-bottom:1px solid var(--line);
}
.content th{
  font-family:'Space Grotesk',sans-serif; font-weight:600; font-size:12.5px;
  text-transform:uppercase; letter-spacing:0.03em; color:var(--ink-soft);
  border-bottom:2px solid var(--ink);
}
.content tbody tr:hover td{background:#F8F8FA;}
.content td code{white-space:nowrap;}
.table-wrap{overflow-x:auto; margin:14px 0; -webkit-overflow-scrolling:touch;}
.table-wrap table{margin:0;}

/* ---------- On-this-page navigation ---------- */
/* Mobile: collapsible, shown above content */
.toc-mobile{
  background:var(--paper-card); border:1px solid var(--line); border-radius:8px;
  margin-bottom:28px;
}
.toc-mobile summary{
  cursor:pointer; list-style:none; padding:13px 16px;
  font-family:'Space Grotesk',sans-serif; font-weight:600; font-size:14px;
  display:flex; align-items:center; justify-content:space-between;
}
.toc-mobile summary::-webkit-details-marker{display:none;}
.toc-mobile summary::after{content:"▾"; font-size:12px; color:var(--ink-soft); transition:transform .15s ease;}
.toc-mobile[open] summary::after{transform:rotate(180deg);}
@media (min-width:960px){ .toc-mobile{display:none;} }

/* Desktop: sticky sidebar */
.toc-desktop{display:none;}
@media (min-width:960px){
  .toc-desktop{
    display:block; position:sticky; top:20px;
    max-height:calc(100vh - 40px); overflow-y:auto;
  }
}
.toc-label{
  font-family:'IBM Plex Mono',monospace; font-size:11px; letter-spacing:0.06em;
  text-transform:uppercase; color:var(--ink-soft); margin:0 0 10px;
}
.toc-list{list-style:none; margin:0; padding:0; display:grid; gap:1px;}
.toc-mobile .toc-list{padding:0 12px 14px;}
.toc-list a{
  display:block; padding:7px 10px; border-radius:6px; font-size:13.5px;
  color:var(--ink-soft); text-decoration:none; border-left:2px solid transparent;
}
.toc-desktop .toc-list a{padding-left:12px;}
.toc-list a:hover{background:var(--paper); color:var(--ink);}
.toc-list a.active{color:var(--ink); font-weight:600; border-left-color:var(--ink); background:var(--paper);}

/* ---------- Back to top ---------- */
.back-to-top{
  position:fixed; bottom:20px; right:20px; z-index:20;
  background:var(--ink); color:#fff; border:none; border-radius:50%;
  width:44px; height:44px; font-size:18px; cursor:pointer;
  display:none; align-items:center; justify-content:center;
  box-shadow:0 3px 10px rgba(27,42,74,0.25);
}
.back-to-top.visible{display:flex;}
@media (max-width:640px){
  .back-to-top{bottom:16px; right:16px; width:40px; height:40px;}
}

/* ---------- PYQ (practice question) callout ---------- */
.pyq{
  background:var(--paper);
  border:1px solid var(--line);
  border-left:3px solid var(--ink);
  border-radius:8px;
  padding:16px 18px;
  margin:20px 0 26px;
}
.pyq-label{
  font-family:'IBM Plex Mono',monospace; font-size:10.5px; letter-spacing:0.06em;
  text-transform:uppercase; color:var(--redpen); margin:0 0 8px; font-weight:600;
}
.pyq-q{font-weight:600; font-size:15.5px; margin:0 0 10px; color:var(--ink);}
.pyq-options{list-style:none; margin:0 0 12px; padding:0; display:grid; gap:5px;}
.pyq-options li{
  font-size:14.5px; color:var(--ink-soft); padding:6px 10px;
  border-radius:5px; border:1px solid transparent;
}
.pyq-options li.correct{
  background:#E8F3EE; border-color:var(--green-ok); color:var(--ink); font-weight:600;
}
.pyq-explain{
  font-size:14px; color:var(--ink-soft); margin:0; padding-top:10px;
  border-top:1px dashed var(--line);
}
.pyq-explain strong{color:var(--ink);}

/* ---------- Flashcards ---------- */
.flashcard-app{max-width:520px; margin:0 auto;}
.flashcard-progress{
  font-family:'IBM Plex Mono',monospace; font-size:12px; color:var(--ink-soft);
  text-align:center; margin-bottom:14px;
}
.flashcard{
  perspective:1200px; height:260px; cursor:pointer; margin-bottom:18px; user-select:none;
}
.flashcard-inner{
  position:relative; width:100%; height:100%;
  transition:transform .45s ease; transform-style:preserve-3d;
}
.flashcard.flipped .flashcard-inner{transform:rotateY(180deg);}
.flashcard-face{
  position:absolute; inset:0; backface-visibility:hidden;
  border-radius:12px; border:1.5px solid var(--ink);
  display:flex; align-items:center; justify-content:center; text-align:center;
  padding:28px; background:var(--paper-card); box-shadow:0 4px 0 var(--ink);
}
.flashcard-face.back{
  transform:rotateY(180deg); background:var(--ink); color:#fff; border-color:var(--ink);
  box-shadow:0 4px 0 var(--ink-soft);
}
.flashcard-tag{
  position:absolute; top:14px; left:16px;
  font-family:'IBM Plex Mono',monospace; font-size:10px; letter-spacing:0.06em;
  text-transform:uppercase; color:var(--ink-soft);
}
.flashcard-face.back .flashcard-tag{color:#C7CEDD;}
.flashcard-text{font-family:'Space Grotesk',sans-serif; font-weight:600; font-size:18px; line-height:1.4;}
.flashcard-controls{display:flex; justify-content:space-between; align-items:center; gap:10px;}
.flashcard-controls .btn{padding:10px 16px; font-size:13.5px;}
.flashcard-hint{text-align:center; font-size:12px; color:var(--ink-soft); margin-top:10px;}
@media (max-width:480px){
  .flashcard{height:220px;}
  .flashcard-text{font-size:16px;}
}

/* ---------- Practice cross-links (cheat sheet → flashcards/MCQs) ---------- */
.practice-links{
  display:flex; align-items:center; gap:10px; flex-wrap:wrap;
  padding-top:16px; margin-top:16px; border-top:1px solid var(--line);
}
.practice-label{
  font-family:'IBM Plex Mono',monospace; font-size:11px; letter-spacing:0.04em;
  text-transform:uppercase; color:var(--ink-soft); margin-right:2px;
}
.practice-link{
  font-family:'Inter',sans-serif; font-weight:600; font-size:13px;
  border:1.5px solid var(--ink); border-radius:20px; padding:6px 14px;
  text-decoration:none; color:var(--ink);
}
.practice-link:hover{background:var(--ink); color:#fff;}

/* Reverse direction: flashcard/MCQ page → linking back to the cheat sheet */
.study-first{
  font-size:13.5px; color:var(--ink-soft); text-align:center;
  margin:-8px 0 24px;
}
.study-first a{color:var(--ink); font-weight:600; text-decoration:underline;}

/* ---------- Ad slots — hidden for now, remove this rule to re-enable ---------- */
.ad-slot{display:none;}

/* ---------- MCQ widget ---------- */
.mcq-app{background:var(--paper-card); border:1px solid var(--line); border-radius:10px; padding:22px 24px; box-shadow:var(--shadow);}
.mcq-progress{font-family:'IBM Plex Mono',monospace; font-size:12px; color:var(--ink-soft); margin-bottom:14px;}
.mcq-question{font-family:'Space Grotesk',sans-serif; font-weight:600; font-size:17px; margin:0 0 16px;}
.mcq-options{display:grid; gap:9px; margin-bottom:16px;}
.mcq-option{
  text-align:left; background:var(--paper); border:1.5px solid var(--line); border-radius:7px;
  padding:11px 14px; font-size:14.5px; cursor:pointer; font-family:'Inter',sans-serif;
}
.mcq-option:hover{border-color:var(--ink);}
.mcq-option.correct{border-color:var(--green-ok); background:#E8F3EE;}
.mcq-option.incorrect{border-color:var(--redpen); background:#FBEAE8;}
.mcq-option:disabled{cursor:default;}
.mcq-footer{display:flex; justify-content:space-between; align-items:center;}
.mcq-score{font-family:'IBM Plex Mono',monospace; font-size:13px; color:var(--ink-soft);}
.mcq-summary{text-align:center; padding:20px 0;}
.mcq-summary .big{font-family:'Space Grotesk',sans-serif; font-weight:700; font-size:32px; margin:0 0 6px;}

.related{padding:30px 0;}
.related h2{font-family:'Space Grotesk',sans-serif; font-size:17px; margin:0 0 14px;}
.related-list{display:grid; gap:10px;}

.blog-card{display:block; background:var(--paper-card); border:1px solid var(--line); border-radius:8px; padding:16px 18px; text-decoration:none; box-shadow:var(--shadow); margin-bottom:12px;}
.blog-card:hover{border-color:var(--ink);}
.blog-card .cat{font-family:'IBM Plex Mono',monospace; font-size:11px; color:var(--redpen); text-transform:uppercase; letter-spacing:0.04em;}
.blog-card .title{font-family:'Space Grotesk',sans-serif; font-weight:600; font-size:16.5px; margin:4px 0;}
.blog-card .meta{font-family:'IBM Plex Mono',monospace; font-size:12px; color:var(--ink-soft);}

footer{margin-top:40px; border-top:1px solid var(--line);}
.footer-grid{
  padding:36px 0 24px; display:grid; gap:28px;
  grid-template-columns:1.2fr 0.8fr 0.8fr 0.8fr;
}
@media (max-width:800px){
  .footer-grid{grid-template-columns:1fr 1fr;}
}
@media (max-width:640px){
  .footer-grid{grid-template-columns:1fr; padding:28px 0 16px;}
}
.footer-logo{font-family:'Space Grotesk',sans-serif; font-weight:700; font-size:15px; margin:0 0 8px;}
.footer-tag{color:var(--ink-soft); font-size:13.5px; margin:0; max-width:320px; line-height:1.6;}
.footer-heading{
  font-family:'IBM Plex Mono',monospace; font-size:11px; letter-spacing:0.06em;
  text-transform:uppercase; color:var(--ink-soft); margin:0 0 12px;
}
.footer-links ul{list-style:none; margin:0; padding:0; display:grid; gap:9px;}
.footer-links a{font-size:14px; text-decoration:none; color:var(--ink);}
.footer-links a:hover{text-decoration:underline;}
.footer-bottom{
  padding:16px 0 32px; border-top:1px solid var(--line);
  font-size:12.5px; color:var(--ink-soft);
}