:root{
  --paper:#FAF5EC; --ink:#141414; --ink-soft:#3d3a34;
  --mint:#CDEFF0; --peach:#FFE0CC; --lav:#E9D8FD; --butter:#FCF3B8; --sky:#CDE9FF; --rose:#FFD9E4; --leaf:#D9F2D0; --sand:#F4E3C9;
  --ok:#1d7a3d; --bad:#b3261e; --warn:#8a6d00;
  --radius:16px; --border:2.5px solid var(--ink); --shadow:5px 5px 0 var(--ink);
  --mono:'JetBrains Mono',ui-monospace,Menlo,Consolas,monospace;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--paper);color:var(--ink);font-family:'Archivo',system-ui,-apple-system,Segoe UI,Roboto,sans-serif;line-height:1.55;font-size:16px}
h1,h2,h3,h4{font-weight:900;letter-spacing:-.01em;line-height:1.15;margin:.2em 0 .45em}
h1{font-size:clamp(1.7rem,5.4vw,2.5rem)} h2{font-size:clamp(1.3rem,4vw,1.7rem)} h3{font-size:1.12rem}
a{color:inherit}
code,pre,.mono{font-family:var(--mono);font-size:.92em}
.container{max-width:1060px;margin:0 auto;padding:0 16px 96px}
.boot{min-height:70vh;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:14px;font-weight:800}
.boot-stamp{width:72px;height:72px;border:4px solid var(--ink);border-radius:16px;background:var(--butter);display:grid;place-items:center;font-size:34px;font-weight:900;transform:rotate(-6deg);box-shadow:var(--shadow)}
/* top bar */
.topbar{position:sticky;top:0;z-index:40;background:var(--paper);border-bottom:var(--border);padding:10px 16px;display:flex;align-items:center;gap:12px;flex-wrap:wrap}
.brand{display:flex;align-items:center;gap:10px;font-weight:900;font-size:1.15rem;text-decoration:none}
.brand .mark{width:38px;height:38px;border:var(--border);border-radius:10px;background:var(--butter);display:grid;place-items:center;font-weight:900;transform:rotate(-6deg);box-shadow:3px 3px 0 var(--ink)}
.brand small{display:block;font-size:.62rem;font-weight:800;letter-spacing:.14em;text-transform:uppercase;color:var(--ink-soft)}
.topbar .spacer{flex:1}
.pillbtn{border:var(--border);background:#fff;border-radius:999px;padding:7px 14px;font-weight:800;font-family:inherit;font-size:.85rem;cursor:pointer;box-shadow:3px 3px 0 var(--ink);transition:transform .06s,box-shadow .06s;text-decoration:none;display:inline-block}
.pillbtn:active{transform:translate(2px,2px);box-shadow:1px 1px 0 var(--ink)}
.pillbtn.on{background:var(--ink);color:var(--butter)}
/* cards */
.grid{display:grid;gap:16px;grid-template-columns:1fr}
@media(min-width:720px){.grid.cols2{grid-template-columns:1fr 1fr}.grid.cols3{grid-template-columns:1fr 1fr 1fr}}
.card{border:var(--border);border-radius:var(--radius);background:#fff;padding:18px;box-shadow:var(--shadow);position:relative}
.card h3{margin-top:0}
.card.mint{background:var(--mint)} .card.peach{background:var(--peach)} .card.lav{background:var(--lav)} .card.butter{background:var(--butter)} .card.sky{background:var(--sky)} .card.rose{background:var(--rose)} .card.leaf{background:var(--leaf)} .card.sand{background:var(--sand)}
.trackcard{display:block;text-decoration:none;color:inherit}
.trackcard .num{font-size:.7rem;font-weight:900;letter-spacing:.12em;text-transform:uppercase;opacity:.7}
.trackcard .go{font-weight:900;margin-top:8px}
/* badges & status */
.badge{display:inline-block;border:2px solid var(--ink);border-radius:999px;padding:2px 10px;font-size:.68rem;font-weight:900;letter-spacing:.06em;text-transform:uppercase;background:#fff}
.badge.working{background:var(--leaf)} .badge.building{background:var(--butter)} .badge.planned{background:#eee}
.badge.done{background:var(--ink);color:var(--leaf)}
.stamp{display:inline-block;border:3px double var(--ok);color:var(--ok);border-radius:8px;padding:3px 12px;font-weight:900;letter-spacing:.18em;transform:rotate(-4deg);text-transform:uppercase}
/* progress */
.meter{height:14px;border:2px solid var(--ink);border-radius:99px;background:#fff;overflow:hidden}
.meter>div{height:100%;background:var(--ink);transition:width .3s}
.small{font-size:.85rem;color:var(--ink-soft)}
/* lesson body */
.lesson-body{background:#fff;border:var(--border);border-radius:var(--radius);padding:20px;box-shadow:var(--shadow);margin-bottom:18px}
.lesson-body h2:first-child{margin-top:0}
.lesson-body pre{background:#1e1c18;color:#f4eee2;border-radius:10px;padding:14px;overflow-x:auto;border:2px solid var(--ink)}
.lesson-body code{background:#efe9dc;border-radius:5px;padding:1px 5px}
.lesson-body pre code{background:none;padding:0}
.lesson-body table{border-collapse:collapse;width:100%;font-size:.9rem}
.lesson-body th,.lesson-body td{border:2px solid var(--ink);padding:6px 9px;text-align:left}
.lesson-body th{background:var(--butter)}
.callout{border:2.5px solid var(--ink);border-radius:12px;padding:12px 14px;margin:12px 0;font-weight:600}
.callout.warn{background:var(--butter)} .callout.risk{background:var(--rose)} .callout.good{background:var(--leaf)} .callout.info{background:var(--sky)}
/* quiz */
.opt{display:block;width:100%;text-align:left;border:var(--border);background:#fff;border-radius:12px;padding:12px 14px;margin:8px 0;font-family:inherit;font-size:.95rem;font-weight:600;cursor:pointer;box-shadow:3px 3px 0 var(--ink)}
.opt:active{transform:translate(2px,2px);box-shadow:1px 1px 0 var(--ink)}
.opt.correct{background:var(--leaf)} .opt.wrong{background:var(--rose)} .opt:disabled{cursor:default}
.explain{border-left:5px solid var(--ink);background:#fff;padding:10px 14px;margin:8px 0;border-radius:0 10px 10px 0}
/* editor */
.editor{width:100%;min-height:170px;font-family:var(--mono);font-size:.88rem;line-height:1.5;border:var(--border);border-radius:12px;padding:12px;background:#1e1c18;color:#f4eee2;tab-size:4;resize:vertical}
.editor.sql{background:#101d2b}
.btnrow{display:flex;gap:10px;flex-wrap:wrap;margin:12px 0}
.bigbtn{border:var(--border);border-radius:12px;background:var(--butter);padding:11px 20px;font-family:inherit;font-weight:900;font-size:.95rem;cursor:pointer;box-shadow:4px 4px 0 var(--ink)}
.bigbtn:active{transform:translate(2px,2px);box-shadow:1px 1px 0 var(--ink)}
.bigbtn.primary{background:var(--mint)} .bigbtn.ghost{background:#fff}
.bigbtn:disabled{opacity:.55;cursor:wait}
.testcase{border:2px solid var(--ink);border-radius:10px;padding:9px 12px;margin:7px 0;font-size:.86rem;background:#fff}
.testcase.pass{background:var(--leaf)} .testcase.fail{background:var(--rose)}
.resultwrap{border:var(--border);border-radius:12px;overflow:auto;background:#fff;max-height:340px;margin-top:10px}
table.result{border-collapse:collapse;width:100%;font-size:.8rem;font-family:var(--mono)}
table.result th,table.result td{border:1.5px solid var(--ink);padding:4px 8px;white-space:nowrap}
table.result th{background:var(--sky);position:sticky;top:0}
.hint{border:2px dashed var(--ink);border-radius:10px;padding:10px 13px;margin:8px 0;background:#fff;font-size:.9rem}
details.schemabox{border:var(--border);border-radius:12px;background:#fff;padding:10px 14px;margin:10px 0}
details.schemabox summary{font-weight:900;cursor:pointer}
.runtime-note{font-size:.8rem;font-weight:700;background:var(--lav);border:2px solid var(--ink);border-radius:10px;padding:8px 12px;margin:8px 0}
/* nav / lists */
.lessonrow{display:flex;align-items:center;gap:12px;border:var(--border);border-radius:12px;background:#fff;padding:11px 14px;margin:9px 0;text-decoration:none;color:inherit;box-shadow:3px 3px 0 var(--ink)}
.lessonrow .dot{width:26px;height:26px;min-width:26px;border:2.5px solid var(--ink);border-radius:50%;display:grid;place-items:center;font-weight:900;font-size:.75rem;background:#fff}
.lessonrow .dot.ok{background:var(--ink);color:var(--leaf)}
.lessonrow .t{flex:1;font-weight:800}
.crumbs{font-size:.82rem;font-weight:800;margin:14px 0}
.crumbs a{text-decoration:none;border-bottom:2px solid var(--ink)}
/* confirm card */
.overlay{position:fixed;inset:0;background:rgba(20,20,20,.45);display:grid;place-items:center;z-index:90;padding:20px}
.confirmbox{background:var(--paper);border:3px solid var(--ink);border-radius:16px;box-shadow:7px 7px 0 var(--ink);max-width:420px;width:100%;padding:22px}
.confirmbox .btnrow{justify-content:flex-end}
/* defense */
textarea.defense{width:100%;min-height:110px;border:var(--border);border-radius:12px;padding:12px;font-family:inherit;font-size:.92rem;background:#fff;resize:vertical}
.checkline{display:flex;gap:10px;align-items:flex-start;margin:8px 0;font-size:.92rem;font-weight:600}
.checkline input{margin-top:4px;transform:scale(1.3)}
.sectionhead{display:flex;align-items:center;gap:10px;flex-wrap:wrap;margin:26px 0 10px}
.sectionhead .rule{flex:1;height:3px;background:var(--ink);border-radius:2px;min-width:40px}
.toc-chips{display:flex;gap:8px;flex-wrap:wrap;margin:10px 0 18px}
.chip{border:2px solid var(--ink);border-radius:999px;padding:4px 12px;font-size:.75rem;font-weight:900;text-decoration:none;background:#fff}
.footer{margin-top:44px;border-top:var(--border);padding-top:18px;font-size:.8rem;color:var(--ink-soft)}
/* keep scrolled content clear of the 112px sticky topbar */
.card, details.schemabox, .sectionhead, .lesson-body, [data-scroll]{scroll-margin-top:130px}
@media(max-width:520px){
 body{font-size:15px}
 .card{padding:14px}
 .topbar{gap:8px;position:static} /* no sticky overlap on phones */
 .bigbtn{padding:10px 14px}
 .lessonrow{flex-wrap:wrap;row-gap:6px}
 .lessonrow .t{flex:1 1 calc(100% - 40px)}
 .hero-compact{padding:14px}
}

details.rubric{margin:14px 0}
details.rubric summary{font-weight:900;cursor:pointer;font-size:1.02rem}
details.rubric .lesson-body{margin-top:10px}