/* ==========================================================================
   LearnAI — deep-dive lesson design system
   Matched to learn.millionroots.com (Cohort): warm off-white paper,
   Inter, big bold grotesk headlines, blue eyebrows, rounded cards,
   dark code blocks, black pill buttons.
   ========================================================================== */

:root{
  --paper:#fbf9f5;         /* page background */
  --paper-2:#fffdf9;       /* raised white card */
  --ink:#1c2230;           /* primary text */
  --ink-soft:#454d5e;      /* body text */
  --muted:#6b7280;         /* secondary text */
  --line:#e7e2d8;          /* hairline borders */
  --line-2:#efeae0;        /* faint dividers */

  --blue:#2f72c0;          /* accent / eyebrow */
  --blue-ink:#1f5aa0;      /* accent text on light */
  --blue-soft:#e6f0fa;     /* light blue fill */
  --blue-border:#afd4ea;   /* light blue border */

  --mint-bg:#e1f5ec;
  --mint-border:#37b78a;
  --mint-text:#1e6b4e;
  --amber-border:#e0c36a;
  --amber-bg:#fdf6e3;

  --code-bg:#0b121a;
  --code-line:#212a33;
  --code-text:#d8e7f0;
  --code-dim:#8695a3;
  --tok-kw:#dc9beb;
  --tok-fn:#dcba5c;
  --tok-num:#62d0a4;
  --tok-str:#9ad4a0;
  --tok-com:#6c7a89;
  --out-text:#a6e0c6;

  --black:#14181f;
  --shadow:0 1px 2px rgba(20,24,31,.04), 0 8px 30px rgba(20,24,31,.06);
  --radius:18px;
  --maxw:760px;
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  font-family:"Inter",ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  color:var(--ink);
  background:
    radial-gradient(1200px 480px at 15% -8%, #eef3fb 0, transparent 60%),
    radial-gradient(1000px 420px at 92% 4%, #fdeede 0, transparent 55%),
    var(--paper);
  line-height:1.65;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
a{color:var(--blue-ink);text-decoration:none}
a:hover{text-decoration:underline}

/* ---------- top bar ---------- */
.topbar{
  position:sticky;top:0;z-index:20;
  backdrop-filter:saturate(1.1) blur(8px);
  background:rgba(251,249,245,.82);
  border-bottom:1px solid var(--line);
}
.topbar .inner{
  max-width:var(--maxw);margin:0 auto;padding:12px 22px;
  display:flex;align-items:center;justify-content:space-between;gap:12px;
}
.brand{display:flex;align-items:center;gap:10px;font-weight:800;color:var(--ink);letter-spacing:-.01em}
.brand:hover{text-decoration:none}
.brand .glyph{
  width:30px;height:30px;border-radius:9px;background:var(--black);color:#fff;
  display:grid;place-items:center;font-size:15px;font-weight:800;
}
.brand small{display:block;font-weight:500;font-size:11px;color:var(--muted);letter-spacing:0}
.topbar .back{
  font-size:13px;font-weight:700;color:var(--ink-soft);
  border:1px solid var(--line);border-radius:999px;padding:7px 14px;background:var(--paper-2);
}
.topbar .back:hover{text-decoration:none;border-color:var(--blue-border);color:var(--blue-ink)}

/* ---------- layout ---------- */
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 22px 100px}
.hero{padding:52px 0 8px}
.eyebrow{
  display:inline-block;font-size:12px;font-weight:800;letter-spacing:.12em;
  text-transform:uppercase;color:var(--blue);margin:0 0 14px;
}
h1{
  font-size:clamp(30px,5.2vw,46px);line-height:1.06;font-weight:800;
  letter-spacing:-.025em;margin:0 0 16px;color:var(--ink);
}
.lead{font-size:clamp(17px,2.3vw,20px);color:var(--ink-soft);margin:0 0 8px;line-height:1.55}

h2{
  font-size:clamp(23px,3.4vw,29px);line-height:1.15;font-weight:800;
  letter-spacing:-.02em;margin:52px 0 4px;color:var(--ink);scroll-margin-top:80px;
}
.section-kicker{font-size:12px;font-weight:800;letter-spacing:.1em;text-transform:uppercase;color:var(--blue);margin:0 0 -2px}
h3{font-size:19px;font-weight:800;letter-spacing:-.01em;margin:30px 0 6px;color:var(--ink)}
p{margin:14px 0;color:var(--ink-soft)}
strong{color:var(--ink);font-weight:700}
em{font-style:italic}
ul,ol{margin:14px 0;padding-left:22px;color:var(--ink-soft)}
li{margin:7px 0}
li::marker{color:var(--blue)}
hr{border:0;border-top:1px solid var(--line-2);margin:40px 0}

.section-intro{font-size:17px;color:var(--ink-soft)}

/* ---------- objective / learning-goal card ---------- */
.objective{
  background:var(--blue-soft);border:1px solid var(--blue-border);
  border-radius:var(--radius);padding:22px 24px;margin:26px 0;
}
.objective .label{font-size:12px;font-weight:800;letter-spacing:.1em;text-transform:uppercase;color:var(--blue-ink);margin:0 0 8px}
.objective h3,.objective h2{margin:0 0 10px}
.objective ul{margin:8px 0 0;padding-left:20px}
.objective li{color:var(--ink)}

/* ---------- analogy / note callouts ---------- */
.callout{
  border-radius:14px;padding:16px 18px;margin:22px 0;border:1px solid var(--line);
  background:var(--paper-2);box-shadow:var(--shadow);
}
.callout .tag{display:flex;align-items:center;gap:8px;font-weight:800;font-size:13.5px;color:var(--ink);margin:0 0 4px}
.callout .em{font-size:18px;line-height:1}
.callout p{margin:4px 0 0;font-size:15px}
.callout.analogy{background:var(--amber-bg);border-color:var(--amber-border)}
.callout.analogy .tag{color:#8a6d1f}
.callout.warn{background:#fdeeee;border-color:#e6b3b3}
.callout.warn .tag{color:#a23b3b}
.callout.key{background:var(--mint-bg);border-color:var(--mint-border)}
.callout.key .tag{color:var(--mint-text)}

/* ---------- code card ---------- */
.code{
  background:var(--code-bg);border:1px solid var(--code-line);border-radius:var(--radius);
  padding:0;margin:24px 0;overflow:hidden;
}
.code .bar{
  display:flex;align-items:center;gap:7px;padding:11px 16px;border-bottom:1px solid var(--code-line);
}
.code .bar .dot{width:11px;height:11px;border-radius:50%;background:#33404d}
.code .bar .name{margin-left:8px;font-size:12px;color:var(--code-dim);font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace}
.code pre{
  margin:0;padding:18px 20px;overflow-x:auto;
  font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;
  font-size:13.5px;line-height:1.7;color:var(--code-text);
}
.code .kw{color:var(--tok-kw)}
.code .fn{color:var(--tok-fn)}
.code .num{color:var(--tok-num)}
.code .str{color:var(--tok-str)}
.code .com{color:var(--tok-com)}
.output{
  margin:16px 20px 20px;background:var(--code-line);color:var(--out-text);
  border-radius:12px;padding:11px 14px;font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;font-size:13px;
}
.output .lbl{display:block;color:var(--code-dim);font-size:10.5px;letter-spacing:.1em;text-transform:uppercase;margin-bottom:5px}

/* comparison / example chips */
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin:22px 0}
.tile{background:var(--paper-2);border:1px solid var(--line);border-radius:14px;padding:16px 18px;box-shadow:var(--shadow)}
.tile h4{margin:0 0 6px;font-size:15px;font-weight:800;color:var(--ink)}
.tile p{margin:0;font-size:14px}
.tile .pill{display:inline-block;font-size:11px;font-weight:700;padding:3px 9px;border-radius:999px;margin-bottom:8px}
.pill.good{background:var(--mint-bg);color:var(--mint-text);border:1px solid var(--mint-border)}
.pill.bad{background:#fdeeee;color:#a23b3b;border:1px solid #e6b3b3}
.pill.info{background:var(--blue-soft);color:var(--blue-ink);border:1px solid var(--blue-border)}

/* ---------- checkpoint quiz ---------- */
.checkpoint{
  background:var(--paper-2);border:1px solid var(--line);border-radius:var(--radius);
  padding:22px 24px;margin:30px 0;box-shadow:var(--shadow);
}
.checkpoint .label{font-size:12px;font-weight:800;letter-spacing:.1em;text-transform:uppercase;color:var(--blue);margin:0 0 10px}
.checkpoint .q{font-weight:800;font-size:16px;color:var(--ink);margin:0 0 14px}
.answers{display:flex;flex-wrap:wrap;gap:9px}
.answer{
  font-size:13.5px;font-weight:700;padding:9px 14px;border-radius:999px;cursor:pointer;
  background:var(--paper);color:var(--ink);border:1px solid var(--amber-border);transition:.15s;
}
.answer:hover{border-color:var(--blue);background:var(--blue-soft)}
.answer.correct.reveal{background:var(--mint-bg);color:var(--mint-text);border-color:var(--mint-border)}
.answer.wrong.reveal{opacity:.5}
.explain{display:none;margin:14px 0 0;font-size:14.5px;color:var(--ink-soft);border-top:1px dashed var(--line);padding-top:12px}
.explain.show{display:block}

/* ---------- project / try-it ---------- */
.project{
  background:linear-gradient(180deg,#fffdf9,#fbf6ec);
  border:1px solid var(--amber-border);border-radius:var(--radius);
  padding:24px 26px;margin:34px 0;box-shadow:var(--shadow);
}
.project .label{font-size:12px;font-weight:800;letter-spacing:.1em;text-transform:uppercase;color:#8a6d1f;margin:0 0 8px}
.project h3{margin:0 0 8px}
.project ol{margin:10px 0 0;padding-left:20px}
.project li{color:var(--ink)}

/* ---------- buttons ---------- */
.btn{
  display:inline-flex;align-items:center;gap:8px;font-weight:800;font-size:15px;
  background:var(--black);color:#fff;border:none;border-radius:999px;padding:13px 22px;cursor:pointer;
  box-shadow:0 6px 18px rgba(20,24,31,.18);
}
.btn:hover{text-decoration:none;transform:translateY(-1px)}
.btn.ghost{background:transparent;color:var(--ink);border:1px solid var(--line);box-shadow:none}
.btn.ghost:hover{border-color:var(--blue-border);color:var(--blue-ink)}

/* ---------- prev / next footer nav ---------- */
.lessonnav{
  display:grid;grid-template-columns:1fr 1fr;gap:14px;margin:56px 0 0;
  border-top:1px solid var(--line);padding-top:28px;
}
.lessonnav a{
  display:block;padding:16px 18px;border:1px solid var(--line);border-radius:14px;
  background:var(--paper-2);box-shadow:var(--shadow);
}
.lessonnav a:hover{text-decoration:none;border-color:var(--blue-border)}
.lessonnav .dir{font-size:11px;font-weight:800;letter-spacing:.1em;text-transform:uppercase;color:var(--muted)}
.lessonnav .ttl{display:block;font-weight:800;color:var(--ink);margin-top:3px;letter-spacing:-.01em}
.lessonnav a.next{text-align:right}
.lessonnav a.disabled{opacity:.4;pointer-events:none}

/* progress dots */
.progress{display:flex;align-items:center;gap:6px;margin:2px 0 30px;flex-wrap:wrap}
.progress .d{width:9px;height:9px;border-radius:50%;background:var(--line);border:1px solid #ddd6c8}
.progress .d.done{background:var(--blue-border);border-color:var(--blue)}
.progress .d.here{background:var(--blue);border-color:var(--blue);box-shadow:0 0 0 4px var(--blue-soft)}
.progress .lbl{font-size:12px;color:var(--muted);margin-left:6px;font-weight:600}

/* footer */
.foot{max-width:var(--maxw);margin:0 auto;padding:36px 22px 10px;color:var(--muted);font-size:13px;border-top:1px solid var(--line-2)}
.foot a{color:var(--blue-ink)}

/* ---------- mobile ---------- */
@media (max-width:640px){
  .grid2{grid-template-columns:1fr}
  .lessonnav{grid-template-columns:1fr}
  .lessonnav a.next{text-align:left}
  .hero{padding:36px 0 4px}
}