/* ============ Reset + Tokens ============ */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
:root{
  --bg:#070912;
  --bg-grad:radial-gradient(ellipse 80% 60% at 20% 0%,rgba(122,162,255,.12),transparent 60%),
            radial-gradient(ellipse 70% 50% at 80% 30%,rgba(157,122,255,.10),transparent 60%),
            radial-gradient(ellipse 60% 80% at 50% 100%,rgba(94,194,255,.08),transparent 60%),
            #070912;
  --panel:rgba(20,26,42,.6);
  --panel-2:rgba(28,36,56,.7);
  --panel-solid:#141a2a;
  --border:rgba(80,100,140,.25);
  --border-strong:rgba(122,162,255,.4);
  --ink:#eef2fa;
  --muted:#a3b0c7;
  --dim:#7884a0;
  --accent:#7aa2ff;
  --accent2:#9d7aff;
  --accent3:#5ec2ff;
  --gold:#ffd166;
  --ok:#3ecf8e;
  --warn:#ffb547;
  --err:#ff6b6b;
  --grad-primary:linear-gradient(135deg,#7aa2ff 0%,#9d7aff 50%,#ff7ad4 100%);
  --grad-text:linear-gradient(135deg,#7aa2ff 0%,#9d7aff 40%,#ffd166 100%);
  --grad-fire:linear-gradient(135deg,#ff7a59 0%,#ffd166 100%);
  --rad:14px; --rad-sm:8px; --rad-lg:22px;
  --shadow-sm:0 1px 2px rgba(0,0,0,.2),0 2px 6px rgba(0,0,0,.15);
  --shadow-md:0 6px 16px rgba(0,0,0,.3),0 2px 6px rgba(0,0,0,.2);
  --shadow-lg:0 24px 48px rgba(0,0,0,.45),0 8px 16px rgba(0,0,0,.25);
  --shadow-glow:0 0 0 1px rgba(122,162,255,.25),0 12px 40px rgba(122,162,255,.18);
  --t-fast:.18s; --t-base:.28s; --t-slow:.55s;
  --ease:cubic-bezier(.4,0,.2,1);
  --ease-out:cubic-bezier(.16,1,.3,1);
}
html{scroll-behavior:smooth;scroll-padding-top:72px}
/* Light mode overrides */
body.theme-light{
  --bg:#f7f8fb;
  --bg-grad:radial-gradient(ellipse 80% 60% at 20% 0%,rgba(122,162,255,.18),transparent 60%),
            radial-gradient(ellipse 70% 50% at 80% 30%,rgba(157,122,255,.14),transparent 60%),
            radial-gradient(ellipse 60% 80% at 50% 100%,rgba(94,194,255,.12),transparent 60%),
            #f4f6fb;
  --panel:rgba(255,255,255,.85);
  --panel-2:rgba(255,255,255,.95);
  --panel-solid:#ffffff;
  --border:rgba(60,72,100,.18);
  --border-strong:rgba(122,162,255,.55);
  --ink:#0e1422;
  --muted:#4a5878;
  --dim:#7884a0;
  --shadow-sm:0 1px 2px rgba(20,40,80,.08),0 2px 6px rgba(20,40,80,.06);
  --shadow-md:0 6px 16px rgba(20,40,80,.12),0 2px 6px rgba(20,40,80,.08);
  --shadow-lg:0 24px 48px rgba(20,40,80,.18),0 8px 16px rgba(20,40,80,.1);
  --shadow-glow:0 0 0 1px rgba(122,162,255,.4),0 12px 40px rgba(122,162,255,.22);
}
body.theme-light .nav{background:rgba(255,255,255,.75)}
body.theme-light .nav.scrolled{background:rgba(255,255,255,.92)}
body.theme-light pre, body.theme-light .codeblock{
  background:linear-gradient(180deg,#1a1f30,#0e1422) !important;
}
body.theme-light .codeblock pre code{color:#d3dcef}
body.theme-light code{background:rgba(255,209,102,.18);color:#9b6b00;border-color:rgba(255,209,102,.3)}
body.theme-light .demo-canvas-wrap, body.theme-light .game-stage{background:rgba(245,247,251,.6)}
body.theme-light .demo-canvas-wrap canvas, body.theme-light .game-stage canvas{background:#ffffff}
body.theme-light .modal{background:linear-gradient(180deg,rgba(255,255,255,.99),rgba(248,250,253,.99))}
body.theme-light .palette{background:linear-gradient(180deg,rgba(255,255,255,.99),rgba(248,250,253,.99))}
body.theme-light .tour-card{background:linear-gradient(180deg,rgba(255,255,255,.99),rgba(248,250,253,.99))}
body.theme-light .modal-header{background:linear-gradient(180deg,rgba(255,255,255,.99),rgba(255,255,255,.9))}
body.theme-light .demos-wrap{background:rgba(255,255,255,.65)}
body{
  background:var(--bg-grad);
  background-attachment:fixed;
  color:var(--ink);
  font-family:'Inter',ui-sans-serif,-apple-system,'Segoe UI',Roboto,Helvetica,Arial,sans-serif;
  line-height:1.65;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
  overflow-x:hidden;
  min-height:100vh;
}
::selection{background:rgba(122,162,255,.4);color:#fff}
a{color:var(--accent);text-decoration:none;transition:color var(--t-fast)}
a:hover{color:var(--accent3)}
button{font-family:inherit;cursor:pointer;border:none;background:none;color:inherit}
img{max-width:100%;display:block}
:focus-visible{outline:2px solid var(--accent);outline-offset:3px;border-radius:4px}

/* ============ Top Nav ============ */
.nav{
  position:fixed;top:0;left:0;right:0;z-index:50;
  background:rgba(7,9,18,.7);
  backdrop-filter:blur(20px) saturate(180%);
  -webkit-backdrop-filter:blur(20px) saturate(180%);
  border-bottom:1px solid var(--border);
  transition:all var(--t-base);
}
.nav.scrolled{background:rgba(7,9,18,.92);box-shadow:var(--shadow-md)}
.nav-inner{
  max-width:1280px;margin:0 auto;padding:14px 24px;
  display:flex;align-items:center;gap:24px;
}
.brand{
  font-family:'Space Grotesk',sans-serif;font-weight:700;font-size:17px;letter-spacing:-.01em;
  background:var(--grad-text);-webkit-background-clip:text;background-clip:text;color:transparent;
  display:flex;align-items:center;gap:10px;flex-shrink:0;
}
.brand-icon{
  width:30px;height:30px;border-radius:8px;
  background:var(--grad-primary);
  display:grid;place-items:center;font-size:16px;color:#fff;
  box-shadow:0 4px 12px rgba(122,162,255,.4);
  animation:pulse-glow 3s ease-in-out infinite;
}
@keyframes pulse-glow{0%,100%{box-shadow:0 4px 12px rgba(122,162,255,.4)}50%{box-shadow:0 4px 24px rgba(157,122,255,.6)}}
.nav-links{display:flex;gap:4px;flex:1;justify-content:center}
.nav-links a{
  color:var(--muted);font-size:14px;font-weight:500;
  padding:8px 14px;border-radius:8px;
  transition:all var(--t-fast);
}
.nav-links a:hover{color:var(--ink);background:rgba(122,162,255,.08)}
.nav-cta{
  background:var(--grad-primary);color:#fff !important;font-weight:600;font-size:14px;
  padding:9px 18px;border-radius:99px;
  box-shadow:0 4px 14px rgba(122,162,255,.35);
  transition:all var(--t-base);
}
.nav-cta:hover{transform:translateY(-2px);box-shadow:0 8px 24px rgba(122,162,255,.5);text-decoration:none}
.nav-toggle{display:none;font-size:24px;color:var(--ink);padding:6px}
@media(max-width:880px){
  .nav-links{position:fixed;top:60px;left:0;right:0;flex-direction:column;background:rgba(7,9,18,.98);backdrop-filter:blur(20px);padding:16px;border-bottom:1px solid var(--border);transform:translateY(-110%);transition:transform var(--t-base);gap:2px}
  .nav-links.open{transform:translateY(0)}
  .nav-links a{padding:12px 16px}
  .nav-toggle{display:block}
}

/* Top progress bar */
.scroll-progress{
  position:fixed;top:0;left:0;height:3px;width:0%;
  background:var(--grad-primary);z-index:51;
  box-shadow:0 0 12px rgba(122,162,255,.6);
  transition:width .1s linear;
}

/* ============ Resume banner ============ */
.resume-banner{
  position:fixed;top:60px;left:0;right:0;z-index:49;
  display:none;
  background:linear-gradient(90deg,rgba(255,209,102,.15),rgba(255,122,212,.12));
  border-bottom:1px solid rgba(255,209,102,.35);
  backdrop-filter:blur(20px);
  padding:12px 24px;
  animation:slide-down .5s var(--ease-out);
}
.resume-banner.show{display:block}
@keyframes slide-down{from{transform:translateY(-100%);opacity:0}to{transform:translateY(0);opacity:1}}
.resume-banner-inner{
  max-width:1200px;margin:0 auto;
  display:flex;align-items:center;gap:16px;flex-wrap:wrap;
}
.resume-banner .icon{font-size:22px}
.resume-banner .msg{flex:1;font-size:14px;color:var(--ink);font-weight:500;min-width:200px}
.resume-banner .msg b{color:var(--gold)}
.resume-banner .actions{display:flex;gap:10px}
.resume-banner .btn-sm{
  padding:8px 16px;border-radius:99px;font-size:13px;font-weight:600;
  background:linear-gradient(135deg,#ffd166,#ff7ad4);color:#1a1208;
  box-shadow:0 4px 14px rgba(255,209,102,.35);
  transition:all var(--t-fast);
}
.resume-banner .btn-sm:hover{transform:translateY(-2px);box-shadow:0 6px 20px rgba(255,209,102,.5);text-decoration:none}
.resume-banner .btn-dismiss{
  padding:8px 14px;border-radius:99px;font-size:13px;
  background:rgba(255,255,255,.06);border:1px solid var(--border);color:var(--muted);
}
.resume-banner .btn-dismiss:hover{background:rgba(255,255,255,.1);color:var(--ink)}
body.has-resume{scroll-padding-top:130px}
@media(max-width:560px){
  .resume-banner{padding:10px 16px}
  .resume-banner .msg{font-size:13px}
}

/* ============ Hero ============ */
.hero{
  position:relative;min-height:100vh;
  padding:120px 24px 80px;
  display:flex;align-items:center;justify-content:center;
  overflow:hidden;
}
#hero-canvas{
  position:absolute;inset:0;width:100%;height:100%;
  z-index:0;opacity:.7;
}
.hero-content{
  position:relative;z-index:2;text-align:center;max-width:920px;
}
.hero-badge{
  display:inline-flex;align-items:center;gap:8px;
  padding:7px 16px;border-radius:99px;
  background:rgba(122,162,255,.1);border:1px solid rgba(122,162,255,.3);
  font-size:13px;color:var(--accent);font-weight:500;
  margin-bottom:28px;
  animation:fade-up .8s var(--ease-out) backwards;
}
.hero-badge .dot{width:6px;height:6px;border-radius:50%;background:var(--accent);box-shadow:0 0 12px var(--accent);animation:blink 2s ease-in-out infinite}
@keyframes blink{0%,100%{opacity:1}50%{opacity:.3}}
.hero h1{
  font-family:'Space Grotesk',sans-serif;
  font-size:clamp(40px,8vw,84px);
  font-weight:700;line-height:1.05;letter-spacing:-.03em;
  margin-bottom:24px;
  animation:fade-up 1s .1s var(--ease-out) backwards;
}
.hero h1 .shimmer{
  background:linear-gradient(110deg,#7aa2ff 0%,#9d7aff 30%,#ff7ad4 50%,#ffd166 70%,#7aa2ff 100%);
  background-size:200% 100%;
  -webkit-background-clip:text;background-clip:text;color:transparent;
  animation:shimmer 6s linear infinite;
  display:inline-block;
}
@keyframes shimmer{0%{background-position:0% 50%}100%{background-position:200% 50%}}
.hero p.lede{
  font-size:clamp(17px,2.2vw,22px);
  color:var(--muted);max-width:680px;margin:0 auto 40px;
  line-height:1.55;font-weight:400;
  animation:fade-up 1s .2s var(--ease-out) backwards;
}
@keyframes fade-up{from{opacity:0;transform:translateY(24px)}to{opacity:1;transform:translateY(0)}}
.hero-ctas{
  display:flex;gap:14px;justify-content:center;flex-wrap:wrap;
  animation:fade-up 1s .3s var(--ease-out) backwards;
}
.btn{
  display:inline-flex;align-items:center;gap:10px;
  padding:14px 28px;border-radius:99px;
  font-weight:600;font-size:15px;letter-spacing:-.005em;
  transition:all var(--t-base) var(--ease);
  cursor:pointer;
}
.btn-primary{
  background:var(--grad-primary);color:#fff;
  box-shadow:0 10px 30px rgba(122,162,255,.35),inset 0 1px 0 rgba(255,255,255,.2);
}
.btn-primary:hover{transform:translateY(-3px);box-shadow:0 16px 40px rgba(122,162,255,.5),inset 0 1px 0 rgba(255,255,255,.3);text-decoration:none}
.btn-ghost{
  background:rgba(255,255,255,.04);color:var(--ink);
  border:1px solid var(--border);
  backdrop-filter:blur(10px);
}
.btn-ghost:hover{background:rgba(255,255,255,.08);border-color:var(--border-strong);transform:translateY(-2px)}
.btn .arrow{transition:transform var(--t-base)}
.btn:hover .arrow{transform:translateX(4px)}

.hero-stats{
  display:flex;gap:48px;justify-content:center;flex-wrap:wrap;
  margin-top:64px;
  animation:fade-up 1s .5s var(--ease-out) backwards;
}
.hero-stat{text-align:center}
.hero-stat .num{
  font-family:'Space Grotesk',sans-serif;
  font-size:clamp(28px,4vw,40px);font-weight:700;
  background:var(--grad-text);-webkit-background-clip:text;background-clip:text;color:transparent;
  line-height:1;
}
.hero-stat .lbl{font-size:13px;color:var(--muted);margin-top:6px;letter-spacing:.02em;text-transform:uppercase;font-weight:500}

.scroll-cue{
  position:absolute;bottom:30px;left:50%;transform:translateX(-50%);
  color:var(--dim);font-size:12px;display:flex;flex-direction:column;align-items:center;gap:6px;
  animation:fade-up 1s .8s var(--ease-out) backwards, bob 2.5s ease-in-out infinite 1s;
}
@keyframes bob{0%,100%{transform:translateX(-50%) translateY(0)}50%{transform:translateX(-50%) translateY(8px)}}
.scroll-cue .arr{font-size:18px}

/* ============ Section base ============ */
section.block{
  padding:100px 24px;position:relative;
}
.container{max-width:1200px;margin:0 auto}
.section-head{text-align:center;margin-bottom:64px}
.section-eyebrow{
  display:inline-block;font-size:13px;font-weight:600;color:var(--accent);
  letter-spacing:.12em;text-transform:uppercase;margin-bottom:14px;
}
.section-head h2{
  font-family:'Space Grotesk',sans-serif;
  font-size:clamp(32px,5vw,52px);font-weight:700;letter-spacing:-.02em;line-height:1.1;
  margin-bottom:18px;
}
.section-head h2 .grad{background:var(--grad-text);-webkit-background-clip:text;background-clip:text;color:transparent}
.section-head p{font-size:18px;color:var(--muted);max-width:680px;margin:0 auto;line-height:1.6}

/* Scroll reveal */
.reveal{opacity:0;transform:translateY(40px);transition:opacity .8s var(--ease-out),transform .8s var(--ease-out)}
.reveal.in{opacity:1;transform:translateY(0)}
.reveal[data-delay="100"]{transition-delay:.1s}
.reveal[data-delay="200"]{transition-delay:.2s}
.reveal[data-delay="300"]{transition-delay:.3s}
.reveal[data-delay="400"]{transition-delay:.4s}

/* ============ Outcomes grid ============ */
.outcomes{
  display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));
  gap:20px;
}
.outcome-card{
  position:relative;
  background:var(--panel);
  border:1px solid var(--border);
  border-radius:var(--rad);padding:32px 28px;
  transition:all var(--t-base);
  overflow:hidden;
  backdrop-filter:blur(10px);
}
.outcome-card::before{
  content:"";position:absolute;inset:0;border-radius:var(--rad);
  background:linear-gradient(135deg,rgba(122,162,255,.1),transparent 60%);
  opacity:0;transition:opacity var(--t-base);pointer-events:none;
}
.outcome-card:hover{
  transform:translateY(-6px);
  border-color:var(--border-strong);
  box-shadow:var(--shadow-glow);
}
.outcome-card:hover::before{opacity:1}
.outcome-icon{
  width:52px;height:52px;border-radius:14px;
  background:var(--grad-primary);
  display:grid;place-items:center;font-size:24px;
  margin-bottom:18px;
  box-shadow:0 8px 20px rgba(122,162,255,.3);
}
.outcome-card h3{font-size:19px;font-weight:700;margin-bottom:10px;letter-spacing:-.01em}
.outcome-card p{font-size:14.5px;color:var(--muted);line-height:1.6}

/* ============ Roadmap timeline ============ */
.roadmap-wrap{position:relative;max-width:1100px;margin:0 auto}
.roadmap-line{
  position:absolute;left:50%;top:0;bottom:0;width:2px;
  background:linear-gradient(180deg,transparent,var(--accent) 8%,var(--accent2) 50%,var(--gold) 92%,transparent);
  transform:translateX(-50%);
  opacity:.35;
}
@media(max-width:780px){
  .roadmap-line{left:22px}
}
.phase{
  display:grid;grid-template-columns:1fr 80px 1fr;
  gap:24px;align-items:start;margin-bottom:48px;position:relative;
}
@media(max-width:780px){
  .phase{grid-template-columns:44px 1fr;gap:16px}
  .phase .phase-side{display:none}
}
.phase-num{
  grid-column:2;justify-self:center;
  width:60px;height:60px;border-radius:50%;
  background:radial-gradient(circle,var(--panel-solid),var(--bg));
  border:2px solid var(--accent);
  display:grid;place-items:center;
  font-family:'Space Grotesk',sans-serif;font-weight:700;font-size:18px;color:var(--accent);
  position:relative;z-index:2;
  box-shadow:0 0 0 8px rgba(7,9,18,.9),0 0 24px rgba(122,162,255,.4);
  transition:all var(--t-base);
}
@media(max-width:780px){
  .phase-num{grid-column:1;width:44px;height:44px;font-size:15px}
}
.phase.in .phase-num{
  background:var(--grad-primary);color:#fff;border-color:transparent;
  transform:scale(1.08);
}
.phase-card{
  background:var(--panel);
  border:1px solid var(--border);border-radius:var(--rad);
  padding:24px 26px;
  backdrop-filter:blur(10px);
  transition:all var(--t-base);
}
.phase-card:hover{border-color:var(--border-strong);transform:translateY(-3px);box-shadow:var(--shadow-md)}
.phase:nth-child(odd) .phase-card{grid-column:1}
.phase:nth-child(odd) .phase-side{grid-column:3}
.phase:nth-child(even) .phase-card{grid-column:3}
.phase:nth-child(even) .phase-side{grid-column:1}
@media(max-width:780px){
  .phase .phase-card,
  .phase:nth-child(odd) .phase-card,
  .phase:nth-child(even) .phase-card{grid-column:2}
}
.phase-side{
  font-size:13px;color:var(--dim);padding-top:18px;
}
.phase:nth-child(odd) .phase-side{text-align:left}
.phase:nth-child(even) .phase-side{text-align:right}
.phase-meta{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:12px}
.tag{
  display:inline-block;font-size:11px;font-weight:600;letter-spacing:.04em;
  padding:4px 10px;border-radius:99px;text-transform:uppercase;
  background:rgba(122,162,255,.1);color:var(--accent);
  border:1px solid rgba(122,162,255,.25);
}
.tag.gold{background:rgba(255,209,102,.1);color:var(--gold);border-color:rgba(255,209,102,.3)}
.tag.purple{background:rgba(157,122,255,.1);color:var(--accent2);border-color:rgba(157,122,255,.3)}
.tag.green{background:rgba(62,207,142,.1);color:var(--ok);border-color:rgba(62,207,142,.3)}
.phase-card h3{
  font-family:'Space Grotesk',sans-serif;font-size:22px;font-weight:700;
  margin-bottom:8px;letter-spacing:-.01em;
}
.phase-eli5{
  font-size:14.5px;color:var(--muted);margin-bottom:14px;
  padding:12px 14px;border-radius:10px;
  background:rgba(122,162,255,.06);
  border-left:3px solid var(--accent);
}
.phase-eli5 b{color:var(--accent);font-weight:600}
.phase-topics{display:flex;flex-wrap:wrap;gap:6px;margin:14px 0 4px}
.topic-pill{
  font-size:12px;padding:4px 10px;border-radius:6px;
  background:rgba(255,255,255,.04);color:var(--muted);
  border:1px solid var(--border);font-weight:500;
}
.phase-projects{margin-top:14px}
.phase-projects b{font-size:12px;color:var(--gold);font-weight:600;letter-spacing:.04em;text-transform:uppercase;display:block;margin-bottom:6px}
.phase-projects ul{list-style:none;padding:0}
.phase-projects li{font-size:13.5px;color:var(--muted);padding:4px 0 4px 22px;position:relative}
.phase-projects li::before{content:"▸";position:absolute;left:6px;color:var(--accent);font-size:12px;top:5px}

.phase-help{
  margin-top:18px;border-top:1px solid var(--border);padding-top:14px;
}
.phase-help summary{
  cursor:pointer;list-style:none;
  display:flex;align-items:center;gap:8px;
  font-size:13px;font-weight:600;color:var(--accent);
  padding:8px 12px;border-radius:8px;
  background:rgba(122,162,255,.06);
  border:1px solid rgba(122,162,255,.18);
  transition:all var(--t-fast);
  user-select:none;
}
.phase-help summary::-webkit-details-marker{display:none}
.phase-help summary:hover{background:rgba(122,162,255,.12);border-color:var(--border-strong)}
.phase-help .help-icon{font-size:14px}
.phase-help .help-count{
  margin-left:auto;
  font-family:'JetBrains Mono',monospace;font-size:11px;
  background:rgba(255,255,255,.08);color:var(--ink);
  padding:2px 7px;border-radius:99px;font-weight:600;
}
.phase-help .help-chev{font-size:12px;transition:transform var(--t-fast);opacity:.7}
.phase-help[open] .help-chev{transform:rotate(180deg)}
.phase-help .help-list{
  list-style:none;padding:14px 0 4px;margin:0;
  display:flex;flex-direction:column;gap:10px;
  animation:help-in .3s var(--ease-out);
}
@keyframes help-in{from{opacity:0;transform:translateY(-6px)}to{opacity:1;transform:translateY(0)}}
.help-item{
  background:rgba(7,9,18,.5);
  border:1px solid var(--border);border-radius:8px;
  padding:10px 12px;
  transition:all var(--t-fast);
}
.help-item:hover{border-color:var(--border-strong);background:rgba(7,9,18,.7);transform:translateX(2px)}
.help-item a{
  display:flex;align-items:center;gap:10px;
  color:var(--ink);font-weight:600;font-size:13.5px;
  text-decoration:none;
}
.help-item a:hover .help-title{color:var(--accent3)}
.help-type{
  font-family:'JetBrains Mono',monospace;font-size:10px;font-weight:700;
  padding:2px 7px;border-radius:4px;letter-spacing:.04em;text-transform:uppercase;
  flex-shrink:0;
}
.help-type-video{background:rgba(255,122,212,.15);color:#ff9ad9;border:1px solid rgba(255,122,212,.3)}
.help-type-article{background:rgba(122,162,255,.15);color:var(--accent);border:1px solid rgba(122,162,255,.3)}
.help-type-docs{background:rgba(94,194,255,.15);color:var(--accent3);border:1px solid rgba(94,194,255,.3)}
.help-type-book{background:rgba(255,209,102,.15);color:var(--gold);border:1px solid rgba(255,209,102,.3)}
.help-type-course{background:rgba(62,207,142,.15);color:var(--ok);border:1px solid rgba(62,207,142,.3)}
.help-type-paper{background:rgba(157,122,255,.15);color:var(--accent2);border:1px solid rgba(157,122,255,.3)}
.help-title{flex:1;line-height:1.3;transition:color var(--t-fast)}
.help-ext{font-size:13px;color:var(--dim);transition:transform var(--t-fast)}
.help-item:hover .help-ext{transform:translate(2px,-2px);color:var(--accent)}
.help-why{
  font-size:12.5px;color:var(--muted);line-height:1.5;
  margin:6px 0 0;padding-left:8px;
  border-left:2px solid rgba(122,162,255,.2);
}

/* ============ Phase checkbox + open button ============ */
.phase-actions{
  display:flex;align-items:center;gap:10px;margin-top:16px;
  padding-top:14px;border-top:1px solid var(--border);
  flex-wrap:wrap;
}
.phase-check{
  display:inline-flex;align-items:center;gap:8px;
  cursor:pointer;user-select:none;
  font-size:13px;color:var(--muted);font-weight:500;
}
.phase-check input{
  appearance:none;-webkit-appearance:none;
  width:20px;height:20px;border-radius:6px;
  border:2px solid var(--border);background:rgba(7,9,18,.4);
  cursor:pointer;position:relative;
  transition:all var(--t-fast);
  flex-shrink:0;
}
.phase-check input:hover{border-color:var(--accent)}
.phase-check input:checked{
  background:var(--grad-primary);border-color:transparent;
}
.phase-check input:checked::after{
  content:"";position:absolute;
  left:5px;top:1px;width:6px;height:11px;
  border:solid #fff;border-width:0 2px 2px 0;
  transform:rotate(45deg);
}
.phase-check.done{color:var(--ok)}
.phase-check.done .lbl::after{content:" ✓"}
.btn-open-lesson{
  margin-left:auto;
  padding:8px 16px;border-radius:8px;
  background:linear-gradient(135deg,rgba(122,162,255,.15),rgba(157,122,255,.1));
  border:1px solid rgba(122,162,255,.3);
  color:var(--accent);font-size:13px;font-weight:600;
  display:inline-flex;align-items:center;gap:6px;
  cursor:pointer;transition:all var(--t-fast);
}
.btn-open-lesson:hover{
  background:linear-gradient(135deg,rgba(122,162,255,.25),rgba(157,122,255,.2));
  color:var(--ink);transform:translateX(2px);
}
.phase.done .phase-num{
  background:linear-gradient(135deg,var(--ok),#2ab87a) !important;
  color:#0a0e16 !important;border-color:transparent;
}
.phase.done .phase-num::after{
  content:"✓";position:absolute;font-size:18px;font-weight:900;
}
.phase.done .phase-card{border-color:rgba(62,207,142,.3)}

/* ============ Progress ring in nav ============ */
.nav-progress{
  display:flex;align-items:center;gap:10px;
  padding:6px 12px;border-radius:99px;
  background:rgba(255,255,255,.04);border:1px solid var(--border);
  font-size:12px;color:var(--muted);
  flex-shrink:0;
}
.nav-progress .ring{
  width:28px;height:28px;position:relative;flex-shrink:0;
}
.nav-progress .ring svg{transform:rotate(-90deg);width:28px;height:28px}
.nav-progress .ring circle{fill:none;stroke-width:3}
.nav-progress .ring .track{stroke:rgba(255,255,255,.08)}
.nav-progress .ring .bar{
  stroke:url(#ringGrad);
  stroke-dasharray:75.4;
  stroke-dashoffset:75.4;
  transition:stroke-dashoffset .6s var(--ease-out);
  stroke-linecap:round;
}
.nav-progress .pct{font-family:'JetBrains Mono',monospace;color:var(--ink);font-weight:700}
.streak-chip{
  display:inline-flex;align-items:center;gap:5px;
  padding:6px 12px;border-radius:99px;
  background:rgba(255,209,102,.1);border:1px solid rgba(255,209,102,.3);
  font-size:12px;color:var(--gold);font-weight:700;
  font-family:'JetBrains Mono',monospace;
  flex-shrink:0;
}
.streak-chip.cold{background:rgba(255,255,255,.04);border-color:var(--border);color:var(--muted)}
@media(max-width:980px){
  .nav-progress .lbl{display:none}
  .streak-chip{padding:6px 10px}
}
@media(max-width:680px){
  .nav-progress,.streak-chip{display:none}
}

/* ============ Modal (deep-dive) ============ */
.modal-bg{
  position:fixed;inset:0;z-index:100;
  background:rgba(7,9,18,.85);backdrop-filter:blur(8px);
  display:none;align-items:center;justify-content:center;
  padding:24px;
  animation:fade-in .2s var(--ease-out);
}
.modal-bg.open{display:flex}
.modal{
  background:linear-gradient(180deg,rgba(20,26,42,.98),rgba(14,18,30,.98));
  border:1px solid var(--border-strong);border-radius:var(--rad-lg);
  width:100%;max-width:880px;max-height:92vh;
  overflow-y:auto;
  box-shadow:0 30px 80px rgba(0,0,0,.6),0 0 0 1px rgba(122,162,255,.15);
  animation:modal-in .3s var(--ease-out);
  position:relative;
  scrollbar-width:thin;
}
.modal::-webkit-scrollbar{width:8px}
.modal::-webkit-scrollbar-track{background:transparent}
.modal::-webkit-scrollbar-thumb{background:var(--border);border-radius:99px}
@keyframes modal-in{from{opacity:0;transform:translateY(20px) scale(.98)}to{opacity:1;transform:translateY(0) scale(1)}}
.modal-header{
  position:sticky;top:0;z-index:2;
  background:linear-gradient(180deg,rgba(20,26,42,.99),rgba(20,26,42,.9));
  backdrop-filter:blur(10px);
  padding:24px 32px 18px;
  border-bottom:1px solid var(--border);
  display:flex;align-items:flex-start;gap:16px;
}
.modal-header .num{
  width:48px;height:48px;border-radius:14px;
  background:var(--grad-primary);
  display:grid;place-items:center;
  font-family:'Space Grotesk',sans-serif;font-weight:700;font-size:20px;
  color:#fff;flex-shrink:0;
  box-shadow:0 6px 18px rgba(122,162,255,.3);
}
.modal-header .info{flex:1;min-width:0}
.modal-header h2{
  font-family:'Space Grotesk',sans-serif;
  font-size:24px;font-weight:700;margin-bottom:6px;letter-spacing:-.01em;
  background:none;-webkit-background-clip:initial;background-clip:initial;color:var(--ink);
}
.modal-header .meta{display:flex;gap:8px;flex-wrap:wrap}
.modal-close{
  position:absolute;top:18px;right:18px;
  width:36px;height:36px;border-radius:50%;
  background:rgba(255,255,255,.06);border:1px solid var(--border);
  color:var(--muted);font-size:18px;
  display:grid;place-items:center;cursor:pointer;
  transition:all var(--t-fast);z-index:3;
}
.modal-close:hover{background:rgba(255,107,107,.15);color:var(--err);border-color:var(--err);transform:rotate(90deg)}
.modal-body{padding:24px 32px 32px}
.modal-body h3{
  font-family:'Space Grotesk',sans-serif;font-size:18px;font-weight:700;
  margin:24px 0 10px;color:var(--accent);letter-spacing:-.005em;
  display:flex;align-items:center;gap:8px;
}
.modal-body h3 .ico{font-size:16px}
.modal-body p{font-size:15px;line-height:1.7;color:var(--ink);margin-bottom:12px}
.modal-body p.lede{font-size:16px;color:var(--muted)}
.modal-body .pro-toggle{
  display:inline-flex;align-items:center;gap:8px;
  padding:6px 14px;border-radius:99px;
  background:rgba(157,122,255,.1);border:1px solid rgba(157,122,255,.3);
  color:var(--accent2);font-size:12px;font-weight:600;
  cursor:pointer;margin-bottom:14px;
  transition:all var(--t-fast);
}
.modal-body .pro-toggle:hover{background:rgba(157,122,255,.18)}
.modal-body .pro-detail{
  display:none;padding:14px 16px;border-radius:10px;
  background:rgba(157,122,255,.06);border:1px solid rgba(157,122,255,.2);
  margin:8px 0 16px;
  animation:fade-in .3s var(--ease-out);
}
.modal-body .pro-detail.show{display:block}
.modal-body .pro-detail b{color:var(--accent2)}
.modal-body .pro-toggle.eli5-toggle{
  background:rgba(94,194,255,.1);border-color:rgba(94,194,255,.3);color:var(--accent3);
  margin-right:8px;
}
.modal-body .pro-toggle.eli5-toggle:hover{background:rgba(94,194,255,.18)}
.modal-body .eli5-detail{
  background:rgba(94,194,255,.06);border-color:rgba(94,194,255,.2);
}
.modal-body .eli5-detail b{color:var(--accent3)}
.callout-block{
  margin:18px 0;padding:14px 18px;border-radius:10px;
  background:rgba(255,255,255,.02);border:1px solid var(--border);
}
.callout-block h4{
  margin:0 0 10px;font-size:13.5px;font-weight:700;
  letter-spacing:.04em;text-transform:uppercase;
  display:flex;align-items:center;gap:8px;
}
.callout-block.pitfalls{background:rgba(255,107,107,.05);border-color:rgba(255,107,107,.25)}
.callout-block.pitfalls h4{color:var(--err)}
.callout-block.rubric{background:rgba(62,207,142,.05);border-color:rgba(62,207,142,.25)}
.callout-block.rubric h4{color:var(--ok)}
.callout-block ul{list-style:none;padding:0;margin:0}
.callout-block li{
  font-size:14px;line-height:1.6;color:var(--ink);
  padding:6px 0 6px 22px;position:relative;
}
.callout-block li::before{
  position:absolute;left:0;top:6px;font-size:14px;
}
.callout-block.pitfalls li::before{content:"⚠";color:var(--err)}
.callout-block.rubric li::before{content:"✓";color:var(--ok);font-weight:700}

/* Inline glossary tooltips */
.glo-tip{
  position:relative;
  border-bottom:1px dashed rgba(122,162,255,.55);
  cursor:help;
  color:inherit;
}
.glo-tip::after{
  content:attr(data-tip);
  position:absolute;left:50%;bottom:calc(100% + 8px);
  transform:translateX(-50%);
  min-width:240px;max-width:340px;width:max-content;
  background:linear-gradient(180deg,rgba(20,26,42,.99),rgba(14,18,30,.99));
  border:1px solid var(--border-strong);
  border-radius:8px;padding:10px 12px;
  font-size:12.5px;font-weight:400;line-height:1.55;color:var(--ink);
  box-shadow:0 10px 30px rgba(0,0,0,.5);
  opacity:0;pointer-events:none;
  transition:opacity .15s ease-out, transform .15s ease-out;
  z-index:10;
  white-space:normal;text-align:left;
  text-decoration:none;
}
.glo-tip:hover::after,.glo-tip:focus::after{opacity:1;transform:translateX(-50%) translateY(-2px)}

/* Code block w/ pseudo-highlight + copy */
.codeblock{
  background:linear-gradient(180deg,#0a1020,#070c1a);
  border:1px solid var(--border);
  border-radius:10px;margin:12px 0;
  overflow:hidden;position:relative;
}
.codeblock-head{
  display:flex;align-items:center;justify-content:space-between;
  padding:8px 14px;
  background:rgba(255,255,255,.03);
  border-bottom:1px solid var(--border);
}
.codeblock-head .lang{
  font-family:'JetBrains Mono',monospace;font-size:11px;
  color:var(--accent);font-weight:600;letter-spacing:.04em;text-transform:uppercase;
}
.codeblock-head .label{font-size:12px;color:var(--muted);font-weight:500}
.codeblock-copy{
  background:rgba(255,255,255,.06);border:1px solid var(--border);
  color:var(--muted);font-size:11px;font-weight:600;
  padding:4px 10px;border-radius:6px;
  cursor:pointer;transition:all var(--t-fast);
  font-family:'Inter',sans-serif;
}
.codeblock-copy:hover{background:rgba(122,162,255,.15);color:var(--accent);border-color:var(--accent)}
.codeblock-copy.copied{background:rgba(62,207,142,.15);color:var(--ok);border-color:var(--ok)}
.codeblock pre{
  background:none;border:none;border-radius:0;box-shadow:none;
  padding:14px 16px;margin:0;
  font-family:'JetBrains Mono',monospace;font-size:13px;line-height:1.6;
  color:#d3dcef;overflow-x:auto;
}
.codeblock .kw{color:#ff9ad9;font-weight:600}
.codeblock .str{color:#ffd166}
.codeblock .num{color:#7ad4ff}
.codeblock .com{color:#7884a0;font-style:italic}
.codeblock .fn{color:#7aa2ff}

/* Quiz */
.quiz-block{
  background:rgba(122,162,255,.04);
  border:1px solid var(--border);border-radius:12px;
  padding:20px 22px;margin:18px 0;
}
.quiz-block h3{margin-top:0 !important}
.quiz-q{margin-bottom:18px}
.quiz-q:last-child{margin-bottom:0}
.quiz-q .q{
  font-weight:600;font-size:15px;color:var(--ink);
  margin-bottom:10px;line-height:1.5;
}
.quiz-q .opts{display:flex;flex-direction:column;gap:6px}
.quiz-q .opts button{
  text-align:left;padding:10px 14px;border-radius:8px;
  background:rgba(7,9,18,.5);border:1px solid var(--border);
  color:var(--ink);font-size:14px;
  cursor:pointer;transition:all var(--t-fast);
  font-family:inherit;
  display:flex;align-items:center;gap:10px;
}
.quiz-q .opts button:hover:not(.correct):not(.wrong){
  background:rgba(122,162,255,.08);border-color:var(--border-strong);
  transform:translateX(2px);
}
.quiz-q .opts button::before{
  content:"";width:18px;height:18px;border-radius:50%;
  border:2px solid var(--border);flex-shrink:0;
  transition:all var(--t-fast);
}
.quiz-q .opts button.correct{
  background:rgba(62,207,142,.12);border-color:var(--ok);color:var(--ok);
}
.quiz-q .opts button.correct::before{background:var(--ok);border-color:var(--ok);box-shadow:inset 0 0 0 3px #0a0e16}
.quiz-q .opts button.wrong{
  background:rgba(255,107,107,.1);border-color:var(--err);color:var(--err);
}
.quiz-q .opts button.wrong::before{background:var(--err);border-color:var(--err)}
.quiz-q .opts button[disabled]{cursor:default;opacity:.7}
.quiz-q .opts button.correct[disabled],.quiz-q .opts button.wrong[disabled]{opacity:1}
.quiz-explain{
  margin-top:10px;padding:10px 14px;border-radius:8px;
  background:rgba(122,162,255,.06);border-left:3px solid var(--accent);
  font-size:13.5px;line-height:1.55;color:var(--muted);
  display:none;animation:fade-in .3s;
}
.quiz-explain.show{display:block}
.quiz-explain b{color:var(--accent)}
.quiz-score{
  margin-top:18px;padding-top:14px;border-top:1px solid var(--border);
  text-align:center;font-size:14px;color:var(--muted);
}
.quiz-score b{color:var(--gold);font-size:18px;font-family:'JetBrains Mono',monospace}
.modal-cta{
  display:flex;gap:10px;margin-top:24px;padding-top:20px;
  border-top:1px solid var(--border);
  flex-wrap:wrap;
}
.btn-complete{
  flex:1;min-width:180px;
  padding:12px 22px;border-radius:10px;
  background:var(--grad-primary);color:#fff;
  font-weight:700;font-size:14px;
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  cursor:pointer;transition:all var(--t-fast);
  box-shadow:0 6px 20px rgba(122,162,255,.35);
}
.btn-complete:hover{transform:translateY(-2px);box-shadow:0 10px 28px rgba(122,162,255,.5)}
.btn-complete.done{background:linear-gradient(135deg,var(--ok),#2ab87a);color:#0a0e16}
.btn-modal-close-alt{
  padding:12px 22px;border-radius:10px;
  background:rgba(255,255,255,.04);border:1px solid var(--border);
  color:var(--muted);font-weight:600;font-size:14px;
  cursor:pointer;transition:all var(--t-fast);
}
.btn-modal-close-alt:hover{color:var(--ink);background:rgba(255,255,255,.08)}

/* ============ Modal section nav (inner) ============ */
.modal-tabs{
  position:sticky;top:88px;z-index:2;
  display:flex;gap:4px;padding:6px;margin:-8px 0 14px;
  background:rgba(7,9,18,.85);
  backdrop-filter:blur(10px);
  border-radius:10px;border:1px solid var(--border);
  overflow-x:auto;scrollbar-width:none;
}
.modal-tabs::-webkit-scrollbar{display:none}
.modal-tab{
  flex:1;min-width:90px;
  padding:8px 12px;border-radius:6px;
  font-size:12.5px;font-weight:600;color:var(--muted);
  display:inline-flex;align-items:center;justify-content:center;gap:6px;
  cursor:pointer;transition:all var(--t-fast);
  white-space:nowrap;
}
.modal-tab:hover{color:var(--ink);background:rgba(122,162,255,.06)}
.modal-tab.active{
  background:linear-gradient(135deg,var(--accent),var(--accent2));
  color:#fff;box-shadow:0 3px 10px rgba(122,162,255,.3);
}
.modal-tab .dot{
  width:6px;height:6px;border-radius:50%;background:currentColor;opacity:.5;
}
.modal-tab.has-content .dot{background:var(--ok);opacity:1}
.modal-section{
  scroll-margin-top:160px;
  padding:8px 0 4px;
  animation:fade-in .4s var(--ease-out);
}

/* Story */
.story{
  background:linear-gradient(135deg,rgba(122,162,255,.05),rgba(157,122,255,.03));
  border:1px solid rgba(122,162,255,.15);
  border-radius:12px;padding:18px 22px;margin:8px 0 18px;
}
.story p{
  font-size:15.5px;line-height:1.75;color:var(--ink);
  margin-bottom:14px;
}
.story p:last-child{margin-bottom:0}
.story p b,.story p strong{color:var(--accent);font-weight:600}
.story p i,.story p em{color:var(--gold);font-style:normal;font-weight:500}
.story .callout{
  margin-top:12px;padding:12px 16px;
  background:rgba(255,209,102,.08);border:1px solid rgba(255,209,102,.25);
  border-left:3px solid var(--gold);
  border-radius:8px;
  font-size:14px;color:var(--ink);line-height:1.6;
}
.story .callout b{color:var(--gold)}

/* Game stage */
.game-stage{
  background:linear-gradient(180deg,rgba(7,9,18,.5),rgba(7,9,18,.7));
  border:1px solid var(--border);border-radius:12px;
  padding:16px;margin:8px 0 14px;
  position:relative;
}
.game-stage canvas{
  width:100%;display:block;border-radius:8px;
  background:rgba(7,9,18,.5);
}
.game-stage .hint{
  font-size:13px;color:var(--muted);margin-bottom:10px;
  display:flex;align-items:center;gap:8px;
}
.game-stage .hint b{color:var(--accent)}
.game-controls{display:flex;gap:10px;flex-wrap:wrap;margin-top:12px;align-items:center}
.game-controls .demo-slider{flex:none}
.game-readout{
  display:flex;gap:18px;flex-wrap:wrap;margin-top:10px;
  font-family:'JetBrains Mono',monospace;font-size:13px;color:var(--muted);
}
.game-readout b{color:var(--accent);font-weight:700;margin-right:4px}
.game-readout .ok{color:var(--ok)}
.game-readout .err{color:var(--err)}
.no-game{
  padding:24px;text-align:center;color:var(--dim);
  background:rgba(255,255,255,.02);border:1px dashed var(--border);border-radius:10px;
  font-size:14px;
}

/* ============ Lesson page mode (opened in new tab) ============ */
body.mode-lesson .nav,
body.mode-lesson .scroll-progress,
body.mode-lesson .hero,
body.mode-lesson .resume-banner,
body.mode-lesson section.block,
body.mode-lesson .cta-final,
body.mode-lesson footer{display:none !important}
body.mode-lesson{padding-top:0}
body.mode-lesson .modal-bg{
  position:static;background:transparent;backdrop-filter:none;
  padding:24px;min-height:100vh;
  animation:none;
}
body.mode-lesson .modal-bg.open{display:flex}
body.mode-lesson .modal{
  max-width:980px;max-height:none;
  box-shadow:var(--shadow-lg);
  background:linear-gradient(180deg,rgba(20,26,42,.85),rgba(14,18,30,.95));
  animation:fade-up .6s var(--ease-out);
}
body.mode-lesson .modal-close,
body.mode-lesson .btn-modal-close-alt{display:none}
body.mode-lesson .modal-tabs{top:8px}
.lesson-page-bar{
  display:none;align-items:center;justify-content:space-between;
  padding:14px 24px;
  background:rgba(7,9,18,.85);backdrop-filter:blur(20px);
  border-bottom:1px solid var(--border);
  position:sticky;top:0;z-index:30;
}
body.mode-lesson .lesson-page-bar{display:flex}
.lesson-page-bar .back{
  display:inline-flex;align-items:center;gap:8px;
  color:var(--muted);font-weight:600;font-size:14px;
  padding:8px 16px;border-radius:99px;
  background:rgba(255,255,255,.04);border:1px solid var(--border);
  transition:all var(--t-fast);
}
.lesson-page-bar .back:hover{color:var(--ink);background:rgba(255,255,255,.08);text-decoration:none}
.lesson-page-bar .brand-mini{
  font-family:'Space Grotesk',sans-serif;font-weight:700;font-size:14px;
  background:var(--grad-text);-webkit-background-clip:text;background-clip:text;color:transparent;
}

/* ============ Command palette ============ */
.palette-bg{
  position:fixed;inset:0;z-index:200;
  background:rgba(7,9,18,.7);backdrop-filter:blur(6px);
  display:none;align-items:flex-start;justify-content:center;
  padding:80px 24px 24px;
  animation:fade-in .15s var(--ease-out);
}
.palette-bg.open{display:flex}
.palette{
  width:100%;max-width:640px;
  background:linear-gradient(180deg,rgba(20,26,42,.98),rgba(14,18,30,.98));
  border:1px solid var(--border-strong);border-radius:14px;
  box-shadow:0 30px 80px rgba(0,0,0,.6),0 0 0 1px rgba(122,162,255,.15);
  overflow:hidden;
  animation:modal-in .25s var(--ease-out);
}
.palette-input{
  width:100%;padding:18px 22px;
  background:none;border:none;color:var(--ink);
  font-size:16px;font-weight:500;
  border-bottom:1px solid var(--border);
  outline:none;
}
.palette-input::placeholder{color:var(--dim)}
.palette-results{
  max-height:60vh;overflow-y:auto;padding:8px;
  scrollbar-width:thin;
}
.palette-results::-webkit-scrollbar{width:6px}
.palette-results::-webkit-scrollbar-thumb{background:var(--border);border-radius:99px}
.palette-item{
  display:flex;align-items:center;gap:12px;
  padding:10px 14px;border-radius:8px;
  cursor:pointer;transition:all var(--t-fast);
}
.palette-item:hover,.palette-item.sel{background:rgba(122,162,255,.1)}
.palette-item.sel{box-shadow:inset 2px 0 0 var(--accent)}
.palette-item .ico{
  width:32px;height:32px;border-radius:8px;
  background:rgba(122,162,255,.1);border:1px solid rgba(122,162,255,.2);
  display:grid;place-items:center;font-size:14px;flex-shrink:0;
}
.palette-item .body{flex:1;min-width:0}
.palette-item .title{font-size:14px;font-weight:600;color:var(--ink);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.palette-item .sub{font-size:12px;color:var(--muted);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.palette-item .kind{
  font-family:'JetBrains Mono',monospace;font-size:10px;color:var(--dim);
  padding:2px 8px;border-radius:99px;background:rgba(255,255,255,.05);
  border:1px solid var(--border);text-transform:uppercase;letter-spacing:.05em;
  flex-shrink:0;
}
.palette-hint{
  padding:10px 14px;font-size:11px;color:var(--dim);
  border-top:1px solid var(--border);
  display:flex;gap:14px;flex-wrap:wrap;
}
.palette-hint kbd{
  background:rgba(255,255,255,.06);border:1px solid var(--border);
  border-radius:4px;padding:1px 6px;font-family:'JetBrains Mono',monospace;
  font-size:10px;color:var(--ink);
}
.kbd-trigger{
  display:none;align-items:center;gap:6px;
  padding:7px 14px;border-radius:99px;
  background:rgba(255,255,255,.04);border:1px solid var(--border);
  font-size:12px;color:var(--muted);cursor:pointer;
  transition:all var(--t-fast);
}
.kbd-trigger:hover{background:rgba(255,255,255,.08);color:var(--ink);border-color:var(--border-strong)}
.kbd-trigger kbd{
  background:rgba(255,255,255,.08);border:1px solid var(--border);
  border-radius:4px;padding:1px 6px;font-family:'JetBrains Mono',monospace;
  font-size:10px;color:var(--ink);
}
@media(min-width:1000px){.kbd-trigger{display:inline-flex}}

/* ============ First-visit tour ============ */
.tour-bg{
  position:fixed;inset:0;z-index:120;
  background:rgba(7,9,18,.78);backdrop-filter:blur(4px);
  display:none;align-items:center;justify-content:center;padding:24px;
  animation:fade-in .2s var(--ease-out);
}
.tour-bg.open{display:flex}
.tour-card{
  width:100%;max-width:440px;
  background:linear-gradient(180deg,rgba(20,26,42,.98),rgba(14,18,30,.99));
  border:1px solid var(--border-strong);border-radius:16px;
  padding:28px;
  box-shadow:0 30px 80px rgba(0,0,0,.6),0 0 0 1px rgba(122,162,255,.15);
  animation:modal-in .3s var(--ease-out);
}
.tour-card h3{font-family:'Space Grotesk',sans-serif;font-size:22px;font-weight:700;margin-bottom:12px;letter-spacing:-.01em}
.tour-card p{color:var(--muted);font-size:15px;line-height:1.65;margin-bottom:18px}
.tour-card kbd{
  background:rgba(255,255,255,.08);border:1px solid var(--border);
  border-radius:5px;padding:2px 8px;font-family:'JetBrains Mono',monospace;
  font-size:12px;color:var(--ink);font-weight:600;
}
.tour-dots{display:flex;gap:6px;justify-content:center;margin:18px 0}
.tour-dots span{width:8px;height:8px;border-radius:50%;background:rgba(255,255,255,.15)}
.tour-dots span.active{background:var(--accent)}
.tour-actions{display:flex;gap:10px;justify-content:flex-end;margin-top:8px}
.tour-actions button{
  padding:9px 18px;border-radius:8px;font-size:13.5px;font-weight:600;cursor:pointer;
  font-family:inherit;transition:all var(--t-fast);
}
.tour-actions .skip{background:transparent;color:var(--muted)}
.tour-actions .skip:hover{color:var(--ink)}
.tour-actions .next{background:var(--grad-primary);color:#fff;border:none;box-shadow:0 4px 12px rgba(122,162,255,.3)}
.tour-actions .next:hover{transform:translateY(-1px)}

/* ============ Confetti canvas ============ */
#confetti{
  position:fixed;inset:0;pointer-events:none;z-index:300;
  display:none;
}
#confetti.go{display:block}

/* ============ Demos section ============ */
.demos-wrap{
  background:var(--panel);
  border:1px solid var(--border);
  border-radius:var(--rad-lg);
  padding:8px;
  backdrop-filter:blur(20px);
  box-shadow:var(--shadow-lg);
}
.demo-tabs{
  display:flex;gap:4px;padding:6px;
  background:rgba(7,9,18,.4);border-radius:14px;margin-bottom:8px;
  flex-wrap:wrap;
}
.demo-tab{
  flex:1;min-width:140px;
  padding:14px 18px;border-radius:10px;
  font-size:14px;font-weight:600;color:var(--muted);
  display:flex;align-items:center;gap:8px;justify-content:center;
  transition:all var(--t-fast);
}
.demo-tab:hover{color:var(--ink);background:rgba(122,162,255,.06)}
.demo-tab.active{
  background:var(--grad-primary);color:#fff;
  box-shadow:0 4px 14px rgba(122,162,255,.4);
}
.demo-tab .ico{font-size:18px}
.demo-panel{
  display:none;padding:32px;
  border-radius:14px;
  background:linear-gradient(180deg,rgba(20,26,42,.4),rgba(14,18,30,.6));
  border:1px solid var(--border);
  animation:fade-in .4s var(--ease-out);
}
.demo-panel.active{display:block}
@keyframes fade-in{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}
.demo-head{margin-bottom:24px}
.demo-head h3{font-family:'Space Grotesk',sans-serif;font-size:24px;font-weight:700;margin-bottom:8px}
.demo-head p{color:var(--muted);font-size:15px;max-width:680px;line-height:1.6}
.demo-canvas-wrap{
  background:rgba(7,9,18,.5);
  border:1px solid var(--border);border-radius:12px;
  padding:16px;margin-bottom:18px;
  position:relative;overflow:hidden;
}
.demo-controls{
  display:flex;gap:12px;flex-wrap:wrap;align-items:center;
}
.demo-btn{
  padding:9px 18px;border-radius:8px;
  background:var(--grad-primary);color:#fff;
  font-weight:600;font-size:13.5px;
  box-shadow:0 4px 12px rgba(122,162,255,.3);
  transition:all var(--t-fast);
}
.demo-btn:hover{transform:translateY(-2px);box-shadow:0 6px 18px rgba(122,162,255,.45)}
.demo-btn.alt{
  background:rgba(255,255,255,.06);
  border:1px solid var(--border);
}
.demo-btn.alt:hover{background:rgba(255,255,255,.1)}
.demo-slider{
  display:flex;align-items:center;gap:10px;
  background:rgba(255,255,255,.04);border:1px solid var(--border);
  padding:8px 14px;border-radius:8px;font-size:13px;color:var(--muted);
}
.demo-slider input{
  -webkit-appearance:none;appearance:none;
  width:120px;height:4px;
  background:rgba(255,255,255,.1);border-radius:99px;outline:none;
}
.demo-slider input::-webkit-slider-thumb{
  -webkit-appearance:none;width:16px;height:16px;border-radius:50%;
  background:var(--accent);cursor:pointer;
  box-shadow:0 0 0 4px rgba(122,162,255,.2);
  transition:all var(--t-fast);
}
.demo-slider input::-webkit-slider-thumb:hover{transform:scale(1.2)}
.demo-slider input::-moz-range-thumb{width:16px;height:16px;border-radius:50%;background:var(--accent);cursor:pointer;border:none}
.demo-slider .val{font-family:'JetBrains Mono',monospace;color:var(--accent);font-weight:600;min-width:36px;text-align:right}

/* NN playground specific */
#nn-canvas{width:100%;height:380px;display:block}
.nn-info{display:flex;gap:20px;flex-wrap:wrap;margin-top:14px;font-size:13px;color:var(--muted)}
.nn-info span{display:inline-flex;align-items:center;gap:6px}
.nn-info code{background:rgba(122,162,255,.1);color:var(--accent);padding:2px 8px;border-radius:4px;font-family:'JetBrains Mono',monospace;font-size:12px;font-weight:600}

/* Tokenizer */
#tok-input{
  width:100%;min-height:80px;
  background:rgba(7,9,18,.6);border:1px solid var(--border);
  border-radius:10px;padding:14px 16px;
  color:var(--ink);font-family:'JetBrains Mono',monospace;font-size:14px;
  resize:vertical;line-height:1.6;
  transition:border-color var(--t-fast);
}
#tok-input:focus{outline:none;border-color:var(--accent);box-shadow:0 0 0 3px rgba(122,162,255,.15)}
#tok-output{
  display:flex;flex-wrap:wrap;gap:6px;
  padding:16px;background:rgba(7,9,18,.5);
  border:1px dashed var(--border);border-radius:10px;
  min-height:80px;margin-top:14px;
}
.tok{
  display:inline-flex;flex-direction:column;align-items:center;
  padding:6px 10px;border-radius:6px;
  font-family:'JetBrains Mono',monospace;font-size:13px;font-weight:600;
  color:#fff;line-height:1.2;
  animation:tok-in .3s var(--ease-out);
}
@keyframes tok-in{from{opacity:0;transform:scale(.7)}to{opacity:1;transform:scale(1)}}
.tok .id{font-size:10px;opacity:.7;font-weight:500;margin-top:2px}
.tok-stats{display:flex;gap:18px;flex-wrap:wrap;margin-top:14px;font-size:13px;color:var(--muted)}
.tok-stats b{color:var(--ink);font-family:'JetBrains Mono',monospace;font-weight:700;margin-right:4px}

/* Attention */
#att-grid{
  display:grid;gap:2px;margin:14px 0;
  background:rgba(7,9,18,.6);padding:14px;border-radius:10px;border:1px solid var(--border);
  overflow-x:auto;
}
.att-row{display:contents}
.att-cell{
  min-width:42px;height:42px;
  display:grid;place-items:center;
  font-size:11px;font-weight:600;
  border-radius:4px;cursor:pointer;
  transition:all var(--t-fast);
  font-family:'JetBrains Mono',monospace;
}
.att-cell.label{
  background:transparent;color:var(--muted);font-weight:700;
  font-family:'Inter',sans-serif;font-size:12px;
}
.att-cell.label.row{justify-self:end;padding-right:6px;text-align:right}
.att-cell.data:hover{transform:scale(1.15);z-index:2;box-shadow:0 0 0 2px var(--accent)}
.att-legend{display:flex;gap:14px;align-items:center;flex-wrap:wrap;font-size:13px;color:var(--muted);margin-top:14px}
.att-bar{
  height:10px;width:160px;border-radius:5px;
  background:linear-gradient(90deg,rgba(122,162,255,.05),rgba(122,162,255,1));
  border:1px solid var(--border);
}

/* Gradient descent */
#gd-canvas{width:100%;height:380px;display:block;border-radius:8px}
.gd-stats{
  display:flex;gap:24px;flex-wrap:wrap;margin-top:14px;
  font-family:'JetBrains Mono',monospace;font-size:13px;color:var(--muted);
}
.gd-stats span{display:inline-flex;align-items:center;gap:6px}
.gd-stats b{color:var(--gold);font-weight:600}

/* ============ Glossary ============ */
.glossary-search{
  width:100%;max-width:560px;margin:0 auto 32px;display:block;
  padding:14px 20px;
  background:rgba(7,9,18,.6);border:1px solid var(--border);
  border-radius:99px;color:var(--ink);
  font-size:15px;
  transition:all var(--t-fast);
}
.glossary-search:focus{outline:none;border-color:var(--accent);box-shadow:0 0 0 3px rgba(122,162,255,.15)}
.glossary-grid{
  display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));
  gap:14px;
}
.glo-item{
  background:var(--panel);border:1px solid var(--border);
  border-radius:var(--rad-sm);padding:18px 20px;
  transition:all var(--t-base);
}
.glo-item:hover{border-color:var(--border-strong);transform:translateY(-2px);box-shadow:var(--shadow-md)}
.glo-item h4{
  font-family:'Space Grotesk',sans-serif;font-size:16px;font-weight:700;
  color:var(--accent);margin-bottom:6px;
}
.glo-item p{font-size:13.5px;color:var(--muted);line-height:1.55}
.glo-item.hidden{display:none}

/* ============ Papers ============ */
.papers-list{
  display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));
  gap:14px;
}
.paper{
  background:var(--panel);border:1px solid var(--border);
  border-radius:var(--rad-sm);padding:18px 20px;
  display:flex;gap:14px;
  transition:all var(--t-base);
}
.paper:hover{border-color:var(--border-strong);transform:translateY(-2px);box-shadow:var(--shadow-md)}
.paper-num{
  width:36px;height:36px;border-radius:8px;
  background:rgba(122,162,255,.1);color:var(--accent);
  display:grid;place-items:center;font-weight:700;font-size:13px;
  font-family:'JetBrains Mono',monospace;flex-shrink:0;
  border:1px solid rgba(122,162,255,.25);
}
.paper-body{flex:1}
.paper h4{font-size:15px;font-weight:600;margin-bottom:4px;line-height:1.3}
.paper .yr{font-size:12px;color:var(--dim);font-family:'JetBrains Mono',monospace}
.paper p{font-size:13px;color:var(--muted);margin-top:6px;line-height:1.55}

/* ============ Tools cheat sheet ============ */
.tools-grid{
  display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));
  gap:12px;
}
.tool-card{
  background:var(--panel);border:1px solid var(--border);
  border-radius:var(--rad-sm);padding:18px;
  transition:all var(--t-base);
}
.tool-card:hover{border-color:var(--border-strong);transform:translateY(-2px)}
.tool-card .lbl{font-size:11px;color:var(--dim);text-transform:uppercase;letter-spacing:.08em;font-weight:600;margin-bottom:6px}
.tool-card .val{font-family:'JetBrains Mono',monospace;font-size:14px;color:var(--accent);font-weight:600}

/* ============ FAQ ============ */
.faq{max-width:780px;margin:0 auto}
.faq-item{
  background:var(--panel);border:1px solid var(--border);
  border-radius:var(--rad-sm);margin-bottom:10px;
  overflow:hidden;
  transition:all var(--t-base);
}
.faq-item:hover{border-color:var(--border-strong)}
.faq-q{
  width:100%;text-align:left;padding:20px 24px;
  font-size:16px;font-weight:600;color:var(--ink);
  display:flex;justify-content:space-between;align-items:center;
}
.faq-q::after{
  content:"+";font-size:22px;color:var(--accent);font-weight:300;
  transition:transform var(--t-base);
}
.faq-item.open .faq-q::after{transform:rotate(45deg)}
.faq-a{
  max-height:0;overflow:hidden;
  transition:max-height var(--t-base) var(--ease);
  color:var(--muted);
  padding:0 24px;
}
.faq-item.open .faq-a{max-height:400px;padding:0 24px 22px}
.faq-a p{font-size:14.5px;line-height:1.65}

/* ============ Deep Concepts ============ */
.concept-item .faq-q{align-items:flex-start;gap:12px}
.concept-item .faq-q > span{display:flex;align-items:center;gap:10px;flex-wrap:wrap;text-align:left}
.concept-tag{
  display:inline-block;font-size:10px;font-weight:700;letter-spacing:.06em;text-transform:uppercase;
  padding:3px 9px;border-radius:99px;
  background:rgba(122,162,255,.12);color:var(--accent);border:1px solid rgba(122,162,255,.3);
  flex-shrink:0;
}
.concept-item.open .concept-body{max-height:none;padding:4px 26px 24px}
.concept-body p{font-size:14.5px;line-height:1.72;color:var(--ink);margin:0 0 12px}
.concept-body p:last-child{margin-bottom:0}
.concept-body b,.concept-body strong{color:var(--accent);font-weight:600}
.concept-body i,.concept-body em{color:var(--gold);font-style:normal}
.concept-body code{font-size:12.5px}
#conceptSearch{margin-bottom:26px}

/* ============ Build an Agent ============ */
#agent-steps{max-width:880px;margin:0 auto;position:relative}
#agent-steps::before{
  content:"";position:absolute;left:19px;top:20px;bottom:20px;width:2px;
  background:linear-gradient(180deg,var(--accent),var(--accent2),var(--gold));
  opacity:.3;
}
@media(max-width:640px){#agent-steps::before{display:none}}
.agent-step{display:flex;gap:18px;margin-bottom:26px;position:relative}
.agent-step-num{
  flex-shrink:0;width:40px;height:40px;border-radius:50%;
  background:radial-gradient(circle,var(--panel-solid),var(--bg));
  border:2px solid var(--accent);color:var(--accent);
  display:grid;place-items:center;font-family:'JetBrains Mono',monospace;font-weight:700;font-size:15px;
  z-index:1;box-shadow:0 0 0 6px var(--bg);
}
.agent-step-main{flex:1;min-width:0}
.agent-step-main h3{
  font-family:'Space Grotesk',sans-serif;font-size:19px;font-weight:700;margin:6px 0 8px;
  color:var(--ink);letter-spacing:-.01em;
}
.agent-why{font-size:14.5px;line-height:1.7;color:var(--muted);margin:0 0 12px}
.agent-why b{color:var(--accent)}
@media(max-width:640px){
  .agent-step{gap:12px}
  .agent-step-num{width:32px;height:32px;font-size:13px}
}

/* ============ Footer CTA ============ */
.cta-final{
  text-align:center;padding:80px 24px;
  background:linear-gradient(135deg,rgba(122,162,255,.06),rgba(157,122,255,.04));
  border-top:1px solid var(--border);border-bottom:1px solid var(--border);
}
.cta-final h2{font-family:'Space Grotesk',sans-serif;font-size:clamp(28px,4.5vw,44px);font-weight:700;margin-bottom:16px;letter-spacing:-.02em}
.cta-final p{color:var(--muted);max-width:520px;margin:0 auto 30px;font-size:17px}

footer{
  padding:60px 24px 40px;text-align:center;
  color:var(--dim);font-size:13px;
}
footer .links{display:flex;gap:24px;justify-content:center;margin-bottom:18px;flex-wrap:wrap}
footer .links a{color:var(--muted);font-weight:500}
footer .links a:hover{color:var(--accent)}
footer .built{font-size:12px;margin-top:14px;opacity:.7}

/* ============ Utilities ============ */
.text-grad{background:var(--grad-text);-webkit-background-clip:text;background-clip:text;color:transparent}
@media(prefers-reduced-motion:reduce){
  *,*::before,*::after{animation:none !important;transition:none !important}
  .reveal{opacity:1;transform:none}
}

/* ============ PRINT — clean study guide ============ */
@media print{
  *,*::before,*::after{
    animation:none !important;transition:none !important;
    background:none !important;box-shadow:none !important;backdrop-filter:none !important;
  }
  body{color:#000;background:#fff !important;font-size:11pt;line-height:1.5}
  .nav,.scroll-progress,.hero,.resume-banner,.demos-wrap,.cta-final,
  .scroll-cue,#playground,#flashcards,#hero-canvas,#confetti,
  .modal-bg,.palette-bg,.tour-bg,.lesson-page-bar,.glossary-search,
  .nav-cta,.kbd-trigger,footer .links{display:none !important}
  section.block{padding:24px 0;page-break-inside:avoid}
  .section-head{margin-bottom:18px;text-align:left}
  .section-head h2,.section-head h2 .grad,h3,h4{color:#000 !important;-webkit-text-fill-color:#000 !important}
  .section-eyebrow{color:#555 !important}
  .section-head p{color:#333 !important}
  .container{max-width:none;padding:0 12mm}
  .phase{display:block !important;margin-bottom:18px;page-break-inside:avoid}
  .phase-num{position:static;display:inline-block;width:auto;height:auto;background:none;color:#000;border:none;box-shadow:none;font-size:14pt;margin-right:8px}
  .phase-num::after{content:""}
  .phase-card{border:1px solid #888;padding:14px;background:none !important}
  .phase-eli5{background:none !important;border:1px solid #aaa;color:#333 !important}
  .phase-meta .tag,.topic-pill,.tag{background:#eee !important;color:#000 !important;border:1px solid #999 !important;-webkit-print-color-adjust:exact;print-color-adjust:exact}
  .phase-projects li{color:#000 !important}
  .phase-projects li::before{content:"-";color:#000}
  .phase-help,.phase-actions,.btn-open-lesson{display:none !important}
  .glossary-grid{display:block;column-count:2;column-gap:18px}
  .glo-item{break-inside:avoid;border:1px solid #ccc;padding:10px;margin:0 0 8px 0;background:none !important}
  .glo-item h4{color:#000 !important}
  .glo-item p{color:#222 !important}
  .papers-list,.tools-grid{display:block}
  .paper,.tool-card{break-inside:avoid;border:1px solid #ccc;padding:10px;margin-bottom:6px;background:none !important}
  .paper h4,.tool-card .val{color:#000 !important}
  .faq-item{border:1px solid #aaa;background:none !important}
  .faq-q::after{content:""}
  .faq-a{max-height:none !important;padding:0 16px 12px !important;color:#222 !important}
  a{color:#000;text-decoration:underline}
  a[href^="http"]::after{content:" (" attr(href) ")";font-size:9pt;color:#666}
  pre,code{border:1px solid #888 !important;background:#f7f7f7 !important;color:#000 !important;-webkit-print-color-adjust:exact;print-color-adjust:exact}
  .reveal{opacity:1 !important;transform:none !important}
  #flashcards,#playground,#why{display:none !important}
}