/* ======================================================================
   Professor of Data — shared stylesheet
   One file powers the home, both track grids, and every course page.
   ====================================================================== */
:root{
  --ground:#eef1f7; --paper:#ffffff; --ink:#0b1220; --ink-soft:#3f4a5f; --ink-faint:#7a869c;
  --rule:#dbe1ec; --teal:#0a6f7d; --teal-deep:#064a54;
  /* level colours */
  --lv-b:#128a4b; --lv-i:#d07a00; --lv-a:#d21f3c; --lv-s:#6d3fc4; --prac:#2563eb;
  --code-bg:#0e1626; --code-ink:#d8e3f2; --hl:#fff2a8;
  /* brand gradient */
  --g1:#0a6f7d; --g2:#3b3fb6; --g3:#6d3fc4;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:74px}
body{margin:0;background:var(--ground);color:var(--ink);
  font-family:"Source Serif 4",Georgia,"Times New Roman",serif;font-size:16px;line-height:1.62;
  -webkit-font-smoothing:antialiased}
h1,h2,h3,h4,.ui{font-family:"IBM Plex Sans Condensed","Helvetica Neue",Arial,sans-serif}
code,pre,.mono{font-family:"IBM Plex Mono",ui-monospace,Menlo,Consolas,monospace}
a{color:inherit;text-decoration:none}
.wrap{max-width:1200px;margin:0 auto;padding:0 26px}
img{max-width:100%}

/* ---------------- header ---------------- */
.top{position:sticky;top:0;z-index:60;
  background:linear-gradient(100deg,var(--g1),var(--g2) 55%,var(--g3));
  color:#eaf0fb;box-shadow:0 2px 18px -8px rgba(10,20,50,.6)}
.top .wrap{display:flex;align-items:center;gap:16px;height:64px}
.logo{display:flex;align-items:center;gap:11px;font-family:"IBM Plex Sans Condensed";font-weight:700;
  font-size:1.24rem;color:#fff;letter-spacing:.005em}
.logo .mark{width:30px;height:30px;border-radius:9px;background:rgba(255,255,255,.16);
  display:grid;place-items:center;font-size:1rem;border:1px solid rgba(255,255,255,.28)}
.logo span{color:#ffe08a}
.nav{display:flex;gap:6px;margin-left:8px}
.nav a{font-family:"IBM Plex Sans Condensed";font-weight:600;font-size:.86rem;color:#dfe7f7;
  padding:7px 13px;border-radius:9px;transition:.15s}
.nav a:hover,.nav a.on{background:rgba(255,255,255,.16);color:#fff}
.top .spacer{flex:1}
.pill{font-family:"IBM Plex Mono";font-size:.66rem;letter-spacing:.14em;text-transform:uppercase;
  color:#fff;border:1px solid rgba(255,255,255,.4);border-radius:999px;padding:5px 12px}
.crumbs{font-family:"IBM Plex Mono";font-size:.72rem;color:#cbd6ee;letter-spacing:.03em}
.crumbs a:hover{color:#fff;text-decoration:underline}

/* ---------------- home / hero ---------------- */
.hero{padding:70px 0 26px;text-align:center;position:relative}
.eyebrow{font-family:"IBM Plex Sans Condensed";font-weight:600;font-size:.82rem;letter-spacing:.22em;
  text-transform:uppercase;color:var(--teal)}
.hero h1{font-size:3.3rem;line-height:1.03;margin:.3em 0 .22em;letter-spacing:-.022em}
.hero h1 .grad{background:linear-gradient(100deg,var(--g1),var(--g3));-webkit-background-clip:text;
  background-clip:text;color:transparent}
.hero p{font-size:1.2rem;color:var(--ink-soft);max-width:660px;margin:0 auto}
.metrics{display:flex;gap:26px;justify-content:center;margin:26px 0 0;flex-wrap:wrap}
.metric{font-family:"IBM Plex Sans Condensed"}
.metric b{display:block;font-size:1.7rem;color:var(--ink);line-height:1}
.metric small{font-size:.74rem;letter-spacing:.12em;text-transform:uppercase;color:var(--ink-faint)}

.tracks{display:grid;grid-template-columns:1fr 1fr;gap:26px;padding:34px 0 60px}
@media(max-width:820px){.tracks{grid-template-columns:1fr}.hero h1{font-size:2.4rem}}
.track{background:var(--paper);border:1px solid var(--rule);border-radius:20px;padding:36px 32px;
  transition:.18s;position:relative;overflow:hidden;display:block}
.track:hover{transform:translateY(-5px);box-shadow:0 22px 46px -24px rgba(10,30,60,.5)}
.track::before{content:"";position:absolute;inset:0 0 auto 0;height:7px}
.track.analytics::before{background:linear-gradient(90deg,#128a4b,#0a9bd1,#2563eb)}
.track.engineering::before{background:linear-gradient(90deg,#d21f3c,#e25a1c,#6d3fc4)}
.track .ki{font-family:"IBM Plex Mono";font-size:.72rem;letter-spacing:.16em;text-transform:uppercase;color:var(--ink-faint)}
.track h2{font-size:2rem;margin:.28em 0 .3em}
.track .desc{color:var(--ink-soft);min-height:50px}
.chips{display:flex;flex-wrap:wrap;gap:7px;margin:16px 0 20px}
.chips span{font-family:"IBM Plex Sans Condensed";font-size:.78rem;background:#eef2f8;border:1px solid var(--rule);
  color:var(--ink-soft);border-radius:7px;padding:4px 9px}
.enter{display:inline-flex;align-items:center;gap:8px;font-family:"IBM Plex Sans Condensed";font-weight:700;color:var(--teal-deep)}
.enter::after{content:"→";transition:.18s}.track:hover .enter::after{transform:translateX(6px)}

/* ---------------- course grid ---------------- */
.phead{padding:44px 0 4px}
.phead .eb{font-family:"IBM Plex Sans Condensed";font-weight:600;font-size:.74rem;letter-spacing:.2em;
  text-transform:uppercase;color:var(--teal)}
.phead h1{font-size:2.5rem;margin:.12em 0}
.phead .sub{color:var(--ink-soft)}
.grouplabel{font-family:"IBM Plex Sans Condensed";font-weight:700;font-size:.72rem;letter-spacing:.16em;
  text-transform:uppercase;color:var(--ink-faint);margin:34px 0 14px;border-bottom:1px solid var(--rule);padding-bottom:7px}
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(236px,1fr));gap:16px;padding-bottom:6px}
.course{--c:#0a6f7d;background:var(--paper);border:1px solid var(--rule);border-radius:14px;
  padding:0 0 16px;overflow:hidden;transition:.16s;position:relative;display:block}
.course:hover{transform:translateY(-4px);box-shadow:0 16px 34px -22px rgba(10,30,60,.45);border-color:var(--c)}
.course .band{height:6px;background:var(--c)}
.course .body{padding:15px 17px 0}
.course .cn{font-family:"IBM Plex Mono";font-size:.66rem;color:var(--c);letter-spacing:.06em;font-weight:600}
.course h3{font-size:1.24rem;margin:.32em 0 .28em}
.course .meta{font-size:.82rem;color:var(--ink-faint);min-height:34px}
.course .lvs{display:flex;gap:5px;margin-top:10px}
.course .lvs i{width:22px;height:6px;border-radius:3px;display:inline-block;opacity:.9}
.i-b{background:var(--lv-b)}.i-i{background:var(--lv-i)}.i-a{background:var(--lv-a)}.i-s{background:var(--lv-s)}.i-p{background:var(--prac)}
.course.soon{opacity:.72}
.badge{position:absolute;top:12px;right:12px;font-family:"IBM Plex Mono";font-size:.58rem;letter-spacing:.1em;
  text-transform:uppercase;border-radius:6px;padding:3px 7px;font-weight:600}
.badge.soon{color:var(--ink-faint);border:1px solid var(--rule);background:#fff}
.badge.ready{color:#fff;background:var(--lv-b)}

/* ---------------- course page ---------------- */
.shell{display:grid;grid-template-columns:256px minmax(0,1fr);gap:0;min-height:calc(100vh - 64px)}
@media(max-width:920px){.shell{grid-template-columns:1fr}.side{display:none}}
.side{position:sticky;top:64px;height:calc(100vh - 64px);overflow:auto;background:var(--ink);color:#c6d2e4;padding:22px 16px 50px}
.side::-webkit-scrollbar{width:8px}.side::-webkit-scrollbar-thumb{background:#28374f;border-radius:8px}
.side .cbrand{font-family:"IBM Plex Sans Condensed";font-weight:700;color:#fff;font-size:1.2rem;line-height:1.1}
.side .cbrand small{display:block;font-size:.64rem;letter-spacing:.16em;text-transform:uppercase;color:var(--c,#29b5e8);margin-bottom:5px}
.side input{width:100%;margin:16px 0 14px;padding:9px 11px;border-radius:8px;border:1px solid #2a3a54;
  background:#131d2f;color:#e6edf7;font-family:"IBM Plex Mono";font-size:.76rem}
.side input::placeholder{color:#5e6e88}
.side input:focus{outline:2px solid var(--teal);outline-offset:1px}
.snav a{display:flex;justify-content:space-between;align-items:center;padding:8px 10px;border-radius:8px;
  color:#aebdd3;font-family:"IBM Plex Sans Condensed";font-size:.92rem;border-left:3px solid transparent;margin-bottom:2px}
.snav a:hover,.snav a.on{background:#16223a;color:#fff}
.snav a.on{border-left-color:var(--teal)}
.snav a .n{font-family:"IBM Plex Mono";font-size:.7rem;color:#6f8099}
.dot::before{content:"";width:8px;height:8px;border-radius:50%;display:inline-block;margin-right:9px;vertical-align:middle}
.dot.b::before{background:var(--lv-b)}.dot.i::before{background:var(--lv-i)}.dot.a::before{background:var(--lv-a)}
.dot.s::before{background:var(--lv-s)}.dot.p::before{background:var(--prac)}
.side .back{display:inline-block;margin-bottom:8px;font-family:"IBM Plex Sans Condensed";font-size:.8rem;color:#8fa0bd}
.side .back:hover{color:#fff}

.main{padding:26px 40px 100px;max-width:920px}
@media(max-width:920px){.main{padding:22px}}
.cover2{border-bottom:2px solid var(--rule);padding-bottom:22px;margin-bottom:8px}
.cover2 .eb{font-family:"IBM Plex Sans Condensed";font-weight:600;font-size:.72rem;letter-spacing:.2em;text-transform:uppercase;color:var(--c,var(--teal))}
.cover2 h1{font-size:2.7rem;margin:.14em 0 .12em}
.cover2 .sub{color:var(--ink-soft)}
.statline{display:flex;gap:8px;flex-wrap:wrap;margin-top:18px}
.stat{font-family:"IBM Plex Sans Condensed";font-weight:600;font-size:.78rem;border-radius:8px;padding:5px 12px;color:#fff}
.stat.b{background:var(--lv-b)}.stat.i{background:var(--lv-i)}.stat.a{background:var(--lv-a)}.stat.s{background:var(--lv-s)}.stat.p{background:var(--prac)}

.cram{position:sticky;top:64px;z-index:30;background:rgba(238,241,247,.95);backdrop-filter:blur(6px);
  display:flex;flex-wrap:wrap;gap:8px;align-items:center;padding:12px 0;border-bottom:1px solid var(--rule);margin-bottom:6px}
.cram .lbl{font-family:"IBM Plex Sans Condensed";font-size:.72rem;letter-spacing:.14em;text-transform:uppercase;color:var(--ink-faint)}
.tog{font-family:"IBM Plex Sans Condensed";font-weight:600;font-size:.82rem;border:1px solid var(--rule);
  background:#fff;color:var(--ink-soft);border-radius:9px;padding:6px 12px;cursor:pointer;transition:.12s}
.tog:hover{border-color:#b9c3d4}
.tog.off{opacity:.45;text-decoration:line-through}
.tog[data-lv="b"][aria-pressed="true"]{background:var(--lv-b);border-color:var(--lv-b);color:#fff}
.tog[data-lv="i"][aria-pressed="true"]{background:var(--lv-i);border-color:var(--lv-i);color:#fff}
.tog[data-lv="a"][aria-pressed="true"]{background:var(--lv-a);border-color:var(--lv-a);color:#fff}
.tog[data-lv="s"][aria-pressed="true"]{background:var(--lv-s);border-color:var(--lv-s);color:#fff}
.tog[data-lv="p"][aria-pressed="true"]{background:var(--prac);border-color:var(--prac);color:#fff}
.count{margin-left:auto;font-family:"IBM Plex Mono";font-size:.74rem;color:var(--ink-faint)}

.sec{margin:36px 0 8px}
.sec .st{font-family:"IBM Plex Sans Condensed";font-weight:700;font-size:1.8rem;display:flex;align-items:center;gap:12px}
.sec .st .tag{font-size:.66rem;letter-spacing:.12em;text-transform:uppercase;color:#fff;border-radius:6px;padding:3px 9px}
.sec .st .tag.b{background:var(--lv-b)}.sec .st .tag.i{background:var(--lv-i)}.sec .st .tag.a{background:var(--lv-a)}.sec .st .tag.s{background:var(--lv-s)}.sec .st .tag.p{background:var(--prac)}
.sec .sd{color:var(--ink-soft);font-size:.96rem;margin-top:2px}

.q{background:var(--paper);border:1px solid var(--rule);border-radius:12px;padding:20px 22px;margin:14px 0;border-top-width:4px}
.q.b{border-top-color:var(--lv-b)}.q.i{border-top-color:var(--lv-i)}.q.a{border-top-color:var(--lv-a)}.q.s{border-top-color:var(--lv-s)}
.q header{display:flex;align-items:center;gap:11px;margin-bottom:8px}
.qn{font-family:"IBM Plex Mono";font-size:.72rem;color:var(--ink-faint)}
.chip{font-family:"IBM Plex Sans Condensed";font-weight:600;font-size:.66rem;color:#fff;border-radius:5px;padding:2px 8px;letter-spacing:.04em}
.chip.b{background:var(--lv-b)}.chip.i{background:var(--lv-i)}.chip.a{background:var(--lv-a)}.chip.s{background:var(--lv-s)}.chip.p{background:var(--prac)}
.q h3{font-size:1.16rem;margin:0;line-height:1.35}
.q .ans{margin-top:8px}
.q .ans>:first-child{margin-top:0}.q .ans>:last-child{margin-bottom:0}
.q p{margin:.55em 0}
.q ul,.q ol{margin:.5em 0;padding-left:20px}.q li{margin:.3em 0}
.q table{border-collapse:collapse;width:100%;margin:.6em 0;font-size:.92rem}
.q th,.q td{border:1px solid var(--rule);padding:6px 10px;text-align:left}
.q th{background:#eef3f4;font-family:"IBM Plex Sans Condensed";font-size:.86rem}
em.key{font-style:normal;background:var(--hl);padding:0 3px;border-radius:3px;font-weight:600}
.q code{background:#eef1f6;color:#0e2a35;border-radius:4px;padding:1px 5px;font-size:.86em}
pre{background:var(--code-bg);color:var(--code-ink);border-radius:10px;padding:14px 16px;overflow:auto;font-size:.82rem;line-height:1.5}
pre code{background:none;color:inherit;padding:0}
.fu{margin-top:14px;background:#eef4f5;border-left:4px solid var(--teal-deep);border-radius:8px;padding:11px 16px}
.fu b{font-family:"IBM Plex Sans Condensed";font-size:.7rem;letter-spacing:.1em;text-transform:uppercase;color:var(--teal-deep)}
.fu ul{margin:6px 0 0;padding-left:18px}.fu li{margin:4px 0;color:var(--ink-soft);font-size:.93rem}
.trap{margin-top:12px;background:#fbecef;border-left:4px solid var(--lv-a);border-radius:8px;padding:11px 16px;font-size:.93rem;color:#6b1020}
.trap b{font-family:"IBM Plex Sans Condensed";font-size:.7rem;letter-spacing:.1em;text-transform:uppercase;color:var(--lv-a);display:block;margin-bottom:3px}

/* practical */
.prob{background:var(--paper);border:1px solid var(--rule);border-radius:12px;padding:20px 22px;margin:14px 0;border-top:4px solid var(--prac)}
.prob header{display:flex;align-items:center;gap:11px;margin-bottom:6px}
.prob h3{font-size:1.14rem;margin:0}
.schema{background:#f4f7fa;border:1px dashed #b9c6d8;border-radius:8px;padding:10px 14px;font-family:"IBM Plex Mono";
  font-size:.78rem;color:var(--ink-soft);margin:10px 0;white-space:pre-wrap}
.reveal{margin-top:12px}
.reveal>button{font-family:"IBM Plex Sans Condensed";font-weight:600;font-size:.82rem;background:#eef2f8;
  border:1px solid var(--rule);border-radius:9px;padding:7px 15px;cursor:pointer;color:var(--teal-deep)}
.reveal>button:hover{background:#e3e9f2}
.reveal>button::after{content:" ▾"}
.reveal.open>button::after{content:" ▴"}
.sol{display:none;margin-top:12px}
.reveal.open .sol{display:block}
.sol .why{font-size:.9rem;color:var(--ink-soft);margin:.5em 0 0}

.note{background:#fff8e6;border:1px solid #f0d79a;border-radius:12px;padding:15px 20px;margin:20px 0;font-size:.95rem}
.note b{font-family:"IBM Plex Sans Condensed"}
.nores{display:none;color:var(--ink-faint);font-style:italic;padding:20px 0}
.foot{color:var(--ink-faint);font-size:.82rem;text-align:center;padding:40px 0 20px;border-top:1px solid var(--rule);margin-top:40px}
body.cramming .cram{box-shadow:0 3px 0 -1px var(--lv-a)}

/* ---------------- header dropdowns ---------------- */
.nav .dd{position:relative}
.nav .dd>a::after{content:" ▾";font-size:.7em;opacity:.8}
.dmenu{position:absolute;top:calc(100% + 8px);left:0;min-width:250px;background:#fff;color:var(--ink);
  border:1px solid var(--rule);border-radius:12px;box-shadow:0 18px 44px -18px rgba(10,20,50,.45);
  padding:8px;display:none;z-index:80}
.nav .dd.open .dmenu{display:block}
.dmenu .dh{font-family:"IBM Plex Sans Condensed";font-size:.62rem;letter-spacing:.16em;text-transform:uppercase;
  color:var(--ink-faint);padding:7px 10px 4px}
.dmenu a{display:flex;align-items:center;gap:9px;padding:7px 10px;border-radius:8px;
  font-family:"IBM Plex Sans Condensed";font-weight:600;font-size:.88rem;color:var(--ink-soft)}
.dmenu a:hover{background:#eef2f8;color:var(--ink)}
.dmenu a .sw{width:9px;height:9px;border-radius:3px;flex:none}
.dmenu a .soon{margin-left:auto;font-family:"IBM Plex Mono";font-size:.56rem;letter-spacing:.08em;
  text-transform:uppercase;color:var(--ink-faint);border:1px solid var(--rule);border-radius:5px;padding:1px 5px}
.dmenu a.ready .go{margin-left:auto;color:var(--lv-b);font-weight:700}
.dmenu .split{display:grid;grid-template-columns:1fr 1fr;gap:0 6px}
@media(max-width:760px){.dmenu{position:fixed;left:12px;right:12px;min-width:0}.dmenu .split{grid-template-columns:1fr}}

/* ---------------- hero CTAs + finder ---------------- */
.ctas{display:flex;gap:12px;justify-content:center;flex-wrap:wrap;margin:30px 0 4px}
.btn{display:inline-flex;align-items:center;gap:9px;font-family:"IBM Plex Sans Condensed";font-weight:700;
  font-size:.95rem;border-radius:12px;padding:12px 22px;cursor:pointer;border:1px solid transparent;transition:.15s}
.btn.primary{background:linear-gradient(100deg,var(--g1),var(--g2));color:#fff;box-shadow:0 10px 24px -12px rgba(30,50,150,.55)}
.btn.primary:hover{transform:translateY(-2px);box-shadow:0 14px 30px -12px rgba(30,50,150,.6)}
.btn.ghost{background:#fff;border-color:var(--rule);color:var(--ink)}
.btn.ghost:hover{border-color:var(--teal);color:var(--teal-deep)}
.finder{position:relative;max-width:520px;margin:26px auto 0}
.finder input{width:100%;padding:14px 18px 14px 44px;border-radius:14px;border:1px solid var(--rule);
  background:#fff;font-family:"IBM Plex Sans Condensed";font-size:1rem;color:var(--ink);
  box-shadow:0 8px 26px -18px rgba(10,30,60,.35)}
.finder input:focus{outline:2px solid var(--teal);outline-offset:1px}
.finder::before{content:"⌕";position:absolute;left:16px;top:50%;transform:translateY(-54%);font-size:1.2rem;color:var(--ink-faint)}
.fres{position:absolute;top:calc(100% + 6px);left:0;right:0;background:#fff;border:1px solid var(--rule);
  border-radius:12px;box-shadow:0 18px 44px -18px rgba(10,20,50,.4);padding:6px;display:none;z-index:70;
  max-height:320px;overflow:auto;text-align:left}
.fres.open{display:block}
.fres a{display:flex;align-items:center;gap:10px;padding:9px 11px;border-radius:8px;
  font-family:"IBM Plex Sans Condensed";font-weight:600;font-size:.92rem;color:var(--ink-soft)}
.fres a:hover,.fres a.sel{background:#eef2f8;color:var(--ink)}
.fres a .tr{margin-left:auto;font-family:"IBM Plex Mono";font-size:.6rem;color:var(--ink-faint)}
.fres .none{padding:10px 12px;color:var(--ink-faint);font-style:italic;font-size:.9rem}

/* ================= HOME v2 — visuals ================= */
/* animated gradient blobs behind hero */
.hero{overflow:visible}
.blobs{position:absolute;inset:-40px 0 0;pointer-events:none;z-index:-1}
.blob{position:absolute;border-radius:50%;filter:blur(70px);opacity:.5;animation:drift 16s ease-in-out infinite alternate}
.blob.b1{width:380px;height:380px;background:#7dd3fc;left:-120px;top:-40px}
.blob.b2{width:320px;height:320px;background:#c4b5fd;right:-100px;top:20px;animation-delay:-6s}
.blob.b3{width:260px;height:260px;background:#86efac;left:38%;top:180px;animation-delay:-11s;opacity:.4}
@keyframes drift{from{transform:translate(0,0) scale(1)}to{transform:translate(40px,26px) scale(1.12)}}
@media (prefers-reduced-motion:reduce){.blob{animation:none}}

/* scroll reveal */
.rv{opacity:0;transform:translateY(18px);transition:opacity .6s ease,transform .6s ease}
.rv.in{opacity:1;transform:none}

/* stats strip with animated counters */
.stats2{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin:8px 0 0}
@media(max-width:760px){.stats2{grid-template-columns:repeat(2,1fr)}}
.stat2{background:var(--paper);border:1px solid var(--rule);border-radius:14px;padding:18px 16px;text-align:center}
.stat2 b{display:block;font-family:"IBM Plex Sans Condensed";font-size:2rem;line-height:1;
  background:linear-gradient(100deg,var(--g1),var(--g3));-webkit-background-clip:text;background-clip:text;color:transparent}
.stat2 small{font-family:"IBM Plex Sans Condensed";font-size:.7rem;letter-spacing:.14em;text-transform:uppercase;color:var(--ink-faint)}

/* section headings */
.sech{text-align:center;margin:64px 0 22px}
.sech .eyebrow{display:block;margin-bottom:6px}
.sech h2{font-size:2rem;margin:0}
.sech p{color:var(--ink-soft);max-width:560px;margin:.5em auto 0}

/* level pipeline */
.pipeline{display:grid;grid-template-columns:repeat(5,1fr);gap:12px}
@media(max-width:900px){.pipeline{grid-template-columns:1fr;max-width:420px;margin:0 auto}}
.step{--sc:#128a4b;background:var(--paper);border:1px solid var(--rule);border-radius:14px;padding:18px 16px;
  position:relative;transition:.16s;border-top:4px solid var(--sc)}
.step:hover{transform:translateY(-4px);box-shadow:0 16px 32px -22px rgba(10,30,60,.45)}
.step .num2{font-family:"IBM Plex Mono";font-size:.66rem;color:var(--sc);font-weight:600;letter-spacing:.1em}
.step h3{font-size:1.16rem;margin:.3em 0 .25em}
.step p{font-size:.87rem;color:var(--ink-soft);margin:0}
.step .qty{display:inline-block;margin-top:10px;font-family:"IBM Plex Sans Condensed";font-weight:700;font-size:.72rem;
  color:#fff;background:var(--sc);border-radius:6px;padding:2px 9px}
.pipeline .step:not(:last-child)::after{content:"→";position:absolute;right:-14px;top:50%;transform:translateY(-50%);
  color:var(--ink-faint);font-size:1.1rem;z-index:2}
@media(max-width:900px){.pipeline .step::after{display:none}}

/* featured course spotlight */
.spot{display:grid;grid-template-columns:1.1fr .9fr;gap:0;background:var(--ink);border-radius:20px;
  overflow:hidden;color:#dbe4f2;box-shadow:0 24px 60px -30px rgba(5,15,40,.7)}
@media(max-width:860px){.spot{grid-template-columns:1fr}}
.spot .left{padding:38px 36px}
.spot .tagr{font-family:"IBM Plex Mono";font-size:.66rem;letter-spacing:.16em;text-transform:uppercase;color:#7ee0c0}
.spot h3{color:#fff;font-size:2rem;margin:.3em 0 .3em}
.spot p{color:#aebdd3;margin:0 0 20px}
.spot .lvrow{display:flex;gap:7px;flex-wrap:wrap;margin-bottom:22px}
.spot .lvrow span{font-family:"IBM Plex Sans Condensed";font-weight:600;font-size:.72rem;color:#fff;border-radius:6px;padding:3px 10px}
.spot .right{background:var(--code-bg);padding:26px 24px;display:flex;align-items:center}
.spot pre{margin:0;width:100%;background:transparent;font-size:.78rem}
.spot .cur{display:inline-block;width:8px;height:15px;background:#7ee0c0;vertical-align:-2px;animation:blink 1s steps(1) infinite}
@keyframes blink{50%{opacity:0}}

/* course universe cloud */
.universe{display:flex;flex-wrap:wrap;gap:9px;justify-content:center;max-width:900px;margin:0 auto}
.uchip{--c:#0a6f7d;display:inline-flex;align-items:center;gap:8px;font-family:"IBM Plex Sans Condensed";
  font-weight:600;font-size:.88rem;background:var(--paper);border:1px solid var(--rule);border-radius:999px;
  padding:8px 15px;color:var(--ink-soft);transition:.15s;cursor:pointer}
.uchip .sw{width:9px;height:9px;border-radius:50%;background:var(--c)}
.uchip:hover{border-color:var(--c);color:var(--ink);transform:translateY(-2px) scale(1.03);
  box-shadow:0 10px 22px -14px rgba(10,30,60,.45)}
.uchip.ready{border-color:var(--lv-b);background:#f0faf4}
.uchip .st{font-family:"IBM Plex Mono";font-size:.58rem;letter-spacing:.06em;text-transform:uppercase;color:var(--ink-faint)}
.uchip.ready .st{color:var(--lv-b);font-weight:700}

/* big footer */
.bigfoot{margin-top:80px;background:var(--ink);color:#aebdd3;border-radius:22px 22px 0 0}
.bigfoot .inner{max-width:1200px;margin:0 auto;padding:44px 26px 26px;display:grid;
  grid-template-columns:1.4fr 1fr 1fr;gap:26px}
@media(max-width:820px){.bigfoot .inner{grid-template-columns:1fr}}
.bigfoot .flogo{font-family:"IBM Plex Sans Condensed";font-weight:700;font-size:1.3rem;color:#fff}
.bigfoot .flogo span{color:#ffe08a}
.bigfoot p{font-size:.9rem;color:#8fa0bd;max-width:340px}
.bigfoot h4{font-family:"IBM Plex Sans Condensed";font-size:.7rem;letter-spacing:.16em;text-transform:uppercase;color:#6f8099;margin:0 0 10px}
.bigfoot a{display:block;font-family:"IBM Plex Sans Condensed";font-size:.92rem;color:#c6d2e4;padding:4px 0}
.bigfoot a:hover{color:#fff}
.bigfoot .base{border-top:1px solid #1d2942;margin-top:26px;padding:16px 26px;text-align:center;
  font-family:"IBM Plex Mono";font-size:.7rem;color:#5e6e88}

/* ---------------- instructor badge (header, top-right) ---------------- */
.instructor{display:flex;align-items:center;gap:11px;padding:5px 12px 5px 6px;border-radius:999px;
  background:rgba(255,255,255,.12);border:1px solid rgba(255,255,255,.28);transition:.15s}
.instructor:hover{background:rgba(255,255,255,.2)}
.instructor img{width:38px;height:38px;border-radius:50%;object-fit:cover;
  border:2px solid #ffe08a;box-shadow:0 2px 10px -2px rgba(0,0,0,.4)}
.instructor .who{line-height:1.14;text-align:left}
.instructor .who b{display:block;font-family:"IBM Plex Sans Condensed";font-weight:700;font-size:.84rem;color:#fff}
.instructor .who small{font-family:"IBM Plex Sans Condensed";font-size:.62rem;letter-spacing:.06em;
  text-transform:uppercase;color:#ffe08a}
@media(max-width:900px){.instructor .who small{display:none}}
@media(max-width:700px){.instructor .who{display:none}.instructor{padding:4px}}

/* ---------------- hero instructor — medium circle ---------------- */
.hero-inst{display:flex;flex-direction:column;align-items:center;gap:10px;margin:6px 0 18px}
.hero-inst .ring{width:190px;height:190px;border-radius:50%;padding:5px;
  background:conic-gradient(from 210deg,var(--g1),var(--g2),var(--g3),#f5b93c,var(--g1));
  animation:spin 9s linear infinite;box-shadow:0 18px 44px -18px rgba(40,50,140,.45)}
@keyframes spin{to{transform:rotate(360deg)}}
.hero-inst .ring img{width:100%;height:100%;border-radius:50%;object-fit:cover;object-position:center top;
  border:4px solid #fff;animation:spin 9s linear infinite reverse;display:block}
@media (prefers-reduced-motion:reduce){.hero-inst .ring,.hero-inst .ring img{animation:none}}
.hero-inst .iname{font-family:"IBM Plex Sans Condensed";font-weight:700;font-size:1.06rem;color:var(--ink)}
.hero-inst .ititle{font-family:"IBM Plex Sans Condensed";font-weight:600;font-size:.7rem;letter-spacing:.14em;
  text-transform:uppercase;color:#fff;background:linear-gradient(100deg,var(--g1),var(--g3));
  border-radius:999px;padding:5px 14px}
@media(max-width:700px){.hero-inst .ring{width:150px;height:150px}}

/* ---------------- instructor — bottom-right corner card ---------------- */
.inst-corner{display:flex;justify-content:flex-end;margin:18px 0 4px}
.ic-card{display:flex;align-items:center;gap:16px;background:var(--paper);border:1px solid var(--rule);
  border-radius:18px;padding:14px 22px 14px 14px;box-shadow:0 14px 34px -22px rgba(10,30,60,.4)}
.ic-card .ring{width:112px;height:112px;flex:none}
.ic-meta{text-align:left}
.ic-meta .iname{font-family:"IBM Plex Sans Condensed";font-weight:700;font-size:1.14rem;color:var(--ink)}
.ic-meta .ititle{margin-top:5px;display:inline-block}
@media(max-width:700px){.inst-corner{justify-content:center}.ic-card{flex-direction:column;text-align:center;padding:16px}.ic-meta{text-align:center}}

/* ---------------- floating instructor circle (bottom-right) ---------------- */
.fab-inst{position:fixed;right:26px;bottom:26px;z-index:90;display:block;width:92px;height:92px}
.fab-inst .ring{position:absolute;inset:0;border-radius:50%;padding:4px;display:block;
  background:conic-gradient(from 210deg,var(--g1),var(--g2),var(--g3),#f5b93c,var(--g1));
  animation:spin 9s linear infinite;box-shadow:0 16px 38px -14px rgba(30,40,120,.55);transition:.18s}
.fab-inst:hover .ring{transform:scale(1.06)}
.fab-inst .ring img{width:100%;height:100%;border-radius:50%;object-fit:cover;object-position:center top;
  border:3px solid #fff;display:block;animation:spin 9s linear infinite reverse}
.fab-inst .li{position:absolute;right:-2px;bottom:-2px;width:30px;height:30px;border-radius:9px;
  background:#0a66c2;color:#fff;font-family:"IBM Plex Sans Condensed";font-weight:700;font-size:.9rem;
  display:grid;place-items:center;border:2px solid #fff;box-shadow:0 4px 12px -4px rgba(0,0,0,.4)}
.fab-inst .tip{position:absolute;right:104px;bottom:8px;background:var(--ink);color:#dbe4f2;border-radius:12px;
  padding:11px 15px;width:max-content;max-width:240px;font-family:"IBM Plex Sans Condensed";font-size:.8rem;
  line-height:1.35;opacity:0;transform:translateX(8px);pointer-events:none;transition:.18s}
.fab-inst .tip b{display:block;color:#fff;font-size:.92rem}
.fab-inst .tip i{display:block;font-style:normal;color:#7ee0c0;margin-top:4px;font-weight:600}
.fab-inst:hover .tip{opacity:1;transform:none}
@media(max-width:700px){.fab-inst{width:72px;height:72px;right:16px;bottom:16px}.fab-inst .tip{display:none}}
@media (prefers-reduced-motion:reduce){.fab-inst .ring,.fab-inst .ring img{animation:none}}

/* ---------------- course page mode tabs (Interview / Learn / etc.) ---------------- */
.modes{display:flex;gap:6px;flex-wrap:wrap;margin:18px 0 0}
.mode{font-family:"IBM Plex Sans Condensed";font-weight:700;font-size:.86rem;border-radius:10px 10px 0 0;
  padding:9px 16px;border:1px solid var(--rule);border-bottom:none;background:#e6ebf3;color:var(--ink-faint);
  display:inline-flex;align-items:center;gap:7px}
.mode.on{background:var(--paper);color:var(--ink);border-top:3px solid var(--c,var(--teal))}
.mode .soon2{font-family:"IBM Plex Mono";font-size:.56rem;letter-spacing:.08em;text-transform:uppercase;
  color:var(--ink-faint);border:1px solid var(--rule);border-radius:5px;padding:1px 5px;background:#fff}

/* FIX: inline-code chip style must not bleed into dark code blocks */
.q pre code, .prob pre code, .sol pre code{background:transparent !important;color:var(--code-ink);padding:0;font-size:inherit;border-radius:0}
/* All button active state */
#allBtn[aria-pressed="true"]{background:var(--ink);border-color:var(--ink);color:#fff}

/* ---------------- course panes (tab-switched sections) ---------------- */
.pane{display:none}
.pane.on{display:block;animation:fade .25s ease}
@keyframes fade{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}
button.mode{cursor:pointer}
/* sidebar: interview nav only in interview mode */
body[data-mode]:not([data-mode="interview"]) .side input,
body[data-mode]:not([data-mode="interview"]) .snav{display:none}
body[data-mode]:not([data-mode="interview"]) .sidehint{display:block}
.sidehint{display:none;margin-top:16px;font-family:"IBM Plex Sans Condensed";font-size:.8rem;color:#8fa0bd;line-height:1.5}
/* learn syllabus */
.syl{display:grid;grid-template-columns:repeat(auto-fit,minmax(250px,1fr));gap:14px;margin-top:16px}
.mod{--mc:var(--teal);background:var(--paper);border:1px solid var(--rule);border-top:4px solid var(--mc);
  border-radius:12px;padding:18px 20px}
.mod .mh{font-family:"IBM Plex Sans Condensed";font-weight:700;font-size:1.05rem;color:var(--mc);margin-bottom:8px}
.mod ul{margin:0;padding-left:18px}
.mod li{margin:.45em 0;font-size:.93rem;color:var(--ink-soft)}
/* dataset/note/blog cards */
.dsgrid{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:14px;margin-top:14px}
.dscard{background:var(--paper);border:1px solid var(--rule);border-radius:12px;padding:18px 20px;margin-top:14px}
.dsgrid .dscard{margin-top:0}
.dscard .dn{font-family:"IBM Plex Mono";font-weight:600;font-size:.95rem;color:var(--ink)}
.dscard .dm{font-family:"IBM Plex Sans Condensed";font-size:.76rem;color:var(--ink-faint);margin:3px 0 8px}
.dscard p{margin:.3em 0 .8em;font-size:.92rem;color:var(--ink-soft)}
.dscard .dl{font-family:"IBM Plex Sans Condensed";font-weight:600;font-size:.76rem;color:var(--teal-deep);
  background:#eef4f5;border:1px solid var(--rule);border-radius:7px;padding:4px 10px}
/* video placeholders */
.vgrid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:14px;margin-top:14px}
.vph{aspect-ratio:16/9;background:var(--code-bg);border-radius:12px;display:flex;flex-direction:column;
  align-items:center;justify-content:center;gap:10px;color:#aebdd3;font-family:"IBM Plex Sans Condensed";font-weight:600}
.vph span{width:52px;height:52px;border-radius:50%;background:rgba(255,255,255,.14);display:grid;place-items:center;
  font-size:1.2rem;color:#fff}

/* ---------------- tool logo marquee (home) ---------------- */
.logostrip{margin-top:26px}
.marq{overflow:hidden;position:relative;padding:6px 0;
  -webkit-mask-image:linear-gradient(90deg,transparent,#000 8%,#000 92%,transparent);
  mask-image:linear-gradient(90deg,transparent,#000 8%,#000 92%,transparent)}
.marq .row{display:flex;gap:14px;width:max-content;animation:scroll 36s linear infinite}
.marq:hover .row{animation-play-state:paused}
@keyframes scroll{to{transform:translateX(-50%)}}
@media (prefers-reduced-motion:reduce){.marq .row{animation:none;flex-wrap:wrap;width:auto;justify-content:center}}
.lg{display:flex;align-items:center;gap:10px;background:var(--paper);border:1px solid var(--rule);
  border-radius:12px;padding:10px 16px;flex:none;transition:.15s}
.lg:hover{transform:translateY(-3px);box-shadow:0 12px 26px -18px rgba(10,30,60,.5)}
.lg img{height:30px;width:auto;max-width:74px;display:block}
.lg b{font-family:"IBM Plex Sans Condensed";font-weight:600;font-size:.86rem;color:var(--ink-soft);white-space:nowrap}

/* logo marquee v2: larger, two counter-scrolling rows */
.marq{padding:8px 0}
.marq + .marq{margin-top:14px}
.marq .row{gap:18px}
.marq .row.rev{animation-direction:reverse}
.lg{padding:13px 22px;border-radius:14px;gap:12px}
.lg img{height:42px;max-width:104px}
.lg b{font-size:.95rem}

/* footer v2: 4 columns + contact lines */
.bigfoot .inner.four{grid-template-columns:1.3fr 1fr 1fr 1fr}
@media(max-width:980px){.bigfoot .inner.four{grid-template-columns:1fr 1fr}}
@media(max-width:600px){.bigfoot .inner.four{grid-template-columns:1fr}}
.cline{display:flex!important;align-items:center;gap:9px}
.cico{width:22px;height:22px;border-radius:6px;border:1px solid #2a3854;display:inline-grid;place-items:center;
  font-size:.8rem;color:#ffe08a;flex:none}
.cimg{width:22px;height:22px;flex:none}
/* binary rain canvas sits with the blobs, behind hero content */
.blobs canvas{position:absolute;inset:0;width:100%;height:100%}

/* ================= animated data pipeline ================= */
.pipe-wrap{background:var(--ink);border-radius:20px;padding:34px 30px 30px;color:#dbe4f2;overflow-x:auto}
.pipe-head{font-family:"IBM Plex Mono";font-size:.66rem;letter-spacing:.16em;text-transform:uppercase;color:#7ee0c0;margin-bottom:22px}
.pipe{display:flex;align-items:center;min-width:760px}
.pnode{flex:none;width:118px;text-align:center}
.pnode .pic{width:58px;height:58px;margin:0 auto 8px;border-radius:16px;display:grid;place-items:center;
  font-size:1.45rem;background:rgba(255,255,255,.07);border:1px solid rgba(255,255,255,.16);
  box-shadow:0 8px 22px -12px rgba(0,0,0,.6)}
.pnode b{display:block;font-family:"IBM Plex Sans Condensed";font-size:.86rem;color:#fff}
.pnode small{font-family:"IBM Plex Mono";font-size:.6rem;color:#8fa0bd}
.pipe .pipeL{flex:1;height:3px;background:rgba(255,255,255,.12);border-radius:3px;position:relative;overflow:visible;min-width:56px}
.pipe .dotf{position:absolute;top:50%;left:0;width:9px;height:9px;border-radius:50%;transform:translate(-50%,-50%);
  background:#7ee0c0;box-shadow:0 0 10px #7ee0c0;animation:flow 2.6s linear infinite}
.pipe .dotf.d2{animation-delay:.9s;background:#ffd166;box-shadow:0 0 10px #ffd166}
.pipe .dotf.d3{animation-delay:1.8s;background:#9fd6ff;box-shadow:0 0 10px #9fd6ff}
@keyframes flow{0%{left:0;opacity:0}12%{opacity:1}88%{opacity:1}100%{left:100%;opacity:0}}
@media (prefers-reduced-motion:reduce){.pipe .dotf{animation:none;opacity:.5;left:50%}}
.pipe-note{margin-top:18px;font-family:"IBM Plex Sans Condensed";font-size:.82rem;color:#8fa0bd}

/* ================= dashboard mock ================= */
.dash{background:var(--paper);border:1px solid var(--rule);border-radius:20px;padding:24px;box-shadow:0 22px 50px -34px rgba(10,30,60,.5)}
.dash .drow{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}
@media(max-width:860px){.dash .drow{grid-template-columns:repeat(2,1fr)}}
.kcard{border:1px solid var(--rule);border-radius:14px;padding:14px 16px;background:#fff}
.kcard small{font-family:"IBM Plex Sans Condensed";font-size:.7rem;letter-spacing:.08em;text-transform:uppercase;color:var(--ink-faint)}
.kcard .kv{display:flex;align-items:baseline;gap:8px;margin:2px 0 6px}
.kcard .kv b{font-family:"IBM Plex Sans Condensed";font-size:1.5rem;color:var(--ink)}
.kcard .up{font-family:"IBM Plex Sans Condensed";font-weight:700;font-size:.68rem;color:#0f8a4b;background:#e5f6ec;border-radius:5px;padding:1px 6px}
.kcard .dn2{color:#c02626;background:#fdeaea}
.kspark{width:100%;height:34px}
.kspark path{fill:none;stroke-width:2;stroke-linecap:round;stroke-dasharray:220;stroke-dashoffset:220}
.dash.in .kspark path{animation:draw 1.4s ease forwards}
.kspark .fillp{fill:var(--sf,rgba(79,70,229,.1));stroke:none;opacity:0}
.dash.in .kspark .fillp{animation:fadein .8s ease .7s forwards}
@keyframes draw{to{stroke-dashoffset:0}}
@keyframes fadein{to{opacity:1}}
.dash .dgrid{display:grid;grid-template-columns:1.2fr .8fr;gap:14px;margin-top:14px}
@media(max-width:860px){.dash .dgrid{grid-template-columns:1fr}}
.dpanel{border:1px solid var(--rule);border-radius:14px;background:#fff;padding:16px 18px}
.dpanel h5{margin:0 0 12px;font-family:"IBM Plex Sans Condensed";font-size:.86rem;color:var(--ink)}
.bars2{display:flex;align-items:flex-end;gap:10px;height:150px}
.bars2 .bcol{flex:1;display:flex;flex-direction:column;align-items:center;gap:6px}
.bars2 .bpair{display:flex;align-items:flex-end;gap:3px;height:120px}
.bars2 .bbar{width:12px;border-radius:4px 4px 0 0;height:0;transition:height 1s cubic-bezier(.2,.7,.2,1)}
.bars2 .bbar.a{background:#4f7cf7}.bars2 .bbar.b{background:#f5a34c}
.dash.in .bars2 .bbar{height:var(--h)}
.bars2 .blab{font-family:"IBM Plex Mono";font-size:.6rem;color:var(--ink-faint)}
.srcline{display:flex;align-items:center;justify-content:space-between;border:1px solid var(--rule);
  border-radius:9px;padding:8px 12px;margin-bottom:8px;font-family:"IBM Plex Sans Condensed";font-size:.84rem;color:var(--ink-soft)}
.srcline b{color:var(--ink)}
.srcline .pct{position:relative;width:86px;height:7px;border-radius:5px;background:#eef1f6;overflow:hidden}
.srcline .pct i{position:absolute;inset:0 100% 0 0;background:linear-gradient(90deg,var(--g1),var(--g3));border-radius:5px;transition:inset 1.1s ease .3s}
.dash.in .srcline .pct i{inset:0 var(--r) 0 0}
.dash-cap{margin-top:12px;font-family:"IBM Plex Sans Condensed";font-size:.78rem;color:var(--ink-faint)}

/* logo marquee v3: 1.5x logo size */
.lg{padding:16px 26px;gap:14px;border-radius:16px}
.lg img{height:63px;max-width:156px}
.lg b{font-size:1.05rem}