:root{
  /* Tokens lifted from the live SPC site. Light everywhere; the header bar is
     the only dark surface, plus the video panel that stands in for the film. */
  --bg:#FFFFFF;--soft:#F4F4F4;--card:#FFFFFF;
  --line:#E5E5E5;--rule:#D8D8D8;
  --ink:#1C1C1C;--muted:#555555;--faint:#8A8A8A;
  --red:#C8102E;--navy:#1F2C39;
}
*{margin:0;padding:0;box-sizing:border-box}
/* No global smooth scrolling. Steps run to 3,300px, so an animated scroll on
   every Next click reels the whole page past the reader; step changes jump
   instantly instead, and only the short transcript-to-video hop animates. */
html{-webkit-text-size-adjust:100%}
body{background:var(--bg);color:var(--ink);
  font-family:Inter,-apple-system,"Segoe UI",Roboto,system-ui,sans-serif;
  font-size:16px;line-height:1.62;-webkit-font-smoothing:antialiased}
em,i,cite,address,dfn{font-style:normal}
a{color:inherit;text-decoration:none}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer}
textarea,input{font:inherit;color:inherit}
::selection{background:var(--red);color:#FFFFFF}
.wrap{max-width:1080px;margin:0 auto;padding:0 32px}
.measure{max-width:820px}
.rule{width:64px;height:3px;background:var(--red);margin:26px 0}

/* site chrome */
header.site{background:var(--navy);padding:18px 0;position:relative;z-index:5}
header.site .wrap{display:flex;align-items:baseline;gap:16px}
.brand{font-weight:700;letter-spacing:2px;font-size:20px;color:#FFFFFF;
  text-transform:uppercase;display:inline-flex;align-items:center;gap:10px}
.brand::before{content:"";display:inline-block;width:8px;height:8px;
  border-radius:50%;background:var(--red);flex-shrink:0}
.tag{font-size:11px;letter-spacing:.2em;color:rgba(255,255,255,.62);
  border:1px solid rgba(255,255,255,.24);padding:2px 8px;border-radius:2px}
nav.crumbs{margin-left:auto;font-size:13px;color:rgba(255,255,255,.72);
  display:flex;gap:20px}
nav.crumbs a:hover{color:#FFFFFF}
footer{border-top:1px solid var(--line);margin-top:110px;
  padding:30px 0 56px;color:var(--faint);font-size:12px}
footer .wrap{display:flex;gap:18px;flex-wrap:wrap}

/* shared type */
.eyebrow{font-size:12px;letter-spacing:.22em;color:var(--faint);
  text-transform:uppercase}
h1{font-size:46px;line-height:1.1;font-weight:800;letter-spacing:-.015em;
  color:var(--ink)}
h2{font-size:28px;line-height:1.2;font-weight:700;letter-spacing:-.01em}
h3{font-size:18px;font-weight:650;line-height:1.35}
p.lede{color:var(--muted);font-size:18px;max-width:680px;margin-top:20px}
p{max-width:74ch}
.faint{color:var(--faint)}

/* home */
.hero{padding:88px 0 56px}
.hero .facts{display:flex;gap:34px;flex-wrap:wrap;margin-top:34px;
  font-size:13px;color:var(--muted)}
.hero .facts b{display:block;color:var(--ink);font-size:22px;
  font-weight:750;letter-spacing:-.01em;margin-bottom:4px;
  font-variant-numeric:tabular-nums}
.author{margin-top:30px;font-size:13px;color:var(--muted)}
.overall{margin:56px 0 0;border-top:1px solid var(--line);padding-top:24px;
  display:flex;align-items:center;gap:20px;font-size:13px;color:var(--muted)}
.overall .bar{flex:1;max-width:420px}
a.inl{color:var(--muted);border-bottom:1px solid var(--rule)}
a.inl:hover{color:var(--ink);border-bottom-color:var(--red)}
.bar{height:2px;background:var(--line);position:relative;overflow:hidden}
.bar i{position:absolute;left:0;top:0;bottom:0;background:var(--red);width:0;
  transition:width .4s ease}
.modules{padding:56px 0 0;display:grid;gap:20px}
.mod{background:var(--card);border:1px solid var(--line);border-radius:4px;
  padding:34px 34px 14px}
.mod-h{display:flex;align-items:baseline;gap:18px;flex-wrap:wrap}
.mod-h h2{font-size:22px;width:100%;margin-top:8px}
.mod-h .count{margin-left:auto;font-size:12px;color:var(--faint);
  letter-spacing:.14em;font-variant-numeric:tabular-nums}
.mod p.blurb{color:var(--muted);font-size:14px;margin-top:10px;max-width:640px}
.mod .bar{margin:22px 0 8px}
.rows{margin-top:14px}
.row{display:flex;gap:18px;align-items:center;padding:15px 0;
  border-top:1px solid var(--line)}
.row .n{font-weight:800;color:var(--red);min-width:30px;font-size:14px;
  font-variant-numeric:tabular-nums}
.row .t{flex:1;min-width:0}
.row .t .title{display:block;font-weight:600;font-size:16px}
.row .t .sub{display:block;color:var(--muted);font-size:13px;margin-top:3px}
.row .d{color:var(--faint);font-size:13px;min-width:48px;text-align:right;
  font-variant-numeric:tabular-nums}
.row .st{min-width:104px;text-align:right;font-size:12px;color:var(--muted);
  letter-spacing:.08em}
a.row:hover .t .title{color:var(--red)}
.row.locked{opacity:.55}
.row.locked .st{color:var(--faint)}
.dot{display:inline-block;width:7px;height:7px;border-radius:50%;
  border:1px solid var(--rule);margin-right:8px;vertical-align:1px}
.dot.part{border-color:var(--red)}
.dot.done{border-color:var(--red);background:var(--red)}
.lockline{font-size:12px;color:var(--faint);padding:16px 0 4px;
  border-top:1px solid var(--line);margin-top:4px}
.tracks{display:grid;grid-template-columns:1fr;gap:20px;padding:56px 0 0}
.card{background:var(--card);border:1px solid var(--line);padding:32px;
  border-radius:4px}
.card .k{font-size:12px;letter-spacing:.18em;color:var(--faint);
  text-transform:uppercase}
.card h2{font-size:22px;margin:10px 0 8px}
.card p{color:var(--muted);font-size:14px}
.badge{display:inline-block;font-size:11px;letter-spacing:.14em;
  padding:4px 10px;border-radius:2px;margin-top:18px;background:var(--soft);
  color:var(--muted);border:1px solid var(--line)}
.b2{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:2px 26px;
  margin-top:22px;font-size:13px;color:var(--muted)}
.b2 span b{color:var(--red);font-weight:700;margin-right:8px;
  font-variant-numeric:tabular-nums}

/* lesson header and step indicator */
.lesson-head{padding:64px 0 0}
.lesson-head h1{font-size:38px;max-width:900px}
.lesson-head .facts{display:flex;gap:28px;flex-wrap:wrap;margin-top:26px;
  font-size:13px;color:var(--faint)}
.lesson-head .facts b{color:var(--ink);font-weight:600}
.stepbar{margin-top:40px;padding-top:20px;border-top:1px solid var(--line);
  display:flex;align-items:center;gap:18px;flex-wrap:wrap}
.dots{display:flex;gap:6px;align-items:center}
.dot-s{width:6px;height:6px;border-radius:50%;background:var(--line);
  transition:background .25s ease}
.dot-s.past{background:var(--rule)}
.dot-s.on{background:var(--red)}
.stepmeta{font-size:11px;letter-spacing:.18em;text-transform:uppercase;
  color:var(--faint);display:flex;gap:10px}
.stepmeta .n{font-variant-numeric:tabular-nums}
.stepmeta .lab{color:var(--muted)}
.steps{max-width:860px}
.step{display:none;padding:44px 0 0}
.step.on{display:block}
.stepnav{display:flex;justify-content:space-between;align-items:center;
  gap:16px;margin-top:72px;padding-top:28px;border-top:1px solid var(--line)}
.stepnav .btn{white-space:nowrap}

.sec-h{display:flex;align-items:baseline;gap:16px;flex-wrap:wrap;
  margin-bottom:28px}
.sec-h .lab{font-size:11px;letter-spacing:.22em;text-transform:uppercase;
  color:var(--red);font-weight:700}
.sec-h h2{width:100%}
.sec-h p{color:var(--muted);font-size:15px;max-width:70ch;margin-top:2px}

/* the one deliberate dark panel: it stands in for the film */
.vslot{border:1px solid var(--navy);background:var(--navy);border-radius:4px;
  position:relative;overflow:hidden}
.vslot:before{content:"";display:block;padding-top:56.25%}
.vslot-in{position:absolute;inset:0;display:flex;flex-direction:column;
  align-items:center;justify-content:center;text-align:center;padding:32px}
.vslot-in:after{content:"";position:absolute;left:50%;bottom:0;
  transform:translateX(-50%);width:64px;height:3px;background:var(--red)}
.vslot .k{font-size:11px;letter-spacing:.22em;color:var(--red);
  text-transform:uppercase;font-weight:700;font-variant-numeric:tabular-nums}
.vslot h3{margin:16px 0 12px;font-size:24px;font-weight:750;max-width:22ch;
  letter-spacing:-.01em;color:#FFFFFF}
.vslot p{color:rgba(255,255,255,.66);font-size:14px;letter-spacing:.02em}
.vslot iframe{position:absolute;inset:0;width:100%;height:100%;border:0}
.vmeta{color:var(--muted);font-size:13px;margin-top:14px;max-width:70ch}

.tr-toggle{font-size:12px;letter-spacing:.14em;text-transform:uppercase;
  color:var(--muted);border:1px solid var(--line);padding:7px 14px;
  border-radius:2px;background:var(--card)}
.tr-toggle:hover{color:var(--ink);border-color:var(--rule)}
.transcript.hid{display:none}
.transcript h4{font-size:11px;letter-spacing:.22em;color:var(--faint);
  text-transform:uppercase;margin:36px 0 14px;font-weight:600}
.transcript h4:first-child{margin-top:0}
.cue{display:flex;gap:20px;margin-bottom:14px}
.cue .ts{color:var(--faint);font-size:13px;font-variant-numeric:tabular-nums;
  min-width:44px;font-weight:600;padding-top:2px}
.cue .ts.live{color:var(--red);cursor:pointer}
.cue .ts.live:hover{text-decoration:underline}
.cue p{color:var(--muted);font-size:15px;max-width:72ch}

.ideas{display:grid;gap:2px;border-top:1px solid var(--line)}
.idea{padding:26px 0;border-bottom:1px solid var(--line);display:flex;gap:24px}
.idea .i{color:var(--red);font-weight:800;font-size:13px;min-width:30px;
  padding-top:3px;font-variant-numeric:tabular-nums}
.idea h3{margin-bottom:8px}
.idea p{color:var(--muted);font-size:15px}

.policy{color:var(--muted);font-size:13px;border-left:2px solid var(--rule);
  padding-left:16px;margin-bottom:34px}
.act p.setup{color:var(--muted);font-size:15px}
.pbox{margin:22px 0 0;border:1px solid var(--line);background:var(--soft);
  border-radius:3px}
.pbox .phead{display:flex;align-items:center;gap:14px;padding:9px 16px;
  border-bottom:1px solid var(--line)}
.pbox .phead .lab{font-size:10px;letter-spacing:.2em;color:var(--faint);
  text-transform:uppercase;font-weight:700}
.pbox .phead button{margin-left:auto;font-size:10px;letter-spacing:.16em;
  text-transform:uppercase;color:var(--muted);border:1px solid var(--rule);
  padding:4px 10px;border-radius:2px;background:var(--card)}
.pbox .phead button:hover{color:var(--ink);border-color:var(--ink)}
.pbox pre{padding:20px 18px;font-family:"SFMono-Regular",Consolas,
  "Liberation Mono",Menlo,monospace;font-size:13.5px;line-height:1.72;
  color:var(--ink);white-space:pre-wrap;word-break:break-word;
  -webkit-user-select:all;user-select:all}
.runline{color:var(--muted);font-size:13px;margin-top:16px}
.reflect{margin-top:24px}
.reflect label{display:block;color:var(--muted);font-size:14px;
  margin-bottom:10px;max-width:74ch}
.reflect textarea{width:100%;min-height:132px;background:var(--card);
  border:1px solid var(--rule);border-radius:3px;padding:16px;
  color:var(--ink);font-size:15px;line-height:1.6;resize:vertical}
.reflect textarea:focus{outline:none;border-color:var(--ink)}
.saved{font-size:11px;letter-spacing:.16em;text-transform:uppercase;
  color:var(--faint);margin-top:8px;min-height:14px}

/* quiz: one question visible at a time */
.quiz{list-style:none}
.q{display:none}
.q.on{display:block}
.q .qt{font-size:17px;font-weight:600;max-width:70ch}
.q .qt .qn{color:var(--red);font-size:12px;font-weight:800;margin-right:14px;
  vertical-align:2px;font-variant-numeric:tabular-nums}
.opts{margin-top:18px;display:grid;gap:8px;max-width:74ch}
.opt{text-align:left;border:1px solid var(--line);background:var(--card);
  border-radius:3px;padding:13px 16px;font-size:15px;color:var(--muted);
  display:flex;gap:12px;align-items:flex-start}
.opt .ltr{color:var(--faint);font-weight:700;font-size:12px;padding-top:3px;
  min-width:14px}
.opt:hover{border-color:var(--rule);color:var(--ink)}
.opt.no{border-color:var(--line);background:var(--soft);color:var(--faint);
  cursor:default}
.opt.yes{border-color:var(--red);background:var(--card);color:var(--ink);
  cursor:default}
.opt.yes .ltr{color:var(--red)}
.q.done .opt{cursor:default}
.q.done .opt:hover{border-color:var(--line);color:var(--muted)}
.q.done .opt.yes:hover{border-color:var(--red);color:var(--ink)}
.fb{margin-top:14px;font-size:14px;color:var(--muted);max-width:70ch;
  display:none;border-left:2px solid var(--rule);padding-left:15px}
.fb.on{display:block}
.fb.right{border-left-color:var(--red)}
.qbar{margin-top:26px;display:flex;align-items:center;gap:20px;flex-wrap:wrap}
.qmeta{font-size:11px;letter-spacing:.18em;text-transform:uppercase;
  color:var(--faint);font-variant-numeric:tabular-nums}
.score{margin-top:26px;padding-top:22px;border-top:1px solid var(--line);
  font-size:13px;color:var(--muted);display:flex;align-items:center;gap:18px}
.score b{color:var(--ink);font-weight:700;font-variant-numeric:tabular-nums}
.score .bar{flex:1;max-width:260px}

.checks{border-top:1px solid var(--line)}
.chk{display:flex;gap:16px;align-items:flex-start;padding:18px 0;
  border-bottom:1px solid var(--line);cursor:pointer;max-width:74ch}
.chk input{appearance:none;-webkit-appearance:none;width:17px;height:17px;
  border:1px solid var(--faint);border-radius:2px;margin-top:3px;flex:0 0 auto;
  cursor:pointer;position:relative;background:var(--card)}
.chk input:checked{background:var(--red);border-color:var(--red)}
.chk input:checked:after{content:"";position:absolute;left:5px;top:1px;
  width:5px;height:10px;border:solid #FFFFFF;border-width:0 2px 2px 0;
  transform:rotate(42deg)}
.chk span{font-size:15px;color:var(--muted)}
.chk input:checked+span{color:var(--ink)}
.donebar{margin-top:34px;display:flex;align-items:center;gap:22px;
  flex-wrap:wrap}
.btn{background:var(--ink);border:1px solid var(--ink);color:#FFFFFF;
  padding:13px 26px;border-radius:3px;font-size:13px;letter-spacing:.14em;
  text-transform:uppercase;font-weight:600;display:inline-block}
.btn:hover{background:#000000;border-color:#000000}
.btn.on{background:var(--red);border-color:var(--red)}
.btn.ghost{background:transparent;border-color:var(--rule);color:var(--muted)}
.btn.ghost:hover{background:transparent;border-color:var(--ink);
  color:var(--ink)}
.donebar .note{font-size:13px;color:var(--muted)}

/* hand-off: the one place the course asks for anything back */
.hand{border:1px solid var(--rule);background:var(--soft);padding:30px 30px 26px;
  margin-top:6px}
.hand h3{font-size:17px;margin-bottom:10px}
.hand p{font-size:15px;color:var(--muted);margin-bottom:18px}
.hand .row{display:flex;gap:14px;flex-wrap:wrap;margin-bottom:14px}
.hand .row > label{flex:1 1 220px;display:block}
.hand label span{display:block;font-size:11px;letter-spacing:.16em;
  text-transform:uppercase;color:var(--faint);margin-bottom:6px}
.hand input,.hand textarea{width:100%;background:var(--card);
  border:1px solid var(--rule);border-radius:2px;padding:11px 12px;
  font-size:15px;line-height:1.5}
.hand textarea{min-height:104px;resize:vertical}
.hand input:focus,.hand textarea:focus{outline:2px solid var(--navy);
  outline-offset:-2px}
.hand .honey{position:absolute;left:-9999px;width:1px;height:1px}
.hand .send{margin-top:6px;display:flex;align-items:center;gap:18px;
  flex-wrap:wrap}
.hand .msg{font-size:13px;color:var(--muted)}
.hand .msg.bad{color:var(--red)}
.hand .fine{font-size:12px;color:var(--faint);margin-top:16px;margin-bottom:0}

/* the gate. One box, one pane showing at a time, plus the old code-only form
   folded away underneath it. Everything here is scoped to .acct or .code-only
   so the hand-off form on the lesson pages keeps the spacing it has. */
.acct .pane{display:none}
.acct .pane.on{display:block}
.acct label{display:block;margin-bottom:14px}
.acct .tabs{display:flex;gap:10px;margin-bottom:24px}
.acct .tab{border:1px solid var(--rule);border-radius:3px;color:var(--muted);
  padding:11px 20px;font-size:12px;letter-spacing:.14em;font-weight:600;
  text-transform:uppercase}
.acct .tab:hover{border-color:var(--ink);color:var(--ink)}
.acct .tab.on{background:var(--ink);border-color:var(--ink);color:#FFFFFF}
.acct .tabpane{display:none}
.acct .tabpane.on{display:block}
.acct .help{font-size:12px;color:var(--faint);margin-top:16px;margin-bottom:0}
.code-only{max-width:520px;margin-top:20px}
.code-only .more{font-size:13px;color:var(--muted);
  border-bottom:1px solid var(--rule)}
.code-only .more:hover{color:var(--ink);border-bottom-color:var(--red)}
.code-only .box{display:none;margin-top:16px}
.code-only.on .box{display:block}
.gate-note{font-size:12px;color:var(--faint);max-width:520px;margin-top:26px}

/* notebook */
.nb-ch{border-top:1px solid var(--line);padding:40px 0}
.nb-ch h2{font-size:20px}
.nb-ch .meta{font-size:12px;letter-spacing:.14em;text-transform:uppercase;
  color:var(--faint);margin-bottom:10px}
.nb-block{margin-top:24px}
.nb-block .k{font-size:11px;letter-spacing:.2em;text-transform:uppercase;
  color:var(--faint);margin-bottom:8px}
.nb-block p{color:var(--muted);font-size:15px;white-space:pre-wrap;
  border-left:2px solid var(--line);padding-left:16px;max-width:74ch}
.nb-empty{color:var(--muted);font-size:14px}
.nb-tools{display:flex;gap:16px;flex-wrap:wrap;margin-top:34px}

/* data page. File names are set in the code face so a reader can match what
   is on the page against what is in their Colab cell at a glance. */
.dnote{color:var(--muted);font-size:15px;max-width:680px;margin-top:16px}
.dnote code{font-family:"SFMono-Regular",Consolas,"Liberation Mono",Menlo,
  monospace;font-size:13px;background:var(--soft);border:1px solid var(--line);
  border-radius:2px;padding:1px 6px}
.dgroup{margin-top:60px}
.dgroup h2{font-size:22px}
.dblurb{color:var(--muted);font-size:14px;margin-top:10px;max-width:640px}
.dfiles{margin-top:10px}
.dfile{border-top:1px solid var(--line);padding:26px 0 6px}
.dfile h3{font-family:"SFMono-Regular",Consolas,"Liberation Mono",Menlo,
  monospace;font-size:15px;font-weight:600}
.dfile p{color:var(--muted);font-size:14px;margin-top:6px}
.dfile .pbox{margin-top:14px}
.dlinks{display:flex;gap:26px;flex-wrap:wrap;margin-top:20px;font-size:14px}

/* the files one lesson opens, sitting at the top of its first activity */
.dbox{border:1px solid var(--line);border-radius:4px;background:var(--card);
  padding:22px 24px 20px;margin-bottom:34px}
.dbox .k{font-size:10px;letter-spacing:.2em;text-transform:uppercase;
  font-weight:700;color:var(--faint)}
.dhit{margin-top:16px}
.dhit .dname{display:block;font-family:"SFMono-Regular",Consolas,
  "Liberation Mono",Menlo,monospace;font-size:13.5px;font-weight:600}
.dhit .pbox{margin-top:8px}
.dmore{color:var(--muted);font-size:13px;margin-top:18px}

@media(max-width:820px){
  .wrap{padding:0 22px}
  h1{font-size:32px}
  .lesson-head h1{font-size:28px}
  h2{font-size:23px}
  .step{padding:32px 0 0}
  .stepnav{margin-top:52px}
  .b2{grid-template-columns:1fr}
  .mod{padding:26px 24px 10px}
  .row{flex-wrap:wrap}
  .row .st{min-width:0;margin-left:auto}
  .btn{padding:12px 18px;font-size:12px}
}