/* ═══════════════════════════════════════════════════════════════════════
   FinMath Curriculum Arena · shared stylesheet (identical on every page)

   Same visual family as the Skills Dashboard / Trading Arena dark theme:
   one accent, a slate neutral, panels on a near-black ground, monospace for
   anything numeric. No build step, no framework, no CDN except KaTeX (which
   is optional and only ever styles formulas).

   THEMING
     --accent / --accent-2 are re-declared on :root by app.js:
       · on a concentration page, from PROGRAM.concentrations[].accent
       · on a course page, from the course's FIRST concentration
       · elsewhere, from SITE_PARAMS.accent (neutral programme colour)
     --accent-3 and --accent-deep are derived when not given. Nothing else in
     this sheet is themed, so a new colour never needs a CSS edit.

   LAYOUT MAP
     index          hero → filters → block groups of .ccard → concentrations
                    → components → privacy
     course         hero + .banner → sticky .weeknav → before-week-1 panels
                    → .week sections (.concept / .widget / .pitfalls / .mcq)
                    → details.qa interview → reappears → dl.gloss
     concentration  hero → .pathrow → .ccard grid → .taglist
     quarter        hero → filters → .qcols → table.cat sequencing
     skills         hero → filters → table.cat

   PRINT
     A course page is meant to be printed as a study guide: chrome, filters,
     week navigator and every widget CONTROL strip are hidden, widget SVGs and
     code output are kept, interview answers and week bodies are forced open.
   ═══════════════════════════════════════════════════════════════════════ */
/* UChicago brand typeface — the same public stylesheet finmath.uchicago.edu
   imports. Each weight is its own family; falls back to system-ui offline. */
@import url("https://uchicago-brand-fonts.s3.us-east-2.amazonaws.com/UChicagoSansSerif.css");
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
:root{
  /* Light scheme matching finmath.uchicago.edu: white page, Maroon #800000
     headings + links, #666 body text, #363636 titles, UChicago Sans Serif. */
  --accent:       #800000;   /* UChicago Maroon — fills, bars, rules, links  */
  --accent-2:     #800000;   /* link + label ink (= accent on light)          */
  --accent-3:     #5c0000;   /* inline code ink                               */
  --accent-deep:  #4d0000;
  --accent-rgb:   128,0,0;
  --accent-2-rgb: 128,0,0;
  --bg:           #ffffff;
  --panel:        #f7f7f7;
  --panel2:       #ededed;
  --panel-2:      #fbfbfb;
  --code-bg:      #f4f4f4;
  --code-head:    #e9e9e9;
  --code-ink:     #222222;
  --out-bg:       #f1f5f1;
  --ink:          #363636;   /* finmath h2 grey                          */
  --ink-dim:      #4a4a4a;
  --muted:        #666666;   /* finmath body text grey                   */
  --dim:          #8a8a8a;
  --line:         #dddddd;
  --line-2:       #c8c8c8;
  --ok:           #58593f;   /* UChicago dark green (finmath site.css)   */
  --warn:         #b45f20;   /* UChicago orange                          */
  --bad:          #8f3931;   /* UChicago red                             */
  --info:         #155f83;   /* UChicago blue                            */
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  --sans: "UChicagoSansSerif-Regular", system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --sans-bold: "UChicagoSansSerif-Bold", system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --sans-semi: "UChicagoSansSerif-SemiBold", system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
html{scroll-behavior:smooth}
body{background:var(--bg);color:var(--ink);font-family:var(--sans);font-size:14px;line-height:1.62;
  -webkit-font-smoothing:antialiased;overflow-wrap:break-word}
a{color:var(--accent-2);text-decoration:none}
/* finmath.uchicago.edu underlines links in running text only */
p a,li a,.lead a,.sub a,td a,dd a,.banner a,.note a,.fb a{text-decoration:underline;text-decoration-color:rgba(var(--accent-rgb),.45);text-underline-offset:2px}
a:hover{text-decoration:underline;text-decoration-color:var(--accent)}
.sr{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
:focus-visible{outline:2px solid var(--accent-2);outline-offset:2px}
img,svg,canvas{max-width:100%}

/* ── nav / footer ───────────────────────────────────────────────────── */
nav.top{position:sticky;top:0;z-index:60;display:flex;align-items:center;gap:16px;flex-wrap:wrap;
  padding:11px 22px;background:var(--accent);border-bottom:none;color:#fff}
nav.top>a:first-child{font-family:var(--sans-semi);font-weight:400;letter-spacing:.2px;color:#fff;font-size:14.5px;
  border-left:3px solid rgba(255,255,255,.55);padding-left:10px}
nav.top a{color:#fff}
nav.top .crumbs{font-size:12px;color:rgba(255,255,255,.78);min-width:0}
nav.top .crumbs b{color:#fff;font-weight:700}
nav.top .spacer{flex:1}
footer{border-top:1px solid var(--line);background:var(--panel);
  padding:26px 22px 34px;text-align:center;font-size:11.5px;color:var(--dim);letter-spacing:.3px}
footer a{color:var(--muted)}

/* ── sections & typography ──────────────────────────────────────────── */
section{max-width:1180px;margin:0 auto;padding:34px 22px 40px;border-top:1px solid var(--line)}
section#hero{border-top:none;padding-top:44px}
.kicker{font-size:10.5px;font-weight:800;letter-spacing:1.9px;text-transform:uppercase;color:var(--accent-2)}
h1{font-family:var(--sans-bold);font-size:clamp(25px,4.2vw,40px);font-weight:400;letter-spacing:-.4px;line-height:1.1;margin:6px 0 8px;color:var(--accent)}
h1 .thin{font-weight:400;color:var(--muted)}
h2{font-family:var(--sans-bold);font-size:21px;font-weight:400;letter-spacing:-.1px;margin:4px 0 4px;color:var(--ink)}
h3{font-size:11px;font-weight:800;letter-spacing:1.2px;text-transform:uppercase;color:var(--muted);
  margin-bottom:11px}
h4{font-family:var(--sans-semi);font-size:13.5px;font-weight:400;margin-bottom:5px}
p{margin:9px 0;max-width:82ch}
.lead{color:var(--muted);font-size:15px;max-width:84ch}
.sub{color:var(--muted);font-size:12.5px}
ul,ol{margin:8px 0 8px 20px}li{margin:4px 0;color:var(--muted);font-size:13px;max-width:80ch}
li strong,li b{color:var(--ink)}
strong{color:var(--ink);font-weight:650}
em.hi{color:var(--accent-2);font-style:normal;font-weight:600}
code,.mono{font-family:var(--mono);font-size:12.5px}
code{background:rgba(var(--accent-2-rgb),.07);color:var(--accent-3);padding:1px 5px;border-radius:4px}
.srcnote{font-size:11.5px;color:var(--dim);margin-top:20px;max-width:none}

/* ── panels / layout ────────────────────────────────────────────────── */
.panel{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:16px 18px;min-width:0}
.panel.tight{padding:13px 14px}
.panel.accent{border-left:4px solid var(--accent)}
.stack{display:grid;gap:14px}
.row{display:flex;gap:10px;align-items:center;flex-wrap:wrap}
.grid2{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:16px;align-items:start}
.cgrid{display:grid;grid-template-columns:repeat(auto-fit,minmax(270px,1fr));gap:14px;margin-top:16px}
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(285px,1fr));gap:14px;margin-top:14px}

/* ── controls ───────────────────────────────────────────────────────── */
.btn{font-family:inherit;font-size:12px;font-weight:650;cursor:pointer;color:var(--ink);
  background:var(--panel2);border:1px solid var(--line);border-radius:7px;padding:7px 14px;transition:.15s}
.btn:hover:not(:disabled){border-color:var(--accent-2);color:var(--accent)}
.btn:disabled{opacity:.45;cursor:default}
.btn:focus-visible{outline:2px solid var(--accent-2);outline-offset:2px}
.btn.primary{background:var(--accent);border-color:var(--accent);color:#fff}
.btn.primary:hover{filter:brightness(1.25)}
.btn.danger:hover{border-color:var(--bad);color:var(--bad)}
.btn.tiny{font-size:10.5px;font-weight:700;letter-spacing:.4px;padding:3px 10px;border-radius:6px;
  background:var(--panel2);color:var(--muted)}
.btn.tiny:hover:not(:disabled){color:var(--accent)}
.btn.copy.ok{border-color:rgba(88,89,63,.6);color:var(--ok)}
select,input[type=text],input[type=search],input[type=number]{font-family:var(--sans);font-size:12.5px;
  color:var(--ink);background:var(--panel2);border:1px solid var(--line);border-radius:7px;
  padding:7px 9px;width:100%}
input[type=range]{width:100%;accent-color:var(--accent)}
label.fl{display:grid;gap:4px;min-width:0}
label.fl>span{font-size:10px;font-weight:800;letter-spacing:1px;text-transform:uppercase;color:var(--dim)}
.filters{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:11px;align-items:end;
  background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:14px;margin-top:14px}
.sw{display:inline-flex;border:1px solid var(--line);border-radius:8px;overflow:hidden;flex-wrap:wrap}
.sw button{font-family:inherit;font-size:11.5px;font-weight:650;cursor:pointer;color:var(--muted);
  background:var(--panel2);border:none;padding:7px 13px;transition:.15s}
.sw button[aria-pressed="true"]{background:var(--accent);color:#fff}
.sw button:focus-visible{outline:2px solid var(--accent-2);outline-offset:-2px}

/* ── pills / chips ──────────────────────────────────────────────────── */
.pill{display:inline-flex;align-items:center;gap:6px;font-size:10.5px;font-weight:700;letter-spacing:.5px;
  padding:3px 9px;border-radius:20px;border:1px solid var(--line);color:var(--muted);white-space:nowrap}
.pill.acc{color:var(--accent-2);border-color:rgba(var(--accent-2-rgb),.5);background:rgba(var(--accent-rgb),.22)}
.pill.ok{color:var(--ok);border-color:rgba(63,185,80,.5);background:rgba(63,185,80,.1)}
.pill.warn{color:var(--warn);border-color:rgba(210,153,34,.5);background:rgba(210,153,34,.1)}
.pill.bad{color:var(--bad);border-color:rgba(248,81,73,.5);background:rgba(248,81,73,.1)}
.pill.lv-screen{color:var(--ok);border-color:rgba(88,89,63,.5);background:rgba(145,171,90,.16)}
.pill.lv-onsite{color:var(--accent-2);border-color:rgba(var(--accent-2-rgb),.55);background:rgba(var(--accent-rgb),.26)}
.pill.lv-senior{color:var(--bad);border-color:rgba(143,57,49,.5);background:rgba(143,57,49,.1)}
.chip{display:inline-block;font-size:10.5px;font-family:var(--mono);padding:3px 8px;border-radius:6px;
  border:1px solid var(--line);background:var(--panel2);color:var(--muted);max-width:100%;
  overflow-wrap:anywhere}
a.chip:hover{border-color:var(--accent-2);color:var(--ink);text-decoration:none}
.chip.on{background:rgba(var(--accent-rgb),.1);border-color:var(--accent);color:var(--accent)}
.chip.built{border-color:rgba(var(--accent-2-rgb),.45);color:var(--accent-2)}
.chip.assumed{border-style:dashed}
.chip.dimchip{color:var(--dim)}
.chips{display:flex;gap:6px;flex-wrap:wrap;margin-top:9px}
.taglist{display:flex;gap:7px;flex-wrap:wrap;margin-top:16px}

/* ── stats strip ────────────────────────────────────────────────────── */
.stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(118px,1fr));gap:1px;
  background:var(--line);border:1px solid var(--line);border-radius:10px;overflow:hidden;margin-top:18px}
.stat{background:var(--panel);padding:10px 12px;min-width:0}
.stat .sl{font-size:9.5px;font-weight:700;letter-spacing:1px;text-transform:uppercase;color:var(--dim)}
.stat .sv{font-family:var(--mono);font-size:15px;font-weight:700;color:var(--ink);margin-top:3px;
  overflow-wrap:anywhere}
.stat .sv.acc{color:var(--accent-2)}
.stat .sv.ok{color:var(--ok)}
.stat .sv.bad{color:var(--bad)}
.stat .sv.warn{color:var(--warn)}

/* ── progress bar / line ────────────────────────────────────────────── */
.bar{height:6px;border-radius:4px;background:#e4e4e4;overflow:hidden;margin:9px 0 5px}
.bar i{display:block;height:100%;width:0;background:var(--accent);
  transition:width .3s}
.bar.thin{height:4px;margin:0 0 5px}
.bar.slim{height:5px;margin:8px 0 0}
.progline{font-family:var(--mono);font-size:11.8px;color:var(--muted);margin-top:16px;max-width:none}

/* ── note / banner ──────────────────────────────────────────────────── */
.note{border-left:3px solid var(--accent);background:rgba(var(--accent-rgb),.06);
  border-radius:0 8px 8px 0;padding:11px 14px;font-size:12.8px;color:var(--muted);margin-top:14px}
.note b{color:var(--ink)}
.note.warn{border-left-color:var(--warn);background:rgba(180,95,32,.08)}
.banner{margin-top:22px;border:1px dashed var(--line-2);border-radius:9px;padding:9px 13px;
  font-size:11.5px;color:var(--dim);max-width:none;line-height:1.55}
.banner b{color:var(--muted);font-weight:700}
.stubstrip{background:rgba(180,95,32,.1);border-bottom:1px solid rgba(180,95,32,.4);
  color:var(--warn);font-size:11.5px;font-weight:650;text-align:center;padding:6px 14px;letter-spacing:.3px}

/* ── links row (header link cards) ──────────────────────────────────── */
.links{display:flex;gap:8px;flex-wrap:wrap;margin-top:18px}
.lk{display:inline-flex;flex-direction:column;gap:2px;background:var(--panel);border:1px solid var(--line);
  border-radius:9px;padding:8px 12px;color:inherit;min-width:0;max-width:100%}
a.lk:hover{border-color:var(--accent-2);text-decoration:none}
.lk .lt{font-size:9.5px;font-weight:800;letter-spacing:1.1px;text-transform:uppercase;color:var(--dim)}
.lk .lv{font-size:12.5px;font-weight:650;color:var(--ink);overflow-wrap:anywhere}

/* ══════════ PROGRAM MAP: block groups and course cards ══════════ */
.blockgrp{margin-top:26px}
.blockhd{display:flex;gap:12px;align-items:baseline;flex-wrap:wrap;border-bottom:1px solid var(--line);
  padding-bottom:8px}
.blockhd .bn{font-size:17px;font-weight:800;letter-spacing:-.3px;color:var(--ink)}
.blockhd .bu{font-family:var(--mono);font-size:11.5px;color:var(--accent-2)}
.blockhd .bb{font-size:12.5px;color:var(--muted);flex:1 1 320px;min-width:0}

.ccard{position:relative;display:block;background:var(--panel);border:1px solid var(--line);
  border-left:4px solid var(--line-2);border-radius:12px;padding:13px 15px 14px;color:inherit;
  transition:.18s;min-width:0}
a.ccard:hover,a.ccard:focus-visible{border-color:var(--accent-2);transform:translateY(-2px);
  text-decoration:none;box-shadow:0 14px 30px -18px rgba(var(--accent-rgb),.95)}
.ccard.unwritten{opacity:.72;border-style:dashed}
.ccard .cc{display:flex;gap:9px;align-items:baseline;justify-content:space-between;flex-wrap:wrap}
.ccard .code{font-family:var(--mono);font-size:12.5px;font-weight:700;color:var(--accent-2);
  letter-spacing:.4px}
.ccard .ti{font-size:15px;font-weight:700;letter-spacing:-.25px;color:var(--ink);margin-top:3px;
  overflow-wrap:anywhere}
.ccard .me{font-size:11.5px;color:var(--muted);margin-top:4px}
.ccard .tags{display:flex;gap:5px;flex-wrap:wrap;margin-top:8px}
.ccard .prog{font-family:var(--mono);font-size:10.5px;color:var(--dim);margin-top:8px}
.ccard .go{font-size:11.5px;font-weight:700;color:var(--accent-2);margin-top:8px}
.ccard .go::after{content:" \2192"}

/* hover/focus prerequisite card */
.prereqpop{position:absolute;z-index:40;left:10px;right:10px;top:calc(100% - 6px);
  background:var(--panel2);border:1px solid var(--accent-2);border-radius:10px;padding:10px 12px;
  box-shadow:0 18px 40px -16px rgba(0,0,0,.25);font-size:11.8px;color:var(--muted);display:none}
.ccard:hover .prereqpop,.ccard:focus-visible .prereqpop,.ccard.pinned .prereqpop{display:block}
.prereqpop b{display:block;font-size:9.5px;font-weight:800;letter-spacing:1px;text-transform:uppercase;
  color:var(--dim);margin-bottom:3px}
.prereqpop b+div{color:var(--ink-dim);margin-bottom:7px}
.prereqpop div:last-child{margin-bottom:0}

/* ══════════ COURSE PAGE ══════════ */
.weeknav{position:sticky;top:43px;z-index:55;display:flex;gap:6px;align-items:center;flex-wrap:wrap;
  padding:8px 22px;background:rgba(255,255,255,.96);border-bottom:1px solid var(--line);overflow-x:auto}
.weeknav .wl{font-size:9.5px;font-weight:800;letter-spacing:1.2px;text-transform:uppercase;
  color:var(--dim);margin-right:4px;flex:none}
.weeknav a{flex:none;font-family:var(--mono);font-size:11.5px;font-weight:700;color:var(--muted);
  background:var(--panel2);border:1px solid var(--line);border-radius:7px;padding:4px 10px;
  transition:.15s;position:relative}
.weeknav a:hover{color:var(--accent);border-color:var(--accent);text-decoration:none}
.weeknav a.on{color:#fff;background:var(--accent);border-color:var(--accent)}
.weeknav a.seen::after{content:"";position:absolute;right:3px;top:3px;width:5px;height:5px;
  border-radius:50%;background:var(--ok)}
.weeknav .spacer{flex:1}

.week{border:1px solid var(--line);border-radius:14px;background:var(--panel-2);margin-top:18px;
  overflow:hidden;scroll-margin-top:92px}
.week>summary{display:flex;gap:13px;align-items:baseline;flex-wrap:wrap;cursor:pointer;list-style:none;
  padding:15px 18px;background:var(--panel)}
.week>summary::-webkit-details-marker{display:none}
.week>summary:hover .wt{color:var(--accent)}
.week>summary:focus-visible{outline:2px solid var(--accent-2);outline-offset:-2px}
.week .wn{flex:none;font-family:var(--mono);font-size:12px;font-weight:800;letter-spacing:1px;
  color:var(--accent-2);background:rgba(var(--accent-rgb),.26);
  border:1px solid rgba(var(--accent-2-rgb),.38);border-radius:7px;padding:3px 9px}
.week .wt{flex:1 1 260px;min-width:0;font-size:17px;font-weight:750;letter-spacing:-.35px;color:var(--ink);
  overflow-wrap:anywhere}
.week .wmeta{display:flex;gap:6px;flex-wrap:wrap}
.week .wbody{padding:4px 18px 20px;border-top:1px solid var(--line)}
.week[open]>summary{border-bottom:1px solid var(--line)}
.topics{display:flex;gap:6px;flex-wrap:wrap;margin:14px 0 4px}
.wintro{margin:14px 0 2px;padding:11px 14px;border-left:3px solid var(--accent);background:rgba(var(--accent-rgb),.05);
  border-radius:0 10px 10px 0;font-size:13.5px;color:var(--ink-dim)}
.wintro p+p{margin-top:7px}

.concept{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:14px 16px 16px;
  margin-top:13px;min-width:0}
.concept .chd{display:flex;gap:12px;align-items:flex-start}
.cnum{flex:none;width:26px;height:26px;border-radius:8px;display:flex;align-items:center;
  justify-content:center;font-family:var(--mono);font-size:12px;font-weight:800;color:var(--accent-2);
  background:rgba(var(--accent-rgb),.26);border:1px solid rgba(var(--accent-2-rgb),.38)}
h4.cti{font-size:15px;font-weight:700;letter-spacing:-.25px;color:var(--ink);margin:2px 0 0}
.ctx{color:var(--ink-dim);font-size:13.2px;margin:8px 0 0;max-width:82ch}
.ctx p{margin:8px 0;color:inherit;font-size:inherit}
.ctx ul,.ctx ol{margin:8px 0 8px 20px}
.formula{margin:12px 0 0;padding:10px 12px;background:var(--panel2);border:1px solid var(--line);
  border-radius:9px;overflow-x:auto;text-align:center;color:var(--ink)}
.formula .texfall{display:inline-block;background:none;color:var(--accent-3);font-size:12.5px;
  white-space:pre-wrap;text-align:left}
.katex{font-size:1.05em}

/* ── code blocks + captured output ──────────────────────────────────── */
.cb{margin:12px 0 0;background:var(--code-bg);border:1px solid var(--line);border-radius:10px;
  overflow:hidden;min-width:0}
.cbh{display:flex;align-items:center;justify-content:space-between;gap:10px;padding:6px 9px 6px 10px;
  background:var(--code-head);border-bottom:1px solid var(--line)}
pre.code{margin:0;padding:12px 14px;overflow-x:auto;white-space:pre;font-family:var(--mono);
  font-size:12.3px;line-height:1.56;color:var(--code-ink);tab-size:2}
pre.code code{background:none;color:inherit;padding:0;border-radius:0;font-size:inherit;
  font-family:inherit;white-space:pre}
.cbo{border-top:1px solid var(--line);background:var(--out-bg)}
.cbo .ol{font-size:9.5px;font-weight:800;letter-spacing:1.1px;text-transform:uppercase;color:var(--dim);
  padding:6px 12px 0}
.cbo pre{margin:0;padding:4px 14px 11px;overflow-x:auto;white-space:pre;font-family:var(--mono);
  font-size:12px;line-height:1.5;color:#2f4f1a}

/* ── pitfalls ───────────────────────────────────────────────────────── */
.pitfalls{margin-top:16px;display:grid;gap:8px}
.pit{display:flex;gap:10px;align-items:flex-start;background:var(--panel);border:1px solid var(--line);
  border-left:3px solid var(--warn);border-radius:0 10px 10px 0;padding:10px 13px;font-size:12.8px;
  color:var(--muted)}
.pit .pm{flex:none;font-size:10px;font-weight:800;letter-spacing:.8px;text-transform:uppercase;
  color:var(--warn);padding-top:2px}

/* ── MCQ ────────────────────────────────────────────────────────────── */
.mcq{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:14px 16px;
  margin-top:11px}
.mcq.answered.right{border-color:rgba(63,185,80,.42)}
.mcq.answered.wrong{border-color:rgba(248,81,73,.38)}
.mcq .q{font-size:13.6px;font-weight:650;color:var(--ink);margin:0 0 11px;max-width:84ch}
.mcq .q .qn{color:var(--accent-2);font-family:var(--mono);margin-right:7px}
.opts{display:grid;gap:7px}
.opt{text-align:left;font-family:inherit;font-size:13px;cursor:pointer;color:var(--muted);
  background:var(--panel2);border:1px solid var(--line);border-radius:8px;padding:9px 12px;transition:.15s}
.opt:hover:not(:disabled){border-color:var(--accent-2);color:var(--ink)}
.opt:focus-visible{outline:2px solid var(--accent-2);outline-offset:2px}
.opt.right{border-color:var(--ok);background:rgba(145,171,90,.2);color:#2f4f1a}
.opt.wrong{border-color:var(--bad);background:rgba(143,57,49,.1);color:var(--bad)}
.opt.dim{opacity:.5}
.opt .ol{font-family:var(--mono);color:var(--dim);margin-right:8px;font-weight:700}
.fb{margin-top:11px;font-size:12.5px;line-height:1.6;color:var(--muted);display:none;
  border-left:3px solid var(--line);padding-left:11px}
.fb.show{display:block}
.fb.show.good{border-left-color:var(--ok)}
.fb.show.poor{border-left-color:var(--bad)}
.fb b{color:var(--ink)}
.checkhd{display:flex;gap:12px;align-items:baseline;justify-content:space-between;flex-wrap:wrap;
  margin-top:22px}
.checkhd .cs{font-family:var(--mono);font-size:11.5px;color:var(--muted)}

/* ── interview Q&A ──────────────────────────────────────────────────── */
#iv{display:grid;gap:9px}
details.qa{background:var(--panel);border:1px solid var(--line);border-radius:11px;min-width:0}
details.qa[open]{border-color:var(--line-2)}
details.qa>summary{display:flex;gap:11px;align-items:baseline;flex-wrap:wrap;cursor:pointer;
  list-style:none;padding:12px 15px}
details.qa>summary::-webkit-details-marker{display:none}
details.qa>summary:hover .qt{color:var(--accent)}
details.qa>summary:focus-visible{outline:2px solid var(--accent-2);outline-offset:-2px;border-radius:11px}
.qa .qn{flex:none;font-family:var(--mono);font-size:11px;font-weight:700;color:var(--dim);min-width:15px}
.qa .qt{flex:1 1 260px;min-width:0;font-size:13.8px;font-weight:650;color:var(--ink);overflow-wrap:anywhere}
details.qa .qb{padding:11px 15px 15px 41px;border-top:1px solid var(--line);margin-top:2px}
.ap{font-size:13.2px;color:var(--ink-dim);margin:9px 0 0;max-width:80ch}
.ap:first-child{margin-top:0}

/* ── brush-up, prerequisites, textbooks, glossary, reappears ────────── */
.brush{display:grid;gap:9px;margin-top:12px}
.bitem{background:var(--panel);border:1px solid var(--line);border-left:3px solid var(--accent);
  border-radius:0 10px 10px 0;padding:10px 13px;min-width:0}
.bitem .bt{font-size:13.2px;font-weight:700;color:var(--ink)}
.bitem .bw{font-size:12.5px;color:var(--muted);margin-top:3px}
.bitem .br{font-size:11.5px;color:var(--accent-2);margin-top:5px;font-family:var(--mono);
  overflow-wrap:anywhere}
.gloss{display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));gap:12px 22px;margin-top:16px}
.gloss .gi{background:var(--panel);border:1px solid var(--line);border-radius:10px;padding:11px 14px;
  min-width:0}
.gloss dt{font-size:13px;font-weight:700;color:var(--accent-2)}
.gloss dd{font-size:12.5px;color:var(--muted);margin-top:4px}
.recard{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:13px 15px;
  color:inherit;transition:.18s;min-width:0;display:block}
a.recard:hover{border-color:var(--accent-2);transform:translateY(-2px);text-decoration:none}
.recard .rc{font-family:var(--mono);font-size:12px;font-weight:700;color:var(--accent-2)}
.recard .rh{font-size:12.8px;color:var(--muted);margin-top:5px}

/* ── paths (concentration page) ─────────────────────────────────────── */
.pathrow{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:13px 16px;
  margin-top:12px;min-width:0}
.pathrow .pn2{font-size:14px;font-weight:700;color:var(--ink)}
.pathseq{display:flex;gap:7px;flex-wrap:wrap;align-items:center;margin-top:9px}
.pathseq .arr{color:var(--dim);font-size:13px}

/* ── quarter columns ────────────────────────────────────────────────── */
.qcols{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:14px;margin-top:18px}
.qcol{background:var(--panel-2);border:1px solid var(--line);border-radius:12px;padding:12px;min-width:0}
.qcol>h3{display:flex;gap:9px;align-items:baseline;justify-content:space-between;color:var(--accent-2);
  font-size:12px;letter-spacing:1px;border-bottom:1px solid var(--line);padding-bottom:8px}
.qcol>h3 span{font-family:var(--mono);color:var(--dim);font-size:10.5px;letter-spacing:.4px}
.qcol .cards{grid-template-columns:minmax(0,1fr);margin-top:11px}

/* ── catalogue table ────────────────────────────────────────────────── */
.tablewrap{margin-top:14px;overflow-x:auto}
table.cat{width:100%;border-collapse:collapse;font-size:12.5px}
table.cat th{font-size:9.5px;font-weight:800;letter-spacing:1px;text-transform:uppercase;color:var(--dim);
  text-align:left;padding:0 9px 8px;border-bottom:1px solid var(--line);white-space:nowrap}
table.cat td{padding:9px;border-bottom:1px solid rgba(39,44,54,.75);color:var(--muted);vertical-align:top}
table.cat td.nm{color:var(--ink);font-weight:650;min-width:170px;overflow-wrap:anywhere}
table.cat td.c{white-space:nowrap}
table.cat tr.gap td{background:rgba(210,153,34,.07)}
table.cat .catdot{display:inline-block;width:8px;height:8px;border-radius:2px;margin-right:6px;flex:none}
.empty{padding:26px 4px;color:var(--muted);font-size:13px}

/* ══════════ WIDGETS (rendered by widgets.js) ══════════ */
.widget{background:var(--panel);border:1px solid var(--line);border-radius:13px;padding:14px 16px 16px;
  margin:16px 0 0;min-width:0}
figcaption.wcap{display:flex;gap:10px;align-items:baseline;justify-content:space-between;flex-wrap:wrap;
  font-size:14px;font-weight:700;color:var(--ink);margin-bottom:11px}
figcaption.wcap .wtype{font-family:var(--mono);font-size:9.5px;font-weight:700;letter-spacing:1px;
  text-transform:uppercase;color:var(--dim);border:1px solid var(--line);border-radius:5px;padding:2px 7px}
svg{display:block;max-width:100%;height:auto}
.svgwrap{background:var(--panel2);border:1px solid var(--line);border-radius:11px;padding:9px;
  overflow-x:auto;margin-bottom:11px}
.svgwrap+.svgwrap{margin-top:-2px}
/* dense diagrams keep a readable size on phones and scroll inside their frame instead */
figure.widget[data-wtype="packet-journey"] svg,figure.widget[data-wtype="transport-ladder"] svg,
figure.widget[data-wtype="tcp-vs-udp"] svg,.osi-anim svg{min-width:600px}
.osi-anim svg{max-width:780px;margin:0 auto}
/* osi-stack: an HTML stack of 44 px layer buttons, the TCP/IP column alongside, a detail panel */
figure.widget[data-wtype="osi-stack"] .wctl .btn,figure.widget[data-wtype="tcp-vs-udp"] .wctl .btn,
figure.widget[data-wtype="tcp-vs-udp"] .wctl input[type=range]{min-height:44px}
.osi-wrap{display:grid;grid-template-columns:minmax(0,1.1fr) minmax(0,1fr);gap:12px;align-items:start;margin-bottom:11px}
.osi-grid{display:grid;grid-template-columns:minmax(0,1fr) 92px;grid-template-rows:auto repeat(7,auto);gap:4px 6px}
.osi-hd{grid-row:1;grid-column:1;font-size:9.5px;font-weight:800;letter-spacing:1px;text-transform:uppercase;color:var(--dim)}
.osi-hd2{grid-column:2}
.osi-l{grid-column:1;display:flex;align-items:center;gap:9px;min-height:46px;width:100%;text-align:left;cursor:pointer;
  font-family:inherit;color:var(--ink);background:var(--panel-2);border:1px solid var(--line);border-left:5px solid var(--line-2);
  border-radius:8px;padding:5px 10px;transition:.15s}
.osi-l:hover{border-color:var(--accent-2)}
.osi-l:focus-visible{outline:2px solid var(--accent-2);outline-offset:1px}
.osi-l.on{background:rgba(var(--accent-rgb),.08);border-top-color:var(--accent);border-right-color:var(--accent);
  border-bottom-color:var(--accent);box-shadow:inset 0 0 0 1px var(--accent)}
.osi-n{font-family:var(--mono);font-size:15px;font-weight:800;color:var(--accent-2);width:16px;flex:none}
.osi-nm{display:grid;min-width:0;flex:1}
.osi-nm b{font-size:13px;font-weight:700;line-height:1.25}
.osi-nm i{font-style:normal;font-size:10.5px;color:var(--muted);line-height:1.3;overflow-wrap:anywhere}
.osi-pdu{font-family:var(--mono);font-size:10px;font-weight:700;color:var(--muted);border:1px solid var(--line);
  border-radius:5px;padding:1px 6px;flex:none}
.osi-g{grid-column:2;display:flex;align-items:center;justify-content:center;text-align:center;font-size:11px;font-weight:700;
  color:var(--accent-2);background:rgba(var(--accent-rgb),.06);border:1px dashed rgba(var(--accent-rgb),.45);border-radius:8px;padding:4px}
.osi-det{background:var(--panel-2);border:1px solid var(--line);border-radius:10px;padding:12px 13px;min-width:0}
.osi-dh{display:flex;gap:7px;align-items:baseline;flex-wrap:wrap}
.osi-dh b{font-size:14px;color:var(--ink);margin-right:3px}
.osi-job{font-size:13px;color:var(--ink-dim);margin:8px 0 10px}
.osi-k{font-size:9.5px;font-weight:800;letter-spacing:1px;text-transform:uppercase;color:var(--dim);margin-bottom:5px}
.osi-hdr{display:flex;flex-wrap:wrap;gap:3px;margin-bottom:11px}
.osi-f{display:grid;flex-basis:62px;min-width:62px;border:1px solid var(--line-2);border-radius:5px;padding:4px 6px;
  font-family:var(--mono);line-height:1.25}
.osi-f b{font-size:10.5px;font-weight:700;color:var(--ink);overflow-wrap:anywhere;min-width:0}
.osi-f i{font-style:normal;font-size:9.5px;color:var(--muted)}
.osi-f.tr{border-style:dashed}
.osi-f.pl{display:flex;align-items:center;justify-content:center;font-family:var(--sans);font-size:10px;color:var(--dim);
  border:1px dashed var(--line-2);min-width:90px}
.osi-none{font-size:12px;color:var(--muted);margin-bottom:11px}
.osi-kv{display:grid;grid-template-columns:max-content minmax(0,1fr);gap:4px 10px;font-size:12.3px}
.osi-kv dt{font-weight:700;color:var(--accent-2)}
.osi-kv dd{color:var(--ink-dim)}
@media (max-width:720px){.osi-wrap{grid-template-columns:minmax(0,1fr)}.osi-grid{grid-template-columns:minmax(0,1fr) 74px}
  .osi-kv{grid-template-columns:minmax(0,1fr)}.osi-kv dd{margin-bottom:5px}}
.wctl{display:grid;grid-template-columns:repeat(auto-fit,minmax(190px,1fr));gap:11px;align-items:end;
  background:var(--panel2);border:1px solid var(--line);border-radius:10px;padding:11px 13px}
.wctl .ctl{display:grid;gap:4px;min-width:0}
.wctl .ctl label{font-size:10px;font-weight:800;letter-spacing:.9px;text-transform:uppercase;
  color:var(--dim);display:flex;gap:7px;justify-content:space-between;align-items:baseline}
.wctl .ctl label b{font-family:var(--mono);font-size:11px;font-weight:700;color:var(--accent-2);
  letter-spacing:0;text-transform:none}
.wctl .sw,.wctl>.btn{align-self:end}
.wctl .btn.on{background:rgba(var(--accent-rgb),.12);border-color:var(--accent);color:var(--accent)}
.widget .stats{margin-top:11px}
.legend{display:flex;gap:14px;flex-wrap:wrap;font-size:11.5px;color:var(--muted);margin-top:10px}
.legend span{display:inline-flex;align-items:center;gap:6px}
.legend i{width:12px;height:12px;border-radius:3px;display:inline-block;flex:none}
.whelp{font-size:11.8px;color:var(--dim);margin-top:11px;max-width:none}
.wnote{font-size:12.5px;color:var(--warn);background:rgba(210,153,34,.1);border:1px solid rgba(210,153,34,.35);
  border-radius:9px;padding:10px 13px;max-width:none}
.wtable{width:100%;border-collapse:collapse;font-size:11.8px;font-family:var(--mono)}
.wtable th{text-align:left;font-size:9.5px;letter-spacing:1px;text-transform:uppercase;color:var(--dim);
  padding:0 8px 6px;border-bottom:1px solid var(--line);font-family:var(--sans)}
.wtable td{padding:5px 8px;border-bottom:1px solid rgba(39,44,54,.6);color:var(--muted)}
.wtable td.chg{color:var(--accent-2);font-weight:700}
.wsplit{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:12px;align-items:start}
.wcode{background:var(--code-bg);border:1px solid var(--line);border-radius:9px;padding:10px 0;
  font-family:var(--mono);font-size:11.8px;line-height:1.6;overflow-x:auto}
.wcode .cl{display:block;padding:0 12px;color:var(--muted);white-space:pre}
.wcode .cl .ln{display:inline-block;width:2.2em;color:var(--dim);text-align:right;margin-right:11px;
  user-select:none}
.wcode .cl.cur{background:rgba(var(--accent-rgb),.12);color:#111}

/* ── prev/next ──────────────────────────────────────────────────────── */
.pn{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:14px;margin-top:6px}
.pncard{display:block;background:var(--panel);border:1px solid var(--line);border-radius:12px;
  padding:14px 16px;color:inherit;transition:.18s;min-width:0}
.pncard:hover{border-color:var(--accent-2);transform:translateY(-2px);text-decoration:none}
.pncard .nl{font-size:10px;font-weight:800;letter-spacing:1.4px;text-transform:uppercase;color:var(--accent-2)}
.pncard .nt{font-size:14.5px;font-weight:700;color:var(--ink);margin-top:5px;overflow-wrap:anywhere}

/* ── responsive (must stay last before print) ───────────────────────── */
@media (prefers-reduced-motion: reduce){
  *{animation:none !important;transition:none !important}
  html{scroll-behavior:auto}
}
@media (max-width:980px){
  .gloss{grid-template-columns:minmax(0,1fr)}
}
@media (max-width:720px){
  section{padding:24px 14px 30px}
  section#hero{padding-top:28px}
  nav.top{padding:10px 14px;gap:8px}
  nav.top .crumbs{font-size:11px}
  .weeknav{top:41px;padding:7px 14px;flex-wrap:nowrap}
  .grid2,.pn,.filters,.cards,.cgrid,.qcols,.wctl,.wsplit,.gloss{grid-template-columns:minmax(0,1fr)}
  [class*="grid"]>*,.stack>*,.panel,.cards>*,.row>*{min-width:0}
  p,.lead,.sub,.ctx,.ap,li{max-width:none}
  .stats{grid-template-columns:repeat(2,minmax(0,1fr));gap:0;background:var(--panel)}
  .stat{border-top:1px solid var(--line);border-right:1px solid var(--line)}
  .stat:nth-child(2n){border-right:none}
  .stat:nth-child(1),.stat:nth-child(2){border-top:none}
  .links{gap:7px}.lk{width:100%}
  pre,pre.code,.cbo pre,.svgwrap,svg,canvas,table,select,input,textarea,.mono,.wcode{max-width:100%}
  pre,pre.code,.cbo pre,.svgwrap,.tablewrap,.wcode{overflow-x:auto}
  code,.mono{overflow-wrap:anywhere}
  .week .wbody{padding:4px 13px 16px}
  .week>summary{padding:13px 14px;gap:9px}
  .concept{padding:13px 13px 15px}
  .widget{padding:13px 13px 15px}
  details.qa>summary{padding:11px 13px;gap:9px}
  details.qa .qb{padding:11px 13px 14px}
  .prereqpop{position:static;display:block;margin-top:10px;box-shadow:none;border-color:var(--line)}
  /* catalogue becomes a card list */
  .tablewrap{overflow-x:visible}
  table.cat thead{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}
  table.cat,table.cat tbody,table.cat tr,table.cat td{display:block;width:auto}
  table.cat caption{display:block;width:auto;text-align:left}
  table.cat tr{background:var(--panel);border:1px solid var(--line);border-radius:11px;
    padding:11px 13px;margin-bottom:10px}
  table.cat td{border:none;padding:3px 0;min-width:0 !important;white-space:normal}
  table.cat td::before{content:attr(data-l) " ";font-size:9.5px;font-weight:800;letter-spacing:1px;
    text-transform:uppercase;color:var(--dim);margin-right:6px}
}

/* ── print: a course page as a study guide ──────────────────────────── */
@media print{
  :root{--ink:#111;--ink-dim:#222;--muted:#333;--dim:#555;--line:#bbb;--line-2:#999;
        --panel:#fff;--panel2:#fff;--panel-2:#fff;--bg:#fff;--code-bg:#f5f5f5;--code-head:#ececec;
        --code-ink:#111;--out-bg:#f0f4f0}
  body{background:#fff;color:#111;font-size:10.5pt}
  nav.top,footer,.noprint,.pn,#nav-sec,.weeknav,.filters,.wctl,.stubstrip,.prereqpop,
  .btn,.sw,#filters-sec,#about-sec{display:none !important}
  a{color:#111;text-decoration:none}
  section{border-top:none;padding:0 0 10px;max-width:none}
  h1{font-size:20pt}h2{font-size:13pt;margin-top:8pt}
  .panel,.concept,.week,.widget,.mcq,.pit,.bitem,.cb,details.qa,.ccard,.recard,.gloss .gi{
    border-color:#bbb;background:#fff;box-shadow:none;break-inside:avoid;page-break-inside:avoid}
  .week{margin-top:14pt}
  .week>summary{background:#fff;border-bottom:1pt solid #999;padding:6pt 0}
  .week .wbody{padding:4pt 0 10pt;border-top:none}
  .concept,.widget,.mcq{padding:8pt 9pt}
  .kicker,.cnum,.week .wn,.ccard .code,.qa .qn,.gloss dt,.recard .rc{color:#333}
  .cnum,.week .wn{background:#eee;border-color:#999}
  .pill,.chip,.pill.acc,.pill.warn,.pill.lv-screen,.pill.lv-onsite,.pill.lv-senior{
    border-color:#999;color:#222;background:#fff}
  .bar{background:#ddd}.bar i{background:#666}
  .stat .sv,.stat .sv.acc,.stat .sv.ok{color:#111}
  pre.code{background:#f5f5f5;color:#111;font-size:8.4pt;white-space:pre-wrap;overflow:visible}
  .cbo pre{color:#123;background:#f0f4f0;font-size:8.4pt;white-space:pre-wrap;overflow:visible}
  .cb,.svgwrap{background:#f7f7f7}
  .cbh{background:#ececec}
  .svgwrap{border-color:#ccc;overflow:visible}
  .whelp{color:#333}
  /* answers, weeks and feedback expanded on paper (JS also opens them on beforeprint) */
  details.qa,.week{margin-bottom:6pt}
  details.qa>summary{padding:8pt 9pt 4pt}
  details.qa .qb{padding:6pt 9pt 9pt;border-top:1px solid #ccc}
  details::details-content{content-visibility:visible !important;display:block !important;
    block-size:auto !important}
  details:not([open])>*:not(summary){display:block !important}
  .fb{display:block !important;border-left-color:#999}
  .opt{background:#fff;border-color:#bbb;color:#222}
  .opt.right{background:#eef7ee;border-color:#3a7;color:#111}
}