/* ============================================================
   CS625 Revision — "Ink, Marker & Red Pen"
   Palette derives from the tools of revision itself:
   ink navy, cool paper, verdict teal, highlighter yellow, red pen.
   ============================================================ */

:root{
  --ink:#0E1B2A;
  --ink-2:#1B2C40;
  --paper:#F4F6F8;
  --card:#FFFFFF;
  --line:#DCE2E9;
  --text:#152232;
  --muted:#5C6B7E;
  --teal:#126E62;
  --teal-soft:#E3F1EE;
  --marker:#FFD84D;
  --marker-soft:#FFF3C4;
  --pen:#CE3A50;
  --pen-soft:#FCE7EA;
  --shadow:0 1px 2px rgba(14,27,42,.06), 0 8px 24px -12px rgba(14,27,42,.18);
  --r:14px;
  --maxw:820px;
}

html[data-theme="dark"]{
  --ink:#060C14;
  --ink-2:#0E1B2A;
  --paper:#0B141F;
  --card:#111E2C;
  --line:#22364A;
  --text:#E4EAF1;
  --muted:#94A6B8;
  --teal:#4CC5B0;
  --teal-soft:#0F2E2C;
  --marker:#FFD84D;
  --marker-soft:#3A3117;
  --pen:#FF7A8C;
  --pen-soft:#331A20;
  --shadow:0 1px 2px rgba(0,0,0,.4), 0 10px 28px -14px rgba(0,0,0,.7);
}

*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{
  margin:0;
  background:var(--paper);
  color:var(--text);
  font-family:"Public Sans",system-ui,-apple-system,Segoe UI,Roboto,sans-serif;
  font-size:16px;
  line-height:1.62;
  -webkit-font-smoothing:antialiased;
  padding-bottom:calc(64px + env(safe-area-inset-bottom));
}
@media (min-width:960px){ body{padding-bottom:0} }

a{color:var(--teal);text-decoration-thickness:1px;text-underline-offset:3px}
:focus-visible{outline:2.5px solid var(--teal);outline-offset:2px;border-radius:4px}
main:focus,main:focus-visible{outline:none}
.skip{position:absolute;left:-999px;top:0;background:var(--ink);color:#fff;padding:10px 14px;z-index:99}
.skip:focus{left:8px;top:8px}

/* ---------- top bar ---------- */
.topbar{
  position:sticky;top:0;z-index:40;
  display:flex;align-items:center;gap:10px;
  padding:10px 14px;
  padding-top:calc(10px + env(safe-area-inset-top));
  background:var(--ink);color:#fff;
  border-bottom:1px solid rgba(255,255,255,.08);
}
.brand{display:flex;flex-direction:column;line-height:1.15;min-width:0;flex:1}
.brand .code{
  font-family:"Fraunces",Georgia,serif;font-weight:700;font-size:20px;letter-spacing:-.2px;
}
.brand .sub{font-size:11.5px;color:#9FB2C6;font-family:"JetBrains Mono",monospace;letter-spacing:.02em;
  white-space:nowrap;overflow:hidden;text-overflow:ellipsis}

.iconbtn{
  display:grid;place-items:center;width:38px;height:38px;flex:0 0 auto;
  background:rgba(255,255,255,.08);border:0;border-radius:10px;color:#fff;cursor:pointer;
}
.iconbtn:active{transform:scale(.94)}
.menu{flex-direction:column;gap:4px}
.menu span{display:block;width:16px;height:2px;background:#fff;border-radius:2px;transition:.2s}
body.navopen .menu span:nth-child(1){transform:translateY(6px) rotate(45deg)}
body.navopen .menu span:nth-child(2){opacity:0}
body.navopen .menu span:nth-child(3){transform:translateY(-6px) rotate(-45deg)}
@media (min-width:960px){ .menu{display:none} }

html[data-theme="light"] .moon{display:none}
html[data-theme="dark"] .sun{display:none}

/* signature element: the cram clock */
.clock{
  display:flex;flex-direction:column;align-items:center;justify-content:center;
  flex:0 0 auto;padding:3px 11px;border-radius:10px;cursor:pointer;
  background:var(--marker);color:#2A1F00;border:0;
  font-family:"JetBrains Mono",monospace;
}
.clock-face{font-size:15px;font-weight:700;letter-spacing:.02em;line-height:1.15}
.clock-label{font-size:8.5px;text-transform:uppercase;letter-spacing:.14em;opacity:.7}
.clock.running{background:var(--teal);color:#fff}
.clock.warn{background:var(--pen);color:#fff;animation:pulse 1.4s ease-in-out infinite}
@keyframes pulse{50%{opacity:.72}}

/* ---------- layout ---------- */
.shell{display:block}
@media (min-width:960px){
  .shell{display:grid;grid-template-columns:280px minmax(0,1fr);align-items:start}
}

.sidebar{
  position:fixed;inset:0 auto 0 0;width:min(84vw,320px);z-index:60;
  background:var(--card);border-right:1px solid var(--line);
  padding:16px 14px calc(24px + env(safe-area-inset-bottom));
  overflow-y:auto;transform:translateX(-102%);transition:transform .26s cubic-bezier(.4,0,.2,1);
}
body.navopen .sidebar{transform:none}
@media (min-width:960px){
  .sidebar{position:sticky;top:59px;height:calc(100dvh - 59px);transform:none;width:auto;inset:auto}
}
.scrim{position:fixed;inset:0;background:rgba(6,12,20,.5);z-index:50;border:0}
body.navopen .scrim{display:block}
@media (min-width:960px){ .scrim{display:none!important} }

main{
  max-width:var(--maxw);width:100%;margin:0 auto;
  padding:18px 16px 40px;
}
@media (min-width:960px){ main{padding:28px 34px 80px} }

/* ---------- sidebar bits ---------- */
.searchwrap{position:relative;margin-bottom:16px}
.searchwrap input{
  width:100%;padding:11px 40px 11px 13px;border-radius:11px;
  border:1px solid var(--line);background:var(--paper);color:var(--text);
  font:inherit;font-size:14.5px;
}
.searchwrap kbd{
  position:absolute;right:9px;top:50%;transform:translateY(-50%);
  font-family:"JetBrains Mono",monospace;font-size:11px;color:var(--muted);
  border:1px solid var(--line);border-radius:5px;padding:1px 6px;background:var(--card);
}
.navhead{
  font-family:"JetBrains Mono",monospace;font-size:10.5px;text-transform:uppercase;
  letter-spacing:.16em;color:var(--muted);margin:18px 0 8px 4px;
}
.navlist{list-style:none;margin:0;padding:0}
.navlist a{
  display:flex;align-items:center;gap:10px;padding:8px 10px;border-radius:9px;
  color:var(--text);text-decoration:none;font-size:14.5px;
}
.navlist a:hover{background:var(--paper)}
.navlist a.active{background:var(--teal-soft);color:var(--teal);font-weight:600}
.navlist a em{margin-left:auto;font-style:normal;font-family:"JetBrains Mono",monospace;font-size:11px;color:var(--muted)}
.ni{
  flex:0 0 auto;display:grid;place-items:center;width:24px;height:24px;border-radius:7px;
  background:var(--paper);border:1px solid var(--line);
  font-family:"JetBrains Mono",monospace;font-size:10.5px;font-weight:700;color:var(--muted);
}
.navlist a.active .ni{background:var(--teal);color:#fff;border-color:transparent}
.navlist a.done .ni{background:var(--teal);color:#fff;border-color:transparent}
.navlist a.done::after{content:"✓";margin-left:auto;color:var(--teal);font-size:13px;font-weight:700}

.progresscard{
  margin-top:22px;padding:14px;border-radius:var(--r);
  background:var(--paper);border:1px solid var(--line);
}
.progresscard p{margin:9px 0 10px;font-size:12.5px;color:var(--muted)}
.pbar{height:7px;border-radius:99px;background:var(--line);overflow:hidden}
.pbar i{display:block;height:100%;width:0;background:var(--teal);transition:width .35s}
.ghost{
  background:transparent;border:1px solid var(--line);color:var(--muted);
  border-radius:8px;padding:6px 11px;font:inherit;font-size:12.5px;cursor:pointer;
}
.ghost:hover{border-color:var(--pen);color:var(--pen)}

/* ---------- bottom tab bar (mobile) ---------- */
.tabbar{
  position:fixed;left:0;right:0;bottom:0;z-index:45;
  display:grid;grid-template-columns:repeat(4,1fr);
  background:var(--card);border-top:1px solid var(--line);
  padding-bottom:env(safe-area-inset-bottom);
}
.tabbar button{
  background:none;border:0;padding:8px 4px 7px;color:var(--muted);
  font:inherit;font-size:10.5px;cursor:pointer;display:grid;justify-items:center;gap:2px;
}
.tabbar svg{width:21px;height:21px;fill:currentColor}
.tabbar button.on{color:var(--teal);font-weight:600}
@media (min-width:960px){ .tabbar{display:none} }

/* ---------- hero ---------- */
.hero{margin-bottom:26px}
.eyebrow{
  font-family:"JetBrains Mono",monospace;font-size:11px;letter-spacing:.18em;
  text-transform:uppercase;color:var(--muted);margin:0 0 8px;
}
h1{
  font-family:"Fraunces",Georgia,serif;font-weight:700;
  font-size:clamp(30px,7.6vw,46px);line-height:1.05;letter-spacing:-.02em;margin:0 0 12px;
}
.lede{font-size:16.5px;color:var(--muted);margin:0 0 18px;max-width:60ch}
.stats{display:grid;grid-template-columns:repeat(3,1fr);gap:9px;margin:18px 0 0}
.stat{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:12px 11px;box-shadow:var(--shadow)}
.stat b{display:block;font-family:"Fraunces",serif;font-size:25px;line-height:1;color:var(--teal)}
.stat span{font-size:11.5px;color:var(--muted);display:block;margin-top:5px;line-height:1.3}

/* ---------- week cards on home ---------- */
.weekgrid{display:grid;gap:11px;margin-top:12px}
.weekcard{
  display:flex;gap:13px;align-items:flex-start;text-align:left;width:100%;
  background:var(--card);border:1px solid var(--line);border-radius:var(--r);
  padding:14px;cursor:pointer;font:inherit;color:inherit;box-shadow:var(--shadow);
  transition:transform .14s,border-color .14s;
}
.weekcard:hover{transform:translateY(-2px);border-color:var(--teal)}
.wnum{
  flex:0 0 auto;width:44px;height:44px;border-radius:12px;display:grid;place-items:center;
  background:var(--ink);color:var(--marker);
  font-family:"JetBrains Mono",monospace;font-weight:700;font-size:16px;
}
.weekcard.done .wnum{background:var(--teal);color:#fff}
.wbody{min-width:0;flex:1}
.wbody h3{margin:0 0 3px;font-family:"Fraunces",serif;font-size:17.5px;font-weight:600;line-height:1.25}
.wbody p{margin:0;font-size:13.5px;color:var(--muted);line-height:1.45}
.stars{font-size:11px;color:var(--marker);letter-spacing:1px;margin-top:6px;display:block;
  -webkit-text-stroke:.4px rgba(0,0,0,.18)}

/* ---------- article typography ---------- */
article h2{
  font-family:"Fraunces",serif;font-weight:700;font-size:clamp(24px,6vw,34px);
  line-height:1.12;letter-spacing:-.02em;margin:0 0 6px;
}
article h3{
  font-family:"Fraunces",serif;font-weight:600;font-size:20px;line-height:1.25;
  margin:30px 0 10px;padding-top:14px;border-top:1px solid var(--line);
}
article h4{font-size:15.5px;font-weight:700;margin:20px 0 8px;color:var(--teal)}
article ul,article ol{padding-left:20px;margin:10px 0}
article li{margin:5px 0}
article li::marker{color:var(--teal);font-weight:700}
article p{margin:10px 0}

mark{
  background:linear-gradient(105deg,transparent 2%,var(--marker-soft) 2%,var(--marker-soft) 96%,transparent 96%);
  color:inherit;padding:1px 3px;border-radius:2px;font-weight:600;
  box-decoration-break:clone;-webkit-box-decoration-break:clone;
}
html[data-theme="dark"] mark{color:var(--marker)}

.def{
  background:var(--teal-soft);border-left:4px solid var(--teal);
  padding:12px 14px;border-radius:0 10px 10px 0;margin:14px 0;font-size:15px;
}
.callout{
  background:var(--card);border:1px solid var(--line);border-radius:var(--r);
  padding:14px 16px;margin:16px 0;box-shadow:var(--shadow);
}
.callout ol,.callout ul{margin:8px 0 0}
.callout.hot{border-color:var(--pen);background:var(--pen-soft)}
.note{
  display:block;font-size:13.5px;color:var(--muted);
  border-left:3px solid var(--line);padding-left:11px;margin:12px 0;
}
.pill{
  display:inline-block;background:var(--pen);color:#fff;border-radius:99px;
  padding:1px 9px;font-size:10.5px;font-family:"JetBrains Mono",monospace;
  letter-spacing:.04em;vertical-align:middle;white-space:nowrap;
}
.formula{
  background:var(--ink);color:#fff;border-radius:var(--r);padding:18px 16px;
  text-align:center;line-height:1.85;font-size:15px;margin:16px 0;
}
.formula b{color:var(--marker)}
.chain{
  display:grid;gap:5px;justify-items:center;text-align:center;
  background:var(--card);border:1px solid var(--line);border-radius:var(--r);
  padding:16px 12px;margin:14px 0;font-size:14px;box-shadow:var(--shadow);
}
.chain span:nth-child(even){color:var(--teal);font-weight:700}
.grid2{display:grid;gap:0 22px}
@media (min-width:620px){ .grid2{grid-template-columns:1fr 1fr} }

.tablewrap{overflow-x:auto;-webkit-overflow-scrolling:touch;margin:16px 0;
  border:1px solid var(--line);border-radius:var(--r);background:var(--card);box-shadow:var(--shadow)}
table{border-collapse:collapse;width:100%;min-width:440px;font-size:14px}
caption{
  caption-side:top;text-align:left;padding:12px 14px 6px;font-weight:700;font-size:13px;
  color:var(--pen);letter-spacing:.01em;
}
th,td{padding:10px 13px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}
thead th{background:var(--paper);font-size:12px;text-transform:uppercase;letter-spacing:.06em;color:var(--muted)}
tbody tr:last-child td{border-bottom:0}

.docnav{display:flex;gap:10px;margin-top:34px;padding-top:20px;border-top:1px solid var(--line)}
.docnav button{
  flex:1;background:var(--card);border:1px solid var(--line);border-radius:var(--r);
  padding:12px;font:inherit;font-size:13.5px;cursor:pointer;color:var(--text);text-align:left;
}
.docnav button:hover{border-color:var(--teal)}
.docnav small{display:block;color:var(--muted);font-size:11px;font-family:"JetBrains Mono",monospace;
  text-transform:uppercase;letter-spacing:.1em}
.docnav button:last-child{text-align:right}

.markdone{
  width:100%;margin-top:22px;padding:13px;border-radius:var(--r);
  border:1.5px dashed var(--line);background:transparent;color:var(--muted);
  font:inherit;font-size:14px;cursor:pointer;
}
.markdone:hover{border-color:var(--teal);color:var(--teal)}
.markdone.on{background:var(--teal);border-color:var(--teal);border-style:solid;color:#fff;font-weight:600}

/* ---------- MCQ ---------- */
.filters{display:flex;gap:7px;overflow-x:auto;padding:2px 0 12px;-webkit-overflow-scrolling:touch}
.chip{
  flex:0 0 auto;background:var(--card);border:1px solid var(--line);border-radius:99px;
  padding:6px 13px;font:inherit;font-size:13px;cursor:pointer;color:var(--muted);white-space:nowrap;
}
.chip.on{background:var(--ink);border-color:var(--ink);color:#fff;font-weight:600}

.scorebar{
  display:flex;align-items:center;gap:10px;flex-wrap:wrap;font-size:14px;background:var(--card);border:1px solid var(--line);
  border-radius:var(--r);padding:11px 14px;margin-bottom:14px;box-shadow:var(--shadow);
  position:sticky;top:59px;z-index:20;
}
.scorebar b{font-family:"JetBrains Mono",monospace;font-size:14px}
.scorebar .right{margin-left:auto;display:flex;gap:8px;flex:0 0 auto}
.scorebar>span:first-child{flex:1 1 auto;min-width:0}

.q{
  background:var(--card);border:1px solid var(--line);border-radius:var(--r);
  padding:16px;margin-bottom:12px;box-shadow:var(--shadow);
}
.qtop{display:flex;gap:10px;align-items:baseline;margin-bottom:9px}
.qnum{font-family:"JetBrains Mono",monospace;font-size:11.5px;color:var(--muted);flex:0 0 auto}
.qwk{
  font-family:"JetBrains Mono",monospace;font-size:10.5px;background:var(--paper);
  border:1px solid var(--line);border-radius:5px;padding:1px 6px;color:var(--muted);margin-left:auto;flex:0 0 auto;
}
.qtext{font-weight:600;font-size:15.5px;line-height:1.45;margin:0 0 12px}
.opts{display:grid;gap:7px}
.opt{
  display:flex;gap:10px;align-items:flex-start;text-align:left;width:100%;
  background:var(--paper);border:1.5px solid var(--line);border-radius:10px;
  padding:10px 12px;font:inherit;font-size:14.5px;cursor:pointer;color:var(--text);
  transition:border-color .12s,background .12s;
}
.opt:hover:not([disabled]){border-color:var(--teal)}
.opt .k{
  flex:0 0 auto;font-family:"JetBrains Mono",monospace;font-size:12px;font-weight:700;
  color:var(--muted);width:16px;
}
.opt.right{background:var(--teal-soft);border-color:var(--teal)}
.opt.right .k{color:var(--teal)}
.opt.wrong{background:var(--pen-soft);border-color:var(--pen)}
.opt.wrong .k{color:var(--pen)}
.opt[disabled]{cursor:default}
.exp{
  margin-top:11px;padding:10px 12px;border-radius:10px;background:var(--paper);
  border-left:3px solid var(--marker);font-size:13.5px;color:var(--muted);
}
.exp b{color:var(--text)}

/* ---------- Q&A accordions ---------- */
.qa{
  background:var(--card);border:1px solid var(--line);border-radius:var(--r);
  margin-bottom:10px;overflow:hidden;box-shadow:var(--shadow);
}
.qa summary{
  list-style:none;cursor:pointer;padding:14px 16px;font-weight:600;font-size:15px;
  display:flex;gap:11px;align-items:flex-start;
}
.qa summary::-webkit-details-marker{display:none}
.qa summary::after{
  content:"+";margin-left:auto;flex:0 0 auto;font-family:"JetBrains Mono",monospace;
  color:var(--teal);font-size:18px;line-height:1;
}
.qa[open] summary::after{content:"–"}
.qa .wk{
  flex:0 0 auto;font-family:"JetBrains Mono",monospace;font-size:10.5px;color:var(--muted);
  background:var(--paper);border:1px solid var(--line);border-radius:5px;padding:1px 6px;margin-top:2px;
}
.qa .ans{padding:0 16px 16px;font-size:14.7px;color:var(--text);border-top:1px solid var(--line);padding-top:13px;margin:0 16px 16px 16px}

/* ---------- cheat sheet ---------- */
.sheet{
  background:var(--card);border:1px solid var(--line);border-radius:var(--r);
  padding:16px;margin-bottom:12px;box-shadow:var(--shadow);
}
.sheet h3{
  margin:0 0 10px;padding:0;border:0;font-family:"Fraunces",serif;font-size:18px;
  color:var(--pen);
}
.sheet ul{margin:0;padding-left:19px}
.sheet li{margin:6px 0;font-size:14.3px;line-height:1.5}

/* ---------- search results ---------- */
.result{
  display:block;width:100%;text-align:left;background:var(--card);border:1px solid var(--line);
  border-radius:var(--r);padding:13px 15px;margin-bottom:9px;font:inherit;cursor:pointer;color:inherit;
}
.result:hover{border-color:var(--teal)}
.result .kind{
  font-family:"JetBrains Mono",monospace;font-size:10px;text-transform:uppercase;letter-spacing:.12em;
  color:var(--teal);display:block;margin-bottom:4px;
}
.result p{margin:0;font-size:14.3px;line-height:1.45}
.empty{text-align:center;color:var(--muted);padding:40px 20px;font-size:15px}

.foot{margin-top:36px;padding-top:18px;border-top:1px solid var(--line);font-size:12.5px;color:var(--muted)}

@media (prefers-reduced-motion:reduce){
  *{animation-duration:.001ms!important;transition-duration:.001ms!important}
}

@media print{
  .topbar,.sidebar,.tabbar,.docnav,.markdone,.filters,.scorebar{display:none!important}
  body{padding:0;background:#fff}
  main{max-width:100%}
  .qa .ans{display:block!important}
}