/* BetterMath site — one stylesheet for every page. Edit here, then run build.py.
   Sleek and minimal: a pale page, every section a white card, one accent colour (cobalt),
   scarlet only for the ">" and for corrections. */
:root{
  --cobalt:#1A47B8; --cobalt-d:#133A99; --scarlet:#C44545; --teal:#287C78; --gold:#A8741A; --navy:#0D1F52;
  --ink:#111317; --ink-2:#2B2F36; --ink-3:#555B66; --ink-4:#7A808B;
  --page:#F5F6F8; --card:#fff; --line:#E5E7EB; --line-2:#EEF0F3; --tint:#EEF2FB; --tint-2:#F7F9FD;
  --serif:"Palatino Linotype",Palatino,"Book Antiqua","Source Serif 4",Georgia,serif;
  --sans:"Source Sans 3",-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif;
  --mono:"IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  --wide:1120px; --text:680px; --r:16px; --r-s:10px;
  --lift:0 1px 2px rgba(17,19,23,.04),0 10px 28px -16px rgba(17,19,23,.18);
  --lattice:url("data:image/svg+xml;utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' width='56' height='97' viewBox='0 0 56 97'%3E%3Cg fill='none' stroke='%231A47B8' stroke-opacity='.075' stroke-width='1'%3E%3Cpath d='M0 0L56 97M56 0L0 97M0 48.5H56'/%3E%3Cpath d='M28 0L56 48.5L28 97L0 48.5Z'/%3E%3C/g%3E%3C/svg%3E");
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{margin:0;background:var(--page);color:var(--ink);font-family:var(--sans);font-size:17px;line-height:1.6;-webkit-font-smoothing:antialiased}
a{color:var(--cobalt);text-underline-offset:3px} a:hover{text-decoration-thickness:2px}
img{max-width:100%;height:auto;display:block}
p{margin:0 0 16px}
h1,h2,h3{font-family:var(--serif);font-weight:700;color:var(--ink);letter-spacing:-.012em;line-height:1.15}
h2{font-size:clamp(26px,3vw,34px);margin:0 0 12px}
:focus-visible{outline:2px solid var(--cobalt);outline-offset:2px;border-radius:4px}
.wrap{max-width:var(--wide);margin:0 auto;padding:0 20px}
.skip{position:absolute;left:-9999px;top:8px;z-index:100;background:var(--cobalt);color:#fff;padding:8px 14px;border-radius:8px;font-weight:700}
.skip:focus{left:12px}
@media (prefers-reduced-motion:reduce){*{transition:none!important;animation:none!important;scroll-behavior:auto!important}}

/* ── header ── */
.bar{position:sticky;top:0;z-index:40;background:rgba(245,246,248,.86);backdrop-filter:saturate(1.6) blur(12px);-webkit-backdrop-filter:saturate(1.6) blur(12px);border-bottom:1px solid transparent;transition:border-color .2s}
.bar .wrap{display:flex;align-items:center;gap:20px;height:64px}
.logo{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--ink);font-family:var(--serif);font-weight:700;font-size:21px;letter-spacing:-.01em}
.logo svg{width:28px;height:28px;flex:0 0 auto}
.nav{margin-left:auto;display:flex;align-items:center;gap:2px}
.nav a{color:var(--ink-3);text-decoration:none;font-weight:600;font-size:15px;padding:7px 12px;border-radius:999px;transition:color .15s,background .15s}
.nav a:hover{color:var(--ink)}
.nav a[aria-current=page]{color:var(--ink);background:#fff;box-shadow:0 0 0 1px var(--line)}
.nav .btn{margin-left:10px}
.menu{display:none;margin-left:auto;background:#fff;border:1px solid var(--line);border-radius:12px;width:42px;height:42px;cursor:pointer;color:var(--ink);align-items:center;justify-content:center}
.menu svg{width:20px;height:20px}
.menu .x{display:none}
.bar.open .menu .x{display:block} .bar.open .menu .h{display:none}
@media (max-width:820px){
  .menu{display:inline-flex}
  .nav{display:none;position:absolute;left:12px;right:12px;top:66px;background:#fff;flex-direction:column;align-items:stretch;gap:0;padding:8px;border:1px solid var(--line);border-radius:var(--r);box-shadow:var(--lift)}
  .bar.open .nav{display:flex}
  .nav a{padding:12px 14px;font-size:17px;border-radius:10px}
  .nav a[aria-current=page]{box-shadow:none;background:var(--page)}
  .nav .btn{margin:8px 0 0;justify-content:center}
}

/* ── buttons, chips, small type ── */
.btn{display:inline-flex;align-items:center;gap:8px;font:inherit;font-weight:600;font-size:15.5px;text-decoration:none;border-radius:999px;padding:11px 20px;cursor:pointer;border:0;transition:background .15s,color .15s,box-shadow .15s;line-height:1.2;white-space:nowrap}
.btn svg{width:17px;height:17px;flex:0 0 auto}
.btn.primary,.nav .btn{background:var(--cobalt);color:#fff}
.btn.primary:hover,.nav .btn:hover{background:var(--cobalt-d);color:#fff}
.btn.ghost{background:#fff;color:var(--ink);box-shadow:inset 0 0 0 1px var(--line)}
.btn.ghost:hover{box-shadow:inset 0 0 0 1px var(--ink-4)}
.btn.small{font-size:14px;padding:8px 14px}
.btn.coffee{background:#fff;color:#8A5226;box-shadow:inset 0 0 0 1px #E9D6C4}
.btn.coffee:hover{box-shadow:inset 0 0 0 1px #8A5226}
.btn[disabled]{opacity:.6;cursor:default}
.chip{display:inline-block;font-size:11.5px;font-weight:700;letter-spacing:.1em;text-transform:uppercase;padding:3px 9px;border-radius:999px;line-height:1.5;background:var(--page);color:var(--ink-3)}
.chip.hl{background:var(--teal);color:#fff;border-radius:3px}
.chip.free{background:var(--tint);color:var(--cobalt)}
.chip.form{background:var(--tint);color:var(--cobalt)}
.chip.teacher{background:#F0ECF8;color:#5B3FA0}
.chip.soon{background:#FBEFEF;color:#A83535}
.eyebrow{font-size:12.5px;font-weight:700;letter-spacing:.14em;text-transform:uppercase;color:var(--ink-4);margin:0 0 10px}
.eyebrow.accent{color:var(--cobalt)} .eyebrow.scarlet{color:var(--scarlet)}
.lede{font-family:var(--serif);font-size:20px;line-height:1.5;color:var(--ink-2);max-width:40ch}
.intro{font-size:17px;color:var(--ink-3);max-width:60ch;margin-bottom:26px}
.fine{font-size:13.5px;color:var(--ink-4);margin:12px 0 0}
.arrow{display:inline-block;font-family:var(--mono);font-weight:700;transition:transform .2s}
a:hover .arrow{transform:translateX(3px)}
.motto{display:flex;align-items:center;gap:14px;margin:26px 0 0}
.motto::before{content:"";flex:0 0 40px;height:1.5px;background:var(--scarlet)}
.motto span{font-family:var(--mono);font-size:15.5px;letter-spacing:.05em;color:var(--cobalt)}
.motto b{color:var(--scarlet);font-weight:700}

/* ── cards: every section is one ── */
main{padding:20px 0 0}
.panel{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:44px 48px;margin:0 0 20px;scroll-margin-top:84px}
.panel.flush{padding:0;overflow:hidden}
.panel > h2:first-child,.panel > .eyebrow:first-child{margin-top:0}
.head-row{display:flex;align-items:flex-end;justify-content:space-between;gap:16px;flex-wrap:wrap;margin-bottom:24px}
.head-row h2{margin:0}
.head-row .intro{margin:8px 0 0}
.more{font-weight:600;font-size:15px;text-decoration:none;white-space:nowrap}
@media (max-width:700px){.panel{padding:28px 22px;border-radius:14px}}
.grid-bg{position:relative;overflow:hidden}
.grid-bg::before{content:"";position:absolute;inset:0;background-image:var(--lattice);background-size:56px 97px;pointer-events:none;-webkit-mask-image:linear-gradient(180deg,#000 0%,rgba(0,0,0,.35) 100%);mask-image:linear-gradient(180deg,#000 0%,rgba(0,0,0,.35) 100%)}
.grid-bg > *{position:relative}

/* ── home hero ── */
.hero{padding:0}
.hero .in{display:grid;grid-template-columns:1.25fr .75fr;gap:40px;align-items:center;padding:60px 56px 44px}
.kicker{font-family:var(--serif);font-variant:small-caps;letter-spacing:.08em;font-size:17px;color:var(--ink-3);margin:0 0 8px;font-weight:700}
.hero h1{font-size:clamp(44px,6.2vw,74px);line-height:1;margin:0}
.hero h1 .sub{display:block;color:var(--cobalt);font-size:.48em;line-height:1.2;margin-top:12px;letter-spacing:-.005em}
.hero .chip.hl{margin-top:16px}
.hero .lede{margin:22px 0 26px}
.cta{display:flex;flex-wrap:wrap;gap:10px;align-items:center}
.meta{font-size:14px;color:var(--ink-4);margin:14px 0 0}
.coverbox{justify-self:center;position:relative;width:min(300px,100%)}
.coverbox img{border-radius:3px 6px 6px 3px;box-shadow:0 1px 2px rgba(0,0,0,.1),0 24px 48px -22px rgba(13,31,82,.45)}
.stats{display:grid;grid-template-columns:repeat(4,1fr);border-top:1px solid var(--line)}
.stat{padding:20px 12px;text-align:center;border-left:1px solid var(--line)}
.stat:first-child{border-left:0}
.stat b{display:block;font-family:var(--serif);font-size:28px;line-height:1.1;color:var(--ink)}
.stat span{font-size:12px;letter-spacing:.1em;text-transform:uppercase;color:var(--ink-4);font-weight:700}
@media (max-width:860px){
  .hero .in{grid-template-columns:1fr;gap:30px;padding:36px 22px 30px}
  .coverbox{width:min(200px,56%);justify-self:start}
}
@media (max-width:560px){.stats{grid-template-columns:repeat(2,1fr)}.stat:nth-child(3){border-left:0}.stat:nth-child(n+3){border-top:1px solid var(--line)}}

/* ── tiles (start here) ── */
.tiles{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}
.tile{display:flex;flex-direction:column;border:1px solid var(--line);border-radius:var(--r-s);padding:22px 20px 18px;text-decoration:none;color:inherit;transition:border-color .2s,box-shadow .2s,transform .2s;background:#fff}
.tile:hover{border-color:#C9D3EE;box-shadow:var(--lift);transform:translateY(-2px)}
.tile .ic{width:38px;height:38px;border-radius:10px;display:grid;place-items:center;background:var(--tint);color:var(--cobalt);margin-bottom:16px}
.tile .ic svg{width:20px;height:20px}
.tile h3{font-size:20px;margin:0 0 6px}
.tile p{font-size:15px;color:var(--ink-3);margin:0 0 14px;flex:1}
.tile .go{font-weight:600;font-size:14.5px;color:var(--cobalt)}
@media (max-width:980px){.tiles{grid-template-columns:repeat(2,1fr)}}
@media (max-width:540px){.tiles{grid-template-columns:1fr}}

/* ── split (home: the notes) ── */
.split{display:grid;grid-template-columns:.8fr 1.2fr;gap:56px;align-items:center}
@media (max-width:860px){.split{grid-template-columns:1fr;gap:34px}}
.ticks{list-style:none;padding:0;margin:0 0 26px}
.ticks li{display:flex;gap:12px;padding:10px 0;border-top:1px solid var(--line-2);font-size:16px;color:var(--ink-2)}
.ticks li:last-child{border-bottom:1px solid var(--line-2)}
.ticks svg{flex:0 0 18px;width:18px;height:18px;margin-top:4px;color:var(--cobalt)}
.stack{position:relative;display:block;width:min(290px,100%);aspect-ratio:936/1313;justify-self:center;margin:6px 34px 26px 0}
.stack img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;border-radius:4px;background:#fff;box-shadow:0 0 0 1px var(--line),0 18px 36px -20px rgba(13,31,82,.4);transition:transform .45s cubic-bezier(.2,.8,.2,1)}
.stack .p3{transform:rotate(6deg) translate(30px,6px)}
.stack .p2{transform:rotate(3deg) translate(15px,3px)}
.stack:hover .p3{transform:rotate(9deg) translate(54px,10px)}
.stack:hover .p2{transform:rotate(4.5deg) translate(27px,5px)}
.stack .peek{position:absolute;left:50%;bottom:-16px;transform:translateX(-50%);background:#fff;color:var(--ink);font-weight:600;font-size:14px;padding:7px 14px;border-radius:999px;white-space:nowrap;box-shadow:0 0 0 1px var(--line),var(--lift)}
@media (max-width:860px){.stack{width:min(220px,60%);justify-self:start}}

/* ── roadmap + list rows ── */
.road{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}
.road .item{border:1px dashed #D5DAE3;border-radius:var(--r-s);padding:20px}
.road .item h3{font-size:19px;margin:12px 0 6px}
.road .item p{font-size:15px;color:var(--ink-3);margin:0}
@media (max-width:820px){.road{grid-template-columns:1fr}}

/* ── teachers ── */
.teach{display:grid;grid-template-columns:1.4fr .6fr;gap:28px;align-items:center}
.teach p{color:var(--ink-3);margin:0;max-width:58ch}
.teach .side{display:flex;flex-direction:column;gap:10px;align-items:stretch;justify-self:end}
@media (max-width:820px){.teach{grid-template-columns:1fr}.teach .side{justify-self:start;flex-direction:row;flex-wrap:wrap}}

/* ── article cards ── */
.posts{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}
.post{display:flex;flex-direction:column;border:1px solid var(--line);border-radius:var(--r-s);padding:22px 20px 18px;background:#fff;text-decoration:none;color:inherit;transition:border-color .2s,box-shadow .2s,transform .2s}
.post:hover{border-color:#C9D3EE;box-shadow:var(--lift);transform:translateY(-2px)}
.post .glyph{width:40px;height:40px;border-radius:10px;display:grid;place-items:center;font-family:var(--serif);font-weight:700;font-size:22px;color:var(--c,var(--cobalt));background:color-mix(in srgb,var(--c,var(--cobalt)) 10%,#fff);margin-bottom:14px}
.post h3{font-size:20px;margin:8px 0 8px}
.post p{font-size:15px;color:var(--ink-3);margin:0 0 14px;flex:1}
.post .d{font-size:13px;color:var(--ink-4)}
.c-cobalt{--c:var(--cobalt)} .c-teal{--c:var(--teal)} .c-scarlet{--c:var(--scarlet)} .c-ink{--c:var(--navy)} .c-gold{--c:var(--gold)}
@media (max-width:900px){.posts{grid-template-columns:repeat(2,1fr)}}
@media (max-width:600px){.posts{grid-template-columns:1fr}}
.empty{border:1px dashed #D5DAE3;border-radius:var(--r-s);padding:24px;color:var(--ink-3)}

/* ── support ── */
.support{display:flex;gap:18px;align-items:center;flex-wrap:wrap}
.support .cup{width:44px;height:44px;border-radius:50%;background:#FBF4EE;display:grid;place-items:center;color:#8A5226;flex:0 0 auto}
.support .cup svg{width:22px;height:22px}
.support div{flex:1 1 280px}
.support b{font-family:var(--serif);font-size:19px;display:block}
.support p{margin:0;color:var(--ink-3);font-size:15px}

/* ── inner page head ── */
.phead{padding:52px 48px 44px}
.phead h1{font-size:clamp(36px,4.8vw,54px);margin:0 0 10px}
.phead .lede{margin:0;max-width:50ch}
.crumbs{font-size:13.5px;margin:0 0 14px;color:var(--ink-4)}
.crumbs a{text-decoration:none;font-weight:600;color:var(--ink-3)}
.crumbs a:hover{color:var(--cobalt)}
@media (max-width:700px){.phead{padding:32px 22px 28px}}

/* ── notes page ── */
.dlrow{display:grid;grid-template-columns:auto 1fr auto;gap:24px;align-items:center;padding-bottom:30px;margin-bottom:30px;border-bottom:1px solid var(--line-2)}
.dlrow img{width:76px;border-radius:2px 4px 4px 2px;box-shadow:0 0 0 1px var(--line),0 10px 20px -12px rgba(13,31,82,.5)}
.dlrow .t{font-family:var(--serif);font-weight:700;font-size:22px;line-height:1.25;margin-top:6px}
.dlrow .d{font-size:14.5px;color:var(--ink-4);margin-top:4px}
@media (max-width:700px){.dlrow{grid-template-columns:1fr}.dlrow img{display:none}}
.feat{display:grid;grid-template-columns:repeat(3,1fr);gap:30px}
.feat .ic{width:36px;height:36px;border-radius:10px;display:grid;place-items:center;background:var(--tint);color:var(--cobalt);margin-bottom:12px}
.feat .ic svg{width:19px;height:19px}
.feat h3{margin:0 0 6px;font-size:17px;font-family:var(--sans);letter-spacing:0}
.feat p{font-size:15px;color:var(--ink-3);margin:0}
@media (max-width:820px){.feat{grid-template-columns:1fr;gap:22px}}
.inside{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}
.inside a{text-decoration:none;color:var(--ink-3);font-weight:600;font-size:14px;text-align:center}
.inside img{border-radius:4px;box-shadow:0 0 0 1px var(--line);margin-bottom:10px;transition:transform .2s,box-shadow .2s}
.inside a:hover img{transform:translateY(-3px);box-shadow:0 0 0 1px #C9D3EE,var(--lift)}
@media (max-width:640px){.inside{grid-template-columns:1fr 1fr}.inside a:last-child{display:none}}
.chapters{display:grid;grid-template-columns:repeat(2,1fr);gap:0 36px}
.chap{display:grid;grid-template-columns:44px 1fr auto;gap:2px 14px;align-items:center;padding:14px 0;border-bottom:1px solid var(--line-2)}
.chap .n{grid-row:span 2;font-family:var(--serif);font-weight:700;font-size:24px;color:var(--cobalt);line-height:1}
.chap .t{font-weight:600;font-size:16.5px;line-height:1.3}
.chap .s{grid-column:2;font-size:13px;color:var(--ink-4)}
.chap .s i{font-style:normal;font-family:var(--mono);font-size:12px}
.chap a.dl{grid-row:1 / span 2;grid-column:3;font-size:13.5px;font-weight:600;text-decoration:none;color:var(--ink-2);border:1px solid var(--line);padding:6px 12px;border-radius:999px;white-space:nowrap;display:inline-flex;gap:6px;align-items:center;transition:all .15s}
.chap a.dl svg{width:14px;height:14px}
.chap a.dl:hover{background:var(--cobalt);color:#fff;border-color:var(--cobalt)}
@media (max-width:820px){.chapters{grid-template-columns:1fr}}
.pills{display:flex;flex-wrap:wrap;gap:6px;margin:0 0 18px}
.pills button{font:inherit;font-size:13.5px;font-weight:600;border:1px solid var(--line);background:#fff;color:var(--ink-3);padding:6px 13px;border-radius:999px;cursor:pointer;transition:all .15s}
.pills button:hover{color:var(--ink);border-color:var(--ink-4)}
.pills button[aria-pressed=true]{background:var(--ink);border-color:var(--ink);color:#fff}

/* ── resources page ── */
.jump{display:flex;flex-wrap:wrap;gap:6px;margin-top:22px}
.jump a{font-size:13.5px;font-weight:600;text-decoration:none;background:#fff;border:1px solid var(--line);color:var(--ink-3);padding:6px 13px;border-radius:999px;display:inline-flex;gap:8px;align-items:center}
.jump a i{width:7px;height:7px;border-radius:2px;background:var(--c);transform:rotate(45deg)}
.jump a:hover{color:var(--ink);border-color:var(--ink-4)}
.shelf-head{display:flex;align-items:center;gap:12px;margin-bottom:6px}
.shelf-head h2{margin:0}
.shelf-head .dot{width:10px;height:10px;border-radius:2px;background:var(--c);transform:rotate(45deg);flex:0 0 auto}
.shelf .intro{margin-bottom:22px}
.items{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}
.item-card{display:flex;flex-direction:column;border:1px solid var(--line);border-radius:var(--r-s);padding:18px;background:#fff;text-decoration:none;color:inherit;transition:border-color .2s,box-shadow .2s,transform .2s}
a.item-card:hover{border-color:#C9D3EE;box-shadow:var(--lift);transform:translateY(-2px)}
.item-card .row{display:flex;gap:8px;align-items:center}
.item-card .kind{margin-left:auto;font-size:12.5px;color:var(--ink-4);font-weight:600}
.item-card h3{font-size:17px;margin:12px 0 6px;font-family:var(--sans);letter-spacing:0}
.item-card p{font-size:14.5px;color:var(--ink-3);margin:0 0 12px;flex:1}
.item-card .go{font-weight:600;font-size:14px;color:var(--cobalt)}
.item-card.soon{border-style:dashed;border-color:#D5DAE3}
.item-card.soon .go{color:var(--ink-4)}
@media (max-width:900px){.items{grid-template-columns:repeat(2,1fr)}}
@media (max-width:600px){.items{grid-template-columns:1fr}}

/* gated downloads */
.gatewrap{display:grid;grid-template-columns:.9fr 1.1fr}
.gatewrap .what{background:var(--tint-2);border-right:1px solid var(--line);padding:40px 36px}
.gatewrap .what h2{font-size:26px}
.gatewrap .what p{color:var(--ink-3);font-size:15.5px}
.gatewrap .what ul{list-style:none;padding:0;margin:8px 0 0}
.gatewrap .what li{display:flex;gap:10px;padding:10px 0;border-top:1px solid var(--line);font-size:15px;font-weight:600}
.gatewrap .what li svg{flex:0 0 16px;width:16px;height:16px;margin-top:4px;color:var(--cobalt)}
.gatewrap .what li small{display:block;color:var(--ink-4);font-size:13px;font-weight:400}
.gatewrap .what .who{font-size:11.5px;font-weight:700;letter-spacing:.12em;text-transform:uppercase;color:var(--ink-4);margin:22px 0 0}
.gatewrap .form{padding:40px 36px}
.gatewrap .form h3{font-size:22px;margin:0 0 4px}
@media (max-width:900px){.gatewrap{grid-template-columns:1fr}.gatewrap .what{border-right:0;border-bottom:1px solid var(--line)}.gatewrap .what,.gatewrap .form{padding:28px 22px}}

/* forms */
form label{display:block;font-size:13.5px;font-weight:600;color:var(--ink-2);margin:0 0 14px}
form label .opt{font-weight:400;color:var(--ink-4)}
form input[type=text],form input[type=email],form select,form textarea{display:block;width:100%;margin-top:6px;font:inherit;font-size:16px;color:var(--ink);background:#fff;border:1px solid #D4D8DF;border-radius:10px;padding:10px 12px;transition:border-color .15s,box-shadow .15s}
form input:focus,form select:focus,form textarea:focus{outline:0;border-color:var(--cobalt);box-shadow:0 0 0 3px rgba(26,71,184,.14)}
form textarea{min-height:120px;resize:vertical}
.row2{display:grid;grid-template-columns:1fr 1fr;gap:0 14px}
.row3{display:grid;grid-template-columns:repeat(3,1fr);gap:0 14px}
@media (max-width:620px){.row2,.row3{grid-template-columns:1fr}}
.check{display:flex!important;gap:10px;align-items:flex-start;font-weight:400!important;color:var(--ink-3)!important;font-size:14.5px!important}
.check input{margin-top:4px;width:16px;height:16px;accent-color:var(--cobalt);flex:0 0 auto}
.err{color:#A83535;font-size:14.5px;font-weight:600;margin:0 0 10px}
.hint{display:block;font-weight:400;font-size:12.5px;color:var(--ink-4);margin-top:2px}
.hp{position:absolute;left:-9999px}
.unlocked h3{font-size:22px;margin:0 0 4px}
.unlocked .grp{font-size:11.5px;font-weight:700;letter-spacing:.12em;text-transform:uppercase;color:var(--ink-4);margin:20px 0 4px}
.unlocked ul{list-style:none;margin:0;padding:0}
.unlocked li{display:flex;align-items:center;gap:12px;padding:10px 0;border-bottom:1px solid var(--line-2)}
.unlocked li .m{flex:1;min-width:0}
.unlocked li b{display:block;font-size:15px;font-weight:600}
.unlocked li small{color:var(--ink-4);font-size:13px}
.unlocked .again{font-size:13.5px;color:var(--ink-4);margin-top:16px}
.report{margin-top:6px}
.sent{border-left:3px solid var(--cobalt);background:var(--tint-2);border-radius:8px;padding:16px 18px;font-family:var(--serif);font-size:17px}
.use{font-family:var(--serif);font-size:17px;color:var(--ink-2);margin:0}
.narrow{max-width:var(--text)}

/* ── syllabus map ── */
.syll .topic{font-size:22px;margin:40px 0 12px}
.syll .topic:first-of-type{margin-top:26px}
.syll table{width:100%;border-collapse:collapse;font-size:15px;margin:0 0 8px}
.syll th{text-align:left;font-size:11.5px;letter-spacing:.12em;text-transform:uppercase;color:var(--ink-4);border-bottom:1px solid var(--ink-4);padding:8px 10px}
.syll td{padding:9px 10px;border-bottom:1px solid var(--line-2);vertical-align:top}
.syll tr:hover td{background:var(--tint-2)}
.syll td.code{font-family:var(--mono);font-size:13.5px;white-space:nowrap;color:var(--ink-3);width:100px}
.syll td.ch,.syll td.dl{white-space:nowrap;text-align:right;width:90px}
.syll td.ch a,.syll td.dl a{font-weight:600;text-decoration:none}
.syll td.codes{font-family:var(--mono);font-size:13.5px}
.syll .cn{display:inline-block;width:28px;font-family:var(--serif);font-weight:700;color:var(--cobalt)}
.syll .hl{display:inline-block;margin-left:6px;font-family:var(--sans);font-size:10px;font-weight:700;letter-spacing:.1em;background:var(--teal);color:#fff;padding:1px 5px;border-radius:2px;vertical-align:2px}
.syll .note{font-size:14px;color:var(--ink-4);margin-top:24px}
.table-scroll{overflow-x:auto}

/* ── articles ── */
.article-head .tags{display:flex;gap:6px;flex-wrap:wrap;margin-bottom:14px}
.article-head h1{max-width:22ch}
.byline{display:flex;align-items:center;gap:12px;font-size:14.5px;color:var(--ink-4);margin-top:18px}
.byline .mono{width:38px;height:38px;font-size:14px}
.byline b{color:var(--ink);display:block;font-size:15px;font-weight:600}
.prose{max-width:var(--text);margin:0 auto;font-family:var(--serif);font-size:19px;line-height:1.72;color:var(--ink-2)}
.prose h2{font-size:27px;margin:44px 0 12px}
.prose h3{font-size:22px;margin:32px 0 10px}
.prose p,.prose ul,.prose ol{margin:0 0 20px}
.prose li{margin:0 0 8px}
.prose blockquote{margin:28px 0;padding:4px 0 4px 20px;border-left:2px solid var(--scarlet);color:var(--ink-3)}
.prose code{font-family:var(--mono);font-size:.84em;background:var(--page);padding:2px 5px;border-radius:4px}
.prose pre{background:var(--ink);color:#E6ECFA;padding:18px 20px;border-radius:10px;overflow:auto;font-size:15px}
.prose pre code{background:none;padding:0;color:inherit}
.prose img{margin:28px auto;border-radius:8px}
.prose table{border-collapse:collapse;width:100%;font-family:var(--sans);font-size:16px;margin:0 0 24px}
.prose th,.prose td{border-bottom:1px solid var(--line);padding:8px 10px;text-align:left}
.prose hr{border:0;height:1px;background:var(--line);margin:40px 0}
.prose .katex-display{margin:22px 0;overflow-x:auto;overflow-y:hidden;padding:4px 0}
.prose > p:first-of-type{font-size:21px;color:var(--ink)}
.pager{max-width:var(--text);margin:36px auto 0;display:grid;grid-template-columns:1fr 1fr;gap:12px}
.pager a{border:1px solid var(--line);border-radius:var(--r-s);padding:14px 16px;text-decoration:none;color:inherit}
.pager a:hover{border-color:var(--ink-4)}
.pager small{display:block;color:var(--ink-4);font-size:12.5px}
.pager b{font-family:var(--serif);font-size:17px}
.pager .next{text-align:right;grid-column:2}

/* ── about ── */
.profile{display:grid;grid-template-columns:auto 1fr;gap:28px;align-items:start}
.mono{width:72px;height:72px;border-radius:50%;background:var(--cobalt);color:#fff;display:grid;place-items:center;font-family:var(--serif);font-weight:700;font-size:25px;letter-spacing:.02em}
.profile .role{color:var(--ink-4);font-size:15.5px;margin:-4px 0 18px}
.profile p{font-family:var(--serif);font-size:18px;color:var(--ink-2)}
.facts{display:grid;grid-template-columns:repeat(4,1fr);gap:0;border:1px solid var(--line);border-radius:var(--r-s);margin-top:26px}
.facts div{padding:16px 18px;border-left:1px solid var(--line)}
.facts div:first-child{border-left:0}
.facts b{display:block;font-family:var(--serif);font-size:24px;line-height:1.15}
.facts span{font-size:13px;color:var(--ink-4)}
.creds{list-style:none;padding:0;margin:26px 0 0;display:grid;grid-template-columns:1fr 1fr;gap:0 30px}
.creds li{padding:12px 0;border-top:1px solid var(--line-2);font-size:15.5px;color:var(--ink-2)}
.creds li small{display:block;font-size:12px;letter-spacing:.1em;text-transform:uppercase;color:var(--ink-4);font-weight:700}
@media (max-width:760px){.profile{grid-template-columns:1fr}.facts{grid-template-columns:1fr 1fr}.facts div:nth-child(3){border-left:0}.facts div:nth-child(n+3){border-top:1px solid var(--line)}.creds{grid-template-columns:1fr}}

/* ── footer ── */
footer{margin-top:40px;border-top:1px solid var(--line);font-size:14.5px;color:var(--ink-3)}
.foot{display:grid;grid-template-columns:1.5fr 1fr 1fr 1fr;gap:30px;padding:48px 0 30px}
.foot .logo{margin-bottom:10px}
.foot p{margin:0;max-width:34ch}
.foot h4{font-family:var(--sans);font-size:11.5px;letter-spacing:.14em;text-transform:uppercase;color:var(--ink-4);margin:6px 0 12px}
.foot ul{list-style:none;padding:0;margin:0}
.foot li{margin:0 0 7px}
.foot a{color:var(--ink-2);text-decoration:none}
.foot a:hover{color:var(--cobalt)}
.legal{border-top:1px solid var(--line);padding:18px 0 30px;display:flex;flex-wrap:wrap;gap:6px 26px;justify-content:space-between;font-size:13px;color:var(--ink-4)}
@media (max-width:860px){.foot{grid-template-columns:1fr 1fr}}
@media (max-width:520px){.foot{grid-template-columns:1fr}}

/* reveal on scroll (only when JS runs) */
.js .rv{opacity:0;transform:translateY(10px);transition:opacity .5s ease,transform .5s ease}
.js .rv.in{opacity:1;transform:none}