/* graph paper: engineering paper, ballpoint blue for links, red pencil for marks. Sister to brown paper. */
:root{
  color-scheme:light;
  --paper:#e9efe5; --grid:rgba(70,124,95,.13); --grid-major:rgba(70,124,95,.28);
  --ink:#1c2923; --ink-2:#4b5e54; --pen:#2348a6; --mark:#b93c17; --line:rgba(28,41,35,.2);
  --hand:"Architects Daughter","Segoe Print","Bradley Hand",cursive;
  --text:"Atkinson Hyperlegible",system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;
  --sq:20px;
}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]){
  color-scheme:dark;
  --paper:#0e1612; --grid:rgba(150,210,175,.07); --grid-major:rgba(150,210,175,.15);
  --ink:#dfe9e2; --ink-2:#9fb3a8; --pen:#a9c0ff; --mark:#ff9d73; --line:rgba(223,233,226,.18);
}}
:root[data-theme="dark"]{
  color-scheme:dark;
  --paper:#0e1612; --grid:rgba(150,210,175,.07); --grid-major:rgba(150,210,175,.15);
  --ink:#dfe9e2; --ink-2:#9fb3a8; --pen:#a9c0ff; --mark:#ff9d73; --line:rgba(223,233,226,.18);
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{
  margin:0; color:var(--ink); font:1.0625rem/1.55 var(--text); background-color:var(--paper);
  background-image:linear-gradient(var(--grid-major) 1px,transparent 1px),linear-gradient(90deg,var(--grid-major) 1px,transparent 1px),
    linear-gradient(var(--grid) 1px,transparent 1px),linear-gradient(90deg,var(--grid) 1px,transparent 1px);
  background-size:calc(var(--sq)*5) calc(var(--sq)*5),calc(var(--sq)*5) calc(var(--sq)*5),var(--sq) var(--sq),var(--sq) var(--sq);
  background-position:-1px -1px; padding-bottom:env(safe-area-inset-bottom,0px);
}
a{color:var(--pen);text-decoration-thickness:1px;text-underline-offset:.2em}
a:hover{text-decoration-color:var(--mark)}
:focus-visible{outline:3px solid var(--mark);outline-offset:2px}
.vh{position:absolute!important;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
.skip{position:absolute;left:-999px;top:0}
.skip:focus{left:1rem;top:1rem;z-index:10;background:var(--paper);padding:.4rem .8rem;border:2px solid var(--ink)}

.top{
  position:sticky; top:0; z-index:5; display:flex; align-items:center; gap:1rem;
  padding:calc(.55rem + env(safe-area-inset-top,0px)) clamp(1rem,4vw,2.5rem) .55rem;
  background:var(--paper); border-bottom:2px solid var(--ink);
}
.brand{display:flex;flex-direction:column;text-decoration:none;color:var(--ink);line-height:1.1}
.brand-n{font-family:var(--hand);font-size:1.65rem}
.brand-s{font-size:.82rem;color:var(--ink-2)}
.sister{margin-left:auto;font-size:.92rem}
.theme{flex:none;width:2.6rem;height:2.6rem;border:2px solid var(--ink);border-radius:50%;background:transparent;color:var(--ink);font-size:1.1rem;line-height:1;cursor:pointer}
@media (max-width:620px){ .sister{display:none} .theme{margin-left:auto} }

main{max-width:960px;margin:0 auto;padding:0 clamp(1rem,4vw,2.5rem)}
.hero{padding:clamp(1.6rem,6vw,4rem) 0 .5rem}
.plot{display:block;width:min(100%,420px);height:auto;margin:0 0 1.1rem;overflow:visible}
.plot .axis,.plot .ticks{fill:none;stroke:var(--ink);stroke-width:2.2;stroke-linecap:round;stroke-linejoin:round}
.plot .ticks{stroke-width:1.6}
.plot .curve{fill:none;stroke:var(--pen);stroke-width:3.2;stroke-linecap:round;stroke-dasharray:1;stroke-dashoffset:1;animation:plot 1.5s .25s ease-out forwards}
.plot .pts path{stroke:var(--mark);stroke-width:1.6}
.plot .pts circle{fill:var(--paper);stroke:var(--mark);stroke-width:2.2}
.plot text{font-family:var(--hand);font-size:17px;fill:var(--ink-2)}
@keyframes plot{to{stroke-dashoffset:0}}
@media (prefers-reduced-motion:reduce){.plot .curve{animation:none;stroke-dashoffset:0}}
h1{font-family:var(--hand);font-weight:400;font-size:clamp(2.1rem,6.5vw,3.5rem);line-height:1.1;margin:0 0 .6rem;max-width:17ch}
.lede{font-size:1.15rem;max-width:56ch;margin:0}

.guide{padding:clamp(2rem,6vw,3.2rem) 0 1.5rem}
h2{font-family:var(--hand);font-weight:400;font-size:clamp(1.8rem,5vw,2.4rem);line-height:1.1;margin:0 0 .4rem}
.note,.meta{color:var(--ink-2);font-size:.95rem;max-width:68ch;margin:0 0 .8rem}
.meta{min-height:1.5em}
.legend{display:flex;flex-wrap:wrap;gap:.45rem;margin:1.1rem 0 .9rem}
.chip{font:inherit;font-size:.92rem;line-height:1.3;padding:.32em .8em;border:2px solid var(--ink);border-radius:2px;background:var(--paper);color:var(--ink);cursor:pointer}
.chip[aria-pressed="true"]{background:var(--ink);color:var(--paper)}
.chip .mk{color:var(--mark)}
.chip[aria-pressed="true"] .mk{color:inherit}
.chip .c{opacity:.7;font-size:.85em;margin-left:.1em}
.chip[hidden]{display:none}
.tools{display:flex;flex-wrap:wrap;gap:.55rem;align-items:center;margin:0 0 1rem}
.search{flex:1 1 230px;max-width:420px}
.field,.sel{font:inherit;font-size:1rem;padding:.45em .7em;border:2px solid var(--ink);border-radius:2px;background:var(--paper);color:var(--ink);min-width:0}
.field{width:100%}
.field::placeholder{color:var(--ink-2)}
.progress{display:flex;flex-wrap:wrap;gap:.6rem 1.2rem;align-items:center;margin:0 0 .7rem}
.progress p{margin:0;color:var(--ink-2)}
.bar{display:block;width:min(300px,60vw);height:6px;margin-top:.35rem;background:var(--grid-major)}
.bar span{display:block;height:100%;background:var(--pen)}

.vlist{list-style:none;margin:0;padding:0;border-top:2px solid var(--ink)}
.v{display:grid;grid-template-columns:2.1rem minmax(0,1fr);gap:0 .6rem;padding:.8rem 0 .85rem;border-bottom:1px solid var(--line)}
.v-tick{position:relative;width:1.35rem;height:1.35rem;margin-top:.15rem;padding:0;border:2px solid var(--ink);border-radius:2px;background:var(--paper);cursor:pointer}
.v-tick[aria-pressed="true"]::after{content:"✓";position:absolute;left:.05rem;top:-.62rem;font:1.6rem/1 var(--hand);color:var(--mark)}
.v-t{font-size:1.08rem;line-height:1.35;color:var(--ink);overflow-wrap:anywhere}
.v.is-seen .v-t{color:var(--ink-2)}
.v-m{display:flex;flex-wrap:wrap;gap:.15rem 1rem;align-items:center;margin:.3rem 0 0;font-size:.88rem;color:var(--ink-2)}
.v-k,.v-lk{font:inherit;font-size:inherit;background:none;border:0;padding:0;color:var(--ink-2);cursor:pointer;text-decoration:underline;text-decoration-thickness:1px;text-underline-offset:.2em}
.v-k span{color:var(--mark)}
.v-lk{color:var(--pen)}
.v-lk[aria-expanded="true"]{font-weight:700}
.v-none{padding:1rem 0;color:var(--ink-2)}
.v-links{margin:.65rem 0 .1rem;padding:.15rem 0 .1rem .9rem;border-left:3px solid var(--pen)}
.lk-h{font-family:var(--hand);font-size:1.02rem;color:var(--ink-2);margin:.6rem 0 .1rem}
.lk-h:first-child{margin-top:0}
.lk-list{list-style:none;margin:0;padding:0}
.lk-list li{margin:.2rem 0;overflow-wrap:anywhere}
.lk-go{font:inherit;color:var(--pen);background:none;border:0;padding:0;cursor:pointer;text-align:left;text-decoration:underline;text-decoration-thickness:1px;text-underline-offset:.2em}
.lk-host{font-size:.8rem;color:var(--ink-2);margin-left:.2em}
.lk-src{font-size:.78rem;color:var(--ink-2);margin:.55rem 0 0}
.btn{font-family:var(--hand);font-size:1.05rem;padding:.55em 1.1em;margin-top:1rem;border:2px solid var(--ink);border-radius:2px;background:var(--paper);color:var(--ink);cursor:pointer}
.btn[hidden]{display:none}

.foot{max-width:960px;margin:2rem auto 0;padding:1.4rem clamp(1rem,4vw,2.5rem) 2.5rem;border-top:2px solid var(--ink);font-size:.92rem;color:var(--ink-2)}
.foot p{margin:.35rem 0;max-width:70ch}

/* the player, shared with brown paper (public/js/player.js) */
.pl{border:0;padding:0;background:transparent;color:var(--ink);width:min(920px,calc(100vw - 1rem));max-width:none;max-height:none;overflow:visible}
.pl::backdrop{background:rgba(8,16,12,.74)}
.pl-sheet{
  position:relative; background-color:var(--paper); border:2px solid var(--ink);
  background-image:linear-gradient(var(--grid) 1px,transparent 1px),linear-gradient(90deg,var(--grid) 1px,transparent 1px);
  background-size:var(--sq) var(--sq); padding:1rem clamp(.75rem,3vw,1.5rem) 1.2rem; max-height:calc(100dvh - 1rem); overflow-y:auto;
}
.pl-close{position:absolute;top:.35rem;right:.45rem;width:2.7rem;height:2.7rem;font-size:1.7rem;line-height:1;background:none;border:0;color:var(--ink);cursor:pointer}
.pl-title{font-family:var(--hand);font-weight:400;font-size:clamp(1.3rem,4vw,1.85rem);line-height:1.2;margin:.1rem 2.7rem .2rem 0}
.pl-meta{margin:0 0 .75rem;color:var(--ink-2);font-size:.95rem}
.pl-meta[hidden]{display:none}
.pl-frame{position:relative;aspect-ratio:16/9;background:#0b120f;border:2px solid var(--ink);overflow:hidden}
.pl-frame iframe,.pl-slot{position:absolute;inset:0;width:100%;height:100%;border:0}
.pl-off{position:absolute;inset:0;margin:0;display:flex;flex-wrap:wrap;gap:.25em;align-items:center;justify-content:center;text-align:center;padding:1rem;color:#dfe9e2;background:#0b120f}
.pl-off[hidden]{display:none}
.pl-off a{color:#a9c0ff}
.pl-acts{display:flex;flex-wrap:wrap;gap:.6rem 1.1rem;align-items:center;margin:.85rem 0 .15rem}
.pl-seen{font-family:var(--hand);font-size:1rem;padding:.42em 1em;border:2px solid var(--ink);border-radius:2px;background:var(--paper);color:var(--ink);cursor:pointer}
.pl-seen[aria-pressed="true"]{background:var(--ink);color:var(--paper)}
.pl-seen[aria-pressed="true"]::before{content:"✓ "}
.pl-note{font-size:.88rem;color:var(--ink-2);margin:.4rem 0 0;min-height:1.3em}
.pl-more{margin-top:.9rem}
.pl-more[hidden]{display:none}
.pl .v-links{margin-left:0}