/* ============================================================================
   GUTS BNL — gutsbnl.com
   A game, not a page. One screen at a time. Never a rolling document.
   White ink on a black field. No third hue, ever.
   Two voices:  Space Grotesk = the interface / the claim ·
                IBM Plex Mono  = the receipt (what reality decided).
   ============================================================================ */


:root{
  --field:#000000;
  --ink:#ffffff;
  --ink-78:rgba(255,255,255,.78);
  --ink-56:rgba(255,255,255,.56);
  --ink-40:rgba(255,255,255,.40);
  --ink-28:rgba(255,255,255,.28);
  --ink-16:rgba(255,255,255,.16);
  --ink-10:rgba(255,255,255,.10);
  --ink-05:rgba(255,255,255,.055);
  --ink-02:rgba(255,255,255,.025);

  --ui:'Space Grotesk',system-ui,-apple-system,'Segoe UI',sans-serif;
  --mono:'IBM Plex Mono',ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;

  --measure:60ch;
  --edge:clamp(1.25rem,5vw,4.5rem);
  --maxw:1180px;
  --bar:58px;
  --ease:cubic-bezier(.22,.61,.36,1);
}

/* ---- reset · the page never scrolls ------------------------------------ */
*{box-sizing:border-box}
html,body{height:100%;margin:0;overflow:hidden}
html{-webkit-text-size-adjust:100%}
body{
  background:var(--field);color:var(--ink);
  font-family:var(--ui);font-weight:400;
  font-size:clamp(1rem,.6rem + .7vw,1.15rem);line-height:1.62;letter-spacing:-.006em;
  -webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;
}
img,svg{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer}
::selection{background:var(--ink);color:var(--field)}
:focus-visible{outline:1px solid var(--ink);outline-offset:3px}

/* ---- type roles -------------------------------------------------------- */
.mono{font-family:var(--mono);font-weight:400;letter-spacing:0}
.eyebrow{font-family:var(--mono);font-size:.68rem;letter-spacing:.26em;text-transform:uppercase;color:var(--ink-40)}
h1,h2,h3{font-family:var(--ui);margin:0;line-height:1.02;letter-spacing:-.03em}
h1{font-weight:500;font-size:clamp(2.4rem,1rem + 5.2vw,5.4rem)}
h2{font-weight:500;font-size:clamp(1.9rem,1.1rem + 3vw,3.3rem);line-height:1.05}
h3{font-weight:500;font-size:clamp(1.2rem,.9rem + 1.3vw,1.7rem);line-height:1.1;letter-spacing:-.02em}
p{margin:0 0 1em}
strong{font-weight:600}
em{font-style:italic}
sup{font-family:var(--mono);font-size:.6em;vertical-align:.5em;color:var(--ink-40)}

/* ============================================================================
   THE DECK — fixed screens, one visible at a time
   ============================================================================ */
.deck{position:fixed;inset:0;overflow:hidden}
.screen{
  position:absolute;inset:0;z-index:1;
  display:flex;flex-direction:column;justify-content:center;
  padding:calc(var(--bar) + clamp(1rem,4vh,3rem)) 0 clamp(2rem,7vh,4rem);
  opacity:0;visibility:hidden;pointer-events:none;
  transform:translateY(4vh);
  transition:opacity .72s var(--ease),transform .9s var(--ease),visibility .9s;
}
.screen.active{opacity:1;visibility:visible;pointer-events:auto;transform:none;z-index:2}
.screen.up{transform:translateY(-4vh)}
.screen__in{width:100%;max-width:var(--maxw);margin-inline:auto;padding-inline:var(--edge)}
/* graceful fallback: if a screen is taller than the viewport (small phones),
   let that one screen scroll inside itself — the deck still never rolls. */
@media(max-height:560px){.screen{justify-content:flex-start;overflow-y:auto}}

/* staged reveal inside the active screen */
.stage{opacity:0;transform:translateY(14px);transition:opacity .8s var(--ease),transform .8s var(--ease)}
.screen.active .stage{opacity:1;transform:none}
.screen.active .stage[data-s="1"]{transition-delay:.10s}
.screen.active .stage[data-s="2"]{transition-delay:.20s}
.screen.active .stage[data-s="3"]{transition-delay:.30s}
.screen.active .stage[data-s="4"]{transition-delay:.40s}

/* ---- masthead ---------------------------------------------------------- */
.masthead{position:fixed;top:0;left:0;right:0;z-index:50;height:var(--bar);
  background:linear-gradient(var(--field),rgba(0,0,0,.55) 60%,transparent);
  display:flex;align-items:center}
.masthead__in{display:flex;align-items:center;justify-content:space-between;gap:1.5rem;
  width:100%;max-width:var(--maxw);margin-inline:auto;padding-inline:var(--edge)}
.brand{display:inline-flex;align-items:center;gap:.7rem;font-family:var(--mono);font-size:.72rem;letter-spacing:.22em;text-transform:uppercase;white-space:nowrap}
.brand__mark{height:27px;width:auto;flex:none;mix-blend-mode:screen}
.brand b{font-weight:500}
.brand .svc{color:var(--ink-40)}
@media(max-width:600px){.brand__mark{height:23px}}
.nav{display:flex;gap:clamp(.9rem,2vw,2rem);font-family:var(--mono);font-size:.64rem;letter-spacing:.16em;text-transform:uppercase;color:var(--ink-56)}
.nav a{position:relative;padding-block:.4rem;transition:color .3s var(--ease)}
.nav a::after{content:"";position:absolute;left:0;right:100%;bottom:.15rem;height:1px;background:var(--ink);transition:right .35s var(--ease)}
.nav a:hover,.nav a[aria-current]{color:var(--ink)}
.nav a:hover::after,.nav a[aria-current]::after{right:0}
@media(max-width:600px){.brand .svc{display:none}.nav{gap:.85rem;font-size:.58rem}.nav a.opt{display:none}}

/* ---- the frontier rail (right) = deck position ------------------------- */
.rail{position:fixed;right:clamp(14px,2.4vw,34px);top:50%;transform:translateY(-50%);z-index:45;
  display:flex;flex-direction:column;align-items:center;gap:13px}
.rail__dot{width:8px;height:8px;border-radius:50%;border:1px solid var(--ink-40);background:transparent;
  transition:background .3s var(--ease),border-color .3s var(--ease),transform .3s var(--ease)}
.rail__dot:hover{border-color:var(--ink)}
.rail__dot[aria-current]{background:var(--ink);border-color:var(--ink);transform:scale(1.25)}
.rail__dot.seen{border-color:var(--ink-56)}
.rail__count{font-family:var(--mono);font-size:.56rem;letter-spacing:.14em;color:var(--ink-28);margin-top:6px;writing-mode:vertical-rl}
@media(max-width:600px){.rail{right:10px;gap:10px}.rail__count{display:none}}

/* ---- advance cue (bottom) ---------------------------------------------- */
.advance{position:fixed;left:50%;bottom:clamp(1.1rem,3.5vh,2.2rem);transform:translateX(-50%);z-index:45;
  display:flex;flex-direction:column;align-items:center;gap:.55rem;
  font-family:var(--mono);font-size:.6rem;letter-spacing:.24em;text-transform:uppercase;color:var(--ink-40);
  transition:opacity .5s var(--ease)}
.advance:hover{color:var(--ink)}
.advance__tick{width:1px;height:26px;background:linear-gradient(var(--ink-40),transparent);animation:tick 2.4s var(--ease) infinite}
@keyframes tick{0%{transform:scaleY(0);transform-origin:top}45%{transform:scaleY(1);transform-origin:top}55%{transform:scaleY(1);transform-origin:bottom}100%{transform:scaleY(0);transform-origin:bottom}}
.advance.end{pointer-events:none}
.advance.end .advance__tick{display:none}

/* ---- helpers ----------------------------------------------------------- */
.measure{max-width:var(--measure)}
.eyebrow-b{display:block;margin-bottom:1.1rem}
.rule{height:1px;background:var(--ink-16);border:0;margin:0}
.dim{color:var(--ink-56)}

/* ============================================================================
   HERO screen
   ============================================================================ */
.hero h1{max-width:15ch;font-weight:500}
.hero h1 .decide{color:var(--ink)}
.hero__sub{margin-top:clamp(1.3rem,3.5vh,2rem);max-width:46ch;color:var(--ink-56);font-size:1.08rem;line-height:1.55}

.collision{margin-top:clamp(1.8rem,5vh,3rem);border-top:1px solid var(--ink-16);border-bottom:1px solid var(--ink-16);
  padding-block:1.05rem;display:grid;grid-template-columns:1fr auto;align-items:center;gap:.8rem 2rem;font-family:var(--mono)}
.collision__claim{font-size:.8rem;letter-spacing:0;color:var(--ink-56);min-width:0}
.collision__claim .k{color:var(--ink)}
.collision__wire{display:flex;align-items:center;gap:.7rem;font-size:.78rem;white-space:nowrap;justify-self:end}
.collision__dot{color:var(--ink-40)}
.collision__hash{color:var(--ink-78)}
.collision__arrow{color:var(--ink-28)}
.verdict{font-family:var(--mono);font-size:.68rem;letter-spacing:.16em;text-transform:uppercase;display:inline-flex;align-items:center;gap:.5rem;color:var(--ink)}
.verdict::before{content:"";width:8px;height:8px;border-radius:50%;border:1px solid var(--ink);background:var(--ink)}
.verdict[data-k="fail"]::before{background:transparent}
.verdict[data-k="null"]::before{background:transparent;border-style:dashed;border-radius:0;transform:rotate(45deg)}
.verdict[data-k="fail"],.verdict[data-k="null"]{color:var(--ink-56)}
@media(max-width:680px){.collision{grid-template-columns:1fr}.collision__wire{justify-self:start}}

/* the one-time overture veil */
.overture{position:fixed;inset:0;z-index:80;background:var(--field);display:flex;align-items:center;justify-content:center;padding:var(--edge)}
.overture__in{display:flex;flex-direction:column;align-items:center;text-align:center}
.overture__mark{height:clamp(52px,10vw,80px);width:auto;margin-bottom:clamp(1.6rem,4vh,2.6rem);mix-blend-mode:screen;opacity:0}
.overture.play .overture__mark{animation:ovmark 3s var(--ease) forwards}
@keyframes ovmark{0%{opacity:0;transform:scale(.94)}20%{opacity:1;transform:none}72%{opacity:1}100%{opacity:0}}
.overture__line{font-family:var(--ui);font-weight:500;font-size:clamp(1.5rem,1rem + 2.6vw,2.8rem);text-align:center;max-width:22ch;line-height:1.2;opacity:0;letter-spacing:-.02em}
.overture.play .overture__line{animation:ovline 3s var(--ease) forwards}
.overture.done{opacity:0;visibility:hidden;transition:opacity .9s var(--ease),visibility .9s}
@keyframes ovline{0%{opacity:0;letter-spacing:.1em}24%{opacity:1;letter-spacing:-.02em}72%{opacity:1}100%{opacity:0}}

/* ============================================================================
   SHARED screen components
   ============================================================================ */
.head{margin-bottom:clamp(1.4rem,4vh,2.4rem)}
.head h2{max-width:20ch}
.head__note{margin-top:1rem;max-width:52ch;color:var(--ink-56)}

.callout{border:1px solid var(--ink-28);padding:clamp(1.2rem,3vw,2rem);margin-block:clamp(1.2rem,3vh,2rem);background:var(--ink-02);max-width:60ch}
.callout__label{font-family:var(--mono);font-size:.6rem;letter-spacing:.22em;text-transform:uppercase;color:var(--ink-78);margin-bottom:.7rem}
.callout p{margin:0;font-size:clamp(1.1rem,.9rem + .7vw,1.45rem);line-height:1.4;letter-spacing:-.02em;font-weight:500}

.pull{font-weight:500;font-size:clamp(1.5rem,1rem + 2.4vw,2.7rem);line-height:1.14;letter-spacing:-.03em;max-width:20ch}

.states{display:flex;flex-wrap:wrap;gap:.55rem;margin-block:1.4rem}
.state{font-family:var(--mono);font-size:.7rem;letter-spacing:.16em;text-transform:uppercase;border:1px solid var(--ink-16);padding:.55rem .9rem;color:var(--ink-78);transition:.25s var(--ease)}
.state:hover{background:var(--ink);color:var(--field)}
.state--forbidden{border-style:dashed;color:var(--ink-40);text-decoration:line-through;text-decoration-thickness:1px}
.state--forbidden:hover{background:transparent;color:var(--ink-56)}

.families{display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%,290px),1fr));gap:1px;background:var(--ink-10);border:1px solid var(--ink-10);margin-block:clamp(1.2rem,3vh,2rem)}
.family{background:var(--field);padding:clamp(1.1rem,2.4vw,1.7rem);transition:background .4s var(--ease)}
.family:hover{background:var(--ink-02)}
.family__n{font-family:var(--mono);font-size:.6rem;letter-spacing:.2em;color:var(--ink-28);margin-bottom:.8rem}
.family h3{margin-bottom:.5rem}
.family p{font-size:.92rem;line-height:1.5;color:var(--ink-56);margin:0}

.domains{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,215px),1fr));gap:1.1rem 2rem;margin-block:clamp(1.2rem,3vh,2rem)}
.domain{border-top:1px solid var(--ink-16);padding-top:.8rem}
.domain__k{font-family:var(--mono);font-size:.6rem;letter-spacing:.2em;text-transform:uppercase;color:var(--ink-40);margin-bottom:.45rem}
.domain h3{font-size:1.05rem;margin-bottom:.35rem}
.domain p{font-size:.86rem;color:var(--ink-56);margin:0;line-height:1.45}

.wall{display:grid;grid-template-columns:1fr 1fr;gap:1px;background:var(--ink-16);border:1px solid var(--ink-16);margin-block:clamp(1.2rem,3vh,2rem)}
.wall__col{background:var(--field);padding:clamp(1.2rem,3vw,2rem)}
.wall__col h3{font-family:var(--mono);font-weight:500;font-size:.78rem;letter-spacing:.14em;text-transform:uppercase;margin-bottom:1rem}
.wall__col--est h3::before{content:"● ";color:var(--ink)}
.wall__col--claim h3::before{content:"○ ";color:var(--ink-40)}
.wall__col--claim{color:var(--ink-56)}
.wall ul{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:.75rem}
.wall li{font-size:.94rem;line-height:1.45;padding-left:1.1rem;position:relative}
.wall li::before{content:"—";position:absolute;left:0;color:var(--ink-28)}
@media(max-width:640px){.wall{grid-template-columns:1fr}}

.stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(130px,1fr));gap:1px;background:var(--ink-10);border-block:1px solid var(--ink-16);margin-block:clamp(1.2rem,3vh,2rem)}
.stat{background:var(--field);padding:clamp(1.2rem,3vw,1.8rem) clamp(.9rem,2vw,1.3rem)}
.stat__n{font-family:var(--ui);font-weight:500;font-size:clamp(2rem,1.3rem + 2.4vw,3.4rem);line-height:1;letter-spacing:-.04em}
.stat__l{font-family:var(--mono);font-size:.6rem;letter-spacing:.15em;text-transform:uppercase;color:var(--ink-40);margin-top:.7rem;line-height:1.35}

.feed{font-family:var(--mono);font-size:.72rem;line-height:1.95;border:1px solid var(--ink-10);background:var(--ink-02);padding:.9rem 1.1rem;max-height:38vh;overflow:auto;margin-block:1.1rem}
.feed__row{white-space:nowrap;overflow:hidden;text-overflow:ellipsis;color:var(--ink-56)}
.feed__row .s{color:var(--ink-28)}.feed__row .h{color:var(--ink-78)}.feed__row .v{color:var(--ink-40)}
.feed::-webkit-scrollbar{width:7px;height:7px}.feed::-webkit-scrollbar-thumb{background:var(--ink-16)}.feed::-webkit-scrollbar-track{background:transparent}

.recompute{border:1px solid var(--ink-16);padding:clamp(1.1rem,3vw,1.8rem);margin-block:clamp(1.2rem,3vh,2rem);font-family:var(--mono);font-size:.8rem;line-height:1.8;max-width:70ch}
.recompute .root{color:var(--ink-78);word-break:break-all}
.recompute .ok{color:var(--ink);border:1px solid var(--ink);padding:.15rem .55rem;letter-spacing:.14em;font-size:.64rem;text-transform:uppercase;display:inline-block;margin-top:.6rem}
.recompute .lbl{color:var(--ink-40);text-transform:uppercase;letter-spacing:.16em;font-size:.6rem}

/* index-list — links to the two rooms / the papers */
.index-list{display:grid;gap:1px;background:var(--ink-10);border-block:1px solid var(--ink-10);margin-block:clamp(1.2rem,3vh,2rem)}
.index-item{background:var(--field);display:grid;grid-template-columns:auto 1fr auto;align-items:center;gap:1.3rem;
  padding:clamp(1.1rem,3vw,1.7rem) 0;transition:background .4s var(--ease)}
.index-item:hover{background:var(--ink-02)}
.index-item__n{font-family:var(--mono);font-size:.68rem;color:var(--ink-40);letter-spacing:.1em;padding-left:clamp(.4rem,2vw,1.3rem)}
.index-item__t h3{font-size:clamp(1.3rem,1rem + 1.2vw,1.9rem)}
.index-item__t p{margin:.35rem 0 0;color:var(--ink-56);font-size:.92rem;max-width:56ch}
.index-item__go{font-family:var(--mono);font-size:.64rem;letter-spacing:.16em;text-transform:uppercase;color:var(--ink-40);padding-right:clamp(.4rem,2vw,1.3rem);white-space:nowrap;transition:color .3s var(--ease)}
.index-item:hover .index-item__go{color:var(--ink)}
@media(max-width:600px){.index-item{grid-template-columns:auto 1fr;gap:.35rem 1rem}.index-item__go{grid-column:2;padding-left:0;text-align:left}}

.cta{display:inline-flex;align-items:center;gap:.7rem;font-family:var(--mono);font-size:.7rem;letter-spacing:.18em;text-transform:uppercase;color:var(--ink);border-bottom:1px solid var(--ink-40);padding-bottom:.35rem;transition:border-color .3s var(--ease),gap .3s var(--ease)}
.cta:hover{border-color:var(--ink);gap:1.1rem}
.cta__arrow{transition:transform .35s var(--ease)}
.cta:hover .cta__arrow{transform:translateX(4px)}

.closing__line{font-weight:500;font-size:clamp(1.2rem,.9rem + 1.5vw,2rem);letter-spacing:-.02em;color:var(--ink-78);line-height:1.4;max-width:28ch}

/* contact / colophon block on the final screen */
.colophon{display:grid;grid-template-columns:1.3fr 1fr 1fr;gap:2rem;margin-top:clamp(1.4rem,4vh,2.4rem)}
.colophon .mark{font-weight:600;font-size:1.5rem;letter-spacing:-.03em}
.colophon p{margin:.6rem 0 0;color:var(--ink-40);font-size:.86rem;max-width:32ch}
.colophon h4{font-family:var(--mono);font-weight:400;font-size:.6rem;letter-spacing:.2em;text-transform:uppercase;color:var(--ink-40);margin:0 0 .9rem}
.colophon ul{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:.55rem;font-family:var(--mono);font-size:.72rem}
.colophon a{color:var(--ink-56);transition:color .3s var(--ease)}.colophon a:hover{color:var(--ink)}
.law{margin-top:clamp(1.4rem,4vh,2.2rem);padding-top:1.2rem;border-top:1px solid var(--ink-10);
  font-family:var(--mono);font-size:.6rem;line-height:1.8;color:var(--ink-28);max-width:92ch}
.law b{color:var(--ink-56);font-weight:400}
@media(max-width:720px){.colophon{grid-template-columns:1fr 1fr}.colophon .brandcol{grid-column:1/-1}}
@media(max-width:440px){.colophon{grid-template-columns:1fr}}

/* ---- reading mode (papers) — a contained scroll frame, deck still fixed - */
.reader{position:fixed;inset:var(--bar) 0 0;overflow-y:auto;overflow-x:hidden;scroll-behavior:smooth}
.reader__in{max-width:var(--measure);margin-inline:auto;padding:clamp(2rem,7vh,5rem) var(--edge) 40vh}
.reader h2{margin-block:clamp(2rem,6vh,3.4rem) 1rem}
.reader h3{font-family:var(--mono);font-weight:500;font-size:.78rem;letter-spacing:.14em;text-transform:uppercase;color:var(--ink-78);margin-block:2rem .8rem}
.reader p{color:var(--ink-78);margin:0 0 1.1em}
.reader .lead{font-size:1.2rem;line-height:1.5;color:var(--ink)}
.thesis{list-style:none;margin:1.2rem 0;padding:0;counter-reset:t}
.thesis li{counter-increment:t;padding:.65rem 0 .65rem 3rem;border-top:1px solid var(--ink-10);position:relative;color:var(--ink-78)}
.thesis li::before{content:counter(t,decimal-leading-zero);position:absolute;left:0;top:.68rem;font-family:var(--mono);font-size:.68rem;color:var(--ink-40)}
.figure{border:1px solid var(--ink-10);padding:clamp(1.3rem,3vw,2.2rem);margin-block:clamp(1.6rem,4vh,2.4rem);background:var(--ink-02)}
.figure svg{width:100%;height:auto}
.figure figcaption{font-family:var(--mono);font-size:.64rem;letter-spacing:.05em;color:var(--ink-40);margin-top:1rem;line-height:1.5}
.figure figcaption b{color:var(--ink-78);font-weight:500}
.svg-ink{fill:var(--ink)}.svg-dim{fill:var(--ink-40)}
.svg-stroke{stroke:var(--ink);fill:none}.svg-stroke-dim{stroke:var(--ink-28);fill:none}
.svg-label{font-family:var(--mono);font-size:11px;letter-spacing:.12em;text-transform:uppercase}

/* ---- reduced motion ---------------------------------------------------- */
@media(prefers-reduced-motion:reduce){
  *{animation-duration:.001ms !important;animation-iteration-count:1 !important}
  .screen{transition:opacity .2s linear}
  .stage{transition:opacity .2s linear;transform:none}
  .overture{display:none}
}