/* ===== DESIGN TOKENS: change look & feel here ===== */
@property --c{syntax:'<color>';inherits:true;initial-value:#8c2f2b}
:root{
  --water:#bfe3f2;        /* default liquid in the game */
  --neutral-red:#c9183c;  /* the indicator dye used in the game */
  --c:#8c2f2b;            /* current page spot-ink colour, set by journey.js */
  --bg:#ddd6c2; --ink:#1b1814; --muted:#5d5546; --line:rgba(27,24,20,.55);
  --media-filter:grayscale(1) contrast(1.15) sepia(.15); /* newsprint photos; set to none to disable */
  --font-head:"Old Standard TT",Georgia,"Times New Roman",serif;
  --font-body:"EB Garamond",Georgia,serif;
  --font-blk:"Old Standard TT",Georgia,"Times New Roman",serif; /* masthead font, must support Cyrillic */
  --bar:3rem; --rail:4.5rem; --gap:clamp(1.25rem,5vw,4rem);
  transition:--c 1.4s cubic-bezier(.6,0,.2,1);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);font:1.28rem/1.5 var(--font-body);padding-left:var(--rail);overflow-x:hidden}
body.lock{overflow:hidden}
/* yellowed edges + faint spot-ink wash + print grain */
body::before{content:"";position:fixed;inset:0;z-index:-2;
  background:radial-gradient(ellipse at center,transparent 50%,rgba(110,85,40,.32)),
             radial-gradient(50vmax 50vmax at 85% 10%,color-mix(in srgb,var(--c) 10%,transparent),transparent 60%)}
body::after{content:"";position:fixed;inset:0;z-index:-1;pointer-events:none;opacity:.4;mix-blend-mode:multiply;
  background:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence baseFrequency='.8' numOctaves='2'/%3E%3C/filter%3E%3Crect width='160' height='160' filter='url(%23n)'/%3E%3C/svg%3E")}
a{color:inherit}
:focus-visible{outline:3px solid var(--c);outline-offset:3px}
p{margin:0 0 .9rem}

/* ===== TOP BAR (slim, fixed) ===== */
.bar{position:fixed;top:0;left:0;right:0;z-index:30;height:var(--bar);padding:0 var(--gap) 0 calc(var(--rail) + 1rem);
  display:flex;align-items:center;justify-content:space-between;background:rgba(221,214,194,.95);border-bottom:1px solid var(--ink)}
.brand{font:700 1.05rem var(--font-blk);text-decoration:none}
.stops-btn{font:700 .85rem var(--font-head);color:var(--ink);background:none;border:1px solid var(--ink);padding:.35rem .9rem;cursor:pointer}
.stops-btn b{color:var(--c);margin-right:.35rem}
.stops-btn:hover{background:var(--ink);color:var(--bg)}
.bar-fill{display:none}

/* ===== SIDE RAIL (desktop): ruler-style page markers ===== */
.rail{position:fixed;left:0;top:0;bottom:0;width:var(--rail);z-index:25;display:flex;align-items:center;justify-content:center}
.rail ol{list-style:none;margin:0;padding:0;height:68vh;width:100%;display:flex;flex-direction:column}
.rail li{flex:1;min-height:0;position:relative}
.rail a{position:absolute;inset:0;display:flex;align-items:center;justify-content:flex-end;padding-right:1.4rem;text-decoration:none}
.rail a::after{content:"";height:1px;width:.9rem;background:var(--line);transition:.25s}
.rail .done a::after{background:var(--ink);width:1.3rem}
.rail .on a::after{background:var(--c);width:2.6rem;height:5px}
.rail a:hover::after{width:2.2rem;background:var(--ink)}
.tip{position:absolute;left:calc(100% - .5rem);white-space:nowrap;padding:.3rem .8rem;background:var(--ink);color:var(--bg);
  font:700 .8rem var(--font-head);opacity:0;transform:translateX(-6px);pointer-events:none;transition:.2s}
.rail a:hover .tip,.rail a:focus-visible .tip{opacity:1;transform:none}

/* ===== INDEX MENU (scales to any number of pages) ===== */
.menu{position:fixed;inset:0;z-index:40;background:rgba(221,214,194,.97);overflow-y:auto;padding:5rem var(--gap) 3rem}
.menu[hidden]{display:none}
.menu ol{list-style:none;margin:0 auto;padding:0;max-width:60rem}
.menu a{display:flex;align-items:baseline;gap:1.2rem;padding:.6rem 0;border-bottom:1px dotted var(--ink);text-decoration:none}
.menu b{font:700 .95rem var(--font-head);color:var(--s)}
.menu span{font:700 clamp(1.5rem,5vw,2.8rem)/1.1 var(--font-head);transition:.2s}
.menu a:hover span{color:var(--s);padding-left:.6rem}
.menu .on span{font-style:italic;text-decoration:underline;text-decoration-color:var(--s);text-decoration-thickness:3px}

/* ===== MASTHEAD ===== */
main{padding-top:var(--bar)}
.masthead{padding:1.25rem var(--gap) 0;text-align:center}
.mast-title{display:block;font:700 clamp(2.1rem,8.5vw,6.5rem)/1.1 var(--font-blk);letter-spacing:.01em;text-decoration:none;
  border-top:4px double var(--ink);padding:.15em 0 .05em}
.dateline{display:flex;justify-content:space-between;gap:1rem;margin:0;padding:.3rem 0;border-top:1px solid var(--ink);border-bottom:4px double var(--ink);font:italic 400 1rem var(--font-body)}

/* ===== PAGE: 3D ===== */
.stage{position:relative;min-height:70svh;display:grid;grid-template-columns:minmax(0,.85fr) minmax(0,1.15fr);gap:var(--gap);align-items:start;padding:2rem var(--gap)}
.stage.flip .tube{order:2}
.tube{margin:0;justify-self:center;width:min(100%,460px)}
.frame{height:min(72svh,680px);position:relative;overflow:hidden;border:1px solid var(--ink);box-shadow:0 0 0 5px var(--bg),0 0 0 6px var(--ink);
  background:#cdc5ae radial-gradient(rgba(27,24,20,.2) 1px,transparent 1.5px) 0 0/7px 7px}
.frame model-viewer{width:100%;height:100%;--poster-color:transparent;filter:var(--media-filter)}
.frame model-viewer::part(default-ar-button){display:none} /* we use our own button, outside the grey filter */
.ar-btn[hidden]{display:none}
/* AR button: newsprint label with a travelling ink/spot-colour rule and a "printed" offset shadow */
@property --a{syntax:'<angle>';inherits:false;initial-value:0deg}
.ar-btn{position:absolute;left:50%;bottom:1rem;transform:translateX(-50%);display:flex;align-items:center;gap:.55rem;white-space:nowrap;
  font:700 1.05rem var(--font-head);color:var(--ink);background:transparent;border:0;padding:.9rem 1.35rem;cursor:pointer;letter-spacing:.02em;filter:none;
  isolation:isolate;animation:arpulse 2.6s ease-in-out infinite,arprint 2.6s ease-in-out infinite}
.ar-btn::before{content:"";position:absolute;inset:0;z-index:-1;
  background:conic-gradient(from var(--a),var(--ink) 0 55%,var(--c) 62% 80%,var(--ink) 88%);animation:arspin 3s linear infinite}
.ar-btn::after{content:"";position:absolute;inset:3px;z-index:-1;background:var(--bg);box-shadow:inset 0 0 0 1px var(--ink),inset 0 0 0 3px var(--bg);transition:background .2s}
.ar-btn:hover,.ar-btn:focus-visible{color:var(--bg)}
.ar-btn:hover::after,.ar-btn:focus-visible::after{background:var(--ink)}
.ar-btn span{font-size:1.35em;line-height:1;display:inline-block;color:var(--c);animation:arping 2.6s ease-in-out infinite}
@keyframes arspin{to{--a:360deg}}
@keyframes arpulse{0%,100%{transform:translateX(-50%) scale(1)}50%{transform:translateX(-50%) scale(1.04)}}
@keyframes arprint{0%,100%{box-shadow:3px 3px 0 var(--c)}50%{box-shadow:9px 9px 0 var(--c)}}
@keyframes arping{0%,60%,100%{transform:scale(1)}30%{transform:scale(1.3) rotate(90deg)}}
figcaption{margin-top:1.1rem;padding-top:.4rem;border-top:1px solid var(--line);font:italic 1rem var(--font-body);color:var(--muted);text-align:center}
.copy{position:relative;max-width:36rem}
.num{position:absolute;z-index:-1;top:-.5em;left:-.05em;font:700 clamp(8rem,22vw,18rem)/1 var(--font-head);color:transparent;-webkit-text-stroke:1.5px var(--ink);opacity:.14;user-select:none}
h1,.head{font:700 clamp(2.1rem,5vw,3.9rem)/1.05 var(--font-head);margin:0 0 1.2rem;padding:.5rem 0;border-top:1px solid var(--ink);border-bottom:4px double var(--ink);overflow-wrap:anywhere;column-span:all}
h2{font:italic 700 1.4rem/1.2 var(--font-head);margin:1.2rem 0 .5rem;padding-bottom:.2rem;border-bottom:1px solid var(--line);break-after:avoid}
.copy p{text-align:justify;hyphens:auto;-webkit-hyphens:auto}
.copy>p:first-of-type::first-letter{float:left;font:700 4.6em/.78 var(--font-head);padding:.06em .08em 0 0;color:var(--c)}
@media (min-width:1180px){.copy{column-count:2;column-gap:2.2rem;column-rule:1px solid var(--line);max-width:48rem}}

/* ===== PAGE: video ===== */
.stage-v{padding:2rem var(--gap) 1rem;position:relative}
.stage-v .num{top:-.1em;right:var(--gap);left:auto}
.stage-v h1,.stage-v .head{max-width:20ch;margin-bottom:2rem}
.vid{aspect-ratio:16/9;max-width:62rem;transform:rotate(-.8deg);border:1px solid var(--ink);box-shadow:0 0 0 5px var(--bg),0 0 0 6px var(--ink),clamp(10px,1.8vw,20px) clamp(10px,1.8vw,20px) 0 var(--c);background:#000}
.vid iframe{width:100%;height:100%;border:0;display:block}
.stage-v .copy{margin:3rem 0 0 auto}
/* text-only page (no video): headline and copy share one left-aligned column */
.stage-v.text h1,.stage-v.text .head{max-width:36rem;margin-bottom:1.5rem}
.stage-v.text .copy{margin:0}
@media (min-width:1180px){.stage-v.text h1,.stage-v.text .head{max-width:48rem}}

/* ===== CONTINUED ON NEXT PAGE ===== */
.next{display:grid;grid-template-columns:1fr auto;align-items:end;gap:.4rem 1rem;margin-top:var(--gap);padding:clamp(2rem,6vw,4rem) var(--gap);background:var(--nc);color:var(--bg);text-decoration:none;border-top:4px double var(--bg);outline:1px solid var(--ink);outline-offset:-10px}
.next small{grid-column:1/-1;font:italic 1.1rem var(--font-body)}
.next span,.next em{font:700 clamp(2rem,8vw,5.5rem)/1 var(--font-head);font-style:normal}
.next em{transition:transform .3s}
.next:hover em{transform:translateX(.3em)}

/* ===== MOBILE ===== */
@media (max-width:860px){
  :root{--rail:0rem;--bar:2.75rem}
  .rail{display:none}
  .bar{padding:0 var(--gap)}
  .bar-fill{display:block;position:absolute;left:0;bottom:-1px;height:4px;width:var(--p);background:var(--c);transition:width .8s}
  .dateline span:nth-child(2){display:none}
  .stage{grid-template-columns:1fr;min-height:0;padding-top:1.5rem}
  .stage.flip .tube{order:0}
  .tube{width:min(90vw,380px)}
  .frame{height:62svh;min-height:340px}
  .ar-btn{font-size:1rem;padding:.9rem 1.1rem}
  .num{top:-.4em}
}
@media (prefers-reduced-motion:reduce){.ar-btn,.ar-btn::before,.ar-btn span{animation:none}*{scroll-behavior:auto!important;transition:none!important}:root{transition:none}}

/* ===== MINI GAME: laboratory reaction test ===== */
.game{padding:2rem var(--gap) 1rem}
.game>h2{font:700 clamp(1.6rem,4vw,2.6rem)/1.1 var(--font-head);font-style:normal;border-top:1px solid var(--ink);border-bottom:4px double var(--ink);padding:.5rem 0;margin:0 0 1rem}
.game>p{max-width:46rem;text-align:justify}
.lab{display:grid;grid-template-columns:minmax(0,260px) minmax(0,1fr);gap:var(--gap);align-items:center;margin-top:1.5rem;padding:clamp(1rem,3vw,2rem);border:1px solid var(--ink);box-shadow:0 0 0 5px var(--bg),0 0 0 6px var(--ink);background:#cdc5ae radial-gradient(rgba(27,24,20,.14) 1px,transparent 1.5px) 0 0/7px 7px}
.flask{width:100%;max-width:260px;justify-self:center;display:block}
.flask .glass{fill:none;stroke:var(--ink);stroke-width:4;stroke-linejoin:round}
.flask .liq{fill:var(--water);transition:fill .5s}
.flask .drop{fill:var(--neutral-red);opacity:0}
.game.ready .liq{fill:var(--neutral-red);transition:none}
.game.waiting .drop{animation:drip 1s ease-in infinite}
.game.early .liq{fill:var(--water)}
@keyframes drip{0%{opacity:1;transform:translateY(0)}80%{opacity:1;transform:translateY(95px)}100%{opacity:0;transform:translateY(100px)}}
.status{font:700 clamp(1.3rem,3vw,1.9rem)/1.2 var(--font-head);margin:0 0 .6rem;min-height:2.4em}
.log{margin:0 0 1rem;padding-left:1.6rem;font-variant-numeric:tabular-nums;min-height:1.6em}
.game-btn{font:700 1.15rem var(--font-head);background:var(--ink);color:var(--bg);border:0;padding:1rem 1.6rem;cursor:pointer;width:100%;max-width:22rem;touch-action:manipulation}
.game.ready .game-btn{background:var(--neutral-red)}
.game-btn:hover{outline:2px solid var(--c);outline-offset:3px}
.best{margin:1rem 0 0;font-style:italic;color:var(--muted)}
@media (max-width:640px){.lab{grid-template-columns:1fr}.flask{max-width:180px}}
@media (prefers-reduced-motion:reduce){.game.waiting .drop{animation:none;opacity:1}}

/* ===== SCIENCE PAGE: text left, game right (stacks on mobile like the other pages) ===== */
@media (min-width:861px){
  .stage.science{grid-template-columns:minmax(0,1fr) minmax(0,1fr)}
  .stage.science .game{padding:0}
  .stage.science .lab{grid-template-columns:minmax(0,150px) minmax(0,1fr);gap:1.5rem}
}
.stage.science .copy{column-count:auto;max-width:40rem}
.stage.science .game{padding-left:0;padding-right:0}

/* ===== QUOTES PAGE ===== */
.quotes{display:grid;gap:2.2rem;max-width:48rem}
.quote{margin:0;padding:0 0 1.8rem 1.4rem;border-left:5px solid var(--c);border-bottom:1px solid var(--line)}
.quote blockquote{margin:0}
.quote blockquote p{margin:0;font:italic 400 clamp(1.45rem,3vw,2.2rem)/1.3 var(--font-body)}
.quote.long blockquote p{font-size:clamp(1.2rem,2.2vw,1.5rem);line-height:1.45}
.quote figcaption{text-align:left;border-top:0;padding-top:0;margin-top:.9rem;font:700 .95rem var(--font-head);color:var(--muted)}

/* ===== SCHOOL PAGE ===== */
.facts{max-width:48rem;margin:2rem 0 0;border-top:4px double var(--ink)}
.facts div{display:grid;grid-template-columns:9rem 1fr;gap:1rem;padding:.6rem 0;border-bottom:1px dotted var(--ink)}
.facts dt{font:700 1rem var(--font-head);color:var(--c)}
.facts dd{margin:0}
.site-link{display:inline-block;margin-top:2rem;font:700 1.1rem var(--font-head);background:var(--ink);color:var(--bg);padding:1rem 1.6rem;text-decoration:none}
.site-link:hover{background:var(--c)}
@media (max-width:640px){.facts div{grid-template-columns:1fr;gap:.1rem}}

/* ===== FILM CREDIT (under the video) ===== */
.credit{max-width:62rem;margin:2rem 0 0;padding-top:.5rem;border-top:1px solid var(--line);font:italic 1.05rem var(--font-body);color:var(--muted)}
.credit b{font:700 1.05rem var(--font-head);font-style:normal;color:var(--ink)}

/* ===== LITERATURE PAGE: list of works ===== */
.list-title{max-width:48rem;margin:2.5rem 0 0;font-style:normal;border-bottom:0}
.facts.works{margin-top:.6rem}
.facts.works div{grid-template-columns:5rem 1fr;align-items:baseline}
.facts.works dt{font-variant-numeric:tabular-nums}
.facts.works dd b{font:700 1.1rem var(--font-head)}
.facts.works dd span{font-style:italic;color:var(--muted)}
@media (max-width:640px){.facts.works div{grid-template-columns:4rem 1fr}}

/* ===== PHOTOS (Паметта page) ===== */
.photos{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:var(--gap);max-width:62rem;margin-top:2.5rem}
.photo{margin:0}
.photo img{display:block;width:100%;height:auto;aspect-ratio:3/4;object-fit:cover;object-position:center top;border:1px solid var(--ink);box-shadow:0 0 0 5px var(--bg),0 0 0 6px var(--ink);background:#cdc5ae}
@media (max-width:640px){.photos{grid-template-columns:1fr;gap:2.5rem}}

/* ===== SINGLE-PAGE NEWSPAPER (paper.html) ===== */
.paper .masthead h1.mast-title{margin:0;border-bottom:0;column-span:none;overflow-wrap:normal}
.chapter{position:relative;scroll-margin-top:var(--bar)}
.paper .stage{min-height:0}
.paper .stage-v.text .head{max-width:none}
.paper .stage-v.text>.copy{max-width:none}
@media (min-width:1180px){.paper .stage-v.text>.copy{column-count:3}}
.paper .quotes{display:block;max-width:none;columns:3 19rem;column-gap:2.4rem;column-rule:1px solid var(--line)}
.paper .quote{break-inside:avoid;margin-bottom:2.2rem}
.paper .quote blockquote p{font-size:clamp(1.3rem,2.2vw,1.65rem)}
.paper .quote.long blockquote p{font-size:1.15rem}
.paper .photos{max-width:none}
.paper .next{margin-top:clamp(2rem,6vw,4rem)}
.paper .rail a{cursor:pointer}
@media (min-width:861px){.paper .stage.flip{grid-template-columns:minmax(0,1.2fr) minmax(0,.8fr)}}
.paper .stage .copy{max-width:none}
.paper .stage .copy>.num{left:auto;right:0}
/* paper: the section rule already marks each start, so drop the extra rules around empty space */
.paper .chapter>.stage,.paper .chapter>.stage-v{padding-top:1.2rem}
.paper .chapter+.chapter{margin-top:clamp(1.5rem,5vw,3.5rem)}
.paper .chapter:first-of-type .head{border-top:0;padding-top:0}
/* paper: every section heading runs the full width, so the rules line up */
.paper .chapter-head{padding:1.2rem var(--gap) 0}
.paper .chapter-head .head{max-width:none;margin-bottom:0}
.paper .chapter>.stage,.paper .chapter>.stage-v{padding-top:1.6rem}

/* "Цял екран" button under the film */
.fs-btn{display:inline-flex;align-items:center;gap:.5rem;margin-top:1.8rem;font:700 1rem var(--font-head);color:var(--ink);background:var(--bg);border:1px solid var(--ink);box-shadow:4px 4px 0 var(--c);padding:.7rem 1.1rem;cursor:pointer;transition:background .2s,color .2s}
.fs-btn svg{color:var(--c);flex:none}
.fs-btn:hover svg,.fs-btn:focus-visible svg{color:var(--bg)}
.fs-btn:hover,.fs-btn:focus-visible{background:var(--ink);color:var(--bg)}
.fs-btn+.credit{margin-top:1.2rem}