:root{
  --black:#000000;
  --white:#FFFFFF;
  --accent:#1F4AFF;

  --ff:"Inter", system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  --mono:"IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;

  --h1:32px;
  --body:15px;
  --micro:12px;

  --lh-h:1.15;
  --lh:1.6;

  --ls-h:-0.02em;
  --ls-m:0.02em;

  --step:8px;

  --pad-x:20px;
  --max:420px;

  --gap-p:16px;
  --gap-b:32px;
  --gap-s:72px;
}

*{ box-sizing:border-box; }
html,body{ height:100%; }

body{
  margin:0;
  background:var(--black);
  color:var(--white);
  font-family:var(--ff);
  font-size:var(--body);
  line-height:var(--lh);
  -webkit-font-smoothing:antialiased;
  text-rendering:geometricPrecision;
}

a{ color:inherit; text-decoration:none; }
button{ font:inherit; color:inherit; background:none; border:none; padding:0; }

.wrap{
  width:100%;
  margin:0 auto;
  padding:0 var(--pad-x);
  max-width:calc(var(--max) + (var(--pad-x) * 2));
}

/* TOPBAR */

.topbar{
  position:sticky;
  top:0;
  z-index:20;
  display:flex;
  align-items:center;
  justify-content:space-between;
  padding:calc(var(--step) * 3) 0;
  background:linear-gradient(to bottom, rgba(0,0,0,0.85), rgba(0,0,0,0));
  backdrop-filter:saturate(120%) blur(8px);
}

.sig{
  font-size:var(--micro);
  letter-spacing:var(--ls-m);
  opacity:0.65;
}

.lang{
  display:inline-flex;
  gap:6px;
  font-size:var(--micro);
  letter-spacing:var(--ls-m);
  opacity:0.75;
  cursor:pointer;
  user-select:none;
}
.lang:focus-visible{
  outline:1px solid var(--accent);
  outline-offset:6px;
}
.lang__k[data-active="1"]{
  color:var(--accent);
  opacity:1;
}
.lang__sep{ opacity:0.5; }

/* SECTIONS */

.screen{
  padding:var(--gap-s) 0;
  border-top:1px solid rgba(255,255,255,0.06);
}
.screen:first-of-type{ border-top:none; }

.stack{
  display:flex;
  flex-direction:column;
  gap:var(--gap-b);
}

/* TYPO */

.h1{
  margin:0;
  font-size:var(--h1);
  line-height:var(--lh-h);
  letter-spacing:var(--ls-h);
  font-weight:500;
}

.h2{
  margin:0;
  font-size:18px;
  line-height:1.25;
  letter-spacing:var(--ls-m);
  font-weight:500;
  opacity:0.95;
}

.meta{
  margin:0;
  font-size:var(--micro);
  letter-spacing:var(--ls-m);
  opacity:0.7;
}

.copy p{
  margin:0 0 var(--gap-p) 0;
  opacity:0.92;
}
.copy p:last-child{ margin-bottom:0; }

/* LANGUAGE */

[data-lang]{ display:none; }

/* block texts (p etc.) */
html[data-locale="ru"] [data-lang="ru"]{ display:block; }
html[data-locale="en"] [data-lang="en"]{ display:block; }
html:not([data-locale]) [data-lang="ru"]{ display:block; }

/* inline texts (spans in meta/h2/footer) */
html[data-locale="ru"] span[data-lang="ru"]{ display:inline; }
html[data-locale="en"] span[data-lang="en"]{ display:inline; }
html:not([data-locale]) span[data-lang="ru"]{ display:inline; }

/* AXIOM */

.screen--axiom .axiom{
  max-width:34ch;
  margin:0 auto;
  padding-top:calc(var(--gap-s) * 0.2);
}
.screen--axiom .copy{
  margin-top:var(--gap-b);
}

/* STD CARD (FULL CLICKABLE) */

.projection{
  display:block;
  border:1px solid rgba(255,255,255,0.10);
  padding:calc(var(--step) * 3);
  cursor:pointer;
}

.tag{
  font-family:var(--mono);
  font-size:var(--micro);
  letter-spacing:0.18em;
  color:var(--accent);
}

.projection__body{
  margin-top:calc(var(--step) * 2);
}

.projection__footer{
  display:flex;
  align-items:center;
  gap:10px;
  margin-top:calc(var(--step) * 2);
  font-size:var(--micro);
  letter-spacing:var(--ls-m);
  opacity:0.85;
}

.arrow{
  font-family:var(--mono);
  color:var(--accent);
}

.projection:hover,
.projection:focus-visible{
  background:var(--white);
  color:var(--black);
  border-color:var(--white);
  outline:none;
}

.projection:hover .tag,
.projection:focus-visible .tag,
.projection:hover .arrow,
.projection:focus-visible .arrow{
  color:var(--black);
}

.projection:focus-visible{
  outline:2px solid var(--accent);
  outline-offset:0;
}

/* PROTOCOL */

.proto{
  display:flex;
  flex-direction:column;
  gap:calc(var(--step) * 3);
}

.proto__row{
  display:grid;
  grid-template-columns:48px 1fr;
  gap:calc(var(--step) * 2);
  align-items:flex-start;
}

.n{
  font-family:var(--mono);
  font-size:var(--micro);
  color:var(--accent);
  letter-spacing:0.12em;
  line-height:1.2;
  padding-top:2px;
}

.proto__txt b{ font-weight:500; }

/* BUTTONS */

.grid1{
  display:grid;
  grid-template-columns:1fr;
  gap:calc(var(--step) * 2);
}

.btn{
  display:flex;
  flex-direction:column;
  gap:8px;
  border:1px solid rgba(255,255,255,0.14);
  padding:calc(var(--step) * 2);
  border-radius:0;
  cursor:pointer;
  text-align:left;
}

.btn__k{
  font-size:var(--body);
  opacity:0.95;
}

.btn__v{
  font-family:var(--mono);
  font-size:var(--micro);
  letter-spacing:0.12em;
  opacity:0.55;
}

.btn:hover,
.btn:focus-visible{
  background:var(--white);
  color:var(--black);
  border-color:var(--white);
  outline:none;
}

.btn:hover .btn__v,
.btn:focus-visible .btn__v{ opacity:0.8; }

.btn:hover .btn__k,
.btn:focus-visible .btn__k{ opacity:1; }

.btn:focus-visible{
  outline:2px solid var(--accent);
  outline-offset:0;
}

/* FOOTER */

.footer{
  padding:calc(var(--gap-s) * 0.8) 0 calc(var(--gap-s) * 0.9);
  border-top:1px solid rgba(255,255,255,0.06);
  display:flex;
  flex-direction:column;
  gap:calc(var(--step) * 3);
}

/* FORMULA: readable on pure black */
.eegg{
  text-align:center;
  opacity:0.92; /* базово видимо */
}

.eegg__f{
  font-family:var(--mono);
  font-size:14px;
  letter-spacing:0.22em;
  color:var(--accent);
  text-shadow:0 0 12px rgba(31,74,255,0.35);
}

.eegg__t{
  margin-top:10px;
  font-size:12px;
  letter-spacing:var(--ls-m);
  color:var(--accent);
  opacity:0.95;
}

.back{
  display:inline-flex;
  align-items:center;
  gap:10px;
  font-size:var(--micro);
  letter-spacing:var(--ls-m);
  opacity:0.55;
  align-self:center;
}

.back:focus-visible{
  outline:1px solid var(--accent);
  outline-offset:6px;
}

@media (min-width:780px){
  .wrap{ max-width:1100px; }
  .screen--axiom .axiom{ max-width:42ch; }
}

@media (prefers-reduced-motion:reduce){
  *{ transition:none!important; }
}