/* ============================================================================
   4КУБ — design system
   ----------------------------------------------------------------------------
   PAPER WORLD. The site reads as warm printed stock: cream ground, near-black
   ink, one terracotta accent, hairline rules, and type that is large and LIGHT
   rather than large and heavy.

   The accent is still the app's own #CC785C (src/theme/index.ts). The surfaces
   are not: the app opens dark, the site opens on paper. That is a deliberate
   split — the marketing site is the poster, the product is the tool — and the
   accent is what holds the two together. Anything that must feel like the
   product (the night bands, .day-stage, .asst-chat) uses --night, which IS the
   app's lacquer.

   ONE ACCENT. --accent is a FILL colour: on cream it measures 2.75:1, which is
   under the 3:1 floor, so it must never carry text. Accent-coloured TEXT uses
   --accent-ink (5.6:1). This is the single easiest mistake to make here.

   SPACING MODEL, DECLARED ONCE: every section owns its own vertical padding via
   .section-pad. There are NO margins between sections and no negative margins
   pulling them together. Changing one section cannot move another.
   ========================================================================== */

/* ---- fonts: self-hosted, cyrillic first --------------------------------- */
/* Downloaded from Google Fonts and served from this origin. The site makes no
   external request — required by the Russian-providers rule, and it is also why
   the page still renders with the network cut after first load.
   Cyrillic is declared BEFORE latin so the Russian face wins the cascade. */

@font-face {
  font-family: 'Exo 2';
  font-style: normal;
  font-weight: 200 600;
  font-display: swap;
  src: url('/fonts/exo2-cyrillic.woff2') format('woff2');
  unicode-range: U+0301, U+0400-045F, U+0490-0491, U+04B0-04B1, U+2116;
}
@font-face {
  font-family: 'Exo 2';
  font-style: normal;
  font-weight: 200 600;
  font-display: swap;
  src: url('/fonts/exo2-latin.woff2') format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA,
                 U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122,
                 U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}

@font-face {
  font-family: 'Zen Old Mincho';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url('/fonts/zenoldmincho-400-cyrillic.woff2') format('woff2');
  unicode-range: U+0301, U+0400-045F, U+0490-0491, U+04B0-04B1, U+2116;
}
@font-face {
  font-family: 'Zen Old Mincho';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url('/fonts/zenoldmincho-400-latin.woff2') format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA,
                 U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122,
                 U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}
@font-face {
  font-family: 'Zen Old Mincho';
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url('/fonts/zenoldmincho-500-cyrillic.woff2') format('woff2');
  unicode-range: U+0301, U+0400-045F, U+0490-0491, U+04B0-04B1, U+2116;
}
@font-face {
  font-family: 'Zen Old Mincho';
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url('/fonts/zenoldmincho-500-latin.woff2') format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA,
                 U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122,
                 U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}

@font-face {
  font-family: 'JetBrains Mono';
  font-style: normal;
  font-weight: 400 600;
  font-display: swap;
  src: url('/fonts/jetbrainsmono-cyrillic.woff2') format('woff2');
  unicode-range: U+0301, U+0400-045F, U+0490-0491, U+04B0-04B1, U+2116;
}
@font-face {
  font-family: 'JetBrains Mono';
  font-style: normal;
  font-weight: 400 600;
  font-display: swap;
  src: url('/fonts/jetbrainsmono-latin.woff2') format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA,
                 U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122,
                 U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}


:root {
  color-scheme: light;

  /* Paper. --paper is the ground; --rice lifts a card off it; --paper-deep is
     the ground seen through something (table headers, pressed states). */
  --paper:         #F4EADC;
  --paper-soft:    #EFE1CE;
  --paper-deep:    #E4D3B8;
  --rice:          #FBF6EE;

  /* Ink. Warm, never neutral grey — grey on cream reads as dirt. */
  --ink:           #241D16;
  --ink-soft:      #4A3D30;
  --ash:           #6E5E4C;

  /* Rules. --line is drawn; --line-soft is barely there. */
  --line:          #CDB99D;
  --line-soft:     rgba(36, 29, 22, 0.13);
  --line-strong:   #B49C7C;

  /* THE accent, unchanged from the app.
     --accent      FILL only  (buttons, dots, the sun, underlines)
     --accent-ink  TEXT       (5.60:1 on paper — safe at any size)
     --accent-deep pressed / hover text                                       */
  --accent:        #CC785C;
  --accent-ink:    #974329;
  --accent-deep:   #77331F;
  --accent-wash:   rgba(204, 120, 92, 0.13);
  /* Accent-coloured TEXT on a night surface. --accent is tuned for paper and
     drops to 1.77:1 over a lit image; this lifted tint clears 4:1 there. */
  --accent-lift:   #E3A183;
  --danger:        #A8321F;

  /* Night. This IS the app's lacquer — the dark bands are the product showing
     through the poster, so they must not drift from src/theme/index.ts. */
  --night:         #14110E;
  --night-soft:    #211B15;
  --night-ink:     #EFE6D8;
  --night-muted:   rgba(239, 230, 216, 0.62);
  --night-line:    rgba(239, 230, 216, 0.16);

  /* Aliases kept so the trust island's self-contained rules need no rewrite. */
  --bg:            var(--paper);
  --bg-deep:       var(--paper-soft);
  --panel:         var(--rice);
  --panel-raised:  var(--paper-soft);
  --ink-muted:     var(--ink-soft);
  --ink-faint:     var(--ash);
  --accent-warm:   var(--accent-ink);
  --accent-quiet:  var(--accent-deep);
  --room-bg:       var(--paper-soft);
  --room-panel:    var(--rice);
  --room-ink:      var(--ink);
  --room-muted:    var(--ink-soft);
  --room-line:     var(--line);
  --room-accent:   var(--accent-ink);

  /* Type. Three voices and no more:
       display — Exo 2 at 200. Squared, technical, and LIGHT. Set uppercase.
       prose   — Zen Old Mincho. A serif for anything meant to be read.
       label   — JetBrains Mono, uppercase, widely tracked. Meta, never prose. */
  --font-display: 'Exo 2', 'Segoe UI Variable Display', 'Segoe UI', system-ui, Arial, sans-serif;
  --font-serif:   'Zen Old Mincho', 'Iowan Old Style', Georgia, 'Times New Roman', serif;
  --font-sans:    'Exo 2', 'Segoe UI Variable Text', 'Segoe UI', system-ui, Arial, sans-serif;
  --font-mono:    'JetBrains Mono', ui-monospace, 'Cascadia Mono', Consolas, monospace;

  --t-display: clamp(2.7rem, 1.3rem + 5.6vw, 6.6rem);
  --t-h2:      clamp(1.85rem, 1.15rem + 2.7vw, 3.4rem);
  --t-h3:      clamp(1.08rem, 1rem + 0.4vw, 1.32rem);
  --t-body:    clamp(1rem, 0.97rem + 0.16vw, 1.0625rem);
  --t-label:   0.6875rem;

  --shell: 1400px;
  /* Squared, not pill. The paper world is set with a ruler. */
  --radius: 3px;
  --radius-lg: 4px;

  --button-ink: #24170F;
  --nav-bg: rgba(244, 234, 220, 0.82);
  --nav-bg-solid: rgba(244, 234, 220, 0.96);

  --shadow-lift: 0 28px 90px rgba(60, 40, 24, 0.16);

  /* One easing vocabulary, so nothing on the page moves in a foreign accent. */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-in-out: cubic-bezier(0.65, 0, 0.35, 1);
}

*, *::before, *::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-serif);
  font-size: var(--t-body);
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

/* Paper grain. Generated, not downloaded: an feTurbulence tile costs no request
   and stays sharp at any zoom. It sits above the background and below content,
   and it must never intercept a click. */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  opacity: 0.5;
  mix-blend-mode: multiply;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Cfilter id='g'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3CfeColorMatrix type='saturate' values='0'/%3E%3C/filter%3E%3Crect width='180' height='180' filter='url(%23g)' opacity='0.22'/%3E%3C/svg%3E");
}
/* Everything real sits above the grain. */
body > * { position: relative; z-index: 1; }

img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; }

/* Focus is visible, always. Keyboard users are not second-class. */
:focus-visible {
  outline: 2px solid var(--accent-ink);
  outline-offset: 3px;
  border-radius: 2px;
}

::selection { background: var(--accent); color: var(--button-ink); }

/* ---- shared primitives (no section-crossing selectors) ------------------- */

.shell {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: clamp(1.25rem, 4vw, 3rem);
}

/* THE spacing model. Sections apply this; they never use margin. */
.section-pad { padding-block: clamp(4.5rem, 9vw, 8.5rem); }

/* Meta, not prose. Mono, uppercase, widely tracked — the reference's tell. */
.eyebrow {
  font-family: var(--font-mono);
  font-size: var(--t-label);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  font-weight: 600;
  color: var(--accent-ink);
  margin: 0 0 1.4rem;
}

.h2 {
  font-family: var(--font-display);
  font-size: var(--t-h2);
  /* See .hero-title: uppercase Cyrillic descenders (Д, Ц, Щ) need the extra
     room that a latin-tuned 1.02 does not leave. */
  line-height: 1.06;
  letter-spacing: 0.005em;
  text-transform: uppercase;
  font-weight: 250;
  margin: 0;
  text-wrap: balance;
}

.lede {
  font-family: var(--font-serif);
  font-size: clamp(1.02rem, 0.98rem + 0.3vw, 1.2rem);
  line-height: 1.75;
  color: var(--ink-soft);
  max-width: 56ch;
  margin: 1.3rem 0 0;
}

/* Buttons. Squared and mono-labelled, like a printed ticket. 48px min height
   clears the 44px touch-target floor. */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.7rem;
  min-height: 48px;
  padding: 0 1.4rem;
  border-radius: var(--radius);
  border: 1px solid transparent;
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  white-space: nowrap;
  position: relative;
  cursor: pointer;
  transition: transform 0.25s var(--ease-out), background-color 0.25s var(--ease-out),
              border-color 0.25s var(--ease-out), color 0.25s var(--ease-out);
}
.btn-primary {
  background: var(--accent);
  color: var(--button-ink);
  border-color: var(--accent);
}
.btn-primary:hover { background: var(--accent-ink); border-color: var(--accent-ink); color: var(--rice); transform: translateY(-2px); }
.btn-ghost { background: transparent; color: var(--ink); border-color: var(--line-strong); }
.btn-ghost:hover { border-color: var(--accent-ink); color: var(--accent-ink); transform: translateY(-2px); }
.btn.btn:active { transform: scale(0.985); }
.btn-lg { min-height: 56px; padding: 0 1.9rem; font-size: 0.79rem; }
.btn-full { width: 100%; }

/* The circled arrow inside a CTA — the reference's ticket button. */
.btn-arrow {
  width: 20px; height: 20px; flex: none;
  border: 1px solid currentColor; border-radius: 50%;
  display: grid; place-items: center;
  transition: transform 0.3s var(--ease-out);
}
.btn-arrow svg { width: 9px; height: 9px; }
.btn:hover .btn-arrow { transform: translateX(3px); }

/* ---- reveal (motion dial 7: fluid storytelling) ------------------------- */

/* Hidden ONLY once JS is confirmed, and confirmed by a synchronous script in
   <head> that runs before first paint.
   The naive form of this (start hidden, un-hide from a .no-js class) flashes:
   the document parses visible, the deferred script strips .no-js, everything
   drops to opacity 0 *with a transition*, and the reader watches the page fade
   out and back in. Gating on .js instead means content is either never hidden
   (no JS) or hidden before it was ever painted. */
.js .reveal {
  opacity: 0;
  transform: translate3d(var(--reveal-x, 0), var(--reveal-y, 34px), 0) scale(var(--reveal-scale, 0.985));
  transition: opacity 0.86s var(--ease-out), transform 0.86s var(--ease-out);
  will-change: opacity, transform;
}
.js .reveal.is-in { opacity: 1; transform: none; will-change: auto; }

/* Staggered children inside one island. Scoped by the parent, never global. */
.js .reveal-group > * { transition-delay: var(--d, 0ms); }

/* Native scroll progress. Unsupported browsers simply omit it; no JavaScript
   scroll loop is needed. The line communicates position on this long page. */
.scroll-progress {
  position: fixed;
  inset: 0 0 auto;
  z-index: 60;
  height: 2px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left center;
  opacity: 0;
  pointer-events: none;
}

@keyframes page-progress { to { transform: scaleX(1); } }

@media (prefers-reduced-motion: no-preference) {
  @supports (animation-timeline: scroll()) {
    .scroll-progress {
      opacity: 1;
      animation: page-progress linear both;
      animation-timeline: scroll(root);
    }
  }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
  /* Reduced motion means no reveal at all, not a faster one — and it must beat
     the .js rule above, hence the same specificity plus !important. */
  .js .reveal { opacity: 1 !important; transform: none !important; }
}

.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  left: 1rem;
  top: -3rem;
  z-index: 100;
  background: var(--accent);
  color: var(--button-ink);
  padding: 0.6rem 1rem;
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-weight: 600;
  transition: top 0.2s var(--ease-out);
}
.skip-link:focus { top: 1rem; }