/* ==========================================================================
   CallYar — Base, global components, chrome
   ========================================================================== */

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  background: var(--ink);
}

body {
  margin: 0;
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font);
  font-size: var(--fs-body);
  font-weight: var(--w-reg);
  line-height: var(--lh-body);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: clip;
}

img, svg, canvas { display: block; max-width: 100%; }
button, input, select, textarea { font: inherit; color: inherit; }
button { cursor: pointer; background: none; border: 0; padding: 0; }
a { color: inherit; }
ul, ol { margin: 0; padding: 0; list-style: none; }
h1, h2, h3, h4, p { margin: 0; }
b, strong { font-weight: var(--w-bold); }

::selection { background: var(--fg); color: var(--bg); }

:focus { outline: none; }
:focus-visible { outline: 2px solid currentColor; outline-offset: 4px; border-radius: 2px; }

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

.skip-link {
  position: fixed;
  inset-block-start: var(--s-4);
  inset-inline-start: var(--s-4);
  z-index: var(--z-skip);
  padding: var(--s-3) var(--s-5);
  background: var(--paper);
  color: var(--ink);
  border-radius: var(--r-pill);
  font-weight: var(--w-bold);
  text-decoration: none;
  transform: translateY(-200%);
  transition: transform var(--t-short) var(--ease-out);
}
.skip-link:focus-visible { transform: none; }

/* ---- Themes --------------------------------------------------------- */
.theme-ink   { --bg: var(--ink);   --fg: var(--paper); --muted: var(--grey-ink);   --rule: var(--rule-ink);   background: var(--bg); color: var(--fg); }
.theme-paper { --bg: var(--paper); --fg: var(--ink);   --muted: var(--grey-paper); --rule: var(--rule-paper); background: var(--bg); color: var(--fg); }

/* ---- Type primitives ------------------------------------------------ */
.title {
  font-weight: var(--w-heavy);
  font-size: var(--fs-h2);
  line-height: var(--lh-head);
  letter-spacing: var(--track-head);
  text-wrap: balance;
}
.title .thin { font-weight: var(--w-thin); color: var(--muted); }

.kicker {
  display: inline-flex;
  align-items: center;
  gap: var(--s-3);
  font-size: var(--fs-micro);
  font-weight: var(--w-med);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
}
:root[lang="fa"] .kicker { letter-spacing: 0; font-size: var(--fs-small); }
.kicker::before {
  content: "";
  inline-size: var(--dot);
  block-size: var(--dot);
  border-radius: 50%;
  background: var(--accent);
}

.lead {
  font-size: var(--fs-lead);
  line-height: 1.6;
  color: var(--muted);
  max-inline-size: 40ch;
  text-wrap: pretty;
}
:root[lang="fa"] .lead { line-height: 1.95; max-inline-size: 44ch; }

.num { font-variant-numeric: tabular-nums; }

/* ---- Buttons: pills, like the bars of the mark ---------------------- */
.btn {
  --btn-bg: var(--fg);
  --btn-fg: var(--bg);
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: var(--s-3);
  min-block-size: 48px;
  padding: 0 var(--s-5);
  border-radius: var(--r-pill);
  background: var(--btn-bg);
  color: var(--btn-fg);
  font-weight: var(--w-bold);
  font-size: 0.9375rem;
  text-decoration: none;
  white-space: nowrap;
  overflow: hidden;
  isolation: isolate;
  transition: transform var(--t-short) var(--ease-out), color var(--t-short) var(--ease-out);
}
.btn::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background: var(--btn-fg);
  border-radius: inherit;
  transform: scaleY(0);
  transform-origin: 50% 100%;
  transition: transform var(--t-short) var(--ease-out);
}
.btn:hover::after { transform: scaleY(1); }
.btn:hover { color: var(--btn-bg); box-shadow: inset 0 0 0 1.5px var(--btn-bg); }
.btn:active { transform: scale(0.97); }
.btn--ghost { --btn-bg: transparent; --btn-fg: var(--fg); box-shadow: inset 0 0 0 1.5px var(--rule); }
.btn--ghost::after { background: var(--fg); }
.btn--ghost:hover { color: var(--bg); box-shadow: inset 0 0 0 1.5px var(--fg); }

.btn__dots { display: inline-grid; grid-template-columns: repeat(3, 4px); gap: 3px; }
.btn__dots i { inline-size: 4px; block-size: 4px; border-radius: 50%; background: currentColor; transition: transform var(--t-short) var(--ease-spring); }
.btn:hover .btn__dots i:nth-child(1) { transform: translateY(-3px); }
.btn:hover .btn__dots i:nth-child(2) { transform: translateY(3px); transition-delay: 40ms; }
.btn:hover .btn__dots i:nth-child(3) { transform: translateY(-2px); transition-delay: 80ms; }

/* ---- The signal: one canvas, above every section -------------------- */
.signal {
  position: fixed;
  inset: 0;
  inline-size: 100%;
  block-size: 100%;
  z-index: var(--z-signal);
  pointer-events: none;
  mix-blend-mode: difference;
}

/* ---- Header ---------------------------------------------------------- */
.site-header {
  position: fixed;
  inset-block-start: 0;
  inset-inline: 0;
  z-index: var(--z-header);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--s-5);
  padding: calc(var(--s-4) + 4px) var(--gutter);
  color: var(--paper);
  pointer-events: none;
}
:root[data-under="paper"] .site-header { color: var(--ink); }
.site-header > * { pointer-events: auto; }
.site-header { transition: padding var(--t-med) var(--ease-out), color var(--t-short) var(--ease-out); }
.site-header.is-compact { padding-block: calc(var(--s-2) + 4px); }

/* Header backdrop — tinted with the colour of the section underneath (set by js/chrome.js),
   blurred, and finished with a halftone fringe instead of a hard line. */
.header-bg {
  --hb: 26, 26, 25;          /* a shade lifted from ink, so the band reads as its own surface */
  --hb-a: 0.86;
  position: fixed;
  inset-block-start: 0;
  inset-inline: 0;
  block-size: 84px;
  z-index: 45;
  pointer-events: none;
  opacity: 0;
  background: rgba(var(--hb), var(--hb-a));
  box-shadow: inset 0 -1px 0 rgba(243, 243, 239, 0.07);
  -webkit-backdrop-filter: blur(14px) saturate(1.15);
  backdrop-filter: blur(14px) saturate(1.15);
  transition: opacity var(--t-med) var(--ease-out), background-color var(--t-med) var(--ease-out), block-size var(--t-med) var(--ease-out);
}
.header-bg::after {
  content: "";
  position: absolute;
  inset-inline: 0;
  inset-block-start: 100%;
  block-size: 14px;
  background: radial-gradient(circle, rgba(var(--hb), 0.95) 1.4px, transparent 1.8px) 0 0 / 6px 6px;
  -webkit-mask-image: linear-gradient(to bottom, #000, transparent);
  mask-image: linear-gradient(to bottom, #000, transparent);
}
.header-bg.is-on { opacity: 1; }
.header-bg.is-compact { block-size: 68px; }
:root[data-under="paper"] .header-bg { --hb: 228, 228, 222; --hb-a: 0.9; box-shadow: inset 0 -1px 0 rgba(11, 11, 11, 0.06); }

.brand { display: inline-flex; text-decoration: none; }
.brand svg { block-size: 28px; inline-size: auto; fill: currentColor; }
@media (max-width: 599px) { .brand svg { block-size: 25px; } }
.brand .logo-fa { display: none; }
:root[lang="fa"] .brand .logo-en { display: none; }
:root[lang="fa"] .brand .logo-fa { display: block; }

.header-actions { display: flex; align-items: center; gap: var(--s-1); }
.chip {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--s-2);
  min-block-size: 44px;
  min-inline-size: 44px;
  padding: 0 var(--s-4);
  border-radius: var(--r-pill);
  font-weight: var(--w-med);
  font-size: var(--fs-small);
  text-decoration: none;
  transition: background var(--t-micro), color var(--t-micro);
}
.chip:hover { background: color-mix(in srgb, currentColor 12%, transparent); }
.chip { white-space: nowrap; }
.chip__short { display: none; }
@media (max-width: 420px) {
  .chip { padding: 0 var(--s-3); }
  .chip__full { display: none; }
  .chip__short { display: inline; }
}
.chip--line { box-shadow: inset 0 0 0 1px color-mix(in srgb, currentColor 32%, transparent); }
.chip--line:hover { box-shadow: inset 0 0 0 1px currentColor; }
.chip--solid { background: var(--paper); color: var(--ink); font-weight: var(--w-bold); }
.chip--solid:hover { background: var(--paper); box-shadow: 0 0 0 4px rgba(243, 243, 239, 0.18); }
:root[data-under="paper"] .chip--solid { background: var(--ink); color: var(--paper); }
:root[data-under="paper"] .chip--solid:hover { box-shadow: 0 0 0 4px rgba(11, 11, 11, 0.12); }
.motion-toggle .mt-bars { display: inline-flex; align-items: center; gap: 2px; block-size: 12px; }
.motion-toggle .mt-bars i { inline-size: 2px; border-radius: 2px; background: currentColor; animation: mt 1.1s var(--ease-in-out) infinite alternate; }
.motion-toggle .mt-bars i:nth-child(1) { block-size: 5px; }
.motion-toggle .mt-bars i:nth-child(2) { block-size: 12px; animation-delay: -0.4s; }
.motion-toggle .mt-bars i:nth-child(3) { block-size: 8px; animation-delay: -0.8s; }
@keyframes mt { to { transform: scaleY(0.35); } }
.motion-off .motion-toggle .mt-bars i { animation: none; block-size: 2px; }
@media (max-width: 599px) { .chip--hide-sm { display: none; } }

/* ---- Chapter rail --------------------------------------------------- */
.rail {
  position: fixed;
  inset-inline-end: clamp(10px, 1.4vw, 24px);
  inset-block-start: 50%;
  transform: translateY(-50%);
  z-index: var(--z-rail);
  display: flex;
  flex-direction: column;
  color: #fff;
  mix-blend-mode: difference;
}
.rail a { position: relative; display: grid; place-items: center; inline-size: 26px; block-size: 24px; text-decoration: none; }
.rail a::before {
  content: "";
  inline-size: 4px; block-size: 4px;
  border-radius: var(--r-pill);
  background: currentColor;
  opacity: 0.4;
  transition: block-size var(--t-short) var(--ease-spring), opacity var(--t-short);
}
.rail a[aria-current="true"]::before { block-size: 16px; opacity: 1; }
.rail a:hover::before { opacity: 1; }
.rail .rail__label {
  position: absolute;
  inset-inline-end: 30px;
  white-space: nowrap;
  font-size: var(--fs-micro);
  font-weight: var(--w-med);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  opacity: 0;
  transform: translateX(6px);
  transition: opacity var(--t-micro), transform var(--t-short) var(--ease-out);
  pointer-events: none;
}
:root[dir="rtl"] .rail .rail__label { transform: translateX(-6px); letter-spacing: 0; text-transform: none; }
.rail a:hover .rail__label, .rail a:focus-visible .rail__label { opacity: 1; transform: none; }
@media (max-width: 899px) { .rail { display: none; } }

/* ---- Section frame -------------------------------------------------- */
.section { position: relative; padding: var(--section-y) var(--gutter); }
.wrap { max-inline-size: var(--max); margin-inline: auto; }

.halftone {
  position: absolute;
  inset-inline: 0;
  inset-block-start: 0;
  block-size: clamp(36px, 4.5vw, 64px);
  transform: translateY(-99%);
  pointer-events: none;
  z-index: 2;
}
.halftone svg { inline-size: 100%; block-size: 100%; }

/* ---- Reveal --------------------------------------------------------- */
.js [data-reveal] {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity var(--t-long) var(--ease-out), transform var(--t-long) var(--ease-out);
  transition-delay: calc(var(--d, 0) * 90ms);
}
.js [data-reveal].is-in { opacity: 1; transform: none; }

.line-mask { display: block; overflow: clip; padding-block: 0.08em; margin-block: -0.08em; }
.line-mask > span { display: inline-block; }
.js .line-mask > span { transform: translateY(110%); transition: transform 1.1s var(--ease-out); transition-delay: calc(var(--d, 0) * 110ms + 100ms); }
.js .is-in .line-mask > span, .js .line-mask.is-in > span { transform: none; }

/* ---- Language wipe -------------------------------------------------- */
.wipe { position: fixed; inset: 0; z-index: var(--z-wipe); pointer-events: none; inline-size: 100%; block-size: 100%; }

/* ---- Reduced motion -------------------------------------------------- */
.motion-off *, .motion-off *::before, .motion-off *::after {
  animation-duration: 1ms !important;
  animation-iteration-count: 1 !important;
  transition-duration: 1ms !important;
  transition-delay: 0ms !important;
}