/* ════════════════════════════════════════════════════════════
   NEXUS — Beyond the Visible
   01 · Tokens, base, chrome, controls
   Source of truth: design-system/nexus/MASTER.md
   ════════════════════════════════════════════════════════════ */

/* ── Tokens ─────────────────────────────────────────────────── */
:root {
  --c-obsidian: #070809;
  --c-ink: #0b0d0f;
  --c-basalt: #121518;
  --c-graphite: #1a1e22;
  --c-ivory: #f2ede4;
  --c-parchment: #e4dbcb;
  --c-ash: #8f8c84;
  --c-copper: #b87333;
  --c-champagne: #d8b98a;
  --c-gold: #c9a227;
  --c-steel: #6e8794;
  --ink-on-light: #12100d;

  --bg: var(--c-obsidian);
  --bg-raised: var(--c-ink);
  --fg: var(--c-ivory);
  --fg-muted: var(--c-ash);
  --accent: var(--c-champagne);
  --accent-metal: var(--c-copper);
  --line: rgba(242, 237, 228, 0.14);
  --line-strong: rgba(242, 237, 228, 0.3);

  --font-display: "Instrument Serif", "Iowan Old Style", "Times New Roman", serif;
  --font-sans: "Manrope", "Segoe UI", system-ui, -apple-system, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, "SFMono-Regular", Consolas, monospace;
  --fs-hero: clamp(4.2rem, 9.6vw, 9.5rem);
  --fs-display: clamp(2.8rem, 6.4vw, 6.6rem);
  --fs-title: clamp(1.9rem, 3.4vw, 3.4rem);
  --fs-lead: clamp(1.05rem, 1.25vw, 1.3rem);
  --fs-body: 1.0625rem;
  --fs-small: 0.875rem;
  --fs-micro: 0.6875rem;

  --gutter: clamp(20px, 4vw, 64px);
  --container: 1560px;
  --grid-gap: clamp(16px, 1.6vw, 28px);
  --section-y: clamp(96px, 12vw, 184px);
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-in-out: cubic-bezier(0.65, 0, 0.35, 1);
  --dur-fast: 180ms;
  --dur-base: 420ms;
  --dur-slow: 900ms;
  --dur-cinema: 1200ms;
}

/* ── Reset + base ───────────────────────────────────────────── */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scrollbar-color: #3a352e var(--c-obsidian);
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  font-weight: 400;
  line-height: 1.6;
  overflow-x: clip;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

body.is-locked {
  overflow: hidden;
}

main {
  display: block;
}

img,
svg,
canvas {
  display: block;
  max-width: 100%;
}

img {
  height: auto;
}

h1,
h2,
h3,
h4,
p,
figure,
blockquote,
dl,
dd {
  margin: 0;
}

ul,
ol {
  margin: 0;
  padding: 0;
  list-style: none;
}

a {
  color: inherit;
  text-decoration: none;
}

button {
  color: inherit;
  font: inherit;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

::selection {
  background: var(--c-champagne);
  color: var(--c-obsidian);
}

:where(a, button, input, textarea, select, summary):focus-visible {
  outline: 1px solid var(--accent);
  outline-offset: 4px;
  border-radius: 1px;
}

:where(button) {
  cursor: pointer;
}

svg {
  overflow: visible;
}

/* Every stroked icon uses the same calm weight. */
svg path,
svg rect,
svg circle,
svg line {
  fill: none;
  stroke: currentColor;
  stroke-width: 1.25;
  stroke-linecap: round;
  stroke-linejoin: round;
  vector-effect: non-scaling-stroke;
}

/* ── Layout helpers ─────────────────────────────────────────── */
.container {
  width: min(calc(100% - var(--gutter) * 2), var(--container));
  margin-inline: auto;
}

.section {
  position: relative;
  padding-block: var(--section-y);
  scroll-margin-top: 88px;
}

.section-head {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--grid-gap);
  align-items: start;
  margin-bottom: clamp(52px, 7vw, 108px);
}

.section-head__aside {
  grid-column: 1 / 3;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 14px;
}

.section-index {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(2.6rem, 4.6vw, 4.4rem);
  line-height: 0.78;
  letter-spacing: -0.02em;
  color: transparent;
  -webkit-text-stroke: 1px rgba(216, 185, 138, 0.55);
}

.section-head__rule {
  display: block;
  width: 30px;
  height: 1px;
  margin-top: 10px;
  background: var(--accent);
  opacity: 0.7;
}

.section-head__title {
  grid-column: 3 / 10;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: var(--fs-display);
  line-height: 0.94;
  letter-spacing: -0.02em;
}

.section-head__title em {
  color: var(--accent);
  font-style: italic;
}

.section-head__lead {
  grid-column: 10 / 13;
  align-self: end;
  max-width: 35ch;
  padding-bottom: 8px;
  color: var(--fg-muted);
  font-size: 0.98rem;
  line-height: 1.72;
}

/* ── Type utilities ─────────────────────────────────────────── */
.mono {
  font-family: var(--font-mono);
  font-size: var(--fs-micro);
  font-weight: 400;
  letter-spacing: 0.18em;
  line-height: 1.5;
  text-transform: uppercase;
}

.eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: var(--fs-micro);
  font-weight: 400;
  letter-spacing: 0.22em;
  line-height: 1.4;
  text-transform: uppercase;
}

.eyebrow__dot {
  width: 5px;
  height: 5px;
  flex: 0 0 auto;
  border-radius: 50%;
  background: var(--c-copper);
  box-shadow: 0 0 10px rgba(184, 115, 51, 0.9);
}

.visually-hidden {
  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;
  top: 12px;
  left: 12px;
  z-index: 1200;
  padding: 12px 18px;
  background: var(--c-ivory);
  color: var(--c-obsidian);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  transform: translateY(-140%);
  transition: transform var(--dur-base) var(--ease-out);
}

.skip-link:focus {
  transform: translateY(0);
}

/* ── Buttons ────────────────────────────────────────────────── */
.btn {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  min-height: 54px;
  padding: 0 26px;
  border: 1px solid transparent;
  border-radius: 2px;
  background: transparent;
  color: var(--fg);
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  line-height: 1;
  text-transform: uppercase;
  transition:
    background-color var(--dur-base) var(--ease-out),
    border-color var(--dur-base) var(--ease-out),
    color var(--dur-base) var(--ease-out),
    transform var(--dur-fast) var(--ease-out);
}

.btn svg {
  flex: 0 0 auto;
  transition: transform var(--dur-base) var(--ease-out);
}

.btn:active {
  transform: translateY(1px);
}

.btn--solid {
  border-color: transparent;
  padding-right: 30px;
  background: linear-gradient(100deg, #e8d0a8 0%, #c9955a 58%, #b87333 100%);
  color: #0a0b0c;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 14px), calc(100% - 14px) 100%, 0 100%);
}

.btn--solid:hover {
  background: linear-gradient(100deg, #f4e3c6 0%, #d8b98a 54%, #c2864a 100%);
}

.btn--solid:hover svg {
  transform: translateX(4px);
}

.btn--ghost {
  border-color: var(--line-strong);
  background: rgba(255, 255, 255, 0.015);
  color: var(--fg);
}

.btn--ghost:hover {
  border-color: var(--accent);
  background: rgba(216, 185, 138, 0.06);
}

.btn--text {
  min-height: 44px;
  padding: 0;
  border: 0;
  background: none;
  color: var(--fg);
  font-size: 0.92rem;
  font-weight: 500;
  letter-spacing: 0.01em;
  text-transform: none;
}

.btn--text::after {
  content: "";
  position: absolute;
  right: 0;
  bottom: 7px;
  left: 0;
  height: 1px;
  background: var(--accent);
  transform: scaleX(1);
  transform-origin: left;
  transition: transform var(--dur-base) var(--ease-out);
}

.btn--text:hover {
  color: var(--accent);
}

.btn--text:hover::after {
  transform: scaleX(0.32);
}

.btn--sm {
  min-height: 44px;
  padding: 0 18px;
  font-size: 0.65rem;
  letter-spacing: 0.12em;
}

.icon-btn {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  min-height: 44px;
  padding: 0 14px;
  border: 1px solid var(--line-strong);
  border-radius: 2px;
  background: rgba(7, 8, 9, 0.4);
  color: rgba(242, 237, 228, 0.82);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  backdrop-filter: blur(8px);
  transition:
    border-color var(--dur-base) var(--ease-out),
    color var(--dur-base) var(--ease-out),
    background-color var(--dur-base) var(--ease-out);
}

.icon-btn:hover {
  border-color: rgba(216, 185, 138, 0.65);
  background: rgba(216, 185, 138, 0.08);
  color: var(--accent);
}

.icon-btn[aria-pressed="true"] {
  border-color: var(--accent);
  color: var(--accent);
}

.icon-btn--square {
  width: 44px;
  padding: 0;
  justify-content: center;
}

/* ── Overlays: grain, progress, cursor ──────────────────────── */
.grain {
  position: fixed;
  inset: 0;
  z-index: 500;
  pointer-events: none;
  opacity: 0.035;
  mix-blend-mode: overlay;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.82' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='180' height='180' filter='url(%23n)' opacity='0.55'/%3E%3C/svg%3E");
  background-size: 180px 180px;
}

.scroll-progress {
  position: fixed;
  top: 0;
  right: 0;
  left: 0;
  z-index: 810;
  height: 1px;
  pointer-events: none;
}

.scroll-progress span {
  display: block;
  height: 100%;
  background: linear-gradient(90deg, rgba(184, 115, 51, 0.2), var(--c-champagne));
  transform: scaleX(0);
  transform-origin: left center;
}

.cursor {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 1100;
  display: grid;
  place-items: center;
  width: 26px;
  height: 26px;
  border: 1px solid rgba(216, 185, 138, 0.65);
  border-radius: 50%;
  pointer-events: none;
  opacity: 0;
  transform: translate3d(-100px, -100px, 0) translate(-50%, -50%);
  transition:
    width 0.32s var(--ease-out),
    height 0.32s var(--ease-out),
    background-color 0.32s var(--ease-out),
    border-color 0.32s var(--ease-out),
    opacity 0.3s linear;
}

.cursor.is-visible {
  opacity: 1;
}

.cursor.is-hover {
  width: 42px;
  height: 42px;
  border-color: rgba(216, 185, 138, 0.85);
  background: rgba(216, 185, 138, 0.05);
}

.cursor.is-active {
  width: 66px;
  height: 66px;
  border-color: rgba(216, 185, 138, 0.95);
  background: rgba(216, 185, 138, 0.09);
  backdrop-filter: blur(2px);
}

.cursor__label {
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  opacity: 0;
  transition: opacity 0.2s linear;
}

.cursor.is-active .cursor__label {
  opacity: 1;
}

@media (pointer: coarse), (prefers-reduced-motion: reduce) {
  .cursor {
    display: none;
  }
}

/* ── Intro veil ─────────────────────────────────────────────── */
.intro {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: none;
  place-items: center;
  background: var(--c-obsidian);
}

html.js .intro {
  display: grid;
}

.intro__inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 18px;
  color: var(--accent);
}

.intro__mark {
  animation: introPulse 2.2s var(--ease-in-out) infinite;
}

.intro__inner p {
  color: rgba(242, 237, 228, 0.58);
}

.intro__bar {
  width: 190px;
  height: 1px;
  overflow: hidden;
  background: rgba(242, 237, 228, 0.14);
}

.intro__bar i {
  display: block;
  width: 100%;
  height: 100%;
  background: var(--accent);
  transform-origin: left center;
  animation: introBar 1.5s var(--ease-in-out) both;
}

body.is-loaded .intro {
  visibility: hidden;
  opacity: 0;
  transition:
    opacity 0.8s var(--ease-out) 0.1s,
    visibility 0s linear 0.95s;
}

@keyframes introBar {
  from {
    transform: scaleX(0);
  }
  to {
    transform: scaleX(1);
  }
}

@keyframes introPulse {
  0%,
  100% {
    opacity: 0.45;
  }
  50% {
    opacity: 1;
  }
}

/* ── Header ─────────────────────────────────────────────────── */
.site-header {
  position: fixed;
  top: 0;
  right: 0;
  left: 0;
  z-index: 800;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  height: 88px;
  padding-inline: var(--gutter);
  border-bottom: 1px solid transparent;
  transition:
    background-color 0.5s var(--ease-out),
    border-color 0.5s var(--ease-out),
    backdrop-filter 0.5s var(--ease-out);
}

.site-header.is-scrolled {
  border-bottom-color: var(--line);
  background: rgba(7, 8, 9, 0.72);
  backdrop-filter: blur(16px) saturate(120%);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  justify-self: start;
  color: var(--c-ivory);
}

.brand__mark {
  color: var(--c-copper);
  transition: transform 0.6s var(--ease-out), color 0.4s linear;
}

.brand:hover .brand__mark {
  color: var(--accent);
  transform: rotate(90deg);
}

.brand__word {
  font-family: var(--font-sans);
  font-size: 0.82rem;
  font-weight: 600;
  letter-spacing: 0.32em;
}

.brand__sup {
  align-self: flex-start;
  margin-top: 4px;
  color: rgba(242, 237, 228, 0.35);
  font-size: 10px;
  letter-spacing: 0.12em;
}

.nav {
  display: flex;
  align-items: center;
  gap: clamp(18px, 2.4vw, 38px);
  justify-self: center;
}

.nav a {
  position: relative;
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  padding: 10px 0;
  color: rgba(242, 237, 228, 0.62);
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  transition: color var(--dur-base) var(--ease-out);
}

.nav a span {
  color: rgba(216, 185, 138, 0.55);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.08em;
}

.nav a::after {
  content: "";
  position: absolute;
  right: 0;
  bottom: 4px;
  left: 0;
  height: 1px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: right;
  transition: transform 0.45s var(--ease-out);
}

.nav a:hover {
  color: var(--c-ivory);
}

.nav a:hover::after {
  transform: scaleX(1);
  transform-origin: left;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  justify-self: end;
}

.menu-btn {
  display: none;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 1px solid var(--line-strong);
  border-radius: 2px;
  background: transparent;
  position: relative;
}

.menu-btn span {
  position: absolute;
  left: 12px;
  width: 18px;
  height: 1px;
  background: var(--fg);
  transition:
    transform 0.4s var(--ease-out),
    top 0.4s var(--ease-out),
    opacity 0.2s linear;
}

.menu-btn span:first-child {
  top: 18px;
}

.menu-btn span:last-child {
  top: 24px;
}

.menu-btn[aria-expanded="true"] span:first-child {
  top: 21px;
  transform: rotate(45deg);
}

.menu-btn[aria-expanded="true"] span:last-child {
  top: 21px;
  transform: rotate(-45deg);
}

/* ── Menu overlay ───────────────────────────────────────────── */
.menu {
  position: fixed;
  inset: 0;
  z-index: 900;
  visibility: hidden;
  opacity: 0;
  transition:
    opacity 0.45s var(--ease-out),
    visibility 0s linear 0.5s;
}

.menu.is-open {
  visibility: visible;
  opacity: 1;
  transition:
    opacity 0.45s var(--ease-out),
    visibility 0s;
}

.menu__backdrop {
  position: absolute;
  inset: 0;
  background: rgba(3, 4, 5, 0.62);
  backdrop-filter: blur(7px);
}

.menu__panel {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  display: flex;
  flex-direction: column;
  width: min(560px, 100%);
  padding: 26px var(--gutter) 34px;
  border-left: 1px solid var(--line);
  background: var(--c-ink);
  transform: translateX(102%);
  transition: transform 0.6s var(--ease-out);
}

.menu.is-open .menu__panel {
  transform: translateX(0);
}

.menu__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 22px;
  border-bottom: 1px solid var(--line);
  color: rgba(242, 237, 228, 0.44);
}

.menu__close {
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 1px solid var(--line-strong);
  border-radius: 50%;
  background: transparent;
  color: var(--fg);
  transition:
    border-color 0.3s linear,
    transform 0.4s var(--ease-out);
}

.menu__close:hover {
  border-color: var(--accent);
  transform: rotate(90deg);
}

.menu__nav {
  display: flex;
  flex-direction: column;
  margin-top: 16px;
}

.menu__nav a {
  display: grid;
  grid-template-columns: 30px 1fr auto;
  align-items: center;
  gap: 14px;
  padding: clamp(14px, 2.2vh, 22px) 0;
  border-bottom: 1px solid var(--line);
  font-family: var(--font-display);
  font-size: clamp(2rem, 5.4vw, 3.5rem);
  line-height: 1;
  letter-spacing: -0.015em;
  transition: color 0.3s linear, padding-left 0.4s var(--ease-out);
}

.menu__nav a span {
  color: rgba(216, 185, 138, 0.55);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.1em;
}

.menu__nav a em {
  font-family: var(--font-sans);
  font-size: 16px;
  font-style: normal;
  opacity: 0;
  transform: translateX(-8px);
  transition:
    opacity 0.3s linear,
    transform 0.4s var(--ease-out);
}

.menu__nav a:hover {
  padding-left: 8px;
  color: var(--accent);
}

.menu__nav a:hover em {
  opacity: 1;
  transform: translateX(0);
}

.menu__foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-top: auto;
  padding-top: 26px;
  color: rgba(242, 237, 228, 0.4);
}

/* ── Chapter rail ───────────────────────────────────────────── */
.rail {
  position: fixed;
  top: 50%;
  right: 20px;
  z-index: 700;
  display: flex;
  flex-direction: column;
  gap: 16px;
  transform: translateY(-50%);
}

.rail__item {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 10px;
  min-height: 20px;
  color: rgba(242, 237, 228, 0.35);
}

.rail__item span {
  font-size: 10px;
  letter-spacing: 0.08em;
  transition: color 0.3s linear;
}

.rail__item i {
  width: 16px;
  height: 1px;
  background: rgba(242, 237, 228, 0.28);
  transition:
    width 0.4s var(--ease-out),
    background-color 0.3s linear;
}

.rail__item em {
  position: absolute;
  right: 52px;
  font-family: var(--font-mono);
  font-size: 10px;
  font-style: normal;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  white-space: nowrap;
  opacity: 0;
  transform: translateX(6px);
  transition:
    opacity 0.3s linear,
    transform 0.4s var(--ease-out);
}

.rail__item:hover span,
.rail__item.is-active span {
  color: var(--accent);
}

.rail__item:hover i,
.rail__item.is-active i {
  width: 28px;
  background: var(--accent);
}

.rail__item:hover em {
  opacity: 1;
  transform: translateX(0);
}

@media (max-width: 1199px) {
  .rail {
    display: none;
  }
}

/* ── Reveal system ──────────────────────────────────────────── */
html.js [data-reveal] {
  opacity: 0;
  transform: translateY(26px);
  transition:
    opacity 0.9s var(--ease-out),
    transform 1.05s var(--ease-out);
  transition-delay: var(--d, 0s);
}

html.js [data-reveal].is-in {
  opacity: 1;
  transform: none;
}

html.js [data-reveal="mask"] {
  opacity: 1;
  transform: none;
}

html.js [data-reveal="mask"] > .frame {
  clip-path: inset(0 0 100% 0);
  transition: clip-path 1.5s var(--ease-out);
  transition-delay: var(--d, 0s);
}

html.js [data-reveal="mask"].is-in > .frame {
  clip-path: inset(0 0 0 0);
}

/* ── Hero entrance ──────────────────────────────────────────── */
html.js body:not(.is-loaded) .anim,
html.js body:not(.is-loaded) .hero__word {
  opacity: 0;
}

body.is-loaded .anim {
  animation: rise 1.15s var(--ease-out) both;
  animation-delay: var(--d, 0s);
}

body.is-loaded .hero__word {
  animation: wordRise 1.2s var(--ease-out) both;
  animation-delay: var(--d, 0s);
}

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(18px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

@keyframes wordRise {
  from {
    opacity: 0;
    transform: translateY(102%);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

/* ── Noscript ───────────────────────────────────────────────── */
.noscript {
  position: fixed;
  right: 12px;
  bottom: 12px;
  left: 12px;
  z-index: 1200;
  padding: 14px 18px;
  border: 1px solid var(--line-strong);
  background: rgba(11, 13, 15, 0.96);
  color: var(--fg-muted);
  font-size: 13px;
  line-height: 1.55;
}

.noscript strong {
  color: var(--accent);
}