/* ==========================================
   IT-IMPULSE — ARTICLES (single page) STYLES
   Подключается ПОСЛЕ style.css и modern.css.
   Содержит:
     • intro hero объединённой страницы
     • sticky chapter navigator (правая боковая)
     • chapter-divider (огромная цифра + sweep)
     • per-chapter accent hue-shift
     • 3D-tilt на .tilt-card
     • per-section reveal animations
     • outro CTA
   ========================================== */

/* ---------- Per-chapter accent palette ---------- */
/* Chapter 1 (Cloud Hall) uses campus charcoal — not legacy neon red */
.chapter[data-accent="0"] {
  --chap-accent: var(--nx-accent, #1c2430);
  --chap-accent-2: var(--campus-impulse, #d4c4a8);
}
.chapter[data-accent="1"] {
  --chap-accent: var(--nx-accent, #1c2430);
  --chap-accent-2: var(--campus-impulse, #d4c4a8);
}
.chapter[data-accent="2"] {
  --chap-accent: var(--nx-accent, #1c2430);
  --chap-accent-2: var(--campus-impulse, #d4c4a8);
}
.chapter[data-accent="3"] {
  --chap-accent: var(--nx-accent, #1c2430);
  --chap-accent-2: var(--campus-impulse, #d4c4a8);
}
.chapter[data-accent="4"] {
  --chap-accent: var(--nx-accent, #1c2430);
  --chap-accent-2: var(--campus-impulse, #d4c4a8);
}

/* ---------- Articles page — общий контейнер ---------- */
.articles-page {
  position: relative;
  /* scroll-snap убран: создавал фантомную область скролла после футера */
}
/* Безопасные хвосты: убрать любой возможный gap после <main>.
   clip вместо hidden — иначе body становится скролл-контейнером и ломает
   position:sticky на странице (подробнее в style.css). */
html, body { overflow-x: clip; }
body { min-height: 0; }

/* ---------- Page intro ---------- */
.ap-intro {
  position: relative;
  min-height: 80vh;
  display: flex;
  align-items: center;
  padding: var(--space-12) 0 var(--space-10);
  overflow: hidden;
  isolation: isolate;
}
.ap-intro::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 60% 50% at 50% 30%, rgba(230,57,70,0.18), transparent 60%),
    radial-gradient(ellipse 40% 40% at 80% 70%, rgba(120,80,255,0.12), transparent 60%);
  filter: blur(20px);
  z-index: -2;
  animation: ap-intro-glow 16s ease-in-out infinite alternate;
}
.ap-intro::after {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, var(--grid-line) 1px, transparent 1px),
    linear-gradient(to bottom, var(--grid-line) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(ellipse 70% 60% at 50% 40%, #000 0%, transparent 75%);
  -webkit-mask-image: radial-gradient(ellipse 70% 60% at 50% 40%, #000 0%, transparent 75%);
  opacity: 0.45;
  z-index: -1;
  pointer-events: none;
}
@keyframes ap-intro-glow {
  0%   { opacity: 0.7; transform: translate3d(0, 0, 0); }
  100% { opacity: 1; transform: translate3d(-2%, 1%, 0); }
}
.ap-intro__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 8px 14px;
  background: rgba(230,57,70,0.06);
  border: 1px solid rgba(230,57,70,0.32);
  border-radius: var(--radius-pill);
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: var(--space-3);
}
.ap-intro__eyebrow::before {
  content: '';
  width: 7px; height: 7px; border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 10px var(--accent);
  animation: ap-pulse 2s ease-out infinite;
}
@keyframes ap-pulse {
  0%   { box-shadow: 0 0 0 0 rgba(230,57,70,0.6); }
  70%  { box-shadow: 0 0 0 10px rgba(230,57,70,0); }
  100% { box-shadow: 0 0 0 0 rgba(230,57,70,0); }
}
.ap-intro__title {
  font-size: clamp(40px, 5.4vw, 76px);
  font-weight: 800;
  line-height: 1.05;
  letter-spacing: -0.035em;
  margin: 0 0 var(--space-3);
  max-width: 980px;
}
.ap-intro__title .accent {
  background: linear-gradient(120deg, #ff4d5a 0%, #ffa1ab 50%, #ff4d5a 100%);
  background-size: 200% 100%;
  background-clip: text;
  -webkit-background-clip: text;
  color: transparent;
  -webkit-text-fill-color: transparent;
  animation: ap-grad-pan 8s linear infinite;
}
@keyframes ap-grad-pan { to { background-position: -200% 0; } }
.ap-intro__sub {
  max-width: 620px;
  font-size: clamp(15px, 1.4vw, 18px);
  color: var(--text-secondary);
  line-height: 1.6;
  margin: 0 0 var(--space-6);
}
.ap-intro__hint {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  padding: 10px 16px;
  border: 1px solid var(--border);
  border-radius: var(--radius-pill);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--text-muted);
  text-transform: uppercase;
}
.ap-intro__hint .hint-line {
  width: 18px; height: 1px;
  background: var(--accent);
  position: relative; overflow: hidden;
}
.ap-intro__hint .hint-line::after {
  content: '';
  position: absolute; inset: 0;
  background: linear-gradient(90deg, transparent, #fff, transparent);
  animation: ap-hint-sweep 1.8s ease-in-out infinite;
}
@keyframes ap-hint-sweep {
  0% { transform: translateX(-100%); }
  100% { transform: translateX(100%); }
}

/* ---------- Sticky chapter navigator ----------
   Legacy styles kept for non-campus pages. Campus overrides live in campus-pages.css.
   БЕЗ leftover transform на предках — иначе fixed «залипает» внутри main. */
.chapter-nav {
  position: fixed;
  top: 50%;
  right: 24px;
  transform: translateY(-50%);
  z-index: 90;
  display: flex;
  flex-direction: column;
  gap: 14px;
  padding: 14px 15px;
  background: var(--bg-elevated);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-pill);
  box-shadow: 0 14px 40px -16px rgba(0,0,0,0.6);
}
body > aside.chapter-nav { position: fixed; z-index: 90; }
[data-theme="light"] .chapter-nav {
  background: rgba(255,255,255,0.7);
  border-color: rgba(15,23,42,0.08);
  box-shadow: 0 14px 40px -16px rgba(15,23,42,0.18);
}
.chapter-nav__dot {
  --size: 10px;
  position: relative;
  display: flex; align-items: center;
  width: var(--size); height: var(--size);
  border-radius: 50%;
  background: rgba(255,255,255,0.32);
  transition: background 250ms var(--ease-out-expo), width 280ms var(--ease-out-expo);
  text-decoration: none;
  color: var(--text-secondary);
}
[data-theme="light"] .chapter-nav__dot { background: rgba(15,23,42,0.18); }
.chapter-nav__dot .dot-num,
.chapter-nav__dot .dot-text {
  position: absolute;
  right: calc(100% + 14px);
  white-space: nowrap;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  background: rgba(21, 21, 31, 0.85);
  color: var(--text-primary);
  padding: 6px 10px;
  border-radius: var(--radius-md);
  border: 1px solid rgba(255,255,255,0.06);
  opacity: 0;
  transform: translateX(8px);
  transition: opacity 200ms ease, transform 200ms var(--ease-out-expo);
  pointer-events: none;
  top: 50%;
  margin-top: -14px;
}
.chapter-nav__dot .dot-num { display: none; }
[data-theme="light"] .chapter-nav__dot .dot-text {
  background: rgba(255,255,255,0.96);
  color: var(--text-primary);
  border-color: rgba(15,23,42,0.08);
  box-shadow: 0 6px 18px -8px rgba(15,23,42,0.18);
}
.chapter-nav__dot:hover .dot-text,
.chapter-nav__dot.is-active .dot-text {
  opacity: 1;
  transform: translateX(0);
}
.chapter-nav__dot:hover { background: rgba(230,57,70,0.7); }
.chapter-nav__dot.is-active {
  background: var(--accent);
  width: 26px;
  border-radius: 6px;
  box-shadow: 0 0 14px rgba(230,57,70,0.55);
}
@media (max-width: 900px) {
  .chapter-nav { right: 12px; }
}
@media (max-width: 600px) {
  .chapter-nav { display: none; }
}

/* ---------- Chapter container ----------
   content-visibility: auto — браузер пропускает рендер невидимых глав,
   огромный выигрыш по перфу при скролле длинной страницы. */
.chapter {
  position: relative;
  isolation: isolate;
  padding: var(--space-12) 0 var(--space-12);
  content-visibility: auto;
  contain-intrinsic-size: 1px 1400px; /* hint для скроллбара */
}
.chapter::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse 50% 35% at 50% 0%, var(--chap-accent, var(--accent)), transparent 70%);
  opacity: 0.10;
  z-index: -1;
  pointer-events: none;
  filter: blur(40px);
}

/* ---------- Живой фон ----------
   Неоновые ленты и кибер-сетка заменены единым фоном .ambient-bg
   (пятна света + canvas-сеть узлов с параллаксом) — см. modern.css
   и initAmbientBackground() в main.js.
   Контент страницы держим выше fixed-фона: */
.articles-page > section { position: relative; z-index: 1; }

/* Анимация большого номера главы — CSS-only через `is-in` (добавляется JS-ом по IO) */
.cd-num span {
  transform: perspective(1000px) rotateX(35deg) translateY(40px) scale(0.85);
  opacity: 0;
  transition: transform 900ms cubic-bezier(0.16, 1, 0.3, 1), opacity 900ms ease;
}
.cd-num.is-in span {
  transform: perspective(1000px) rotateX(0) translateY(0) scale(1);
  opacity: 1;
}
@media (prefers-reduced-motion: reduce) {
  .cd-num span { transform: none; opacity: 1; transition: none; }
}

/* ---------- Chapter divider — большой номер + sweep ---------- */
.chapter-divider {
  position: relative;
  margin: 0 auto var(--space-8);
  max-width: 1200px;
  padding: var(--space-10) var(--space-4);
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: var(--space-4);
  align-items: center;
}
.cd-num {
  position: relative;
  display: inline-block;
  perspective: 1000px;
  transform-style: preserve-3d;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(96px, 16vw, 220px);
  line-height: 0.85;
  letter-spacing: -0.06em;
  filter: drop-shadow(0 18px 30px rgba(0,0,0,0.45));
}
.cd-num span {
  display: inline-block;
  background: linear-gradient(135deg, var(--chap-accent, var(--accent)) 0%, var(--chap-accent-2, #ff8b95) 55%, rgba(230,57,70,0.10) 100%);
  background-clip: text;
  -webkit-background-clip: text;
  color: transparent;
  -webkit-text-fill-color: transparent;
  -webkit-text-stroke: 1px color-mix(in srgb, var(--chap-accent, var(--accent)) 70%, transparent);
  transform-origin: center;
  will-change: transform, opacity;
}
[data-theme="light"] .cd-num { filter: drop-shadow(0 14px 24px rgba(15,23,42,0.18)); }
.cd-line {
  height: 1px;
  background: linear-gradient(90deg, var(--chap-accent, var(--accent)), transparent);
  position: relative;
  overflow: hidden;
}
.cd-line::after {
  content: '';
  position: absolute;
  top: 0; left: -50%;
  width: 50%; height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.7), transparent);
  animation: cd-line-sweep 4s ease-in-out infinite;
}
@keyframes cd-line-sweep {
  0%   { transform: translateX(0%); }
  100% { transform: translateX(400%); }
}
.cd-meta {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--text-muted);
  text-align: right;
  display: flex; flex-direction: column; gap: 4px;
}
.cd-meta span:first-child {
  color: var(--chap-accent, var(--accent));
  font-weight: 600;
}

/* ---------- Article wrap внутри главы ---------- */
.chapter .art-wrap {
  max-width: 920px;
  margin: 0 auto;
  padding: 0 var(--space-4);
}

/* Per-chapter accent overrides (вместо --accent в дочерних элементах) */
.chapter .art-eyebrow::before,
.chapter .art-eyebrow span,
.chapter .read-time,
.chapter .tldr-label,
.chapter .stage-num,
.chapter .stage-icon,
.chapter .stage-arrow,
.chapter .q-head .num,
.chapter .ic-metric {
  color: var(--chap-accent, var(--accent));
}
.chapter .art-eyebrow::before { background: var(--chap-accent, var(--accent)); }
.chapter .tldr li::before { color: var(--chap-accent, var(--accent)); }
.chapter .tldr {
  border-left-color: var(--chap-accent, var(--accent));
  border-color: color-mix(in srgb, var(--chap-accent, var(--accent)) 25%, transparent);
}
.chapter .inline-case { border-left-color: var(--chap-accent, var(--accent)); }

/* ---------- 3D tilt cards ---------- */
.tilt-card {
  perspective: 800px;
  transform-style: preserve-3d;
  transition: transform 400ms var(--ease-out-expo), box-shadow 400ms var(--ease-out-expo);
  will-change: transform;
}
.tilt-card::after {
  /* Glow overlay (показывается на hover, следует за курсором) */
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: radial-gradient(circle 200px at var(--tilt-mx, 50%) var(--tilt-my, 50%),
    rgba(255,255,255,0.10), transparent 60%);
  opacity: 0;
  transition: opacity 350ms ease;
  pointer-events: none;
  z-index: 1;
}
.tilt-card:hover::after { opacity: 1; }
.tilt-card > * { position: relative; z-index: 0; }

/* Tilt-card stage-box: добавим вспомогательный hover-lift */
.stage-box.tilt-card {
  position: relative;
  transition: transform 400ms var(--ease-out-expo), border-color 250ms ease, box-shadow 400ms var(--ease-out-expo);
  cursor: default;
}
.stage-box.tilt-card:hover {
  border-color: var(--chap-accent, var(--accent));
  box-shadow: 0 18px 40px -20px rgba(0,0,0,0.55);
}
.tldr.tilt-card { position: relative; cursor: default; }
.tldr.tilt-card:hover { box-shadow: 0 24px 56px -22px rgba(0,0,0,0.6); }
.inline-case.tilt-card { position: relative; cursor: default; }
.inline-case.tilt-card:hover { box-shadow: 0 18px 40px -20px rgba(0,0,0,0.55); }

[data-theme="light"] .tldr.tilt-card:hover,
[data-theme="light"] .inline-case.tilt-card:hover,
[data-theme="light"] .stage-box.tilt-card:hover { box-shadow: 0 18px 40px -22px rgba(15,23,42,0.18); }

/* ---------- Per-section anim (safe-by-default: видно если JS не загрузился) ---------- */
[data-anim-fade] {
  transition: opacity 700ms var(--ease-out-expo), transform 700ms var(--ease-out-expo);
}
/* Скрываем ТОЛЬКО когда JS явно поставил pending (без !important — если JS-ошибка, контент не пропадёт) */
[data-anim-fade][data-anim-fade-pending] {
  opacity: 0;
  transform: translate3d(0, 24px, 0);
}
[data-anim-fade][data-anim-fade-in] {
  opacity: 1;
  transform: translate3d(0, 0, 0);
}

/* ---------- Outro CTA ---------- */
.ap-outro {
  padding: var(--space-8) 0 var(--space-6);
  position: relative;
}
/* Убираем margin-top футера + пустоту между outro и футером.
   articles.css подключается только в articles.html, так что не повлияет на index. */
.articles-page + .footer,
.footer {
  margin-top: 0;
}
/* Футер полупрозрачным фоном — живой фон (.ambient-bg) слегка просвечивает */
.articles-page ~ .footer,
.footer {
  background: var(--bg-card-2) !important;
  background: color-mix(in srgb, var(--bg-card-2) 82%, transparent) !important;
  position: relative;
  z-index: 2;
}
/* Последняя глава — меньше нижнего padding (есть ap-outro ниже) */
.chapter:last-of-type { padding-bottom: var(--space-4); }
.ap-outro__inner {
  max-width: 1100px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr auto;
  gap: var(--space-6);
  align-items: center;
  padding: var(--space-6) var(--space-8);
  background: linear-gradient(135deg, rgba(230,57,70,0.10) 0%, rgba(255,255,255,0.02) 60%);
  border: 1px solid rgba(230,57,70,0.25);
  border-radius: var(--radius-xl);
  position: relative;
  overflow: hidden;
}
.ap-outro__inner::before {
  content: '';
  position: absolute;
  inset: -1px;
  border-radius: inherit;
  background: linear-gradient(135deg, rgba(230,57,70,0.4), transparent 50%, rgba(120,80,255,0.3));
  -webkit-mask: linear-gradient(#000, #000) content-box, linear-gradient(#000, #000);
          mask: linear-gradient(#000, #000) content-box, linear-gradient(#000, #000);
  -webkit-mask-composite: xor;
          mask-composite: exclude;
  padding: 1px;
  opacity: 0.6;
  pointer-events: none;
}
.ap-outro__eyebrow {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 10px;
}
.ap-outro__title {
  font-size: clamp(22px, 2.4vw, 32px);
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: -0.02em;
  margin: 0;
}
.ap-outro__btns { display: flex; gap: 14px; flex-wrap: wrap; }

@media (max-width: 768px) {
  .ap-outro__inner { grid-template-columns: 1fr; padding: var(--space-5); text-align: left; }
  .ap-outro__btns { width: 100%; }
}

/* ---------- Mobile chapter divider ---------- */
@media (max-width: 768px) {
  .chapter-divider {
    grid-template-columns: 1fr;
    text-align: center;
    padding: var(--space-6) var(--space-3);
  }
  .cd-meta { text-align: center; }
}

/* ---------- Reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  .ap-intro::before, .ap-intro__title .accent, .cd-line::after, .ap-intro__eyebrow::before, .ap-intro__hint .hint-line::after {
    animation: none !important;
  }
  .tilt-card { transform: none !important; }
}