/* =============================================================
   layout.css — сцена, слайды, навигация, прогресс
   ============================================================= */

/* --- Глобальный фон со свечением и зерном ----------------- */
.stage {
  position: fixed;
  inset: 0;
  background:
    radial-gradient(110% 80% at 50% -10%, rgba(255,255,255,0.035), rgba(255,255,255,0) 50%),
    radial-gradient(70% 55% at 100% 110%, rgba(70,80,110,0.06), rgba(0,0,0,0) 55%),
    var(--bg-1);
  overflow: hidden;
}

/* Тонкое анимированное «дыхание» свечения за сценой */
.stage::before {
  content: "";
  position: absolute;
  inset: -20% -10%;
  background: var(--grad-glow);
  filter: blur(40px);
  opacity: 0.7;
  pointer-events: none;
  animation: breathe 14s var(--ease-in-out) infinite;
}

/* Лёгкое зерно поверх — добавляет «дорогую» текстуру */
.stage::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: 0.035;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='2'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  mix-blend-mode: overlay;
}

/* Виньетка — едва заметное затемнение углов, фокусирует взгляд */
.vignette {
  position: fixed;
  inset: 0;
  z-index: 20;
  pointer-events: none;
  background:
    radial-gradient(130% 110% at 50% 50%,
      rgba(0,0,0,0) 55%,
      rgba(0,0,0,0.22) 88%,
      rgba(0,0,0,0.42) 100%);
}

/* --- Фон-носитель анимированной сетки точек --------------- */
.surface-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  opacity: 0;
  pointer-events: none;
  transition: opacity 900ms var(--ease-out);
}
/* Виден только когда дека на титульном слайде (data-active="0") */
.stage[data-active="0"] .surface-bg { opacity: 1; }
/* Лёгкая виньетка снизу, чтобы текст титула не спорил с точками */
.surface-bg::after {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(
      120% 100% at 50% 120%,
      rgba(4, 4, 6, 0.85) 0%,
      rgba(4, 4, 6, 0.25) 45%,
      rgba(4, 4, 6, 0) 70%);
  pointer-events: none;
}

/* --- Дека слайдов ----------------------------------------- */
.deck {
  position: relative;
  width: 100%;
  height: 100%;
  z-index: 1;
}

.slide {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  padding: clamp(2rem, 2vw + 1.5rem, 5rem) clamp(1.5rem, 4vw, 7rem);
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.slide__inner {
  width: min(1180px, 100%);
  max-height: 100%;
}

/* --- Хедер слайда: метка / надзаголовок ------------------- */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.6em;
  font-size: var(--fs-eyebrow);
  font-weight: 500;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--text-2);
  margin-bottom: 1.4rem;
}
.eyebrow::before {
  content: "";
  width: 28px;
  height: 1px;
  background: var(--grad-line);
}

.chapter-tag {
  display: inline-block;
  font-size: var(--fs-eyebrow);
  font-weight: 500;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--text-1);
  padding: 0.4em 0.9em;
  border: 1px solid var(--glass-border);
  border-radius: 999px;
  background: var(--glass-bg);
  -webkit-backdrop-filter: blur(var(--glass-blur));
  backdrop-filter: blur(var(--glass-blur));
  margin-bottom: 1.4rem;
}

.slide h2 {
  font-size: var(--fs-h2);
  max-width: 22ch;
}
.slide__lead {
  font-size: var(--fs-lead);
  color: var(--text-1);
  max-width: 62ch;
  margin-top: 1.4rem;
}

/* =============================================================
   Навигация
   ============================================================= */

/* --- Прогресс-бар сверху ---------------------------------- */
.progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 2px;
  width: 100%;
  background: rgba(255, 255, 255, 0.06);
  z-index: 40;
}
.progress__fill {
  position: relative;
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, #6b7280, #ffffff);
  box-shadow: 0 0 8px rgba(255, 255, 255, 0.35);
  transition: width var(--t-slide) var(--ease-out);
}

/* --- Счётчик слайдов (угол) ------------------------------- */
.counter {
  position: fixed;
  top: clamp(1rem, 2.5vh, 1.8rem);
  right: clamp(1.2rem, 3vw, 2.4rem);
  z-index: 30;
  font-size: 0.82rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--text-2);
  -webkit-font-feature-settings: "tnum";
  font-feature-settings: "tnum";
}
.counter b {
  color: var(--text-0);
  font-weight: 700;
}

/* --- Подсказка по клавишам (исчезает) --------------------- */
.hint {
  position: fixed;
  bottom: clamp(1.2rem, 3vh, 2.2rem);
  right: clamp(1.2rem, 3vw, 2.4rem);
  z-index: 30;
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.78rem;
  color: var(--text-2);
  transition: opacity 600ms var(--ease-out);
}
.hint.is-hidden { opacity: 0; pointer-events: none; }
.hint__sep {
  width: 1px;
  height: 16px;
  background: var(--line-strong);
  margin: 0 4px;
}
.kbd {
  display: inline-grid;
  place-items: center;
  min-width: 26px;
  height: 26px;
  padding: 0 6px;
  border-radius: 7px;
  border: 1px solid var(--glass-border);
  background: var(--glass-bg);
  color: var(--text-1);
  font-size: 0.8rem;
}

/* --- Адаптив: на узких экранах прячем подсказку ----------- */
@media (max-width: 720px) {
  .hint { display: none; }
}