/* ============================================================
   Дизайн-система «PROBeton»
   Шрифт: Manrope (400/500/800). Палитра: графит + фирменный красный
   (из логотипа PROBeton: красный/чёрный/белый).
   Шкала отступов: 4/8/12/16/24/32/48/64/96. Mobile-first.
   ============================================================ */

:root {
  --c-bg: #ffffff;
  --c-soft: #f4f5f7;
  --c-dark: #15181e;
  --c-dark-2: #1c2027;
  --c-text: #23272f;
  --c-muted: #5b6470;
  --c-muted-dark: #9aa3b0;
  --c-accent: #d92323;
  --c-accent-hover: #b81b1b;
  --c-line: #e3e6ea;
  --c-line-dark: #2a2f38;

  --font: "Manrope", system-ui, -apple-system, "Segoe UI", sans-serif;
  --radius: 14px;
  --shadow: 0 8px 28px rgba(21, 24, 30, 0.10);
  --container: 1140px;
  --transition: 200ms ease;
}

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

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  font-size: 1rem;
  line-height: 1.65;
  color: var(--c-text);
  background: var(--c-bg);
  -webkit-font-smoothing: antialiased;
}

img, iframe { max-width: 100%; }

h1, h2, h3 {
  font-weight: 800;
  line-height: 1.15;
  margin: 0 0 16px;
  letter-spacing: -0.01em;
}

h1 { font-size: clamp(2rem, 6vw, 3.4rem); }
h2 { font-size: clamp(1.5rem, 4vw, 2.25rem); }
h3 { font-size: 1.125rem; margin-bottom: 8px; }

p { margin: 0 0 16px; }
p:last-child { margin-bottom: 0; }

a { color: var(--c-accent); }

:focus-visible {
  outline: 3px solid var(--c-accent);
  outline-offset: 2px;
  border-radius: 4px;
}

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 16px;
}

.container--narrow { max-width: 780px; }

/* ---------- Кнопки ---------- */
.btn {
  display: inline-block;
  padding: 14px 28px;
  border-radius: var(--radius);
  font-weight: 800;
  font-size: 1rem;
  text-decoration: none;
  text-align: center;
  transition: background var(--transition), color var(--transition), border-color var(--transition), transform var(--transition);
}

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

.btn--accent {
  background: var(--c-accent);
  color: #fff;
}
.btn--accent:hover { background: var(--c-accent-hover); }

.btn--ghost {
  border: 2px solid var(--c-line-dark);
  color: #fff;
}
.btn--ghost:hover { border-color: var(--c-accent); color: var(--c-accent); }

/* ---------- Шапка ---------- */
.header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(21, 24, 30, 0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--c-line-dark);
}

.header__in {
  display: flex;
  align-items: center;
  gap: 24px;
  min-height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 1.125rem;
  color: #fff;
  text-decoration: none;
  letter-spacing: -0.01em;
}

.logo__mark {
  width: 14px;
  height: 26px;
  border-radius: 4px;
  background: linear-gradient(180deg, var(--c-accent) 60%, #fff 60%);
}

.logo__accent { color: var(--c-accent); margin-left: 2px; }

.nav {
  display: none; /* мобильное меню по кнопке */
  gap: 24px;
}

.nav a {
  color: #d7dbe1;
  text-decoration: none;
  font-weight: 500;
  transition: color var(--transition);
}
.nav a:hover { color: var(--c-accent); }

.header__phone {
  display: none;
  margin-left: auto;
  color: #fff;
  font-weight: 800;
  text-decoration: none;
  white-space: nowrap;
}
.header__phone:hover { color: var(--c-accent); }

.burger {
  margin-left: auto;
  width: 44px;
  height: 44px;
  display: grid;
  place-content: center;
  gap: 5px;
  background: none;
  border: 0;
  cursor: pointer;
}
.burger span {
  display: block;
  width: 22px;
  height: 2px;
  background: #fff;
  transition: transform var(--transition), opacity var(--transition);
}
.burger[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.burger[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.burger[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* мобильная панель меню */
.nav.is-open {
  display: flex;
  position: absolute;
  top: 64px;
  left: 0;
  right: 0;
  flex-direction: column;
  gap: 0;
  background: var(--c-dark);
  border-bottom: 1px solid var(--c-line-dark);
  padding: 8px 0;
}
.nav.is-open a { padding: 14px 24px; }

/* ---------- Hero ---------- */
.hero {
  background:
    radial-gradient(1200px 500px at 80% -10%, rgba(217, 35, 35, 0.20), transparent 60%),
    linear-gradient(180deg, var(--c-dark) 0%, var(--c-dark-2) 100%);
  color: #fff;
  padding: 64px 0 48px;
}

.hero__tag {
  display: inline-block;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--c-muted-dark);
  border: 1px solid var(--c-line-dark);
  border-radius: 999px;
  padding: 6px 14px;
  margin-bottom: 24px;
}

.hero__sub {
  max-width: 620px;
  font-size: 1.125rem;
  color: #c9ced6;
  margin-bottom: 32px;
}

.hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 48px;
}

.hero__facts {
  list-style: none;
  margin: 0;
  padding: 24px 0 0;
  border-top: 1px solid var(--c-line-dark);
  display: grid;
  gap: 16px;
}

.hero__facts li { display: grid; gap: 2px; }
.hero__facts strong { font-size: 1.25rem; }
.hero__facts span { color: var(--c-muted-dark); font-size: 0.9375rem; }

/* ---------- Секции ---------- */
.section { padding: 64px 0; }

.section--soft { background: var(--c-soft); }

.section--dark {
  background: var(--c-dark);
  color: #fff;
}

.section__lead {
  max-width: 640px;
  color: var(--c-muted);
  margin-bottom: 32px;
}
.section__lead--dark { color: var(--c-muted-dark); }

.section__cta { margin-top: 32px; text-align: center; }

/* ---------- Карточки ---------- */
.cards {
  display: grid;
  gap: 16px;
}

.card {
  background: var(--c-bg);
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  padding: 24px;
  transition: box-shadow var(--transition), transform var(--transition);
}
.card:hover { box-shadow: var(--shadow); transform: translateY(-2px); }

.card p { color: var(--c-muted); font-size: 0.9375rem; }

.card__icon {
  font-size: 1.5rem;
  color: var(--c-accent);
  margin-bottom: 12px;
}

.card--dark {
  background: var(--c-dark-2);
  border-color: var(--c-line-dark);
}
.card--dark p { color: var(--c-muted-dark); }

/* ---------- Шаги ---------- */
.steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 16px;
  counter-reset: step;
}

.steps__item {
  position: relative;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  padding: 24px;
}

.steps__num {
  display: inline-grid;
  place-content: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--c-accent);
  color: #fff;
  font-weight: 800;
  margin-bottom: 12px;
}

.steps__item p { color: var(--c-muted); font-size: 0.9375rem; }

/* ---------- Видео ---------- */
.videos {
  display: grid;
  gap: 16px;
}

.video {
  position: relative;
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--c-dark-2);
  border: 1px solid var(--c-line-dark);
  aspect-ratio: 16 / 9;
}

.video iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

.video__btn {
  position: absolute;
  inset: 0;
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  background:
    radial-gradient(400px 200px at 50% 120%, rgba(217, 35, 35, 0.28), transparent),
    var(--c-dark-2);
  border: 0;
  cursor: pointer;
  color: #fff;
  font-family: var(--font);
  font-size: 0.9375rem;
  font-weight: 500;
  padding: 16px;
  text-align: center;
  transition: background var(--transition);
}
.video__btn:hover .video__play { background: var(--c-accent-hover); transform: scale(1.06); }

.video__play {
  display: grid;
  place-content: center;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: var(--c-accent);
  color: #fff;
  font-size: 1.25rem;
  transition: background var(--transition), transform var(--transition);
}

.videos__empty {
  grid-column: 1 / -1;
  border: 1px dashed var(--c-line-dark);
  border-radius: var(--radius);
  padding: 32px;
  text-align: center;
  color: var(--c-muted-dark);
}

/* ---------- О нас ---------- */
.about {
  display: grid;
  gap: 32px;
}

.about__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
  align-content: start;
}

.about__list li {
  padding: 14px 16px 14px 44px;
  background: var(--c-soft);
  border-radius: var(--radius);
  position: relative;
  font-weight: 500;
}

.about__list li::before {
  content: "✓";
  position: absolute;
  left: 16px;
  color: var(--c-accent);
  font-weight: 800;
}

/* ---------- FAQ ---------- */
.faq {
  background: var(--c-bg);
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  margin-bottom: 12px;
}

.faq summary {
  cursor: pointer;
  font-weight: 800;
  padding: 18px 48px 18px 20px;
  position: relative;
  list-style: none;
}
.faq summary::-webkit-details-marker { display: none; }

.faq summary::after {
  content: "+";
  position: absolute;
  right: 20px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--c-accent);
  font-size: 1.5rem;
  font-weight: 500;
  transition: transform var(--transition);
}
.faq[open] summary::after { transform: translateY(-50%) rotate(45deg); }

.faq p {
  padding: 0 20px 18px;
  color: var(--c-muted);
}

/* ---------- Контакты ---------- */
.contacts {
  display: grid;
  gap: 32px;
}

.contacts__phone {
  display: inline-block;
  font-size: clamp(1.5rem, 5vw, 2.25rem);
  font-weight: 800;
  color: #fff;
  text-decoration: none;
  margin: 8px 0 4px;
}
.contacts__phone:hover { color: var(--c-accent); }

.contacts__note { color: var(--c-muted-dark); }

.contacts__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-content: start;
}

/* ---------- Футер ---------- */
.footer {
  background: var(--c-dark-2);
  color: var(--c-muted-dark);
  border-top: 1px solid var(--c-line-dark);
  padding: 24px 0;
  font-size: 0.875rem;
}

.footer__in {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: space-between;
}

.footer a { color: var(--c-muted-dark); text-decoration: none; }
.footer a:hover { color: var(--c-accent); }

/* ============================================================
   Адаптивность: 768 и 1024
   ============================================================ */

@media (min-width: 768px) {
  .container { padding: 0 24px; }

  .section { padding: 96px 0; }

  .hero { padding: 96px 0 64px; }

  .hero__facts {
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
  }

  .cards { grid-template-columns: repeat(3, 1fr); }
  .cards--4 { grid-template-columns: repeat(2, 1fr); }

  .steps { grid-template-columns: repeat(2, 1fr); }

  .videos { grid-template-columns: repeat(2, 1fr); }

  .about { grid-template-columns: 1.2fr 1fr; gap: 48px; }

  .contacts { grid-template-columns: 1.2fr 1fr; align-items: center; }
  .contacts__links { justify-content: flex-end; }
}

@media (min-width: 1024px) {
  .nav { display: flex; }
  .header__phone { display: inline; }
  .burger { display: none; }

  .cards--4 { grid-template-columns: repeat(4, 1fr); }
  .steps { grid-template-columns: repeat(4, 1fr); }
  .videos { grid-template-columns: repeat(3, 1fr); }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; }
}