/* ============================================================
   Каркас единой шапки для разделов со своим оформлением
   (learn/, academy/): полоса шапки, логотип, бургер и выдвижная
   панель. Значения повторяют blog.css, токены - с запасными
   значениями. Подключается ПОСЛЕ стилей страницы и ПЕРЕД
   site-nav.css (тот добавляет выпадающие меню и правый блок).
   ============================================================ */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: transparent;
  border-bottom: 1px solid transparent;
  transition:
    transform 300ms cubic-bezier(0.2, 0, 0, 1),
    background-color 220ms cubic-bezier(0.2, 0, 0, 1),
    backdrop-filter 220ms cubic-bezier(0.2, 0, 0, 1),
    -webkit-backdrop-filter 220ms cubic-bezier(0.2, 0, 0, 1),
    border-color 220ms cubic-bezier(0.2, 0, 0, 1);
}
/* Скрыта при прокрутке вниз, возвращается при движении вверх */
.site-header.hide { transform: translateY(-100%); }
@media (prefers-reduced-motion: reduce) {
  .site-header.hide { transform: none; }
}
.site-header.scrolled {
  background: rgba(250, 248, 244, 0.92);
  -webkit-backdrop-filter: saturate(140%) blur(12px);
  backdrop-filter: saturate(140%) blur(12px);
  border-bottom-color: rgba(10, 10, 10, 0.06);
}

.site-header__inner {
  max-width: var(--container, 1280px);
  margin: 0 auto;
  padding: 0 var(--pad-x, 32px);
  display: flex;
  align-items: center;
  gap: 32px;
  height: 72px;
}

.brand {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  line-height: 1;
  border: none;
  text-decoration: none;
}
.brand img { display: block; height: 31px; width: auto; }
@media (max-width: 768px) {
  .brand img { height: 26px; }
}

/* ---------- Бургер ---------- */
.burger {
  display: none;
  background: none;
  border: none;
  padding: 8px;
  margin: -8px -8px -8px 0;
  cursor: pointer;
  width: 40px;
  height: 40px;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  align-items: flex-end;
}
.burger span {
  display: block;
  width: 22px;
  height: 1.5px;
  background: var(--ink, #0a0a0a);
  border-radius: 2px;
  transition: transform 280ms cubic-bezier(.22,1,.36,1), opacity 200ms ease, width 200ms ease;
  transform-origin: center;
}
.burger span:nth-child(2) { width: 16px; background: var(--accent, #7A1F2B); }
.burger.is-open span:nth-child(1) { transform: translateY(6.5px) rotate(45deg); width: 22px; }
.burger.is-open span:nth-child(2) { opacity: 0; width: 22px; }
.burger.is-open span:nth-child(3) { transform: translateY(-6.5px) rotate(-45deg); width: 22px; }

/* ---------- Выдвижная панель ---------- */
.mobile-drawer {
  position: fixed;
  inset: 0;
  z-index: 1000;
  pointer-events: none;
  visibility: hidden;
  opacity: 0;
  transition: visibility 0s linear 320ms, opacity 250ms ease;
}
.mobile-drawer.is-open {
  pointer-events: auto;
  visibility: visible;
  opacity: 1;
  transition: visibility 0s linear 0s, opacity 250ms ease;
}
.mobile-drawer__backdrop {
  position: absolute;
  inset: 0;
  background: rgba(10, 10, 10, 0.36);
  opacity: 0;
  z-index: 1;
  transition: opacity 300ms ease;
}
.mobile-drawer.is-open .mobile-drawer__backdrop { opacity: 1; }
.mobile-drawer__inner {
  position: absolute;
  top: 0; right: 0; bottom: 0;
  width: min(86%, 360px);
  background: var(--bg, #FAF8F4);
  border-left: 1px solid var(--line, rgba(26, 22, 20, 0.08));
  padding: 84px 36px 36px;
  transform: translateX(100%);
  transition: transform 360ms cubic-bezier(.22,1,.36,1);
  display: flex;
  flex-direction: column;
  overflow-y: auto;
  z-index: 2;
}
.mobile-drawer.is-open .mobile-drawer__inner { transform: translateX(0); }
.mobile-drawer__close {
  position: absolute;
  top: 18px;
  right: 24px;
  background: none;
  border: none;
  font: inherit;
  font-size: 32px;
  line-height: 1;
  color: var(--ink-2, #555);
  cursor: pointer;
  padding: 6px;
}
.mobile-drawer__close:hover { color: var(--ink, #0a0a0a); }
.mobile-drawer__nav { display: flex; flex-direction: column; }
.mobile-drawer__nav a {
  font-family: var(--serif, "Fraunces", Georgia, serif);
  font-weight: 400;
  font-size: 22px;
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--ink, #0a0a0a);
  padding: 14px 0;
  border: none;
  border-bottom: 1px solid var(--line-2, #E8E5DF);
  text-decoration: none;
}
.mobile-drawer__nav a:last-child { border-bottom: none; }
.mobile-drawer__nav a:hover { color: var(--accent, #7A1F2B); }
.mobile-drawer__cta {
  margin-top: 28px;
  align-self: flex-start;
  padding: 14px 24px;
  font-size: 15px;
}
body.no-scroll { overflow: hidden; }

/* ---------- Мобильная раскладка ---------- */
@media (min-width: 901px) {
  .mobile-drawer { display: none; }
}
@media (max-width: 900px) {
  .burger { display: inline-flex; margin-left: auto; }
  .site-header__inner { height: 64px; gap: 16px; padding: 0 24px; }
  .site-header__nav, .site-header__right { display: none; }
}