/* Шапка: стекло у верхнего края, после скролла - остров. Методичка полупрозрачной шапки. */
:root {
  --hdr-glass: rgba(var(--bg-rgb), .62);
  --hdr-glass-float: rgba(var(--surface-rgb), .5);
  --hdr-glass-home: rgba(var(--bg-rgb), .28);
  --hdr-shadow: rgba(0, 0, 0, .55);
  --hdr-scrim: rgba(var(--bg-rgb), .7);
  --hdr-z: 60;
}

.site-header {
  position: fixed; inset-inline: 0; top: 0; z-index: var(--hdr-z);
  padding-top: max(10px, env(safe-area-inset-top)); padding-bottom: 10px;
  background: transparent;
  transition: top .5s var(--ease), left .5s var(--ease), right .5s var(--ease), padding .5s var(--ease), border-radius .5s var(--ease), box-shadow .5s var(--ease);
}
.site-header::before {
  content: ""; position: absolute; inset: 0; z-index: -1; border-radius: inherit;
  background: var(--hdr-glass); border-bottom: 1px solid var(--glass-line);
  -webkit-backdrop-filter: blur(18px) saturate(130%); backdrop-filter: blur(18px) saturate(130%);
  transition: background .5s var(--ease);
}
body[data-page="home"] .site-header:not(.is-float)::before { background: var(--hdr-glass-home); border-bottom-color: transparent; }
body[data-page="home"] .site-header-slot { display: none; }

.site-header.is-float {
  top: max(12px, env(safe-area-inset-top)); left: 12px; right: 12px;
  padding-top: 6px; padding-bottom: 6px; border-radius: var(--r-island);
  box-shadow: 0 18px 48px var(--hdr-shadow), inset 0 1px 0 rgba(var(--text-rgb), .08);
}
.site-header.is-float::before { background: var(--hdr-glass-float); border: 1px solid var(--glass-line); }

.site-wrap { max-width: 1440px; margin: 0 auto; padding-inline: var(--gutter); display: flex; align-items: center; gap: clamp(16px, 2.4vw, 40px); min-height: 52px; }
.site-header.is-float .site-wrap { padding-inline: clamp(14px, 2vw, 28px); }

.site-logo-link { flex: 0 0 auto; display: inline-flex; align-items: center; gap: 12px; color: var(--color-text); text-decoration: none; }
.site-logo-mark { width: 34px; height: 34px; transition: width .4s var(--ease), height .4s var(--ease); }
.site-header.is-float .site-logo-mark { width: 28px; height: 28px; }
.site-logo-word { font-size: 24px; font-weight: 600; letter-spacing: .08em; line-height: 1; }

.site-nav { flex: 1 1 auto; display: flex; align-items: center; justify-content: center; gap: clamp(14px, 1.8vw, 30px); }
.site-nav a {
  position: relative; font-size: 13px; font-weight: 700; letter-spacing: .07em; text-transform: uppercase;
  color: var(--color-text); text-decoration: none; padding: 8px 0; white-space: nowrap;
}
/* строп: линия растёт из центра */
.site-nav > a::after {
  content: ""; position: absolute; left: 50%; right: 50%; bottom: 2px; height: 1px; background: var(--color-text);
  transition: left .35s var(--ease), right .35s var(--ease), background-color .2s;
}
@media (hover: hover) and (pointer: fine) {
  .site-nav > a:hover::after { left: 0; right: 0; }
}
.site-nav > a[aria-current="page"]::after { left: 0; right: 0; height: 2px; background: var(--color-primary); }
.site-nav-extra { display: none; }

.site-tools { flex: 0 0 auto; display: flex; align-items: center; gap: 18px; }
.lang { display: inline-flex; border: 1px solid var(--color-border-strong); border-radius: var(--r); }
.lang { overflow: hidden; }
.lang button { appearance: none; border: 0; background: transparent; color: var(--color-text-muted); font-size: 12px; letter-spacing: .08em; padding: 6px 9px; cursor: pointer; min-width: 36px; min-height: 32px; }
.lang button[aria-pressed="true"] { background: var(--color-text); color: var(--color-text-inverse); }
@media (hover: hover) { .lang button[aria-pressed="false"]:hover { color: var(--color-text); } }
.site-phone { font-size: 14px; color: var(--color-text); text-decoration: none; white-space: nowrap; }
@media (hover: hover) { .site-phone:hover { color: var(--color-focus-ring); } }

.site-burger { display: none; }

@media (max-width: 1320px) { .site-phone--top { display: none; } }

/* мобила: панель опускается сверху, как груз на стропах */
@media (max-width: 1080px) {
  .site-header { padding-bottom: 8px; }
  .site-wrap { min-height: 48px; }
  .site-nav {
    position: fixed; inset: 0; z-index: 70; flex-direction: column; align-items: stretch; justify-content: flex-start; gap: 0;
    padding: max(88px, calc(env(safe-area-inset-top) + 76px)) var(--gutter) max(28px, env(safe-area-inset-bottom));
    background: linear-gradient(180deg, var(--color-surface) 0%, var(--color-background) 100%);
    clip-path: inset(0 0 100% 0); visibility: hidden;
    transition: clip-path .55s var(--ease), visibility 0s .55s;
    overflow-y: auto;
  }
  .site-nav::before { /* трос, на котором «висит» меню */
    content: ""; position: absolute; left: calc(var(--gutter) + 6px); top: 0; width: 1px; height: 0; background: var(--color-border-strong);
    transition: height .6s var(--ease) .1s;
  }
  .site-header.is-open .site-nav { clip-path: inset(0 0 0 0); visibility: visible; transition: clip-path .55s var(--ease); }
  .site-header.is-open .site-nav::before { height: 100%; }
  .site-nav > a {
    font-size: clamp(26px, 7vw, 40px); font-weight: 700; letter-spacing: 0; text-transform: none;
    padding: 12px 0 12px 28px; border-bottom: 1px solid var(--color-border);
    opacity: 0; transform: translateY(-14px); transition: opacity .35s, transform .45s var(--ease);
  }
  .site-nav > a::after { display: none; }
  .site-nav > a[aria-current="page"] { color: var(--color-focus-ring); }
  .site-header.is-open .site-nav > a { opacity: 1; transform: none; }
  .site-header.is-open .site-nav > a:nth-child(1) { transition-delay: .12s; }
  .site-header.is-open .site-nav > a:nth-child(2) { transition-delay: .16s; }
  .site-header.is-open .site-nav > a:nth-child(3) { transition-delay: .2s; }
  .site-header.is-open .site-nav > a:nth-child(4) { transition-delay: .24s; }
  .site-header.is-open .site-nav > a:nth-child(5) { transition-delay: .28s; }
  .site-header.is-open .site-nav > a:nth-child(6) { transition-delay: .32s; }
  .site-header.is-open .site-nav > a:nth-child(7) { transition-delay: .36s; }
  .site-nav-extra { display: block; padding: 28px 0 0 28px; }
  .site-nav-extra .site-phone { font-size: 20px; }

  .site-tools { margin-left: auto; position: relative; z-index: 80; }
  .site-burger {
    display: block; position: relative; z-index: 80; width: 44px; height: 44px; padding: 0; border: 1px solid var(--color-border-strong);
    border-radius: var(--r); background: transparent; cursor: pointer;
  }
  .site-burger span { position: absolute; left: 11px; width: 20px; height: 2px; background: var(--color-text); transition: transform .35s var(--ease), opacity .2s; }
  .site-burger span:nth-child(1) { top: 14px; }
  .site-burger span:nth-child(2) { top: 20px; }
  .site-burger span:nth-child(3) { top: 26px; }
  .site-header.is-open .site-burger span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
  .site-header.is-open .site-burger span:nth-child(2) { opacity: 0; }
  .site-header.is-open .site-burger span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }
  .site-logo-link { position: relative; z-index: 80; }
  .site-header.is-float { left: 8px; right: 8px; top: max(8px, env(safe-area-inset-top)); }
  html { scroll-padding-top: calc(80px + env(safe-area-inset-top)); }
}
@media (max-width: 420px) {
  .site-logo-word { font-size: 20px; }
  .site-logo-mark { width: 28px; height: 28px; }
  .site-tools { gap: 10px; }
}
.site-nav-scrim { position: fixed; inset: 0; z-index: 65; background: var(--hdr-scrim); }
.site-nav-scrim[hidden] { display: none; }

.site-header-slot { height: 72px; }

@media (prefers-reduced-motion: reduce) {
  .site-header, .site-header::before, .site-nav, .site-nav > a, .site-nav::before, .site-burger span { transition: none !important; }
}