/* ============================================================
   Altus Conseil — design-system/header.css
   ------------------------------------------------------------
   Header "Architecture du calme" — fixe, translucide,
   rétrécit au scroll, adaptation auto claire/sombre.
   À charger après colors_and_type.css.
   ============================================================ */

.altus-header {
  position: fixed;
  top: 14px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 100;
  width: 100%;
  max-width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 48px;
  padding: 18px 40px;
  border-radius: 0;
  /* Repos : aucun fond, aucun blur — le header est totalement transparent
     et laisse passer le contenu de la première section. */
  background: none;
  -webkit-backdrop-filter: none;
          backdrop-filter: none;
  color: var(--altus-fg1);
  font-family: var(--altus-font);
  transition:
    max-width        220ms var(--altus-ease),
    padding          220ms var(--altus-ease),
    border-radius    220ms var(--altus-ease),
    background       220ms var(--altus-ease),
    backdrop-filter  220ms var(--altus-ease),
    color            220ms var(--altus-ease);
}

/* Schéma de couleurs au repos — uniquement la teinte du texte
   bascule entre clair (texte ivoire) et sombre (texte charbon). */
.altus-header[data-altus-theme-active="light"] { color: var(--altus-fg1); }
.altus-header[data-altus-theme-active="dark"]  { color: var(--altus-fg1-inverse); }

/* Scrolled — rétrécit en largeur, rayon doux, ET apparition du
   blur seul. Pas de fond opaque : le blur + saturate suffit à
   poser la barre sans interrompre le flux du contenu. */
.altus-header[data-scrolled="true"] {
  max-width: 95%;
  border-radius: 14px;
  -webkit-backdrop-filter: blur(20px) saturate(140%);
          backdrop-filter: blur(20px) saturate(140%);
}

/* Logo — deux assets superposés, bascule en opacité.
   Au repos : 120 px de large. Au scroll : 60 px. */
.altus-header-logo {
  display: inline-flex;
  align-items: center;
  text-decoration: none;
  outline: none;
  width: 120px;
  transition: width 220ms var(--altus-ease);
}
.altus-header[data-scrolled="true"] .altus-header-logo { width: 40px; }

.altus-header-logo .alt-logo-stack {
  position: relative;
  display: inline-block;
  width: 100%;
}
.altus-header-logo .alt-logo-stack img {
  width: 100%;
  height: auto;
  display: block;
}
.altus-header-logo .alt-logo-stack img + img {
  position: absolute;
  top: 0; left: 0;
}
.altus-header-logo .alt-logo-on-dark  { opacity: 1; transition: opacity 220ms var(--altus-ease); }
.altus-header-logo .alt-logo-on-light { opacity: 0; transition: opacity 220ms var(--altus-ease); }
.altus-header[data-altus-theme-active="dark"] .alt-logo-on-dark  { opacity: 0; }
.altus-header[data-altus-theme-active="dark"] .alt-logo-on-light { opacity: 1; }

/* Navigation principale */
.altus-header-nav {
  display: flex;
  align-items: center;
  gap: 32px;
}
.altus-header-nav a {
  font-family: var(--altus-font);
  font-weight: var(--altus-w-medium);
  font-size: 14px;
  letter-spacing: 0.04em;
  color: inherit;
  text-decoration: none;
  opacity: 0.85;
  transition: opacity 200ms var(--altus-ease);
  position: relative;
  padding: 4px 0;
}
.altus-header-nav a:hover,
.altus-header-nav a:focus-visible { opacity: 1; outline: none; }
.altus-header-nav a[aria-current="page"]::after {
  content: '';
  position: absolute;
  left: 0; right: 0; bottom: 0;
  height: 1px;
  background: currentColor;
  opacity: 0.45;
}

/* Burger — Lucide stroke 1, sobre */
.altus-header-burger {
  display: none;
  background: transparent;
  border: 0;
  padding: 8px;
  margin: -8px;
  cursor: pointer;
  color: inherit;
  -webkit-tap-highlight-color: transparent;
}
.altus-header-burger svg {
  width: 22px;
  height: 22px;
  stroke: currentColor;
  stroke-width: 1;
  fill: none;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.altus-header-burger .alt-burger-close { display: none; }
.altus-header[data-mobile-open="true"] .altus-header-burger .alt-burger-open  { display: none; }
.altus-header[data-mobile-open="true"] .altus-header-burger .alt-burger-close { display: inline; }

/* Mobile — burger + accordéon vertical */
@media (max-width: 768px) {
  .altus-header { padding: 14px 22px; gap: 16px; max-width: 95%; border-radius: 14px; }
  .altus-header-logo { width: 88px; }
  .altus-header[data-scrolled="true"] .altus-header-logo { width: 52px; }
  .altus-header-nav {
    position: absolute;
    top: calc(100% - 1px);
    left: 0; right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 0 22px;
    max-height: 0;
    overflow: hidden;
    background: inherit;
    border-radius: 0 0 14px 14px;
    -webkit-backdrop-filter: inherit;
            backdrop-filter: inherit;
    transition: max-height 280ms var(--altus-ease), padding 280ms var(--altus-ease);
  }
  .altus-header[data-mobile-open="true"] .altus-header-nav {
    max-height: 70vh;
    padding: 8px 22px 18px;
  }
  .altus-header-nav a {
    padding: 18px 0;
    font-size: 16px;
    opacity: 1;
    border-bottom: 1px solid rgba(127, 127, 127, 0.16);
  }
  .altus-header-nav a:last-child { border-bottom: 0; }
  .altus-header-burger { display: inline-flex; }
}

@media (prefers-reduced-motion: reduce) {
  .altus-header,
  .altus-header *,
  .altus-header-nav { transition: none !important; }
}