/* header.css */
:root { scroll-padding-top: calc(var(--header-h) + env(safe-area-inset-top, 0px) + 1rem); }

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  padding-top: env(safe-area-inset-top, 0px);
  background: rgb(255 255 255 / 0.96);
  border-bottom: 1px solid var(--line);
  backdrop-filter: saturate(1.2) blur(6px);
}
:root[data-theme="dark"] .site-header { background: rgb(14 20 32 / 0.92); }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .site-header { background: rgb(14 20 32 / 0.92); }
}

.site-header__bar {
  display: flex;
  align-items: center;
  gap: var(--s-3);
  min-height: var(--header-h);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  min-width: 0;
  font-family: var(--font-display);
  font-size: clamp(1.05rem, 3.6vw, 1.45rem);
  font-weight: 800;
  letter-spacing: -0.01em;
  text-decoration: none;
  white-space: nowrap;
}
.brand svg { width: 1.7rem; height: 1.7rem; flex: none; color: var(--stitch); }

.nav {
  display: flex;
  align-items: center;
  gap: var(--s-1);
  margin-left: auto;
}
.nav__link {
  padding: 0.5rem 0.85rem;
  border-bottom: 3px solid transparent;
  font-weight: 700;
  text-decoration: none;
}
.nav__link:hover { color: var(--stitch-deep); }
.nav__link[aria-current="page"] { border-bottom-color: var(--stitch); }

.nav-toggle { display: none; flex: none; }

.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: none;
  width: 2.5rem;
  height: 2.5rem;
  padding: 0;
  border: 1px solid var(--line-strong);
  border-radius: 50%;
  background: none;
  cursor: pointer;
}
.theme-toggle:hover { background: var(--chalk); }
.theme-toggle svg { width: 1.2rem; height: 1.2rem; }
.theme-toggle .icon-sun { display: none; }
:root[data-theme="dark"] .theme-toggle .icon-moon { display: none; }
:root[data-theme="dark"] .theme-toggle .icon-sun { display: inline; }

/* Sign-in / account menu */
.session { position: relative; margin-left: var(--s-2); }
.session summary { list-style: none; cursor: pointer; }
.session summary::-webkit-details-marker { display: none; }

.session__menu {
  position: absolute;
  right: 0;
  top: calc(100% + 0.5rem);
  z-index: 50;
  width: max(18rem, min(90vw, 20rem));
  max-height: min(28rem, calc(100dvh - var(--header-h) - 2rem));
  overflow-y: auto;
  padding: var(--s-2);
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--r-m);
  box-shadow: var(--shadow-pop);
}
.session__group {
  padding: 0.4rem 0.75rem 0.2rem;
  font-size: var(--text-xs);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--ink-faint);
}
.session__item {
  display: block;
  width: 100%;
  padding: 0.65rem 0.75rem;
  border: 0;
  border-radius: var(--r-s);
  background: none;
  text-align: left;
  text-decoration: none;
  font-weight: 700;
  color: var(--ink);
  cursor: pointer;
}
.session__item:hover { background: var(--chalk); }
.session__item small { display: block; font-weight: 400; color: var(--ink-soft); }
.session__note { padding: 0.5rem 0.75rem 0.25rem; font-size: var(--text-xs); color: var(--ink-faint); }

@media (max-width: 52em) {
  .nav-toggle { display: inline-flex; }

  .nav {
    display: none;
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    flex-direction: column;
    align-items: stretch;
    max-height: calc(100dvh - var(--header-h) - env(safe-area-inset-top, 0px));
    overflow-y: auto;
    padding: var(--s-3) var(--gutter) calc(var(--s-4) + env(safe-area-inset-bottom, 0px));
    background: var(--paper);
    border-bottom: 1px solid var(--line);
    box-shadow: var(--shadow-pop);
  }
  .nav[data-open="true"] { display: flex; }

  .nav__link {
    padding: 0.85rem 0.75rem;
    border-bottom: 0;
    border-left: 3px solid transparent;
  }
  .nav__link[aria-current="page"] { border-left-color: var(--stitch); }

  .session { margin: var(--s-3) 0 0; width: 100%; }
  .session summary .btn { width: 100%; }
  .session__menu { position: static; width: 100%; margin-top: var(--s-2); box-shadow: none; max-height: none; }
}