/* ============================================================
   Site header — the shared top nav component.

   Used by BOTH front-end systems (see CLAUDE.md "Two design
   systems"): the hand-built pages via _layouts/default.html, and
   the Kubio homepage (index.html), which links this file directly.
   The markup for both comes from _includes/header.html.

   This is why the header lives here and not in styles.css: the
   homepage can load *this* safely, but not styles.css (whose
   body/heading globals would clobber the Kubio export).

   Requires tokens.css. Load order: tokens.css → site-header.css.

   Deliberately uses plain class selectors, no #kubio scoping —
   verified that the Kubio CSS has no bare `a`/`button`/`strong`
   or `#kubio a` rules that would out-specify these.

   Note: the .brand / .brand-mark / .brand-text lockup below is also
   reused by the site footer, which restyles it via .footer-brand
   overrides in styles.css (loaded after this file).
   ============================================================ */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--surface);
  border-bottom: 2px solid var(--navy);
  box-shadow: var(--shadow-sm);
  /* Set explicitly so the header renders identically on the homepage,
     where the surrounding Kubio page has a different body font. */
  font-family: var(--font);
}

/* Scoped copy of the .container width formula. styles.css defines
   .container globally for the hand-built pages, but the homepage
   doesn't load styles.css and the header markup uses that class. */
.site-header .container {
  width: min(var(--max), calc(100% - 32px));
  margin: 0 auto;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 0;
  gap: 16px;
  min-width: 0;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none !important;
  /* Allow the brand to shrink so it can never push the nav toggle
     off-screen on narrow viewports. */
  min-width: 0;
  flex: 0 1 auto;
}
.brand-mark {
  width: 38px; height: 38px;
  flex: none;
  display: grid; place-items: center;
  border-radius: 7px;
  background: var(--navy);
  color: #fff;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: .85rem;
  letter-spacing: -.3px;
}
.brand-text {
  display: flex;
  gap: 6px;
  align-items: baseline;
  min-width: 0;
}
.brand-text strong {
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--navy);
  /* Last-resort backstop: truncate rather than overflow the header. */
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.brand-text .muted { font-size: .875rem; white-space: nowrap; }

.site-nav {
  display: flex;
  align-items: center;
  gap: 2px;
}
.site-nav a {
  padding: 8px 14px;
  border-radius: 6px;
  color: var(--muted);
  font-family: var(--font-head);
  font-size: .95rem;
  font-weight: 500;
  text-decoration: none;
  white-space: nowrap;
  transition: background .15s, color .15s;
}
.site-nav a:hover { background: var(--navy-lt); color: var(--navy); text-decoration: none; }
.site-nav a.active { background: var(--navy-lt); color: var(--navy); }

/* "Join" nav item gets gold pill treatment. Keyed off an explicit
   class rather than [href="..."] — the href varies by page depth and
   the old attribute selectors silently stopped matching. */
.site-nav a.nav-cta {
  margin-left: 8px;
  background: var(--gold);
  color: #1a1a1a;
  font-weight: 700;
  border-radius: 6px;
}
.site-nav a.nav-cta:hover { background: var(--gold-dk); text-decoration: none; }

.nav-toggle {
  display: none;
  width: 40px; height: 40px;
  flex: none;
  border-radius: 7px;
  border: 1px solid var(--line);
  background: var(--surface);
  cursor: pointer;
  padding: 10px;
}
.nav-toggle span {
  display: block;
  height: 2px;
  background: var(--navy);
  margin: 5px 0;
  border-radius: 2px;
}

/* Stack the brand lockup before it gets tight enough to truncate. */
@media (max-width: 560px) {
  .brand-text {
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    line-height: 1.25;
  }
  .brand-text strong { font-size: .98rem; }
  .brand-text .muted { font-size: .8rem; }
}

@media (max-width: 760px) {
  .nav-toggle { display: block; }
  .site-nav {
    position: absolute;
    right: 16px;
    /* Anchored to the header box (.site-header is sticky, so it's the
       positioned ancestor). Using 100% instead of a hardcoded offset
       keeps the dropdown attached when the header grows — e.g. once
       the brand lockup stacks at <=560px. */
    top: calc(100% + 6px);
    flex-direction: column;
    align-items: stretch;
    width: min(280px, calc(100% - 32px));
    padding: 8px;
    border-radius: var(--radius);
    background: var(--surface);
    border: 1px solid var(--line);
    box-shadow: var(--shadow-md);
    display: none;
  }
  .site-nav.open { display: flex; }
  .site-nav a { width: 100%; }
  .site-nav a.nav-cta {
    margin-left: 0;
    text-align: center;
    margin-top: 4px;
  }
}