/* Page frame: container, header + nav, sections, footer. */

.container {
  width: min(100% - 2 * var(--gutter), var(--max));
  margin-inline: auto;
}

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  padding-block: 0.9rem;
  transition: background var(--dur) var(--ease-out), border-color var(--dur) var(--ease-out),
    translate var(--dur) var(--ease-out);
  border-bottom: 1px solid transparent;
  view-transition-name: site-header;
}
.site-header.is-scrolled {
  background: color-mix(in srgb, var(--bg) 78%, transparent);
  -webkit-backdrop-filter: saturate(1.4) blur(14px);
  backdrop-filter: saturate(1.4) blur(14px);
  border-bottom-color: var(--line);
}
.site-header.is-hidden { translate: 0 -100%; }

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-s);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  text-decoration: none;
}
.brand-mark {
  display: grid;
  place-items: center;
  width: 2.2rem;
  height: 2.2rem;
  border-radius: 50%;
  background: var(--ink);
  color: var(--bg);
  font-size: 0.95rem;
  font-style: italic;
  font-variation-settings: "SOFT" 100, "WONK" 1;
  transition: rotate var(--dur-slow) var(--ease-spring), background var(--dur) var(--ease-out);
}
.brand:hover .brand-mark { rotate: -12deg; background: var(--accent); color: var(--accent-ink); }
.brand-name { display: none; }
@media (min-width: 560px) { .brand-name { display: inline; } }

.header-actions { display: flex; align-items: center; gap: 0.4rem; }

/* Nav: 4 items max (Hick's law). The pill indicator slides between pages via view transitions. */
.nav ul { display: flex; gap: 0.15rem; }
.nav a {
  position: relative;
  display: block;
  padding: 0.5rem 0.8rem;
  border-radius: 999px;
  font-size: var(--step--1);
  font-weight: 500;
  color: var(--muted);
  text-decoration: none;
  transition: color var(--dur-fast) var(--ease-out);
}
.nav a:hover { color: var(--ink); }
/* The current-page pill lives on the link itself, so it morphs between nav positions on page change. */
.nav a[aria-current="page"] {
  color: var(--ink);
  background: var(--bg-raised);
  box-shadow: inset 0 0 0 1px var(--line);
  view-transition-name: nav-pill;
}
@media (max-width: 520px) {
  .nav a { padding: 0.5rem 0.45rem; font-size: 0.8rem; }
}
/* Very narrow phones: the theme toggle moves from the header to the footer so the 4 nav items fit. */
.site-footer .theme-toggle { display: none; }
@media (max-width: 400px) {
  .site-header .theme-toggle { display: none; }
  .site-footer .theme-toggle { display: grid; }
  .brand-mark { width: 2rem; height: 2rem; }
}

/* ---------- Sections ---------- */
.page-head {
  padding-block: clamp(3rem, 2rem + 6vw, 7rem) var(--space-l);
}
.page-head h1 {
  font-size: var(--step-4);
  margin-top: var(--space-s);
  view-transition-name: page-title;
}
.page-head .lede { margin-top: var(--space-m); }

.section { padding-block: var(--space-xl); }
.section + .section { padding-top: 0; }
.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: end;
  justify-content: space-between;
  gap: var(--space-s);
  margin-bottom: var(--space-l);
}
.section-head h2 { font-size: var(--step-3); }

/* ---------- Footer ---------- */
.site-footer {
  margin-top: var(--space-xl);
  padding-block: var(--space-l) var(--space-m);
  border-top: 1px solid var(--line);
  font-size: var(--step--1);
  color: var(--muted);
}
.footer-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-s);
}
.footer-links { display: flex; flex-wrap: wrap; gap: 0.25rem 1.25rem; }
.footer-links a { text-decoration: none; }
.footer-links a:hover { color: var(--ink); text-decoration: underline; }