/* ============================================================
   layout.css — page chrome (header, footer) & section frames
   ============================================================ */

.container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--container-pad);
}

/* ---------- Sticky header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--bg);
  border-bottom: var(--border);
  height: var(--header-height);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  height: 100%;
}

.brand {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-md);
  letter-spacing: 0.06em;
  text-decoration: none;
  white-space: nowrap;
}
.brand__bracket { color: var(--accent); }

/* Mobile hamburger button (the label, since the input is hidden) */
.hamburger {
  display: inline-flex;
  flex-direction: column;
  justify-content: space-between;
  width: 36px;
  height: 28px;
  padding: 4px;
  border: var(--border);
  background: var(--bg);
  cursor: pointer;
  order: 3; /* push to right on mobile */
}
.hamburger__bar {
  display: block;
  height: 3px;
  background: var(--ink);
  transition: transform var(--t-med) var(--ease),
              opacity var(--t-fast) var(--ease);
  transform-origin: center;
}

/* Theme switch (the visible label) */
.theme-switch {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  border: var(--border);
  font-size: var(--fs-xs);
  font-weight: 700;
  letter-spacing: 0.08em;
  background: var(--bg);
  cursor: pointer;
  user-select: none;
  white-space: nowrap;
}
.theme-switch__icon { transition: opacity var(--t-fast) var(--ease); }

/* ---------- Primary nav ---------- */
.primary-nav {
  /* Mobile: full-screen drawer hidden by default.
     Desktop styles (>=641px) override this further down. */
  position: fixed;
  inset: var(--header-height) 0 0 0;
  background: var(--bg);
  border-top: var(--border);
  transform: translateY(-100%);
  transition: transform var(--t-med) var(--ease);
  z-index: 90;
  padding: var(--space-7) var(--container-pad);
}

.primary-nav__list {
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
}

.primary-nav a {
  display: inline-block;
  font-size: var(--fs-xl);
  font-weight: 700;
  text-decoration: none;
  border-bottom: var(--border-thick);
  padding-bottom: var(--space-2);
}
.primary-nav a:hover,
.primary-nav a:focus-visible {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

/* ---------- Section vertical rhythm ---------- */
main > section {
  padding-block: var(--space-8);
  border-bottom: var(--border);
  scroll-margin-top: calc(var(--header-height) + var(--space-2));
}

main > section:nth-of-type(even) {
  background: var(--bg-alt);
}

/* ---------- Footer ---------- */
.site-footer {
  border-top: var(--border-thick);
  padding-block: var(--space-6);
  background: var(--ink);
  color: var(--bg);
}
.site-footer a { color: var(--bg); text-decoration-color: var(--accent); }
.site-footer__inner {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  text-align: center;
  font-size: var(--fs-sm);
}
.site-footer__copy span { color: var(--muted); }

/* ============================================================
   Breakpoints
   ============================================================ */

@media (min-width: 641px) {

  .hamburger { display: none; }

  .primary-nav {
    position: static;
    inset: auto;
    transform: none;
    border-top: 0;
    padding: 0;
    background: transparent;
  }

  .primary-nav__list {
    flex-direction: row;
    align-items: center;
    gap: var(--space-5);
  }

  .primary-nav a {
    font-size: var(--fs-sm);
    border-bottom: 0;
    padding-bottom: 0;
    letter-spacing: 0.08em;
  }

  .site-footer__inner {
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
    text-align: left;
  }
}

@media (min-width: 1024px) {
  main > section { padding-block: var(--space-9); }
}