/* ==========================================================================
   layout.css — shell, header, drawer, section frame, footer
   ========================================================================== */

.shell {
  width: min(100% - 2.5rem, var(--shell));
  margin-inline: auto;
}

/* --------------------------------------------------------------------------
   header
   -------------------------------------------------------------------------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(251, 250, 247, 0.88);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid transparent;
  transition: border-color .3s ease, background-color .3s ease;
}
.site-header.is-stuck { border-bottom-color: var(--rule); }

.header-inner {
  height: var(--header-h);
  display: flex;
  align-items: center;
  gap: var(--gap-md);
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  text-decoration: none;
  flex-shrink: 0;
}
.brand img { width: 56px; height: auto; }
.brand-name {
  font-family: var(--font-serif);
  font-size: 0.9rem;
  letter-spacing: 0.1em;
  color: var(--ink-soft);
  white-space: nowrap;
}
.brand:hover { color: inherit; }

.site-nav {
  display: flex;
  gap: 1.9rem;
  margin-left: auto;
}
.site-nav a {
  font-size: 0.83rem;
  letter-spacing: 0.08em;
  text-decoration: none;
  color: var(--ink-soft);
  padding-block: 0.4rem;
  border-bottom: 1px solid transparent;
}
.site-nav a:hover { color: var(--ink); border-bottom-color: var(--ink); }

.header-cta { flex-shrink: 0; }

.nav-toggle {
  display: none;
  width: 40px;
  height: 40px;
  margin-left: auto;
  padding: 0;
  background: none;
  border: 0;
  cursor: pointer;
  position: relative;
}
.nav-toggle span {
  position: absolute;
  left: 9px;
  width: 22px;
  height: 1px;
  background: var(--ink);
  transition: transform .25s ease, opacity .25s ease;
}
.nav-toggle span:nth-child(1) { top: 17px; }
.nav-toggle span:nth-child(2) { top: 23px; }
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(3px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { transform: translateY(-3px) rotate(-45deg); }

.drawer {
  display: none;
  flex-direction: column;
  border-top: 1px solid var(--rule);
  background: var(--paper);
  padding: 0.5rem 1.25rem 1.5rem;
}
.drawer a {
  padding: 1.05rem 0.25rem;
  border-bottom: 1px solid var(--rule);
  text-decoration: none;
  font-size: 0.95rem;
  letter-spacing: 0.06em;
}
.drawer .drawer-cta {
  margin-top: 1.2rem;
  border: 0;
  background: var(--ink);
  color: var(--paper);
  text-align: center;
  padding: 1.1rem;
}
.drawer[hidden] { display: none; }

/* --------------------------------------------------------------------------
   sections
   -------------------------------------------------------------------------- */

.section {
  padding-block: var(--gap-xl);
  border-top: 1px solid var(--rule);
}
.section-alt { background: var(--paper-alt); }
.section-dark {
  background: var(--dark-bg);
  color: var(--dark-text);
  border-top-color: var(--dark-bg);
}
.section-dark .section-no,
.section-dark .section-lead { color: var(--dark-muted); }
.section-dark .section-title { color: var(--dark-text); }

.section-head {
  margin-bottom: var(--gap-lg);
}
.section-no {
  font-family: var(--font-serif);
  font-size: 0.78rem;
  letter-spacing: 0.3em;
  color: var(--ink-faint);
  margin-bottom: 1.1rem;
}
.section-title {
  font-size: clamp(1.55rem, 3.4vw, 2.3rem);
  line-height: 1.55;
}
.section-lead {
  margin-top: 1.5rem;
  max-width: 46em;
  color: var(--ink-muted);
  font-size: 0.95rem;
}

/* two-column split: narrative + side block */
.split {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
  gap: var(--gap-lg);
  align-items: start;
}
.split-main { font-size: 1.02rem; }

/* --------------------------------------------------------------------------
   footer
   -------------------------------------------------------------------------- */

.site-footer {
  border-top: 1px solid var(--rule);
  padding-block: var(--gap-lg) var(--gap-md);
}
.footer-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--gap-md);
}
.footer-brand {
  display: flex;
  align-items: center;
  gap: 0.7rem;
}
.footer-brand img { width: 52px; height: auto; }
.footer-brand p {
  margin: 0;
  font-family: var(--font-serif);
  font-size: 0.88rem;
  letter-spacing: 0.1em;
}
.footer-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 1.4rem;
  margin-left: auto;
}
.footer-nav a {
  font-size: 0.8rem;
  color: var(--ink-muted);
  text-decoration: none;
}
.footer-nav a:hover { color: var(--ink); }
.copyright {
  width: 100%;
  margin: 0;
  padding-top: var(--gap-md);
  border-top: 1px solid var(--rule);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--ink-faint);
}

/* --------------------------------------------------------------------------
   responsive
   -------------------------------------------------------------------------- */

@media (max-width: 1000px) {
  .site-nav { display: none; }
  .header-cta { display: none; }
  .nav-toggle { display: block; }
  .drawer:not([hidden]) { display: flex; }
}

@media (max-width: 860px) {
  :root { --gap-xl: 4.5rem; --gap-lg: 2.6rem; --header-h: 66px; }
  .brand img { width: 44px; }
  .footer-brand img { width: 44px; }
  .split { grid-template-columns: 1fr; gap: var(--gap-md); }
  .footer-nav { margin-left: 0; width: 100%; }
}