/* ═══════════════════════════════════════════════
   READER SHELL — layout, navigation, base styles
═══════════════════════════════════════════════ */

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  background-color: var(--deep);
  color: var(--parchment);
  font-family: var(--font-body);
  font-size: 18px;
  line-height: 1.85;
  font-weight: 300;
  min-height: 100vh;
  background-image:
    radial-gradient(ellipse at 20% 0%,  rgba(44,55,35,0.4) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 100%, rgba(60,30,15,0.3) 0%, transparent 50%);
}

/* Grain overlay */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)' opacity='0.04'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: 1000;
  opacity: 0.6;
}

/* Skip link */
.skip-link {
  position: absolute;
  top: -100px;
  left: 0;
  background: var(--rust);
  color: var(--cream);
  padding: 8px 16px;
  font-family: var(--font-heading);
  font-size: 12px;
  z-index: 9999;
  transition: top 0.2s;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  text-decoration: none;
}
.skip-link:focus { top: 0; }

/* ── ARC BANNER ── */
.arc-banner {
  background: var(--rust);
  color: var(--cream);
  text-align: center;
  padding: 9px 20px;
  font-family: var(--font-heading);
  font-size: 10px;
  letter-spacing: 0.35em;
  text-transform: uppercase;
  position: sticky;
  top: 0;
  z-index: 200;
}
.arc-banner span { opacity: 0.6; margin: 0 0.8em; }

/* ── PRIMARY NAV ── */
.reader-nav {
  position: sticky;
  top: 36px; /* below ARC banner */
  z-index: 190;
  background: rgba(13,11,8,0.96);
  border-bottom: 1px solid rgba(61,82,53,0.3);
  display: flex;
  align-items: stretch;
  backdrop-filter: blur(8px);
  height: var(--nav-height);
}

.nav-tab {
  font-family: var(--font-heading);
  font-size: 9px;
  letter-spacing: 0.38em;
  text-transform: uppercase;
  color: var(--muted);
  background: transparent;
  border: none;
  border-right: 1px solid rgba(61,82,53,0.2);
  padding: 0 22px;
  cursor: pointer;
  transition: color 0.18s, background 0.18s;
  white-space: nowrap;
  height: 100%;
  display: flex;
  align-items: center;
}

.nav-tab:hover {
  color: var(--dim);
  background: rgba(30,43,26,0.3);
}

.nav-tab.active {
  color: var(--fn-text);
  background: rgba(30,43,26,0.5);
  border-bottom: 2px solid var(--fn-border);
}

.nav-tab:focus-visible {
  outline: 2px solid var(--dim);
  outline-offset: -2px;
}

/* Chapter subnav — appears below primary nav when Chapters is active */
.chapter-nav {
  position: sticky;
  top: calc(36px + var(--nav-height));
  z-index: 180;
  background: rgba(13,11,8,0.9);
  border-bottom: 1px solid rgba(61,82,53,0.2);
  display: none;
  flex-wrap: wrap;
  gap: 0;
  padding: 0 24px;
  backdrop-filter: blur(6px);
}

.chapter-nav.visible { display: flex; }

.chapter-nav-item {
  font-family: var(--font-heading);
  font-size: 8px;
  letter-spacing: 0.3em;
  text-transform: uppercase;
  color: var(--muted);
  background: transparent;
  border: none;
  padding: 10px 16px;
  cursor: pointer;
  transition: color 0.18s;
  white-space: nowrap;
}

.chapter-nav-item:hover  { color: var(--dim); }
.chapter-nav-item.active { color: var(--fn-text); }
.chapter-nav-item:focus-visible {
  outline: 2px solid var(--dim);
  outline-offset: -2px;
}

/* ── MAIN CONTENT AREA ── */
.reader-main {
  max-width: var(--reader-width);
  margin: 0 auto;
  padding: 0 40px var(--space-xl);
}

/* ── SECTION PANELS ── */
.section-panel {
  display: none;
  animation: fadeUp 0.4s ease both;
}
.section-panel.active { display: block; }

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ── PAGE FURNITURE ── */
.section-label {
  font-family: var(--font-heading);
  font-size: 10px;
  letter-spacing: 0.45em;
  text-transform: uppercase;
  color: var(--rust);
  margin-bottom: var(--space-md);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding-top: var(--space-lg);
}
.section-label::after {
  content: '';
  flex: 1;
  height: 1px;
  background: linear-gradient(to right, rgba(122,59,46,0.4), transparent);
}

.page-break {
  width: 100%;
  height: 1px;
  background: linear-gradient(to right, transparent, rgba(184,176,160,0.15), transparent);
  margin: var(--space-lg) 0;
  position: relative;
}
.page-break::before {
  content: '✦';
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  background: var(--deep);
  padding: 0 16px;
  font-size: 10px;
  color: var(--muted);
}

.asterism {
  text-align: center;
  color: var(--muted);
  font-size: 20px;
  margin: 48px 0;
  letter-spacing: 0.5em;
}

/* ── LOADING STATE ── */
.loading-state {
  text-align: center;
  padding: var(--space-xl) 0;
  font-family: var(--font-heading);
  font-size: 10px;
  letter-spacing: 0.4em;
  text-transform: uppercase;
  color: var(--muted);
  animation: pulse 1.5s ease infinite;
}
@keyframes pulse {
  0%, 100% { opacity: 0.4; }
  50%       { opacity: 1; }
}

/* ── ERROR STATE ── */
.error-state {
  border: 1px solid rgba(122,59,46,0.4);
  padding: var(--space-md);
  margin: var(--space-md) 0;
  font-size: 14px;
  color: var(--muted);
  font-style: italic;
}

/* ── RESPONSIVE ── */
@media (max-width: 600px) {
  .reader-main { padding: 0 20px var(--space-xl); }
  .nav-tab { padding: 0 14px; font-size: 8px; letter-spacing: 0.25em; }
}

/* ── PRINT ── */
@media print {
  .arc-banner, .reader-nav, .chapter-nav { display: none !important; }
  .section-panel { display: block !important; }
  body { background: white; color: var(--ink); }
}