/* ============================================================
 * base.css — typography, paper, layout primitives
 * Recognition Forest — website edition (W1)
 * ============================================================ */

/* --- Self-hosted fonts ------------------------------------- */

@font-face {
  font-family: 'Newsreader';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url('../fonts/newsreader-400.woff2') format('woff2');
}
@font-face {
  font-family: 'Newsreader';
  font-style: italic;
  font-weight: 400;
  font-display: swap;
  src: url('../fonts/newsreader-400-italic.woff2') format('woff2');
}
@font-face {
  font-family: 'Newsreader';
  font-style: normal;
  font-weight: 600;
  font-display: swap;
  src: url('../fonts/newsreader-600.woff2') format('woff2');
}
@font-face {
  font-family: 'IBM Plex Sans';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url('../fonts/plex-sans-400.woff2') format('woff2');
}
@font-face {
  font-family: 'IBM Plex Sans';
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url('../fonts/plex-sans-500.woff2') format('woff2');
}
@font-face {
  font-family: 'IBM Plex Mono';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url('../fonts/plex-mono-400.woff2') format('woff2');
}
@font-face {
  font-family: 'IBM Plex Mono';
  font-style: italic;
  font-weight: 400;
  font-display: swap;
  src: url('../fonts/plex-mono-400-italic.woff2') format('woff2');
}
@font-face {
  font-family: 'IBM Plex Mono';
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url('../fonts/plex-mono-500.woff2') format('woff2');
}

/* --- Variables --------------------------------------------- */

:root {
  --paper: #f4f0e6;
  --paper-deep: #ebe5d4;
  --paper-branch: #f2efe6;
  --ink: #1a1612;
  --ink-soft: #4a4036;
  --ink-faint: #8a7d6a;
  --branch: #8b3a2e;
  --branch-faint: #b8a896;
  --branch-spent: #c4b8a3;
  --rule: #d4c9b0;
  --max-text: 38rem;
  --max-text-narrow: 32rem;

  --serif: 'Newsreader', 'Iowan Old Style', 'Charter', Georgia, serif;
  --sans:  'IBM Plex Sans', system-ui, -apple-system, 'Segoe UI', sans-serif;
  --mono:  'IBM Plex Mono', ui-monospace, 'SF Mono', Menlo, Monaco, monospace;
}

/* --- Reset ------------------------------------------------- */

* { box-sizing: border-box; margin: 0; padding: 0; }

html {
  font-size: 17px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--serif);
  font-weight: 400;
  background: var(--paper);
  color: var(--ink);
  line-height: 1.7;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  background-image:
    radial-gradient(at 20% 10%, rgba(139, 58, 46, 0.02) 0%, transparent 50%),
    radial-gradient(at 80% 90%, rgba(26, 22, 18, 0.025) 0%, transparent 50%);
  transition: background-color 1s ease;
}

body.branched {
  background-color: var(--paper-branch);
}

/* Paper grain — subtle SVG noise overlay */
body::before {
  content: "";
  position: fixed; inset: 0;
  pointer-events: none; opacity: 0.32; z-index: 1;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='200' height='200'><filter id='n'><feTurbulence baseFrequency='0.85' numOctaves='2' stitchTiles='stitch'/><feColorMatrix values='0 0 0 0 0.1, 0 0 0 0 0.08, 0 0 0 0 0.06, 0 0 0 0.04 0'/></filter><rect width='100%25' height='100%25' filter='url(%23n)'/></svg>");
  mix-blend-mode: multiply;
}

/* --- Layout primitives ------------------------------------- */

.container {
  max-width: 64rem;
  margin: 0 auto;
  padding: 4rem 2rem 8rem;
  position: relative;
  z-index: 2;
}

article {
  max-width: var(--max-text);
  margin: 0 auto;
  position: relative;
}

p {
  margin-bottom: 1.4rem;
  font-size: 1.05rem;
  line-height: 1.7;
  text-wrap: pretty;
  hyphens: auto;
  position: relative;
}

em { font-style: italic; }
strong { font-weight: 600; }

a {
  color: var(--branch);
  text-decoration: none;
  background-image: linear-gradient(var(--branch), var(--branch));
  background-position: 0 100%;
  background-repeat: no-repeat;
  background-size: 0% 1px;
  transition: background-size 240ms ease;
  padding-bottom: 1px;
}
a:hover, a:focus-visible {
  background-size: 100% 1px;
}

/* --- Masthead (page header) -------------------------------- */

.masthead {
  text-align: center;
  margin-bottom: 4rem;
  padding-bottom: 2rem;
  border-bottom: 1px solid var(--rule);
  position: relative;
}

.imprint {
  font-family: var(--mono);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  color: var(--ink-faint);
  margin-bottom: 1.5rem;
  transition: color 0.4s;
}

.imprint a {
  color: inherit;
  background: none;
  padding-bottom: 0;
}
.imprint a:hover {
  color: var(--branch);
  background: none;
}

body.branched .imprint { color: var(--branch); }

.masthead h1 {
  font-family: var(--serif);
  font-weight: 400;
  font-style: italic;
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  letter-spacing: -0.005em;
  margin-bottom: 0.5rem;
  color: var(--ink);
  transition: color 0.4s;
}

.beat-number {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--ink-soft);
  transition: color 0.4s;
}

body.branched .beat-number { color: var(--branch); }

/* --- Footer ------------------------------------------------ */

footer {
  max-width: var(--max-text);
  margin: 6rem auto 0;
  padding-top: 2.5rem;
  border-top: 1px solid var(--rule);
  text-align: center;
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

.branch-status { margin-bottom: 1rem; }
.branch-status .branch-name { color: var(--branch); }

.system-note {
  font-style: italic;
  text-transform: none;
  letter-spacing: normal;
  font-family: var(--serif);
  font-size: 0.85rem;
  color: var(--ink-faint);
  margin-top: 1.5rem;
  line-height: 1.6;
  min-height: 2em;
  transition: opacity 0.6s ease;
  opacity: 0;
}
.system-note.visible { opacity: 1; }

.footer-nav {
  margin-top: 1.5rem;
  display: flex;
  gap: 1.5rem;
  justify-content: center;
  flex-wrap: wrap;
}
.footer-nav a {
  color: var(--ink-faint);
  background: none;
  padding: 0;
  letter-spacing: 0.18em;
}
.footer-nav a:hover { color: var(--branch); background: none; }

/* --- Sidebar (slide-in TOC, hover-triggered) ---------------
   Design intent: nearly invisible at rest. A 1px ochre tick at
   the left edge — about the height of an em — is the only hint.
   On mouseenter near the left edge or focus on a hidden anchor,
   the sidebar slides in with a fade. No box, no border, no hard
   edge. Soft shadow on the right when open. Typography does the
   work: italic serif chapter titles, faint mono numbers.
   ------------------------------------------------------------ */

.sidebar-trigger {
  position: fixed;
  top: 0;
  left: 0;
  width: 14px;
  height: 100vh;
  z-index: 59;
  background: transparent;
}

/* The only visual clue: a very faint 1em vertical tick,
   centered vertically. Subtle on hover. */
.sidebar-trigger::after {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 1px;
  height: 1.6em;
  background: var(--branch-faint);
  opacity: 0.4;
  transition: opacity 320ms ease, height 320ms ease;
  pointer-events: none;
}

.sidebar-trigger:hover::after {
  opacity: 0.85;
  height: 2.6em;
}

/* Hide the tick when the sidebar is already open. */
body:has(.sidebar.open) .sidebar-trigger::after {
  opacity: 0;
}

.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: 19.5rem;
  height: 100vh;
  background: var(--paper);
  /* No border, no hard edge. A very soft shadow when open. */
  box-shadow: 0 0 0 rgba(26, 22, 18, 0);
  transform: translateX(-100%);
  opacity: 0;
  transition:
    transform 420ms cubic-bezier(0.32, 0.72, 0.24, 1),
    opacity 280ms ease,
    box-shadow 420ms ease;
  z-index: 60;
  overflow-y: auto;
  padding: 4.5rem 2rem 2rem 2.4rem;
  pointer-events: none;
}

.sidebar.open {
  transform: translateX(0);
  opacity: 1;
  box-shadow: 12px 0 32px rgba(26, 22, 18, 0.04);
  pointer-events: auto;
}

.sidebar-heading {
  font-family: var(--mono);
  font-size: 0.6rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-bottom: 2rem;
  line-height: 1.3;
}
.sidebar-heading a {
  color: inherit;
  background: none;
  padding: 0;
}
.sidebar-heading a:hover {
  color: var(--branch);
  background: none;
}

.sidebar-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.sidebar-list li {
  margin-bottom: 0.65rem;
}

.sidebar-list a {
  display: block;
  background: none;
  padding: 0.15rem 0;
  font-size: 1rem;
  line-height: 1.35;
  color: var(--ink-soft);
  transition: color 200ms ease, transform 240ms cubic-bezier(0.32, 0.72, 0.24, 1);
}
.sidebar-list a:hover {
  color: var(--branch);
  background: none;
  transform: translateX(2px);
}

.sidebar-list .n {
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.18em;
  color: var(--ink-faint);
  display: inline-block;
  width: 1.5rem;
  margin-right: 0.4rem;
  text-align: left;
  vertical-align: 0.05em;
}
.sidebar-list .t {
  font-family: var(--serif);
  font-style: italic;
  font-size: 0.96rem;
  white-space: nowrap;
}

.sidebar-list a.current .n,
.sidebar-list a.current .t {
  color: var(--branch);
}

/* Substantial whitespace separates Making from the story chapters —
   no visible rule. Different typographic treatment too:
   smaller, mono caps, faint color, multi-line. */
.sidebar-list .meta-link {
  margin-top: 5rem;
}

.sidebar-list .meta-link a {
  display: block;
  padding: 0.4rem 0;
}

.sidebar-list .meta-link .t {
  font-style: normal;
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-faint);
  white-space: normal;
  line-height: 1.6;
  display: block;
}

.sidebar-list .meta-link a:hover .t,
.sidebar-list .meta-link a:focus-visible .t {
  color: var(--branch);
}

.sidebar-list .meta-link a.current .t {
  color: var(--branch);
}

@media (max-width: 720px) {
  .sidebar, .sidebar-trigger { display: none; }
}

/* --- Reading-progress thread (right margin, chapter pages) --
   A 1px ochre line on the right edge of the viewport that fills
   from top to bottom as the reader scrolls the chapter. Looks
   like a bookmark thread descending the page. Set --progress in
   JS (chapter.js); transition keeps it smooth. */

.reading-progress {
  position: fixed;
  top: 0;
  right: 0.6rem;
  width: 3px;
  height: 100vh;
  background: var(--branch-faint);
  opacity: 0.45;
  z-index: 50;
  pointer-events: none;
  border-radius: 1px;
}

.reading-progress::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: var(--progress, 0%);
  background: var(--branch);
  border-radius: 1px;
  transition: height 120ms linear;
}

body.is-intro .reading-progress { display: none; }

@media (max-width: 720px) {
  .reading-progress { right: 0.3rem; width: 2px; opacity: 0.4; }
}

/* --- Info icon (top-right, fixed) -------------------------- */

.info-icon {
  position: fixed;
  top: 1.4rem;
  right: 1.4rem;
  width: 1.6rem;
  height: 1.6rem;
  border-radius: 50%;
  border: 1px solid var(--branch-faint);
  background: transparent;
  color: var(--branch-faint);
  font-family: var(--serif);
  font-style: italic;
  font-size: 0.85rem;
  line-height: 1;
  cursor: pointer;
  z-index: 65;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0;
  transition: color 200ms ease, border-color 200ms ease, transform 200ms ease;
  opacity: 0.6;
}
.info-icon:hover, .info-icon:focus-visible {
  color: var(--branch);
  border-color: var(--branch);
  opacity: 1;
  outline: none;
  transform: scale(1.05);
}

/* --- Info modal -------------------------------------------- */

.info-modal {
  position: fixed;
  inset: 0;
  z-index: 70;
  pointer-events: none;
  opacity: 0;
  transition: opacity 280ms ease;
}
.info-modal.open {
  pointer-events: auto;
  opacity: 1;
}

.info-modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(26, 22, 18, 0.18);
  backdrop-filter: blur(2px);
}

.info-modal-card {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%) translateY(8px);
  background: var(--paper);
  max-width: 32rem;
  width: calc(100% - 3rem);
  padding: 2.4rem 2.4rem 2rem;
  box-shadow: 0 24px 60px rgba(26, 22, 18, 0.14);
  transition: transform 320ms cubic-bezier(0.32, 0.72, 0.24, 1);
}
.info-modal.open .info-modal-card {
  transform: translate(-50%, -50%) translateY(0);
}

.info-modal-card p {
  font-family: var(--serif);
  font-size: 0.98rem;
  line-height: 1.7;
  color: var(--ink);
  margin-bottom: 1rem;
  font-style: italic;
}
.info-modal-card p:last-child { margin-bottom: 0; }

.info-modal-close {
  position: absolute;
  top: 0.6rem;
  right: 0.8rem;
  background: transparent;
  border: none;
  color: var(--ink-faint);
  font-size: 1.4rem;
  line-height: 1;
  cursor: pointer;
  padding: 0.4rem 0.6rem;
  transition: color 200ms ease;
}
.info-modal-close:hover { color: var(--branch); }

@media (max-width: 720px) {
  .info-icon { top: 1rem; right: 1rem; width: 1.4rem; height: 1.4rem; font-size: 0.75rem; }
  .info-modal-card { padding: 1.8rem 1.4rem 1.4rem; }
}

/* --- Intro / landing slideshow ----------------------------- */

/* Hide the page chrome on the intro */
body.is-intro {
  overflow: hidden;  /* no scroll; one viewport per slide */
}
body.is-intro .info-icon { display: none; }
body.is-intro .sidebar,
body.is-intro .sidebar-trigger { display: none; }
body.is-intro .container { padding: 0; max-width: none; }

.intro {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  z-index: 5;
}

.intro-slide {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: min(34rem, calc(100% - 3rem));
  text-align: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 700ms cubic-bezier(0.32, 0.72, 0.24, 1);
}

.intro-slide.active {
  opacity: 1;
  pointer-events: auto;
}

.intro-title {
  font-family: var(--serif);
  font-style: italic;
  font-weight: 400;
  font-size: clamp(2.4rem, 6vw, 3.8rem);
  letter-spacing: -0.01em;
  line-height: 1.1;
  color: var(--ink);
  margin-bottom: 1.4rem;
}

.intro-imprint {
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

.intro-prose {
  font-family: var(--serif);
  font-style: italic;
  font-size: 1.15rem;
  line-height: 1.75;
  color: var(--ink-soft);
}

.intro-emphasis {
  font-family: var(--serif);
  font-style: italic;
  font-size: 1.2rem;
  line-height: 1.5;
  color: var(--ink);
}

.intro-cta {
  display: inline-block;
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--branch);
  border: 1px solid var(--branch);
  padding: 0.85rem 2rem;
  background: transparent;
  background-image: none;
  background-size: 0;
  transition: background-color 220ms ease, color 220ms ease, transform 220ms ease;
}
.intro-cta:hover, .intro-cta:focus-visible {
  background: var(--branch);
  color: var(--paper);
  background-image: none;
  transform: translateY(-1px);
  outline: none;
}

.intro-secondary {
  margin-top: 1.5rem;
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}
.intro-secondary a {
  color: var(--ink-faint);
  background: none;
  padding: 0;
}
.intro-secondary a:hover, .intro-secondary a:focus-visible {
  color: var(--branch);
  background: none;
}

/* "tap to continue" hint — fades in after current slide settles */
.intro-hint {
  position: fixed;
  bottom: 2.2rem;
  left: 50%;
  transform: translateX(-50%);
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--ink-faint);
  opacity: 0;
  transition: opacity 600ms ease 1200ms;
  pointer-events: none;
}
.intro-hint.show { opacity: 0.6; }

@media (prefers-reduced-motion: reduce) {
  .intro-slide { transition: opacity 0.01ms; }
}

/* --- Chapter footer nav (prev/next box) -------------------- */

.chapter-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.2rem;
  max-width: var(--max-text);
  margin: 5rem auto 0;
}

.chapter-nav.single-next { grid-template-columns: 1fr; }
.chapter-nav.single-prev { grid-template-columns: 1fr; }
.chapter-nav.single-prev .nav-card { justify-self: start; max-width: 22rem; }
.chapter-nav.single-next .nav-card { justify-self: end; max-width: 22rem; }

.nav-card {
  display: block;
  background: var(--paper-deep);
  padding: 1.1rem 1.3rem;
  border-left: 2px solid var(--branch);
  background-image: none;
  background-size: 0;
  transition: background-color 200ms ease, transform 200ms ease;
  color: inherit;
}
.nav-card:hover {
  background: var(--paper);
  background-image: none;
  background-size: 0;
  transform: translateX(2px);
}
.nav-card.next {
  border-left: none;
  border-right: 2px solid var(--branch);
  text-align: right;
}
.nav-card.next:hover { transform: translateX(-2px); }

.nav-card .label {
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--branch);
  margin-bottom: 0.35rem;
  display: block;
}
.nav-card .title {
  font-family: var(--serif);
  font-style: italic;
  font-size: 1.15rem;
  color: var(--ink);
  display: block;
  line-height: 1.3;
}

@media (max-width: 720px) {
  .chapter-nav { grid-template-columns: 1fr; gap: 0.8rem; margin-top: 3.5rem; }
  .chapter-nav .nav-card.next { text-align: left; border-right: none; border-left: 2px solid var(--branch); }
  .chapter-nav.single-next .nav-card,
  .chapter-nav.single-prev .nav-card { max-width: none; }
}

/* --- Mobile (general) -------------------------------------- */

@media (max-width: 720px) {
  .container { padding: 2rem 1.5rem 5rem; }
  .masthead { margin-bottom: 3rem; }
  p { font-size: 1rem; line-height: 1.7; }
}