:root {
  color-scheme: dark;
  --ink: #f4f7fb;
  --muted: #9ba3ad;
  --line: rgba(244, 247, 251, 0.16);
  --black: #050608;
  --panel: #0d1116;
  --accent: #9dd8ff;
  --display: "Arial Narrow", "Roboto Condensed", "Segoe UI", sans-serif;
  --body: "Segoe UI", Arial, sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; background: var(--black); }
body {
  margin: 0;
  background: var(--black);
  color: var(--ink);
  font-family: var(--body);
}
a { color: inherit; }
.skip-link {
  position: fixed;
  top: 8px;
  left: 8px;
  z-index: 100;
  padding: 10px 14px;
  background: white;
  color: black;
  transform: translateY(-150%);
}
.skip-link:focus { transform: none; }

.reader-header {
  position: fixed;
  inset: 0 0 auto;
  z-index: 30;
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 64px;
  padding: 0 4vw;
  border-bottom: 1px solid rgba(255,255,255,.09);
  background: rgba(5,6,8,.78);
  backdrop-filter: blur(16px);
}
.reader-brand,
.reader-top-nav a {
  font-family: var(--display);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .08em;
  text-decoration: none;
  text-transform: uppercase;
}
.reader-brand span { color: var(--accent); }
.reader-top-nav { display: flex; gap: 28px; }
.reader-top-nav a { color: var(--muted); }
.reader-top-nav a:hover,
.reader-top-nav a:focus-visible { color: var(--ink); }

.notebook-hero {
  position: relative;
  display: flex;
  align-items: flex-end;
  min-height: min(76vh, 760px);
  padding: 130px 6vw 72px;
  overflow: hidden;
  isolation: isolate;
  background-position: center;
  background-size: cover;
}
.notebook-hero::after {
  content: "";
  position: absolute;
  inset: auto 0 0;
  z-index: -1;
  height: 45%;
  background: linear-gradient(transparent, var(--black));
}
.notebook-hero-shade {
  position: absolute;
  inset: 0;
  z-index: -2;
  background: linear-gradient(90deg, rgba(3,4,6,.94) 0%, rgba(3,4,6,.68) 40%, rgba(3,4,6,.08) 76%);
}
.notebook-hero-copy { max-width: 760px; }
.notebook-eyebrow,
.document-head p,
.notebook-status {
  margin: 0;
  color: var(--accent);
  font-family: var(--display);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .1em;
  text-transform: uppercase;
}
.notebook-hero h1 {
  max-width: 780px;
  margin: 18px 0 16px;
  font-family: var(--display);
  font-size: clamp(54px, 7vw, 112px);
  line-height: .92;
  letter-spacing: 0;
  text-transform: uppercase;
}
.notebook-subtitle {
  max-width: 680px;
  margin: 0 0 22px;
  color: rgba(244,247,251,.8);
  font-size: clamp(17px, 2vw, 24px);
  line-height: 1.45;
}
.notebook-status { color: rgba(244,247,251,.56); }
.read-button {
  display: inline-flex;
  gap: 28px;
  align-items: center;
  margin-top: 34px;
  padding: 15px 20px;
  border: 1px solid rgba(244,247,251,.45);
  font-family: var(--display);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .05em;
  text-decoration: none;
  text-transform: uppercase;
}
.read-button:hover,
.read-button:focus-visible { background: var(--ink); color: var(--black); }

.scenario-switch {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  max-width: 1260px;
  margin: 0 auto;
  padding: 36px 4vw;
}
.scenario-switch a {
  display: grid;
  min-height: 104px;
  padding: 24px;
  border: 1px solid var(--line);
  text-decoration: none;
}
.scenario-switch a + a { border-left: 0; }
.scenario-switch small {
  color: var(--muted);
  font-family: var(--display);
  font-size: 10px;
  letter-spacing: .08em;
  text-transform: uppercase;
}
.scenario-switch strong {
  align-self: end;
  font-family: var(--display);
  font-size: clamp(18px, 2vw, 27px);
  text-transform: uppercase;
}
.scenario-switch a[aria-current="page"] {
  color: var(--black);
  background: var(--accent);
  border-color: var(--accent);
}

.document-shell {
  padding: 58px 4vw 80px;
  background: #090b0e;
}
.document-head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  max-width: 1180px;
  margin: 0 auto 30px;
}
.document-head h2 {
  margin: 8px 0 0;
  font-family: var(--display);
  font-size: clamp(28px, 4vw, 52px);
  text-transform: uppercase;
}
.document-progress { color: var(--muted) !important; text-align: right; }
.pdf-pages {
  display: grid;
  gap: 24px;
  max-width: 1180px;
  margin: 0 auto;
}
.pdf-page {
  position: relative;
  display: grid;
  place-items: center;
  min-height: 240px;
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--panel);
  box-shadow: 0 18px 60px rgba(0,0,0,.28);
}
.pdf-page canvas {
  display: block;
  width: 100%;
  height: auto;
}
.pdf-page-number {
  position: absolute;
  right: 12px;
  bottom: 10px;
  z-index: 2;
  padding: 5px 8px;
  background: rgba(5,6,8,.72);
  color: rgba(244,247,251,.7);
  font-size: 10px;
}
.pdf-page-loading { color: var(--muted); font-size: 13px; }
.reader-error {
  max-width: 720px;
  margin: 30px auto;
  padding: 24px;
  border: 1px solid #7d3535;
  color: #ffb2b2;
}
.scenario-switch-bottom { padding-top: 70px; padding-bottom: 70px; }
.reader-footer {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  padding: 30px 4vw;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 12px;
}
.reader-footer p { margin: 0; }

@media (max-width: 720px) {
  .reader-header { min-height: 58px; padding: 0 20px; }
  .reader-top-nav a:first-child,
  .reader-top-nav a:nth-child(2) { display: none; }
  .notebook-hero {
    min-height: 78svh;
    padding: 110px 24px 54px;
    background-position: center;
  }
  .notebook-hero-shade { background: linear-gradient(0deg, rgba(3,4,6,.96), rgba(3,4,6,.08) 86%); }
  .notebook-hero h1 { font-size: clamp(48px, 15vw, 68px); }
  .scenario-switch { grid-template-columns: 1fr; padding: 24px 18px; }
  .scenario-switch a + a { border-top: 0; border-left: 1px solid var(--line); }
  .scenario-switch a { min-height: 88px; padding: 19px; }
  .document-shell { padding: 42px 10px 60px; }
  .document-head { align-items: start; padding: 0 8px; }
  .document-progress { max-width: 105px; }
  .pdf-pages { gap: 12px; }
  .pdf-page { min-height: 130px; }
  .reader-footer { flex-direction: column; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}