/* ─── Applied Worlds · Design System ──────────────────────────────── */

:root {
  /* Color */
  --bg:           #f7f8fc;
  --surface:      #eef0f7;
  --ink:          #0f1729;
  --muted:        #5c6b84;
  --rule:         #dde1ea;
  --line:         #c8cedd;
  --accent:       #2752d8;
  --accent-muted: #8aa4e8;
  --accent-warm:  #d45f2e;

  /* Typography */
  --font-serif: Charter, "Iowan Old Style", Palatino, Georgia, serif;
  --font-sans:  "Avenir Next", "Gill Sans", "Trebuchet MS", sans-serif;
  --font-mono:  SFMono-Regular, Menlo, Monaco, "Cascadia Mono", monospace;

  /* Layout */
  --max-w: min(1080px, calc(100% - 3rem));
}

/* ─── Reset ──────────────────────────────────────────────────────── */

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; -webkit-font-smoothing: antialiased; }
body { background: var(--bg); color: var(--ink); font-family: var(--font-serif); line-height: 1.6; }
a { color: inherit; text-decoration: none; }
ul, ol { list-style: none; }

/* ─── Layout ─────────────────────────────────────────────────────── */

.container { width: var(--max-w); margin-inline: auto; }
section { margin-top: 5rem; }

/* ─── Typography ─────────────────────────────────────────────────── */

h1 {
  font-family: var(--font-sans);
  font-size: clamp(2.1rem, 5vw, 3.2rem);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.025em;
  color: var(--ink);
}

h2 {
  font-family: var(--font-sans);
  font-size: 1.4rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--ink);
}

h3 {
  font-family: var(--font-sans);
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.lede {
  font-family: var(--font-serif);
  font-size: 1.1rem;
  line-height: 1.68;
  color: var(--muted);
  max-width: 52ch;
  margin-top: 1.25rem;
}

.prose {
  font-family: var(--font-serif);
  font-size: 1rem;
  line-height: 1.78;
  max-width: 62ch;
  text-align: justify;
  hyphens: auto;
  color: var(--ink);
}

/* ─── Eyebrow ────────────────────────────────────────────────────── */

.eyebrow {
  font-family: var(--font-mono);
  font-size: 0.67rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
}

.eyebrow::before {
  content: '';
  display: block;
  width: 22px;
  height: 1px;
  background: var(--accent);
  flex-shrink: 0;
}

/* ─── Navigation ─────────────────────────────────────────────────── */

nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(247, 248, 252, 0.88);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--rule);
}

.nav-inner {
  width: var(--max-w);
  margin-inline: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 54px;
}

.nav-brand {
  font-family: var(--font-sans);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--ink);
}

.nav-links {
  display: flex;
  align-items: center;
}

.nav-links a {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  padding: 0.35rem 0.9rem;
  position: relative;
  transition: color 0.18s;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -1px;
  left: 0.9rem;
  right: 0.9rem;
  height: 2px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.2s ease;
}

.nav-links a:hover { color: var(--ink); }
.nav-links a:hover::after { transform: scaleX(1); }
.nav-links a.active { color: var(--ink); }
.nav-links a.active::after { transform: scaleX(1); }

/* ─── Hero ───────────────────────────────────────────────────────── */

.hero {
  position: relative;
  padding: 5rem 0 4.5rem;
  overflow: hidden;
}

/* dot grid */
.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image: radial-gradient(circle at 1px 1px, var(--line) 1px, transparent 0);
  background-size: 28px 28px;
  opacity: 0.5;
  pointer-events: none;
}

/* indigo glow bleed */
.hero::after {
  content: '';
  position: absolute;
  top: 0;
  left: -5%;
  width: 55%;
  height: 100%;
  background: radial-gradient(ellipse at 25% 40%, rgba(39, 82, 216, 0.07) 0%, transparent 65%);
  pointer-events: none;
}

.hero-inner {
  position: relative;
  z-index: 1;
  width: var(--max-w);
  margin-inline: auto;
  display: grid;
  grid-template-columns: 1.4fr 0.9fr;
  gap: 4rem;
  align-items: start;
}

.hero-left { padding-top: 0.25rem; }
.hero-left h1 { margin-top: 0.85rem; }

.hero-cta {
  display: flex;
  gap: 0.75rem;
  margin-top: 2rem;
  flex-wrap: wrap;
}

/* ─── Signal Bar ─────────────────────────────────────────────────── */

.signal-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0;
  margin-top: 2.25rem;
  border-top: 1px solid var(--rule);
  padding-top: 1.25rem;
}

.signal-bar span {
  font-family: var(--font-mono);
  font-size: 0.63rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
  padding-right: 1rem;
  margin-right: 1rem;
  border-right: 1px solid var(--rule);
}

.signal-bar span:last-child { border-right: none; margin-right: 0; }

/* ─── Hero Right: Question Block ─────────────────────────────────── */

.hero-question {
  background: var(--surface);
  border: 1px solid var(--rule);
  border-top: 3px solid var(--accent);
  padding: 1.75rem;
}

.hero-question .eyebrow { margin-bottom: 1rem; }

.hero-question blockquote {
  font-family: var(--font-serif);
  font-size: 0.93rem;
  line-height: 1.72;
  color: var(--ink);
  font-style: italic;
}

/* Thread list inside hero right */
.hero-thread-list {
  margin-top: 1.5rem;
  border-top: 1px solid var(--rule);
  padding-top: 1rem;
}

.hero-thread-list li {
  display: flex;
  align-items: baseline;
  gap: 0.75rem;
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--rule);
}

.hero-thread-list li:first-child { border-top: 1px solid var(--rule); }

.tnum {
  font-family: var(--font-mono);
  font-size: 0.62rem;
  color: var(--accent);
  letter-spacing: 0.05em;
  flex-shrink: 0;
}

.tname {
  font-family: var(--font-sans);
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--ink);
}

/* ─── World Diagram ──────────────────────────────────────────────── */

.world-diagram-wrap {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.25rem 1.75rem;
}

.world-diagram-wrap svg {
  width: 100%;
  max-width: 175px;
  opacity: 0.85;
}

/* ─── Buttons ────────────────────────────────────────────────────── */

.btn-primary {
  display: inline-flex;
  align-items: center;
  font-family: var(--font-sans);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  background: var(--ink);
  color: #fff;
  padding: 0.65rem 1.35rem;
  border-radius: 2px;
  transition: background 0.18s;
}

.btn-primary:hover { background: var(--accent); }

.btn-secondary {
  display: inline-flex;
  align-items: center;
  font-family: var(--font-sans);
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--muted);
  padding: 0.65rem 1.35rem;
  border: 1px solid var(--line);
  border-radius: 2px;
  transition: color 0.18s, border-color 0.18s;
}

.btn-secondary:hover { color: var(--ink); border-color: var(--ink); }

/* ─── Section Header ─────────────────────────────────────────────── */

.section-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  padding-bottom: 1.75rem;
  border-bottom: 1px solid var(--rule);
  margin-bottom: 2.5rem;
}

.section-title {
  font-family: var(--font-sans);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink);
}

.section-count {
  font-family: var(--font-mono);
  font-size: 0.63rem;
  color: var(--muted);
  letter-spacing: 0.06em;
}

/* ─── At a Glance ────────────────────────────────────────────────── */

.glance-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
}

.glance-item {
  padding: 0 1.75rem 0 0;
  border-right: 1px solid var(--rule);
}

.glance-item:first-child { padding-left: 0; }
.glance-item:last-child { border-right: none; }
.glance-item:not(:first-child) { padding-left: 1.75rem; }

.glance-label {
  font-family: var(--font-mono);
  font-size: 0.63rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.5rem;
}

.glance-value {
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--ink);
  line-height: 1.4;
}

/* ─── Research Threads ───────────────────────────────────────────── */

.threads-list { display: flex; flex-direction: column; }

.thread {
  display: grid;
  grid-template-columns: 72px 1fr;
  gap: 2.5rem;
  padding: 2.5rem 0;
  border-top: 1px solid var(--rule);
}

.thread:last-child { border-bottom: 1px solid var(--rule); }

.thread-num {
  font-family: var(--font-mono);
  font-size: 3.2rem;
  font-weight: 700;
  color: var(--rule);
  line-height: 1;
  padding-top: 0.1rem;
  letter-spacing: -0.04em;
  user-select: none;
  transition: color 0.2s;
}

.thread:hover .thread-num { color: var(--line); }

.thread-label {
  font-family: var(--font-mono);
  font-size: 0.63rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.5rem;
}

.thread h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  letter-spacing: -0.01em;
}

.thread p {
  font-size: 0.92rem;
  color: var(--muted);
  line-height: 1.68;
  max-width: 64ch;
}

.thread-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-top: 1.25rem;
}

.tag {
  font-family: var(--font-mono);
  font-size: 0.6rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent);
  background: rgba(39, 82, 216, 0.06);
  border: 1px solid rgba(39, 82, 216, 0.18);
  padding: 0.2rem 0.55rem;
  border-radius: 2px;
}

/* ─── Four-col Grid ──────────────────────────────────────────────── */

.four-col {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 2.5rem;
}

.item-label {
  font-family: var(--font-mono);
  font-size: 0.63rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.5rem;
}

.item-title {
  font-family: var(--font-sans);
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--ink);
  margin-bottom: 0.4rem;
}

.item-text {
  font-family: var(--font-serif);
  font-size: 0.87rem;
  color: var(--muted);
  line-height: 1.65;
}

/* ─── Editorial List ─────────────────────────────────────────────── */

.editorial-list { display: flex; flex-direction: column; }

.editorial-item {
  display: grid;
  grid-template-columns: 150px 1fr;
  gap: 1.5rem;
  padding: 1.1rem 0;
  border-top: 1px solid var(--rule);
  align-items: baseline;
}

.editorial-item:last-child { border-bottom: 1px solid var(--rule); }

.rule-label {
  font-family: var(--font-mono);
  font-size: 0.63rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
}

.rule-text {
  font-family: var(--font-sans);
  font-size: 0.87rem;
  color: var(--muted);
  line-height: 1.55;
}

/* ─── Artifact Index ─────────────────────────────────────────────── */

.artifact-filters {
  display: flex;
  gap: 1.5rem;
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--rule);
  flex-wrap: wrap;
}

.artifact-filters a {
  font-family: var(--font-mono);
  font-size: 0.63rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
  transition: color 0.18s;
}

.artifact-filters a:hover { color: var(--accent); }
.artifact-filters a.active { color: var(--accent); }

.artifact-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.87rem;
}

.artifact-table th {
  font-family: var(--font-mono);
  font-size: 0.6rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
  text-align: left;
  padding: 0 1.5rem 0.75rem 0;
  border-bottom: 1px solid var(--rule);
  font-weight: normal;
}

.artifact-table td {
  padding: 1rem 1.5rem 1rem 0;
  border-bottom: 1px solid var(--rule);
  vertical-align: top;
}

.empty-state {
  padding: 4.5rem 0;
  text-align: center;
}

.empty-state p {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

/* ─── Footer ─────────────────────────────────────────────────────── */

footer {
  margin-top: 7rem;
  border-top: 1px solid var(--rule);
  padding: 2.5rem 0;
}

.footer-inner {
  width: var(--max-w);
  margin-inline: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
}

.footer-brand {
  font-family: var(--font-sans);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink);
}

.footer-meta {
  font-family: var(--font-mono);
  font-size: 0.62rem;
  letter-spacing: 0.06em;
  color: var(--muted);
  margin-top: 0.2rem;
}

.footer-links {
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.footer-links a {
  font-family: var(--font-mono);
  font-size: 0.63rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  transition: color 0.18s;
}

.footer-links a:hover { color: var(--accent); }

/* ─── Responsive ─────────────────────────────────────────────────── */

@media (max-width: 900px) {
  .hero-inner {
    grid-template-columns: 1fr;
    gap: 2.5rem;
  }

  .glance-grid {
    grid-template-columns: repeat(2, 1fr);
    row-gap: 2rem;
  }

  .glance-item {
    border-right: none;
    border-bottom: 1px solid var(--rule);
    padding: 0 0 1.5rem;
  }

  .glance-item:last-child { border-bottom: none; }
  .glance-item:not(:first-child) { padding-left: 0; }

  .thread {
    grid-template-columns: 48px 1fr;
    gap: 1.25rem;
  }

  .thread-num { font-size: 2rem; }

  .four-col { grid-template-columns: repeat(2, 1fr); gap: 1.75rem; }

  .editorial-item { grid-template-columns: 1fr; gap: 0.35rem; }

  .core-question-inner { grid-template-columns: 1fr; gap: 1.5rem; }
}

@media (max-width: 580px) {
  h1 { font-size: 1.85rem; }
  .four-col { grid-template-columns: 1fr; }
  .glance-grid { grid-template-columns: 1fr; }
}