@import url('https://fonts.googleapis.com/css2?family=Syne:wght@400;500;600;700;800&family=IBM+Plex+Serif:ital,wght@0,300;0,400;0,500;1,300;1,400&family=JetBrains+Mono:wght@300;400;500&display=swap');

/* ─── TOKENS ─── */
:root {
  --bg:          #040508;
  --surface:     #0C0D14;
  --surface-2:   #12141F;
  --border:      rgba(153, 69, 255, 0.12);
  --border-glow: rgba(153, 69, 255, 0.35);
  --purple:      #9945FF;
  --green:       #14F195;
  --text-1:      #E8E8F2;
  --text-2:      #9090A8;
  --text-3:      #55556A;
  --grad: linear-gradient(135deg, #9945FF, #14F195);
  --font-display: 'Syne', sans-serif;
  --font-body:    'IBM Plex Serif', Georgia, serif;
  --font-mono:    'JetBrains Mono', monospace;
  --nav-w:        240px;
  --ease:         cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

/* ─── RESET ─── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  background: var(--bg);
  color: var(--text-1);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  overflow-x: hidden;
}

/* ─── NOISE OVERLAY ─── */
body::before {
  content: '';
  position: fixed; inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 512 512' 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='0.03'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: 0;
  opacity: 0.4;
}

/* ─── SIDEBAR NAV ─── */
.sidebar {
  position: fixed;
  top: 0; left: 0;
  width: var(--nav-w);
  height: 100vh;
  display: flex;
  flex-direction: column;
  padding: 40px 28px;
  border-right: 1px solid var(--border);
  background: var(--bg);
  z-index: 100;
  gap: 0;
}

.sidebar-logo {
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--text-1);
  text-decoration: none;
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding-bottom: 32px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 32px;
}

.sidebar-logo .logo-sub {
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 400;
  color: var(--green);
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.sidebar-logo .logo-glyph {
  font-size: 22px;
  font-weight: 800;
  background: var(--grad);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1.1;
}

nav {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

nav a {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 400;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-3);
  text-decoration: none;
  padding: 9px 12px;
  border-radius: 6px;
  transition: all 0.2s var(--ease);
  display: flex;
  align-items: center;
  gap: 10px;
  position: relative;
}

nav a .nav-dot {
  width: 5px; height: 5px;
  border-radius: 50%;
  background: var(--text-3);
  flex-shrink: 0;
  transition: all 0.2s var(--ease);
}

nav a:hover {
  color: var(--text-1);
  background: var(--surface);
}

nav a:hover .nav-dot {
  background: var(--purple);
  box-shadow: 0 0 8px var(--purple);
}

nav a.active {
  color: var(--text-1);
  background: var(--surface);
}

nav a.active .nav-dot {
  background: var(--green);
  box-shadow: 0 0 8px var(--green);
}

.sidebar-footer {
  margin-top: auto;
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
}

.sidebar-footer a {
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-3);
  text-decoration: none;
  letter-spacing: 0.08em;
  transition: color 0.2s;
}

.sidebar-footer a:hover { color: var(--green); }

/* ─── MAIN CONTENT ─── */
.main {
  margin-left: var(--nav-w);
  flex: 1;
  padding: 72px 80px;
  max-width: calc(900px + var(--nav-w));
  position: relative;
  z-index: 1;
}

/* ─── PAGE HEADER ─── */
.page-header {
  margin-bottom: 56px;
}

.page-eyebrow {
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--green);
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.page-eyebrow::before {
  content: '';
  display: inline-block;
  width: 24px; height: 1px;
  background: var(--green);
}

h1 {
  font-family: var(--font-display);
  font-size: clamp(36px, 5vw, 52px);
  font-weight: 800;
  line-height: 1.08;
  letter-spacing: -0.02em;
  color: var(--text-1);
  margin-bottom: 20px;
}

h1 .grad-text {
  background: var(--grad);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.lead {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  color: var(--text-2);
  max-width: 580px;
  font-weight: 300;
}

.lead a {
  color: var(--purple);
  text-decoration: none;
  border-bottom: 1px solid rgba(153,69,255,0.3);
  transition: border-color 0.2s;
}

.lead a:hover { border-color: var(--purple); }

/* ─── SECTION LABEL ─── */
.section-label {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--text-3);
  margin-bottom: 28px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.section-label::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--border);
}

/* ─── PAPER CARDS ─── */
.paper-list {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.paper-card {
  padding: 28px 0;
  border-bottom: 1px solid var(--border);
  position: relative;
  transition: all 0.2s var(--ease);
}

.paper-card:first-child { border-top: 1px solid var(--border); }

.paper-card::before {
  content: '';
  position: absolute;
  left: -80px; top: 0;
  width: 2px; height: 0;
  background: var(--grad);
  transition: height 0.3s var(--ease);
}

.paper-card:hover::before { height: 100%; }

.paper-meta {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 10px;
}

.paper-date {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-3);
  letter-spacing: 0.06em;
}

.paper-authors {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-3);
}

.paper-authors strong { color: var(--purple); }

.paper-title {
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 600;
  line-height: 1.35;
  color: var(--text-1);
  margin-bottom: 12px;
  letter-spacing: -0.01em;
}

.paper-abstract {
  font-family: var(--font-body);
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-2);
  font-style: italic;
  margin-bottom: 16px;
  font-weight: 300;
}

.paper-links {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.chip {
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-2);
  padding: 5px 14px;
  border: 1px solid var(--border);
  border-radius: 20px;
  text-decoration: none;
  transition: all 0.2s var(--ease);
  background: transparent;
}

.chip:hover {
  color: var(--green);
  border-color: var(--green);
  box-shadow: 0 0 12px rgba(20, 241, 149, 0.15);
}

/* ─── HOME PAGE SPECIFIC ─── */
.home-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 48px;
}

.home-stat {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 20px 24px;
  display: flex;
  flex-direction: column;
  gap: 4px;
  transition: border-color 0.2s;
}

.home-stat:hover { border-color: var(--border-glow); }

.stat-label {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-3);
}

.stat-value {
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 700;
  color: var(--text-1);
}

.stat-value.grad { 
  background: var(--grad);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* Tags strip */
.tag-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 32px;
}

.tag {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-3);
  padding: 4px 12px;
  border: 1px solid var(--border);
  border-radius: 4px;
}

/* ─── BOOK PAGE ─── */
.book-hero {
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 40px;
  align-items: start;
  margin-bottom: 56px;
}

.book-cover {
  width: 180px;
  aspect-ratio: 2/3;
  background: var(--surface-2);
  border: 1px solid var(--border-glow);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
  box-shadow: 6px 6px 30px rgba(0,0,0,0.5), -1px 0 0 rgba(153,69,255,0.3);
}

.book-cover::before {
  content: '';
  position: absolute; inset: 0;
  background: linear-gradient(145deg, rgba(153,69,255,0.25) 0%, rgba(20,241,149,0.1) 100%);
}

.book-cover-inner {
  position: relative;
  text-align: center;
  padding: 20px;
}

.book-cover-title {
  font-family: var(--font-display);
  font-size: 13px;
  font-weight: 800;
  color: var(--text-1);
  line-height: 1.2;
  margin-bottom: 8px;
}

.book-cover-sub {
  font-family: var(--font-mono);
  font-size: 9px;
  color: var(--green);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.book-spine {
  position: absolute;
  left: 0; top: 0;
  width: 6px; height: 100%;
  background: var(--grad);
}

.book-meta-block { display: flex; flex-direction: column; gap: 20px; }

.book-title-lg {
  font-family: var(--font-display);
  font-size: clamp(28px, 3.5vw, 40px);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.02em;
}

.book-desc {
  font-family: var(--font-body);
  font-size: 15px;
  line-height: 1.75;
  color: var(--text-2);
  font-weight: 300;
  max-width: 480px;
}

.book-cta-row { display: flex; gap: 12px; flex-wrap: wrap; }

.btn-primary {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: #000;
  background: var(--green);
  padding: 10px 24px;
  border-radius: 6px;
  text-decoration: none;
  transition: all 0.2s var(--ease);
  border: none;
  cursor: pointer;
}

.btn-primary:hover { box-shadow: 0 0 20px rgba(20,241,149,0.4); transform: translateY(-1px); }

.btn-outline {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-2);
  background: transparent;
  padding: 10px 24px;
  border-radius: 6px;
  text-decoration: none;
  border: 1px solid var(--border);
  transition: all 0.2s var(--ease);
  cursor: pointer;
}

.btn-outline:hover { border-color: var(--purple); color: var(--purple); }

/* TOC */
.toc {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 32px;
  margin-bottom: 40px;
}

.toc-title {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--text-3);
  margin-bottom: 20px;
}

.toc-list { list-style: none; display: flex; flex-direction: column; gap: 0; }

.toc-item {
  display: grid;
  grid-template-columns: 32px 1fr auto;
  align-items: baseline;
  gap: 12px;
  padding: 10px 0;
  border-bottom: 1px solid var(--border);
  text-decoration: none;
  color: var(--text-2);
  transition: color 0.2s;
}

.toc-item:last-child { border-bottom: none; }
.toc-item:hover { color: var(--text-1); }

.toc-num {
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-3);
}

.toc-name {
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 400;
}

.toc-badge {
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 2px 8px;
  border-radius: 10px;
  background: rgba(20,241,149,0.1);
  color: var(--green);
}

.toc-badge.draft {
  background: rgba(153,69,255,0.1);
  color: var(--purple);
}

/* ─── MOBILE NAV ─── */
.mobile-nav-toggle {
  display: none;
  position: fixed;
  top: 16px; right: 16px;
  z-index: 200;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text-1);
  padding: 10px 14px;
  border-radius: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  cursor: pointer;
  letter-spacing: 0.06em;
}

/* ─── RESPONSIVE ─── */
@media (max-width: 900px) {
  :root { --nav-w: 0px; }

  .sidebar {
    transform: translateX(-100%);
    width: 260px;
    transition: transform 0.3s var(--ease);
  }

  .sidebar.open { transform: translateX(0); }

  .mobile-nav-toggle { display: block; }

  .main {
    margin-left: 0;
    padding: 48px 24px;
  }

  .home-grid { grid-template-columns: 1fr; }
  .book-hero { grid-template-columns: 1fr; }
  .book-cover { width: 140px; }
}

/* ─── FADE IN ─── */
.fade-up {
  opacity: 0;
  transform: translateY(20px);
  animation: fadeUp 0.6s var(--ease) forwards;
}

.fade-up:nth-child(1) { animation-delay: 0.05s; }
.fade-up:nth-child(2) { animation-delay: 0.12s; }
.fade-up:nth-child(3) { animation-delay: 0.19s; }
.fade-up:nth-child(4) { animation-delay: 0.26s; }
.fade-up:nth-child(5) { animation-delay: 0.33s; }
.fade-up:nth-child(6) { animation-delay: 0.40s; }
.fade-up:nth-child(7) { animation-delay: 0.47s; }

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

/* Glow pulse on active dot */
@keyframes pulse {
  0%, 100% { box-shadow: 0 0 8px var(--green); }
  50% { box-shadow: 0 0 16px var(--green), 0 0 4px var(--green); }
}

nav a.active .nav-dot { animation: pulse 2s infinite; }