/* ============================================================
   Quantum AI Hub — Shared Stylesheet
   Dark academic theme with quantum-inspired aesthetics
   ============================================================ */

:root {
  --bg:        #080c18;
  --surface:   #0f1629;
  --card:      #16203a;
  --card-hov:  #1e2d4f;
  --border:    #243050;
  --primary:   #7c5cfc;
  --primary-l: #a07bff;
  --cyan:      #22d3ee;
  --green:     #4ade80;
  --amber:     #fbbf24;
  --red:       #f87171;
  --text:      #e2e8f0;
  --muted:     #8b9ab5;
  --code-bg:   #0d1117;
  --radius:    10px;
  --shadow:    0 4px 24px rgba(0,0,0,0.5);
  --glow:      0 0 20px rgba(124,92,252,0.25);
}

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

html { scroll-behavior: smooth; font-size: 16px; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Inter', 'Segoe UI', system-ui, sans-serif;
  line-height: 1.7;
  min-height: 100vh;
}

/* ---- Typography ---- */
h1,h2,h3,h4,h5 {
  font-family: 'IBM Plex Mono', 'Fira Code', monospace;
  font-weight: 600;
  line-height: 1.3;
  color: var(--text);
}
h1 { font-size: clamp(1.8rem, 4vw, 2.8rem); }
h2 { font-size: clamp(1.4rem, 3vw, 2rem); }
h3 { font-size: 1.25rem; }
h4 { font-size: 1.05rem; color: var(--cyan); }

p { margin-bottom: 1em; color: var(--text); }
a { color: var(--primary-l); text-decoration: none; transition: color .2s; }
a:hover { color: var(--cyan); }
strong { color: var(--text); font-weight: 600; }
em { color: var(--cyan); font-style: italic; }

code {
  font-family: 'IBM Plex Mono', 'Fira Code', monospace;
  background: var(--code-bg);
  color: var(--cyan);
  padding: .15em .45em;
  border-radius: 4px;
  font-size: .88em;
}
pre {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.2rem 1.4rem;
  overflow-x: auto;
  margin: 1.2em 0;
}
pre code { background: none; padding: 0; color: var(--text); font-size: .85em; }

/* ---- Layout ---- */
.container { max-width: 1200px; margin: 0 auto; padding: 0 1.5rem; }
.container-wide { max-width: 1400px; margin: 0 auto; padding: 0 1.5rem; }
.container-narrow { max-width: 860px; margin: 0 auto; padding: 0 1.5rem; }

/* ---- Navigation ---- */
nav {
  position: sticky; top: 0; z-index: 100;
  background: rgba(8,12,24,.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: 0;
}
.nav-inner {
  display: flex; align-items: stretch; gap: 0;
  max-width: 1400px; margin: 0 auto; padding: 0 1.25rem;
  height: 48px;
}
.nav-logo {
  font-family: 'IBM Plex Mono', monospace;
  font-weight: 700;
  font-size: 1rem;
  color: var(--primary-l);
  white-space: nowrap;
  display: flex; align-items: center;
  padding-right: 1.25rem;
  border-right: 1px solid var(--border);
  flex-shrink: 0;
}
.nav-logo span { color: var(--cyan); }

/* Section anchors (left group) */
.nav-sections {
  display: flex; align-items: center; gap: 0;
  padding: 0 .5rem;
  border-right: 1px solid var(--border);
  flex-shrink: 0;
}
.nav-sections a {
  color: var(--muted);
  padding: 0 .7rem;
  height: 48px; line-height: 48px;
  font-size: .82rem; font-weight: 600;
  letter-spacing: .02em;
  transition: color .2s, background .2s;
  white-space: nowrap;
  text-transform: uppercase;
}
.nav-sections a:hover, .nav-sections a.active {
  color: var(--text);
  background: rgba(124,92,252,.12);
}

/* Paper sub-page links (right group) */
.nav-papers {
  display: flex; align-items: center; gap: 0;
  padding: 0 .5rem;
  flex: 1;
  overflow: hidden;
}
.nav-papers a {
  color: var(--muted);
  padding: 0 .55rem;
  height: 48px; line-height: 48px;
  font-size: .78rem; font-weight: 500;
  transition: color .2s;
  white-space: nowrap;
}
.nav-papers a:hover, .nav-papers a.active { color: var(--primary-l); }

/* Separator dot between paper links */
.nav-sep {
  color: var(--border);
  font-size: .7rem;
  padding: 0 .1rem;
  line-height: 48px;
  user-select: none;
  flex-shrink: 0;
}

/* Search */
.nav-search {
  display: flex; align-items: center;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 7px;
  padding: .28rem .7rem;
  gap: .35rem;
  margin: auto 0 auto .75rem;
  flex-shrink: 0;
}
.nav-search input {
  background: none; border: none; outline: none;
  color: var(--text); font-size: .8rem;
  width: 130px;
}
.nav-search input::placeholder { color: var(--muted); }
.nav-kbd {
  font-size: .65rem; color: var(--muted);
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 3px; padding: .05rem .3rem;
  font-family: 'IBM Plex Mono', monospace;
}

/* ---- Hero ---- */
.hero {
  position: relative;
  padding: 5rem 0 4rem;
  overflow: hidden;
  text-align: center;
}
.hero-bg {
  position: absolute; inset: 0; z-index: 0;
  background: radial-gradient(ellipse 80% 60% at 50% -10%,
    rgba(124,92,252,.18) 0%, transparent 70%);
}
.hero-grid {
  position: absolute; inset: 0; z-index: 0;
  background-image:
    linear-gradient(rgba(36,48,80,.4) 1px, transparent 1px),
    linear-gradient(90deg, rgba(36,48,80,.4) 1px, transparent 1px);
  background-size: 60px 60px;
  mask-image: radial-gradient(ellipse 80% 80% at 50% 50%, black 30%, transparent 80%);
}
.hero-inner { position: relative; z-index: 1; }
.hero-badge {
  display: inline-flex; align-items: center; gap: .5rem;
  background: rgba(124,92,252,.15);
  border: 1px solid rgba(124,92,252,.4);
  border-radius: 999px;
  padding: .3rem 1rem;
  font-size: .8rem;
  color: var(--primary-l);
  margin-bottom: 1.5rem;
  font-family: 'IBM Plex Mono', monospace;
}
.hero-badge::before { content: '⬡'; font-size: 1rem; }
.hero h1 { margin-bottom: 1rem; }
.hero h1 .hl { color: var(--primary-l); }
.hero h1 .hl2 { color: var(--cyan); }
.hero p.lead {
  font-size: 1.15rem;
  color: var(--muted);
  max-width: 680px;
  margin: 0 auto 2rem;
}
.hero-stats {
  display: flex; justify-content: center; gap: 2.5rem;
  flex-wrap: wrap; margin-top: 2rem;
}
.stat { text-align: center; }
.stat-num {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 2rem; font-weight: 700;
  color: var(--primary-l);
  display: block;
}
.stat-label { font-size: .8rem; color: var(--muted); text-transform: uppercase; letter-spacing: .05em; }

/* ---- Section ---- */
section { padding: 3.5rem 0; }
.section-title {
  display: flex; align-items: center; gap: .75rem;
  margin-bottom: 2rem;
}
.section-title h2 { margin: 0; }
.section-icon {
  width: 36px; height: 36px;
  background: rgba(124,92,252,.2);
  border: 1px solid rgba(124,92,252,.4);
  border-radius: 8px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.1rem; flex-shrink: 0;
}
.section-line {
  flex: 1;
  height: 1px;
  background: linear-gradient(90deg, var(--border), transparent);
}

/* ---- Cards ---- */
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  transition: all .25s;
  position: relative;
  overflow: hidden;
}
.card:hover {
  border-color: var(--primary);
  box-shadow: var(--glow);
  transform: translateY(-2px);
}
.card::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--primary), var(--cyan));
  opacity: 0;
  transition: opacity .25s;
}
.card:hover::before { opacity: 1; }

/* ---- Paper Card ---- */
.paper-card { margin-bottom: 1rem; }
.paper-meta {
  display: flex; flex-wrap: wrap; align-items: center; gap: .5rem;
  margin-bottom: .6rem;
}
.paper-year {
  font-family: 'IBM Plex Mono', monospace;
  font-size: .75rem; font-weight: 700;
  color: var(--bg); background: var(--primary-l);
  padding: .15rem .5rem; border-radius: 4px;
}
.tag {
  font-size: .72rem;
  padding: .15rem .5rem;
  border-radius: 4px;
  border: 1px solid;
  font-weight: 500;
  font-family: 'IBM Plex Mono', monospace;
}
.tag-nlp    { color: #a78bfa; border-color: rgba(167,139,250,.35); background: rgba(167,139,250,.08); }
.tag-vision { color: #34d399; border-color: rgba(52,211,153,.35);  background: rgba(52,211,153,.08); }
.tag-gen    { color: #f472b6; border-color: rgba(244,114,182,.35); background: rgba(244,114,182,.08); }
.tag-theory { color: #fbbf24; border-color: rgba(251,191,36,.35);  background: rgba(251,191,36,.08); }
.tag-hw     { color: #22d3ee; border-color: rgba(34,211,238,.35);  background: rgba(34,211,238,.08); }
.tag-hybrid { color: #fb923c; border-color: rgba(251,146,60,.35);  background: rgba(251,146,60,.08); }
.tag-algo   { color: #e879f9; border-color: rgba(232,121,249,.35); background: rgba(232,121,249,.08); }
.tag-news   { color: #4ade80; border-color: rgba(74,222,128,.35);  background: rgba(74,222,128,.08); }

.paper-title { font-size: 1rem; font-weight: 600; margin-bottom: .3rem; }
.paper-title a { color: var(--text); }
.paper-title a:hover { color: var(--primary-l); }
.paper-authors { font-size: .82rem; color: var(--muted); margin-bottom: .4rem; }
.paper-abstract { font-size: .88rem; color: var(--muted); line-height: 1.6; }
.paper-links { display: flex; gap: .6rem; margin-top: .8rem; flex-wrap: wrap; }
.btn {
  display: inline-flex; align-items: center; gap: .3rem;
  padding: .3rem .75rem;
  border-radius: 6px;
  font-size: .78rem; font-weight: 600;
  transition: all .2s;
  cursor: pointer; border: none;
  font-family: 'IBM Plex Mono', monospace;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-l); color: #fff; }
.btn-ghost { background: var(--card-hov); color: var(--text); border: 1px solid var(--border); }
.btn-ghost:hover { border-color: var(--primary); color: var(--primary-l); }
.btn-cyan { background: rgba(34,211,238,.15); color: var(--cyan); border: 1px solid rgba(34,211,238,.3); }
.btn-cyan:hover { background: rgba(34,211,238,.25); }

/* ---- Grid layouts ---- */
.grid-2 { display: grid; grid-template-columns: repeat(auto-fill, minmax(420px,1fr)); gap: 1rem; align-items: start; }
.grid-3 { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px,1fr)); gap: 1rem; align-items: start; }
.grid-4 { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px,1fr)); gap: 1rem; align-items: stretch; }

/* ---- Timeline ---- */
.timeline { position: relative; }
.timeline-year-group { margin-bottom: 2rem; }
.timeline-year-header {
  display: flex; align-items: center; gap: 1rem;
  margin-bottom: 1rem;
}
.timeline-year-label {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 1.4rem; font-weight: 700;
  color: var(--primary-l);
  min-width: 60px;
}
.timeline-year-line {
  flex: 1; height: 1px;
  background: linear-gradient(90deg, var(--border), transparent);
}

/* ---- Hardware milestone cards ---- */
.hw-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.2rem 1.4rem;
}

/* Remove default list bullets — milestone cards use ::before ▸ instead */
.milestone-highlights,
.hw-card ul {
  list-style: none;
  padding-left: 0;
  margin: 0;
}

.hw-card .hw-name {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 1rem; font-weight: 700;
  color: var(--cyan);
  margin-bottom: .3rem;
}
.hw-card .hw-org { font-size: .8rem; color: var(--muted); margin-bottom: .6rem; }
.hw-spec { display: flex; flex-wrap: wrap; gap: .4rem; margin-top: .6rem; }
.hw-spec-item {
  font-size: .75rem;
  background: rgba(34,211,238,.08);
  border: 1px solid rgba(34,211,238,.2);
  border-radius: 4px;
  padding: .2rem .5rem;
  color: var(--cyan);
  font-family: 'IBM Plex Mono', monospace;
}

/* ---- Conference table ---- */
.conf-table { width: 100%; border-collapse: collapse; font-size: .9rem; }
.conf-table th {
  text-align: left; padding: .7rem 1rem;
  background: var(--surface);
  color: var(--muted); font-weight: 600;
  font-family: 'IBM Plex Mono', monospace;
  font-size: .78rem; text-transform: uppercase; letter-spacing: .05em;
  border-bottom: 1px solid var(--border);
}
.conf-table td {
  padding: .75rem 1rem;
  border-bottom: 1px solid rgba(36,48,80,.5);
  vertical-align: top;
}
.conf-table tr:hover td { background: var(--card); }
.conf-name { font-weight: 600; color: var(--text); }
.conf-deadline { color: var(--amber); font-family: 'IBM Plex Mono', monospace; font-size: .82rem; }
.conf-date { color: var(--muted); font-size: .82rem; }

/* ---- MathJax overrides ---- */
.mjx-chtml { color: var(--text) !important; }
.math-block {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.2rem 1.5rem;
  margin: 1.2em 0;
  overflow-x: auto;
  text-align: center;
}
.math-label {
  text-align: right;
  font-size: .78rem;
  color: var(--muted);
  font-family: 'IBM Plex Mono', monospace;
  margin-top: .4rem;
}

/* ---- Architecture diagram ---- */
.arch-diagram {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.4rem;
  overflow-x: auto;
  margin: 1.2em 0;
}
.arch-diagram pre {
  background: none; border: none; padding: 0; margin: 0;
  font-size: .82rem; line-height: 1.5;
  color: var(--cyan);
}

/* ---- Paper page layout ---- */
.paper-page-header {
  padding: 3rem 0 2rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 2.5rem;
}
.paper-page-meta {
  display: flex; flex-wrap: wrap; gap: .5rem;
  margin-bottom: 1rem;
}
.paper-page-title { margin-bottom: .75rem; }
.paper-page-authors {
  font-size: 1rem;
  color: var(--muted);
  margin-bottom: .5rem;
}
.paper-page-venue {
  font-size: .85rem;
  font-family: 'IBM Plex Mono', monospace;
  color: var(--cyan);
}
.toc {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.2rem 1.5rem;
  margin-bottom: 2rem;
}
.toc h4 { font-size: .8rem; text-transform: uppercase; letter-spacing: .08em; color: var(--muted); margin-bottom: .7rem; }
.toc ol { padding-left: 1.2rem; }
.toc li { margin-bottom: .3rem; font-size: .88rem; }
.content-section { margin-bottom: 2.5rem; }
.content-section h2 {
  font-size: 1.35rem;
  color: var(--text);
  border-bottom: 1px solid var(--border);
  padding-bottom: .5rem;
  margin-bottom: 1.2rem;
}
.content-section h3 {
  font-size: 1.1rem;
  color: var(--primary-l);
  margin: 1.2rem 0 .6rem;
}
.highlight-box {
  background: rgba(124,92,252,.08);
  border-left: 3px solid var(--primary);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 1rem 1.2rem;
  margin: 1rem 0;
}
.callout {
  background: rgba(34,211,238,.06);
  border-left: 3px solid var(--cyan);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 1rem 1.2rem;
  margin: 1rem 0;
}
.callout-warn {
  background: rgba(251,191,36,.06);
  border-left: 3px solid var(--amber);
}

/* ---- Breadcrumb ---- */
.breadcrumb {
  display: flex; align-items: center; gap: .4rem;
  font-size: .82rem; color: var(--muted);
  margin-bottom: 1.5rem;
}
.breadcrumb a { color: var(--muted); }
.breadcrumb a:hover { color: var(--primary-l); }
.breadcrumb-sep { opacity: .4; }

/* ---- Search overlay ---- */
#search-overlay {
  display: none;
  position: fixed; inset: 0; z-index: 200;
  background: rgba(8,12,24,.85);
  backdrop-filter: blur(8px);
  align-items: flex-start;
  justify-content: center;
  padding-top: 10vh;
}
#search-overlay.active { display: flex; }
.search-box {
  background: var(--card);
  border: 1px solid var(--primary);
  border-radius: 12px;
  width: 100%; max-width: 640px;
  box-shadow: var(--glow);
  overflow: hidden;
}
.search-input {
  width: 100%; background: none; border: none; outline: none;
  padding: 1rem 1.2rem;
  color: var(--text); font-size: 1.1rem;
  font-family: 'IBM Plex Mono', monospace;
}
.search-results { border-top: 1px solid var(--border); max-height: 420px; overflow-y: auto; }
.search-result-item {
  display: block; padding: .9rem 1.2rem;
  border-bottom: 1px solid rgba(36,48,80,.5);
  transition: background .15s;
  color: var(--text);
}
.search-result-item:hover { background: var(--card-hov); }
.search-result-title { font-weight: 600; margin-bottom: .2rem; }
.search-result-meta { font-size: .78rem; color: var(--muted); }
.search-hint {
  padding: .6rem 1.2rem;
  font-size: .75rem; color: var(--muted);
  font-family: 'IBM Plex Mono', monospace;
  border-top: 1px solid var(--border);
}

/* ---- Footer ---- */
footer {
  border-top: 1px solid var(--border);
  padding: 1.5rem 0;
  color: var(--muted);
  font-size: .83rem;
  background: var(--surface);
}

/* ---- Utility ---- */
.text-muted { color: var(--muted); }
.text-cyan { color: var(--cyan); }
.text-primary { color: var(--primary-l); }
.text-green { color: var(--green); }
.text-amber { color: var(--amber); }
.monospace { font-family: 'IBM Plex Mono', monospace; }
.divider { height: 1px; background: var(--border); margin: 2rem 0; }

/* ---- arXiv category cards (uniform height, flex column) ---- */
.arxiv-cat-card {
  padding: 1rem 1rem 1.1rem;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  min-height: 110px;
}
.arxiv-cat-tag {
  font-family: 'IBM Plex Mono', monospace;
  font-size: .95rem;
  font-weight: 700;
  color: var(--cyan);
  margin-bottom: .3rem;
  letter-spacing: .03em;
}
.arxiv-cat-label {
  font-size: .72rem;
  font-weight: 600;
  color: var(--text);
  text-transform: uppercase;
  letter-spacing: .06em;
  margin-bottom: .45rem;
}
.arxiv-cat-desc {
  font-size: .78rem;
  color: var(--muted);
  line-height: 1.5;
}

/* ---- Scrollbar ---- */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--primary); }

/* ---- Responsive ---- */
@media (max-width: 768px) {
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .hero { padding: 3rem 0 2.5rem; }
  .hero-stats { gap: 1.5rem; }
  .nav-links { display: none; }
  .nav-search input { width: 100px; }
}

/* ---- Animations ---- */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(16px); }
  to   { opacity: 1; transform: translateY(0); }
}
.fade-up { animation: fadeUp .5s ease both; }
.fade-up-d1 { animation-delay: .1s; }
.fade-up-d2 { animation-delay: .2s; }
.fade-up-d3 { animation-delay: .3s; }

@keyframes pulse-glow {
  0%, 100% { box-shadow: 0 0 8px rgba(124,92,252,.3); }
  50%       { box-shadow: 0 0 20px rgba(124,92,252,.7); }
}
.pulse { animation: pulse-glow 2.5s ease-in-out infinite; }

/* ---- Quantum circuit SVG style ---- */
.circuit-container {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem;
  overflow-x: auto;
  margin: 1.2em 0;
}
.circuit-container svg { display: block; margin: 0 auto; }