/* NeuroNet — standalone CSS – Dark theme */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:          #0f1117;
  --card:        #161b27;
  --border:      #1e2535;
  --fg:          #e8ecf0;
  --muted:       #8494a8;
  --primary:     #38bdf8;
  --brain:       #a78bfa;
  --brain-light: #1e1b36;
  --ai:          #34d399;
  --ai-light:    #0e2519;
  --tag-brain-bg:#27224a; --tag-brain-fg:#c4b5fd;
  --tag-ai-bg:   #0d2b20; --tag-ai-fg:   #6ee7b7;
  --radius:      .75rem;
  font-size:     16px;
  color-scheme:  dark;
}

body {
  background: var(--bg);
  color: var(--fg);
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  line-height: 1.6;
  min-height: 100vh;
}

a { color: inherit; text-decoration: none; }
a:hover { color: var(--primary); }

/* Container */
.wrap { max-width: 75rem; margin-inline: auto; padding-inline: 1.25rem; }
@media (min-width: 640px)  { .wrap { padding-inline: 1.5rem; } }
@media (min-width: 1024px) { .wrap { padding-inline: 2rem; } }
.wrap-sm { max-width: 48rem; margin-inline: auto; padding-inline: 1.25rem; }
@media (min-width: 640px)  { .wrap-sm { padding-inline: 1.5rem; } }
@media (min-width: 1024px) { .wrap-sm { padding-inline: 2rem; } }

/* Header */
header {
  position: sticky; top: 0; z-index: 50;
  border-bottom: 1px solid var(--border);
  background: color-mix(in srgb, var(--card) 85%, transparent);
  backdrop-filter: blur(12px);
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 4rem; gap: 1rem;
}
.logo { display: flex; align-items: center; gap: .5rem; font-weight: 700; font-size: 1.2rem; }
.logo-diamond { color: var(--primary); font-size: 1rem; }
nav { display: flex; gap: 1.5rem; }
nav a { font-size: .875rem; font-weight: 500; color: var(--muted); transition: color .15s; }
nav a:hover, nav a.active { color: var(--fg); }
.lang-switch { display: flex; gap: .5rem; }
.lang-btn {
  font-size: .75rem; font-weight: 600; padding: .25rem .6rem;
  border: 1px solid var(--border); border-radius: .4rem;
  background: var(--card); color: var(--muted); cursor: pointer;
  transition: all .15s; text-decoration: none;
}
.lang-btn:hover, .lang-btn.active { border-color: var(--primary); color: var(--primary); }

/* Hero */
.hero { padding: 5rem 0 3.5rem; text-align: center; }
.hero h1 {
  font-size: clamp(2.25rem, 5vw, 3.75rem); font-weight: 800;
  letter-spacing: -.03em; line-height: 1.1; color: var(--fg);
  max-width: 48rem; margin-inline: auto;
}
.hero p { margin-top: 1.25rem; font-size: 1.125rem; color: var(--muted); max-width: 36rem; margin-inline: auto; }
.hero-btns { display: flex; gap: .75rem; justify-content: center; margin-top: 2rem; flex-wrap: wrap; }

/* Buttons */
.btn {
  display: inline-flex; align-items: center; gap: .5rem;
  padding: .6rem 1.4rem; border-radius: .6rem; font-size: .875rem; font-weight: 600;
  cursor: pointer; border: none; transition: all .15s; text-decoration: none;
}
.btn-brain { background: var(--brain-light); color: var(--brain); }
.btn-brain:hover { background: #26224e; color: var(--brain); }
.btn-ai    { background: var(--ai-light);   color: var(--ai); }
.btn-ai:hover    { background: #12362a; color: var(--ai); }

/* Cards grid */
.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem; }
@media (max-width: 640px) { .grid2 { grid-template-columns: 1fr; } }
.grid3 { display: grid; grid-template-columns: repeat(3,1fr); gap: 1rem; }
@media (max-width: 900px) { .grid3 { grid-template-columns: 1fr 1fr; } }
@media (max-width: 560px) { .grid3 { grid-template-columns: 1fr; } }

/* Card */
.card {
  display: flex; flex-direction: column; gap: 1rem;
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 2rem;
  transition: box-shadow .2s, border-color .2s;
  color: var(--fg); text-decoration: none;
}
.card:hover { box-shadow: 0 0 0 1px var(--border), 0 8px 24px #0007; border-color: var(--muted); }
.card-icon {
  width: 3rem; height: 3rem; display: flex; align-items: center; justify-content: center;
  border-radius: .6rem; font-size: 1.4rem;
}
.card-icon-brain { background: var(--brain-light); color: var(--brain); }
.card-icon-ai    { background: var(--ai-light);    color: var(--ai); }
.card h2 { font-size: 1.5rem; font-weight: 700; }
.card h3 { font-size: 1.125rem; font-weight: 700; }
.card p, .card-desc  { font-size: .875rem; color: var(--muted); flex: 1; }
.card-arrow { font-size: .8rem; color: var(--muted); margin-top: auto; }
.card:hover .card-arrow { color: var(--primary); }
.card-arrow-brain { color: var(--brain); }
.card-arrow-ai    { color: var(--ai); }

/* Mini card (related section) */
.mini-card {
  display: flex; align-items: flex-start; gap: 1rem;
  background: var(--card); border: 1px solid var(--border);
  border-radius: .6rem; padding: 1.25rem 1.5rem;
  transition: border-color .15s; text-decoration: none; color: var(--fg);
}
.mini-card:hover { border-color: var(--muted); }
.mini-dot-brain { width: .5rem; height: .5rem; border-radius: 50%; background: var(--brain); margin-top: .45rem; flex-shrink: 0; }
.mini-dot-ai    { width: .5rem; height: .5rem; border-radius: 50%; background: var(--ai);    margin-top: .45rem; flex-shrink: 0; }
.mini-card-body h4 { font-size: .9rem; font-weight: 600; }
.mini-card-body p  { font-size: .8rem; color: var(--muted); margin-top: .25rem; }

/* Tags */
.tags { display: flex; flex-wrap: wrap; gap: .5rem; margin-top: 1rem; }
.tag-brain { font-size: .75rem; padding: .2rem .6rem; border-radius: 999px; background: var(--tag-brain-bg); color: var(--tag-brain-fg); }
.tag-ai    { font-size: .75rem; padding: .2rem .6rem; border-radius: 999px; background: var(--tag-ai-bg);    color: var(--tag-ai-fg); }

/* Article badge */
.article-badge {
  display: inline-flex; align-items: center; gap: .5rem;
  font-size: .75rem; font-weight: 600; padding: .35rem .75rem;
  border-radius: .4rem; margin-bottom: 1rem;
}
.article-badge-brain { background: var(--brain-light); color: var(--brain); }
.article-badge-ai    { background: var(--ai-light);    color: var(--ai); }

/* Article page */
.article { padding-top: 3rem; padding-bottom: 5rem; }
.back-link { display: inline-flex; align-items: center; gap: .4rem; font-size: .875rem; color: var(--muted); margin-bottom: 1.5rem; }
.back-link:hover { color: var(--fg); }
.article h1 { font-size: clamp(1.75rem, 4vw, 2.5rem); font-weight: 800; letter-spacing: -.02em; line-height: 1.15; margin-top: .25rem; }
.article-subtitle { margin-top: .5rem; font-size: 1.1rem; color: var(--muted); }
.section-divider { height: 1px; background: var(--border); margin: 2rem 0; }
.article-section h2 { font-size: 1.2rem; font-weight: 700; margin-bottom: 1rem; }
.article-section p  { color: var(--muted); line-height: 1.75; margin-bottom: .75rem; }
.article-section ul { list-style: none; display: flex; flex-direction: column; gap: .5rem; }
.article-section li { display: flex; align-items: flex-start; gap: .75rem; font-size: .9rem; color: var(--muted); }
.li-dot { width: .4rem; height: .4rem; border-radius: 50%; background: var(--primary); margin-top: .55rem; flex-shrink: 0; }
.li-dot-brain { background: var(--brain); }
.li-dot-ai    { background: var(--ai); }
.related { margin-top: 3rem; }
.related h2 { font-size: 1rem; font-weight: 600; color: var(--muted); margin-bottom: 1rem; }

/* Page hero (section overview) */
.page-hero { padding: 3.5rem 0 2rem; }
.page-hero h1 { font-size: clamp(1.75rem, 4vw, 2.75rem); font-weight: 800; letter-spacing: -.02em; }
.page-hero p   { margin-top: .75rem; color: var(--muted); font-size: 1rem; }

/* Footer */
footer { border-top: 1px solid var(--border); padding: 2rem 0; margin-top: 4rem; }
.footer-inner { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 1rem; font-size: .8rem; color: var(--muted); }
.footer-links { display: flex; gap: .5rem; align-items: center; }
.footer-links a { font-size: .8rem; color: var(--muted); transition: color .15s; }
.footer-links a:hover { color: var(--fg); }

/* Utility */
.mt1 { margin-top: .5rem; }
.mt2 { margin-top: 1rem; }
.mt3 { margin-top: 1.5rem; }
.mt4 { margin-top: 2rem; }
.mb2 { margin-bottom: 1rem; }
.pb4 { padding-bottom: 2rem; }
.space-y > * + * { margin-top: 1rem; }

@media (max-width: 640px) {
  nav { display: none; }
  .hero { padding: 3rem 0 2rem; }
  .article { padding-top: 2rem; padding-bottom: 3rem; }
  .grid3 { grid-template-columns: 1fr; }
}