/* ============================================================
   andriidanylov.com — shared stylesheet
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600&family=Space+Grotesk:wght@400;500;600;700&display=swap');

:root {
  --ink:           #0d1117;
  --ink-2:         #1c2333;
  --ink-3:         #243047;
  --surface:       #111827;
  --surface-2:     #1a2332;
  --surface-3:     #1e2d40;
  --accent:        #2563eb;
  --accent-bright: #3b82f6;
  --accent-glow:   rgba(59,130,246,0.12);
  --accent-muted:  rgba(59,130,246,0.08);
  --text-1:        #f0f6ff;
  --text-2:        #94a3b8;
  --text-3:        #64748b;
  --border:        rgba(148,163,184,0.10);
  --border-accent: rgba(59,130,246,0.30);
  --display:       'Space Grotesk', sans-serif;
  --body:          'Inter', sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  background: var(--ink);
  color: var(--text-1);
  font-family: var(--body);
  font-size: 16px;
  line-height: 1.7;
  overflow-x: hidden;
}

/* ── NAV ── */
nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: rgba(13,17,23,0.88);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
  padding: 0 2rem;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-family: var(--display);
  font-size: 17px;
  font-weight: 600;
  color: var(--text-1);
  letter-spacing: -0.3px;
  text-decoration: none;
}
.nav-logo span { color: var(--accent-bright); }

.nav-links {
  display: flex;
  gap: 1.75rem;
  list-style: none;
  align-items: center;
}
.nav-links a {
  font-size: 13.5px;
  color: var(--text-2);
  text-decoration: none;
  letter-spacing: 0.01em;
  transition: color 0.2s;
}
.nav-links a:hover,
.nav-links a.active { color: var(--text-1); }

.nav-cta {
  background: var(--accent) !important;
  color: white !important;
  padding: 6px 16px;
  border-radius: 6px;
  font-size: 13px !important;
  font-weight: 500;
}
.nav-cta:hover { background: var(--accent-bright) !important; }

.nav-mobile-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text-2);
  cursor: pointer;
  font-size: 22px;
}

/* ── BUTTONS ── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 22px;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 500;
  text-decoration: none;
  transition: all 0.2s;
  cursor: pointer;
  border: none;
  font-family: var(--body);
}
.btn-primary { background: var(--accent); color: white; }
.btn-primary:hover { background: var(--accent-bright); transform: translateY(-1px); }
.btn-outline {
  background: transparent;
  color: var(--text-1);
  border: 1px solid var(--border-accent);
}
.btn-outline:hover { background: var(--accent-muted); border-color: var(--accent-bright); }
.btn-sm { padding: 7px 16px; font-size: 13px; }

/* ── LAYOUT HELPERS ── */
.container { max-width: 1100px; margin: 0 auto; }
section { padding: 6rem 2rem; }

.section-eyebrow {
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent-bright);
  font-weight: 500;
  margin-bottom: 0.6rem;
}
.section-title {
  font-family: var(--display);
  font-size: clamp(1.9rem, 3.5vw, 2.6rem);
  font-weight: 700;
  letter-spacing: -0.025em;
  color: var(--text-1);
  margin-bottom: 1.5rem;
  line-height: 1.15;
}

/* ── TAGS ── */
.tag {
  display: inline-block;
  font-size: 12px;
  padding: 5px 12px;
  border-radius: 20px;
  background: var(--accent-muted);
  border: 1px solid var(--border-accent);
  color: var(--accent-bright);
  letter-spacing: 0.01em;
}
.tag-neutral {
  background: rgba(255,255,255,0.04);
  border: 1px solid var(--border);
  color: var(--text-3);
}

/* ── CARDS ── */
.card {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem 1.75rem;
  transition: border-color 0.25s;
}
.card:hover { border-color: var(--border-accent); }

/* ── ARTICLE CARDS ── */
.article-card {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem;
  text-decoration: none;
  display: block;
  transition: all 0.25s;
  position: relative;
}
.article-card:hover {
  border-color: var(--border-accent);
  transform: translateY(-2px);
  background: var(--surface-3);
}
.article-meta { display: flex; align-items: center; gap: 10px; margin-bottom: 0.75rem; }
.article-cat {
  font-size: 11px; padding: 3px 10px; border-radius: 20px;
  background: var(--accent-muted); border: 1px solid var(--border-accent);
  color: var(--accent-bright); text-transform: uppercase; letter-spacing: 0.08em; font-weight: 500;
}
.article-date { font-size: 12px; color: var(--text-3); }
.article-title {
  font-family: var(--display); font-size: 1rem; font-weight: 600;
  color: var(--text-1); line-height: 1.4; margin-bottom: 0.6rem;
}
.article-excerpt { font-size: 0.875rem; color: var(--text-2); line-height: 1.65; }
.article-arrow {
  position: absolute; bottom: 1.5rem; right: 1.5rem;
  color: var(--accent-bright); opacity: 0;
  transform: translateX(-4px); transition: all 0.2s; font-size: 18px;
}
.article-card:hover .article-arrow { opacity: 1; transform: translateX(0); }

/* ── FOOTER ── */
footer {
  background: var(--ink);
  border-top: 1px solid var(--border);
  padding: 2rem;
  text-align: center;
  font-size: 13px;
  color: var(--text-3);
}
footer a { color: var(--text-3); text-decoration: none; }
footer a:hover { color: var(--accent-bright); }

/* ── FADE-IN ── */
.fade-in {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.fade-in.visible { opacity: 1; transform: translateY(0); }

/* ── PROSE (articles/research) ── */
.prose { max-width: 720px; margin: 0 auto; }
.prose h2 {
  font-family: var(--display); font-size: 1.5rem; font-weight: 700;
  color: var(--text-1); margin: 2.5rem 0 0.75rem; letter-spacing: -0.02em;
}
.prose h3 {
  font-family: var(--display); font-size: 1.1rem; font-weight: 600;
  color: var(--text-1); margin: 2rem 0 0.6rem;
}
.prose p { color: var(--text-2); margin-bottom: 1.3rem; line-height: 1.8; }
.prose ul { color: var(--text-2); padding-left: 1.5rem; margin-bottom: 1.3rem; }
.prose ul li { margin-bottom: 0.4rem; line-height: 1.75; }
.prose strong { color: var(--text-1); font-weight: 600; }
.prose code {
  background: var(--surface-3); border: 1px solid var(--border);
  color: var(--accent-bright); font-size: 0.85em;
  padding: 2px 7px; border-radius: 4px; font-family: monospace;
}
.prose pre {
  background: var(--surface-2); border: 1px solid var(--border);
  border-radius: 10px; padding: 1.25rem 1.5rem; overflow-x: auto;
  margin: 1.5rem 0;
}
.prose pre code {
  background: none; border: none; padding: 0; color: var(--text-2);
  font-size: 0.875rem; line-height: 1.7;
}

/* diagram placeholder */
.diagram-placeholder {
  background: var(--surface-2); border: 1px dashed var(--border-accent);
  border-radius: 10px; padding: 2.5rem 2rem;
  text-align: center; margin: 2rem 0; color: var(--text-3);
  font-size: 0.9rem;
}
.diagram-placeholder .icon { font-size: 2rem; margin-bottom: 0.5rem; }

/* callout box */
.callout {
  background: var(--accent-muted); border: 1px solid var(--border-accent);
  border-left: 3px solid var(--accent-bright);
  border-radius: 8px; padding: 1rem 1.25rem; margin: 1.5rem 0;
  font-size: 0.9rem; color: var(--text-2);
}

/* ── ARTICLE PAGE HERO ── */
.article-hero {
  padding: 7rem 2rem 3rem;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}
.article-hero-inner { max-width: 720px; margin: 0 auto; }
.article-hero-cat {
  display: inline-block; font-size: 11px; padding: 4px 12px; border-radius: 20px;
  background: var(--accent-muted); border: 1px solid var(--border-accent);
  color: var(--accent-bright); text-transform: uppercase; letter-spacing: 0.1em;
  font-weight: 500; margin-bottom: 1rem;
}
.article-hero h1 {
  font-family: var(--display); font-size: clamp(1.8rem, 4vw, 2.8rem);
  font-weight: 700; letter-spacing: -0.03em; color: var(--text-1);
  line-height: 1.1; margin-bottom: 1rem;
}
.article-hero-meta { font-size: 13px; color: var(--text-3); display: flex; gap: 1.5rem; flex-wrap: wrap; }

/* ── MOBILE ── */
@media (max-width: 768px) {
  .nav-links { display: none; }
  .nav-links.open {
    display: flex; flex-direction: column;
    position: absolute; top: 60px; left: 0; right: 0;
    background: var(--ink-2); padding: 1rem 2rem 1.5rem;
    border-bottom: 1px solid var(--border); gap: 1rem;
  }
  .nav-mobile-toggle { display: block; }
  section { padding: 4rem 1.25rem; }
}