/* ===== Design tokens ===== */
:root {
  --bg: #0a0a0f;
  --bg-elev: #121218;
  --bg-elev-2: #191922;
  --border: #24242f;
  --text: #e8e8ee;
  --text-muted: #9a9aab;
  --text-dim: #6b6b7c;
  --accent-1: #2dd4bf;
  --accent-2: #8b5cf6;
  --accent-grad: linear-gradient(135deg, var(--accent-1), var(--accent-2));
  --radius: 12px;
  --max-width: 1080px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { animation-duration: 0.001ms !important; animation-iteration-count: 1 !important; transition-duration: 0.001ms !important; }
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

section { padding: 96px 0; border-bottom: 1px solid var(--border); }
section:last-of-type { border-bottom: none; }

.eyebrow {
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent-1);
  margin: 0 0 12px;
}

h2.section-title {
  font-size: clamp(28px, 4vw, 38px);
  margin: 0 0 40px;
  letter-spacing: -0.01em;
}

/* ===== Nav ===== */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: rgba(10, 10, 15, 0.8);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 16px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-logo {
  font-weight: 700;
  font-family: var(--mono);
  background: var(--accent-grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  font-size: 18px;
}
.nav-links {
  display: flex;
  gap: 28px;
  list-style: none;
  margin: 0;
  padding: 0;
}
.nav-links a {
  font-size: 14px;
  color: var(--text-muted);
  transition: color 0.2s;
  padding: 4px 0;
  border-bottom: 2px solid transparent;
}
.nav-links a:hover,
.nav-links a.active {
  color: var(--text);
  border-bottom-color: var(--accent-1);
}
.nav-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text);
  font-size: 24px;
  cursor: pointer;
}

@media (max-width: 768px) {
  .nav-toggle { display: block; }
  .nav-links {
    position: absolute;
    top: 100%; left: 0; right: 0;
    background: var(--bg-elev);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    gap: 0;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.25s ease;
  }
  .nav-links.open { max-height: 400px; }
  .nav-links li { width: 100%; }
  .nav-links a {
    display: block;
    padding: 14px 24px;
    border-bottom: 1px solid var(--border);
    border-left: 2px solid transparent;
  }
  .nav-links a.active { border-bottom-color: var(--border); border-left-color: var(--accent-1); }
}

/* ===== Hero ===== */
.hero {
  padding: 160px 0 96px;
  border-bottom: 1px solid var(--border);
  position: relative;
}
.hero::before {
  content: "";
  position: absolute;
  top: -10%; right: -10%;
  width: 500px; height: 500px;
  background: radial-gradient(circle, rgba(139, 92, 246, 0.15), transparent 70%);
  pointer-events: none;
}
.hero-kicker {
  font-family: var(--mono);
  color: var(--accent-1);
  font-size: 14px;
  margin: 0 0 16px;
}
.hero h1 {
  font-size: clamp(36px, 6vw, 60px);
  line-height: 1.08;
  margin: 0 0 16px;
  letter-spacing: -0.02em;
}
.hero h1 .grad {
  background: var(--accent-grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero-sub {
  font-size: clamp(16px, 2vw, 19px);
  color: var(--text-muted);
  max-width: 640px;
  margin: 0 0 36px;
}
.hero-stats {
  display: flex;
  gap: 40px;
  flex-wrap: wrap;
  margin-bottom: 40px;
}
.stat .num {
  font-family: var(--mono);
  font-size: 28px;
  font-weight: 700;
  background: var(--accent-grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.stat .label {
  font-size: 13px;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.hero-cta { display: flex; gap: 16px; flex-wrap: wrap; }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 22px;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  border: 1px solid var(--border);
  transition: transform 0.15s, border-color 0.15s, background 0.15s;
}
.btn:hover { transform: translateY(-2px); }
.btn-primary {
  background: var(--accent-grad);
  color: #0a0a0f;
  border: none;
}
.btn-secondary {
  background: var(--bg-elev);
  color: var(--text);
}
.btn-secondary:hover { border-color: var(--accent-1); }

/* ===== Reveal ===== */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity 0.6s ease, transform 0.6s ease; }
.reveal.in-view { opacity: 1; transform: translateY(0); }

/* ===== About ===== */
.about-text { max-width: 720px; color: var(--text-muted); font-size: 17px; }
.about-text p { margin: 0 0 18px; }
.about-text strong { color: var(--text); }

/* ===== Skills ===== */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 24px;
}
.skill-group {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
}
.skill-group h3 {
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--accent-1);
  margin: 0 0 14px;
  font-family: var(--mono);
}
.chip-list { display: flex; flex-wrap: wrap; gap: 8px; }
.chip {
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 5px 12px;
  font-size: 13px;
  color: var(--text-muted);
}

/* ===== Experience timeline ===== */
.timeline { position: relative; padding-left: 32px; }
.timeline::before {
  content: "";
  position: absolute;
  left: 6px; top: 6px; bottom: 6px;
  width: 2px;
  background: var(--border);
}
.timeline-item { position: relative; margin-bottom: 48px; }
.timeline-item:last-child { margin-bottom: 0; }
.timeline-item::before {
  content: "";
  position: absolute;
  left: -32px; top: 4px;
  width: 14px; height: 14px;
  border-radius: 50%;
  background: var(--accent-grad);
  border: 3px solid var(--bg);
}
.timeline-item h3 { margin: 0 0 4px; font-size: 19px; }
.timeline-meta {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  align-items: baseline;
  color: var(--text-dim);
  font-size: 13px;
  margin-bottom: 12px;
  font-family: var(--mono);
}
.timeline-meta .company { color: var(--accent-1); }
.timeline-item ul { margin: 0; padding-left: 20px; color: var(--text-muted); }
.timeline-item li { margin-bottom: 6px; }
.lead-achievement {
  margin: 0 0 10px;
  padding-left: 14px;
  border-left: 2px solid var(--accent-1);
  color: var(--text);
  font-size: 15px;
}
.timeline-item details { margin-top: 4px; }
.timeline-item summary {
  cursor: pointer;
  color: var(--text-dim);
  font-size: 13px;
  font-family: var(--mono);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 10px;
}
.timeline-item summary:hover { color: var(--accent-1); }
.timeline-item details ul { margin-top: 10px; }

/* ===== Projects ===== */
.project-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}
.project-card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  display: flex;
  flex-direction: column;
  transition: border-color 0.2s, transform 0.2s;
}
.project-card:hover { border-color: var(--accent-1); transform: translateY(-4px); }
.project-card.featured {
  grid-column: 1 / -1;
  background: linear-gradient(135deg, rgba(45, 212, 191, 0.06), rgba(139, 92, 246, 0.06));
  border-color: rgba(139, 92, 246, 0.3);
}
.project-card-head {
  display: flex;
  justify-content: space-between;
  align-items: start;
  gap: 12px;
  margin-bottom: 10px;
}
.project-card h3 { margin: 0; font-size: 18px; }
.project-card .badge {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--accent-1);
  border: 1px solid var(--border);
  padding: 3px 8px;
  border-radius: 999px;
  white-space: nowrap;
}
.project-card p { color: var(--text-muted); font-size: 14px; margin: 0 0 16px; flex-grow: 1; }
.arch-diagram { width: 100%; height: auto; margin: 4px 0 16px; }
.project-tags { display: flex; gap: 6px; flex-wrap: wrap; margin-bottom: 16px; }
.project-tags .tag {
  font-size: 11px;
  color: var(--text-dim);
  background: var(--bg-elev-2);
  padding: 3px 9px;
  border-radius: 999px;
}
.project-link {
  font-size: 13px;
  font-weight: 600;
  color: var(--accent-1);
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.project-link:hover { text-decoration: underline; }
.project-note { font-size: 12.5px; color: var(--text-dim); font-style: italic; margin: 0; }

/* ===== Certifications ===== */
.cert-tier { margin-bottom: 28px; }
.cert-tier:last-child { margin-bottom: 0; }
.cert-tier h3 {
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--accent-1);
  margin: 0 0 14px;
  font-family: var(--mono);
}
.cert-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
}
.cert-card-featured {
  border-image: var(--accent-grad) 1;
  border-width: 1.5px;
  font-weight: 600;
}
.cert-card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 14px;
}
.cert-card .cert-icon {
  width: 32px; height: 32px;
  flex-shrink: 0;
  border-radius: 8px;
  background: var(--accent-grad);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 15px;
  color: #0a0a0f;
  font-weight: 700;
}
/* ===== Contact ===== */
.contact-inner { text-align: center; }
.contact-inner p { color: var(--text-muted); max-width: 480px; margin: 0 auto 32px; }
.contact-links { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

footer {
  padding: 32px 24px;
  text-align: center;
  color: var(--text-dim);
  font-size: 13px;
}

/* ===== Writing / post pages ===== */
.writing-post { padding-top: 140px; }
.post-meta {
  font-family: var(--mono);
  font-size: 13px;
  color: var(--text-dim);
  margin: 0 0 40px;
}
.post-body { max-width: 720px; color: var(--text-muted); font-size: 16px; }
.post-body p { margin: 0 0 20px; }
.post-body h2 {
  color: var(--text);
  font-size: 22px;
  margin: 44px 0 16px;
  letter-spacing: -0.01em;
}
.post-body ul { margin: 0 0 20px; padding-left: 22px; }
.post-body li { margin-bottom: 10px; }
.post-body strong { color: var(--text); }
.post-body code {
  font-family: var(--mono);
  font-size: 0.9em;
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 2px 6px;
  color: var(--accent-1);
}
.post-back { display: inline-block; margin-top: 24px; }