/* ===========================
   CSS Reset & Variables
   =========================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --bg: #0d1117;
  --bg-secondary: #161b22;
  --bg-card: #1c2128;
  --border: #30363d;
  --text: #e6edf3;
  --text-muted: #8b949e;
  --accent: #58a6ff;
  --accent-green: #3fb950;
  --accent-orange: #d29922;
  --accent-red: #f85149;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  --radius: 8px;
  --radius-lg: 12px;
  --shadow: 0 4px 24px rgba(0,0,0,0.4);
  --transition: 0.2s ease;
  --max-w: 1100px;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  font-size: 16px;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: opacity var(--transition);
}
a:hover { opacity: 0.8; }

ul { list-style: none; }

/* ===========================
   Navbar
   =========================== */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: rgba(13, 17, 23, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: background var(--transition);
}

.nav-container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--text);
  letter-spacing: -0.02em;
}
.nav-brand:hover { opacity: 1; color: var(--accent); }

.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-links a {
  color: var(--text-muted);
  font-size: 0.9rem;
  font-weight: 500;
  transition: color var(--transition);
}
.nav-links a:hover { color: var(--text); opacity: 1; }

.btn-nav {
  background: var(--accent) !important;
  color: var(--bg) !important;
  padding: 6px 16px;
  border-radius: 6px;
  font-weight: 600 !important;
  font-size: 0.85rem !important;
}
.btn-nav:hover { opacity: 0.9 !important; }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}
.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text);
  transition: var(--transition);
}

/* ===========================
   Sections
   =========================== */
.section {
  padding: 96px 24px;
}
.section-dark {
  background: var(--bg-secondary);
}

.container {
  max-width: var(--max-w);
  margin: 0 auto;
}

.section-title {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  margin-bottom: 12px;
  color: var(--text);
}
.section-title::after {
  content: '';
  display: block;
  width: 48px;
  height: 3px;
  background: var(--accent);
  margin-top: 10px;
  border-radius: 2px;
}

.section-subtitle {
  color: var(--text-muted);
  font-size: 1.05rem;
  margin-bottom: 48px;
  margin-top: 8px;
}

/* ===========================
   Hero
   =========================== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 100px 24px 60px;
  max-width: var(--max-w);
  margin: 0 auto;
  gap: 60px;
}

.hero-content {
  flex: 1;
  min-width: 0;
}

.hero-eyebrow {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  margin-bottom: 16px;
}

.hero-title {
  font-size: clamp(2.5rem, 6vw, 4rem);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.04em;
  margin-bottom: 24px;
  color: var(--text);
}

.accent {
  color: var(--accent);
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--text-muted);
  max-width: 520px;
  margin-bottom: 36px;
  line-height: 1.8;
}

.hero-cta {
  display: flex;
  gap: 16px;
  margin-bottom: 36px;
  flex-wrap: wrap;
}

.btn {
  display: inline-block;
  padding: 12px 28px;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 0.95rem;
  transition: var(--transition);
  cursor: pointer;
}
.btn-primary {
  background: var(--accent);
  color: var(--bg);
}
.btn-primary:hover { opacity: 0.88; }
.btn-secondary {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
}
.btn-secondary:hover { border-color: var(--accent); color: var(--accent); opacity: 1; }

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag {
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--text-muted);
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  padding: 4px 12px;
  border-radius: 20px;
  font-family: var(--font-mono);
}

.hero-visual {
  flex: 1;
  min-width: 0;
  max-width: 500px;
}

/* Code Block */
.code-block {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow);
}
.code-header {
  background: var(--bg-card);
  padding: 12px 16px;
  display: flex;
  align-items: center;
  gap: 8px;
  border-bottom: 1px solid var(--border);
}
.dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
}
.dot.red { background: #ff5f57; }
.dot.yellow { background: #febc2e; }
.dot.green { background: #28c840; }
.code-title {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-left: 8px;
}
.code-body {
  padding: 24px 20px;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  line-height: 1.7;
  overflow-x: auto;
}
code { color: var(--text); }
.kw { color: #ff7b72; }
.cm { color: var(--text-muted); font-style: italic; }
.str { color: var(--accent-green); }
.num { color: #79c0ff; }

/* ===========================
   About
   =========================== */
.about-grid {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 60px;
  align-items: start;
  margin-top: 40px;
}

.about-text p {
  color: var(--text-muted);
  margin-bottom: 16px;
  font-size: 1.05rem;
}
.about-text p strong { color: var(--text); }

.about-links {
  display: flex;
  gap: 16px;
  margin-top: 24px;
}
.social-link {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--accent);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition);
}
.social-link:hover { border-color: var(--accent); }

.about-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}
.stat-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  text-align: center;
}
.stat-num {
  display: block;
  font-size: 2rem;
  font-weight: 800;
  color: var(--accent);
  letter-spacing: -0.04em;
}
.stat-label {
  display: block;
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 4px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

/* ===========================
   Timeline
   =========================== */
.timeline {
  margin-top: 48px;
  position: relative;
  padding-left: 32px;
}
.timeline::before {
  content: '';
  position: absolute;
  left: 0;
  top: 8px;
  bottom: 0;
  width: 2px;
  background: var(--border);
}

.timeline-item {
  position: relative;
  margin-bottom: 52px;
}

.timeline-dot {
  position: absolute;
  left: -39px;
  top: 8px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent);
  border: 3px solid var(--bg-secondary);
}

.timeline-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
  flex-wrap: wrap;
}

.timeline-content h3 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 4px;
}

.timeline-period {
  font-size: 0.8rem;
  color: var(--accent);
  font-family: var(--font-mono);
  white-space: nowrap;
  font-weight: 500;
}

.timeline-company {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 12px;
}

.timeline-bullets {
  list-style: disc;
  padding-left: 20px;
}
.timeline-bullets li {
  color: var(--text-muted);
  font-size: 0.92rem;
  margin-bottom: 6px;
}

/* ===========================
   Projects
   =========================== */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 24px;
  margin-top: 48px;
}

.project-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  transition: border-color var(--transition), transform var(--transition);
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.project-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}
.project-card.featured {
  border-color: rgba(88, 166, 255, 0.3);
}

.project-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
}
.project-icon { font-size: 1.8rem; }

.project-badges {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.badge {
  font-size: 0.7rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 4px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.badge-python { background: #3776ab22; color: #79c0ff; border: 1px solid #3776ab55; }
.badge-jupyter { background: #f3722422; color: #f37224; border: 1px solid #f3722455; }
.badge-featured { background: #58a6ff22; color: var(--accent); border: 1px solid #58a6ff44; }

.project-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text);
}

.project-desc {
  color: var(--text-muted);
  font-size: 0.9rem;
  line-height: 1.65;
  flex: 1;
}

.project-tech {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--accent-green);
}

.project-link {
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--accent);
  margin-top: 8px;
  align-self: flex-start;
}

/* ===========================
   Skills
   =========================== */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 32px;
  margin-top: 48px;
}

.skill-group-title {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 16px;
}

.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.skill-tag {
  font-size: 0.8rem;
  color: var(--text-muted);
  background: var(--bg-card);
  border: 1px solid var(--border);
  padding: 4px 12px;
  border-radius: 20px;
  transition: border-color var(--transition), color var(--transition);
}
.skill-tag:hover { border-color: var(--accent); color: var(--text); }

/* ===========================
   Blog
   =========================== */
.blog-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 24px;
  margin-top: 48px;
}

.blog-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  transition: border-color var(--transition);
}
.blog-card:hover { border-color: var(--accent); }

.blog-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
}

.blog-tag {
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.blog-date {
  font-size: 0.78rem;
  color: var(--text-muted);
}

.blog-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 10px;
  line-height: 1.4;
}

.blog-excerpt {
  font-size: 0.88rem;
  color: var(--text-muted);
  line-height: 1.65;
  margin-bottom: 16px;
}

.blog-link, .blog-link-placeholder {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-muted);
  font-style: italic;
}
a.blog-link {
  color: var(--accent);
  font-style: normal;
  text-decoration: none;
  transition: opacity var(--transition);
}
a.blog-link:hover { opacity: 0.75; text-decoration: underline; }

.blog-published-badge {
  display: inline-block;
  font-size: 0.68rem;
  font-weight: 700;
  color: #3fb950;
  background: rgba(63,185,80,0.12);
  border: 1px solid rgba(63,185,80,0.28);
  padding: 2px 8px;
  border-radius: 4px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  vertical-align: middle;
}
.blog-read-time {
  font-size: 0.75rem;
  color: var(--text-muted);
  vertical-align: middle;
  margin-left: 8px;
}
.blog-links-row {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  margin-top: 16px;
  align-items: center;
}
.blog-topics {
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-bottom: 14px;
  line-height: 1.6;
}

/* ===========================
   Contact
   =========================== */
.contact-links {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
  margin-top: 48px;
}

.contact-card {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 28px;
  color: var(--text);
  font-weight: 500;
  transition: border-color var(--transition);
}
.contact-card:hover { border-color: var(--accent); opacity: 1; }

.contact-icon { font-size: 1.4rem; }
.contact-label { font-size: 0.95rem; }

/* ===========================
   Footer
   =========================== */
.footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border);
  padding: 32px 24px;
  text-align: center;
}
.footer p {
  color: var(--text-muted);
  font-size: 0.85rem;
  margin-bottom: 4px;
}
.footer a { color: var(--text-muted); }
.footer a:hover { color: var(--accent); }

/* ===========================
   Resume Page
   =========================== */
.resume-page {
  padding-top: 100px;
  min-height: 100vh;
}

.resume-header {
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
  padding: 48px 24px;
}

.resume-name {
  font-size: 2.4rem;
  font-weight: 800;
  letter-spacing: -0.04em;
  margin-bottom: 4px;
}

.resume-title {
  color: var(--accent);
  font-size: 1.1rem;
  font-weight: 500;
  margin-bottom: 16px;
}

.resume-contact {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  font-size: 0.88rem;
  color: var(--text-muted);
}

.resume-download {
  margin-top: 24px;
}

.resume-body {
  max-width: 860px;
  margin: 0 auto;
  padding: 60px 24px;
}

.resume-section {
  margin-bottom: 52px;
}

.resume-section-title {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--accent);
  border-bottom: 1px solid var(--border);
  padding-bottom: 10px;
  margin-bottom: 28px;
}

.resume-role {
  margin-bottom: 32px;
}

.resume-role-header {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 2px;
}

.resume-role-title {
  font-size: 1.02rem;
  font-weight: 700;
  color: var(--text);
}

.resume-role-period {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--accent);
}

.resume-role-company {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 12px;
}

.resume-role-bullets {
  list-style: disc;
  padding-left: 20px;
}
.resume-role-bullets li {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: 6px;
  line-height: 1.6;
}

.resume-skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 20px;
}

.resume-skill-category {
  margin-bottom: 8px;
}

.resume-skill-category-name {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 6px;
}

.resume-skill-list {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.6;
}

.resume-edu-item {
  margin-bottom: 20px;
}

.resume-degree {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text);
}

.resume-school {
  font-size: 0.88rem;
  color: var(--text-muted);
}

.resume-gpa {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--accent-green);
}

/* ===========================
   Responsive
   =========================== */
@media (max-width: 900px) {
  .hero {
    flex-direction: column;
    text-align: center;
  }
  .hero-visual { max-width: 100%; }
  .hero-cta { justify-content: center; }
  .hero-tags { justify-content: center; }

  .about-grid {
    grid-template-columns: 1fr;
  }
  .about-stats {
    grid-template-columns: repeat(4, 1fr);
  }

  .timeline-header {
    flex-direction: column;
  }
}

@media (max-width: 640px) {
  .nav-links {
    display: none;
    flex-direction: column;
    position: absolute;
    top: 64px;
    left: 0; right: 0;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    padding: 16px 24px 24px;
    gap: 16px;
  }
  .nav-links.open { display: flex; }
  .nav-toggle { display: flex; }

  .section { padding: 64px 20px; }
  .hero { padding: 90px 20px 60px; }

  .about-stats { grid-template-columns: 1fr 1fr; }

  .contact-links { flex-direction: column; }
}