/* ── Design tokens ──────────────────────────────────────────── */
:root {
  --bg:           #0d1117;
  --bg-card:      #161b22;
  --bg-card-alt:  #1c2330;
  --border:       #30363d;
  --border-light: #21262d;
  --accent:       #7c3aed;
  --accent-hover: #6d28d9;
  --accent-glow:  rgba(124, 58, 237, 0.15);
  --green:        #10b981;
  --flutter-blue: #02569B;
  --kotlin-purple:#7F52FF;
  --text:         #e6edf3;
  --text-muted:   #8b949e;
  --text-dim:     #656d76;
  --font-sans:    'Inter', system-ui, -apple-system, sans-serif;
  --font-mono:    'JetBrains Mono', 'Fira Code', monospace;
  --radius:       10px;
  --radius-lg:    16px;
  --transition:   0.18s ease;
  --shadow:       0 4px 24px rgba(0, 0, 0, 0.4);
  --shadow-card:  0 2px 12px rgba(0, 0, 0, 0.3);
  --max-w:        1100px;
}

/* ── Reset ──────────────────────────────────────────────────── */
*, *::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: var(--font-sans);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
img { display: block; max-width: 100%; }
a { color: var(--accent); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--accent-hover); }
ul, ol { list-style: none; }
h1, h2, h3, h4 { line-height: 1.25; }
code {
  font-family: var(--font-mono);
  background: var(--bg-card);
  border: 1px solid var(--border);
  padding: 0.1em 0.4em;
  border-radius: 4px;
  font-size: 0.875em;
}

/* ── Layout helpers ─────────────────────────────────────────── */
.container {
  max-width: var(--max-w);
  margin-inline: auto;
  padding-inline: 1.5rem;
}
.section { padding-block: 5rem; }
.section + .section { border-top: 1px solid var(--border-light); }

/* ── Section titles ─────────────────────────────────────────── */
.section-title {
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 700;
  margin-bottom: 0.5rem;
  color: var(--text);
  position: relative;
  display: inline-block;
}
.section-title::after {
  content: '';
  display: block;
  width: 2.5rem;
  height: 3px;
  background: var(--accent);
  border-radius: 2px;
  margin-top: 0.4rem;
}
.section-subtitle {
  color: var(--text-muted);
  margin-top: 0.5rem;
  margin-bottom: 2rem;
}

/* ── Buttons ────────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.6rem 1.25rem;
  border-radius: var(--radius);
  font-size: 0.9rem;
  font-weight: 500;
  font-family: var(--font-sans);
  cursor: pointer;
  transition: all var(--transition);
  white-space: nowrap;
  border: 1.5px solid transparent;
  text-decoration: none;
}
.btn-primary {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}
.btn-primary:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
  color: #fff;
  transform: translateY(-1px);
  box-shadow: 0 4px 12px var(--accent-glow);
}
.btn-outline {
  background: transparent;
  color: var(--text);
  border-color: var(--border);
}
.btn-outline:hover {
  border-color: var(--accent);
  color: var(--accent);
  transform: translateY(-1px);
}
.btn-sm { padding: 0.4rem 0.9rem; font-size: 0.825rem; }

/* ── Badges ─────────────────────────────────────────────────── */
.badge-stack {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-block: 0.75rem;
}
.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.2rem 0.65rem;
  border-radius: 999px;
  font-size: 0.775rem;
  font-weight: 500;
  background: var(--bg-card-alt);
  color: var(--text-muted);
  border: 1px solid var(--border);
  font-family: var(--font-mono);
}
.badge-kotlin {
  background: rgba(127, 82, 255, 0.12);
  color: #a78bfa;
  border-color: rgba(127, 82, 255, 0.3);
}
.badge-flutter {
  background: rgba(2, 86, 155, 0.15);
  color: #60a5fa;
  border-color: rgba(2, 86, 155, 0.35);
}
.badge-swift {
  background: rgba(255, 95, 41, 0.12);
  color: #ff5f29;
  border-color: rgba(255, 95, 41, 0.3);
}
.badge-java {
  background: rgba(0, 116, 190, 0.12);
  color: #4a9fd4;
  border-color: rgba(0, 116, 190, 0.3);
}
.badge-google-play {
  background: rgba(1, 135, 134, 0.12);
  color: #01ac4e;
  border-color: rgba(1, 135, 134, 0.3);
}
.badge-firebase {
  background: rgba(255, 160, 0, 0.12);
  color: #ffa000;
  border-color: rgba(255, 160, 0, 0.3);
}
.badge-android {
  background: rgba(61, 220, 132, 0.12);
  color: #3ddc84;
  border-color: rgba(61, 220, 132, 0.3);
}
.badge-ios {
  background: rgba(160, 160, 160, 0.12);
  color: #a0a0a0;
  border-color: rgba(160, 160, 160, 0.3);
}
.badge-logo {
  height: 14px;
  width: auto;
  object-fit: contain;
  display: block;
}

/* ── Header / Nav ───────────────────────────────────────────── */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(13, 17, 23, 0.92);
  border-bottom: 1px solid var(--border-light);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 3.75rem;
}
.nav-logo {
  font-family: var(--font-mono);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.5px;
}
.nav-logo .accent { color: var(--accent); }
.nav-logo:hover { color: var(--text); }
.nav-links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}
.nav-links a {
  color: var(--text-muted);
  font-size: 0.875rem;
  padding: 0.4rem 0.7rem;
  border-radius: 6px;
  transition: color var(--transition), background var(--transition);
}
.nav-links a:hover { color: var(--text); background: var(--bg-card); }
.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-muted);
  border-radius: 2px;
  transition: all 0.2s;
}

/* ── Hero ───────────────────────────────────────────────────── */
.hero {
  padding-block: 6rem 4rem;
}
.hero-inner {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  gap: 3rem;
}
.hero-greeting {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--accent);
  display: block;
  margin-bottom: 0.5rem;
}
.hero-name {
  font-size: clamp(2.5rem, 6vw, 4rem);
  font-weight: 800;
  letter-spacing: -1px;
  color: var(--text);
  margin-bottom: 0.3rem;
}
.hero-title {
  font-size: clamp(1.1rem, 2.5vw, 1.5rem);
  font-weight: 400;
  color: var(--text-muted);
  margin-bottom: 1.25rem;
}
.hero-tagline {
  font-size: 1.05rem;
  color: var(--text-muted);
  max-width: 520px;
  line-height: 1.75;
  margin-bottom: 2rem;
}
.hero-ctas {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}
.hero-photo-wrap {
  flex-shrink: 0;
}
.profile-photo {
  width: 220px;
  height: 220px;
  object-fit: cover;
  border-radius: 50%;
  border: 3px solid var(--border);
  box-shadow: 0 0 0 6px var(--accent-glow), var(--shadow);
}

/* ── About ──────────────────────────────────────────────────── */
.about-body p {
  color: var(--text-muted);
  max-width: 680px;
  margin-bottom: 1rem;
}
.about-body strong { color: var(--text); }
.about-skills { margin-top: 1.5rem; }

/* ── Experience ─────────────────────────────────────────────── */
.experience-list {
  display: flex;
  flex-direction: column;
  gap: 0;
  margin-top: 2rem;
  position: relative;
}
.experience-list::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(to bottom, var(--accent), transparent);
}
.experience-item {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 1.5rem;
  padding: 1.75rem 0 1.75rem 1.75rem;
  border-bottom: 1px solid var(--border-light);
  position: relative;
}
.experience-item::before {
  content: '';
  position: absolute;
  left: -4px;
  top: 2rem;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid var(--bg);
}
.experience-meta {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  padding-top: 0.15rem;
}
.experience-period {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-dim);
}
.experience-type {
  font-size: 0.75rem;
  color: var(--accent);
  background: var(--accent-glow);
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  width: fit-content;
}
.experience-role {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 0.15rem;
}
.experience-company {
  font-size: 0.9rem;
  color: var(--accent);
  font-weight: 500;
}
.experience-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-top: 0.5rem;
  margin-bottom: 0.5rem;
  max-width: 600px;
}

/* ── Education ──────────────────────────────────────────────── */
.education-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
  margin-top: 2rem;
}
.education-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  transition: border-color var(--transition);
}
.education-card:hover { border-color: var(--accent); }
.education-degree {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.35rem;
}
.education-field {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 0.35rem;
  line-height: 1.35;
}
.education-institution {
  font-size: 0.825rem;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}
.education-period {
  font-family: var(--font-mono);
  font-size: 0.775rem;
  color: var(--text-dim);
}

/* ── Projects grid ──────────────────────────────────────────── */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.25rem;
  margin-top: 2rem;
}
.project-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: transform var(--transition), border-color var(--transition), box-shadow var(--transition);
  display: flex;
  flex-direction: column;
}
.project-card:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
  box-shadow: 0 8px 32px rgba(124, 58, 237, 0.12);
}
.project-card-image {
  height: 180px;
  overflow: hidden;
  background: var(--bg-card-alt);
  display: flex;
  align-items: center;
  justify-content: center;
}
.project-card-image img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  padding: 1rem;
}
.project-card-image--placeholder {
  background: linear-gradient(135deg, var(--bg-card-alt), rgba(124,58,237,0.1));
}
.project-card-initial {
  font-size: 4rem;
  font-weight: 800;
  color: rgba(124, 58, 237, 0.3);
  font-family: var(--font-mono);
  user-select: none;
}
.project-card-body {
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  flex: 1;
}
.project-title {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 0.4rem;
}
.project-title a { color: var(--text); }
.project-title a:hover { color: var(--accent); }
.project-desc {
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.65;
  flex: 1;
}
.project-card-links {
  display: flex;
  gap: 0.75rem;
  margin-top: 1rem;
  flex-wrap: wrap;
}
.card-link {
  font-size: 0.825rem;
  color: var(--text-muted);
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  transition: color var(--transition);
}
.card-link:hover { color: var(--text); }
.card-link--primary { color: var(--accent); }
.card-link--primary:hover { color: var(--accent-hover); }

/* ── Project detail ─────────────────────────────────────────── */
.project-detail { padding-block: 4rem; }
.back-link {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 2rem;
}
.back-link:hover { color: var(--text); }
.project-detail-hero {
  margin-bottom: 2rem;
  border-radius: var(--radius-lg);
  overflow: hidden;
  max-height: 360px;
  background: var(--bg-card);
  display: flex;
  align-items: center;
  justify-content: center;
}
.project-detail-img {
  max-height: 360px;
  object-fit: contain;
}
.project-detail-header { margin-bottom: 2.5rem; }
.project-detail-title {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 800;
  margin-bottom: 1rem;
}
.project-detail-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.25rem;
}
.project-content {
  max-width: 720px;
  color: var(--text-muted);
  line-height: 1.8;
}
.project-content h2, .project-content h3 { color: var(--text); margin-block: 1.5rem 0.75rem; }
.project-content p { margin-bottom: 1rem; }
.project-content ul, .project-content ol { padding-left: 1.5rem; margin-bottom: 1rem; list-style: revert; }
.project-content a { color: var(--accent); }
.project-content table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1.5rem;
  font-size: 0.875rem;
}
.project-content th,
.project-content td {
  text-align: left;
  padding: 0.6rem 1rem;
  border: 1px solid var(--border);
}
.project-content th {
  background: var(--bg-card-alt);
  color: var(--text);
  font-weight: 600;
  font-family: var(--font-mono);
  font-size: 0.8rem;
}
.project-content td { color: var(--text-muted); }
.project-content tr:nth-child(even) td { background: rgba(255,255,255,0.02); }

/* ── Knowledge Portfolio card ───────────────────────────────── */
.knowledge-card {
  display: flex;
  gap: 1.5rem;
  align-items: flex-start;
  background: linear-gradient(135deg, var(--bg-card), rgba(124, 58, 237, 0.06));
  border: 1px solid rgba(124, 58, 237, 0.3);
  border-radius: var(--radius-lg);
  padding: 2rem;
  margin-top: 2rem;
  color: var(--text);
  transition: border-color var(--transition), box-shadow var(--transition), transform var(--transition);
  text-decoration: none;
}
.knowledge-card:hover {
  border-color: var(--accent);
  box-shadow: 0 8px 32px var(--accent-glow);
  transform: translateY(-2px);
  color: var(--text);
}
.knowledge-card-icon {
  flex-shrink: 0;
  width: 56px;
  height: 56px;
  background: var(--accent-glow);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 8px;
}
.knowledge-card-title {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  color: var(--text);
}
.knowledge-card-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 0.75rem;
}
.knowledge-card-cta {
  font-size: 0.875rem;
  color: var(--accent);
  font-weight: 500;
}

/* ── Articles ───────────────────────────────────────────────── */
.articles-list {
  display: flex;
  flex-direction: column;
  gap: 0;
  margin-top: 2rem;
}
.article-item {
  display: grid;
  grid-template-columns: 140px 1fr;
  gap: 1rem;
  padding-block: 1.25rem;
  border-bottom: 1px solid var(--border-light);
  transition: background var(--transition);
}
.article-item:first-child { border-top: 1px solid var(--border-light); }
.article-meta time {
  font-family: var(--font-mono);
  font-size: 0.775rem;
  color: var(--text-dim);
  padding-top: 0.2rem;
}
.article-title {
  font-size: 0.975rem;
  font-weight: 600;
  margin-bottom: 0.3rem;
}
.article-title a { color: var(--text); }
.article-title a:hover { color: var(--accent); }
.article-excerpt {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.6;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.articles-more { margin-top: 1.75rem; }
.articles-empty {
  margin-top: 2rem;
  padding: 2rem;
  background: var(--bg-card);
  border: 1px dashed var(--border);
  border-radius: var(--radius);
  color: var(--text-muted);
  font-size: 0.9rem;
}
.articles-empty p { margin-bottom: 1rem; }

/* ── Contact ────────────────────────────────────────────────── */
.contact-inner { text-align: center; }
.contact-desc {
  max-width: 500px;
  margin-inline: auto;
  margin-block: 1rem 2rem;
  color: var(--text-muted);
}
.contact-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.75rem;
}

/* ── Footer ─────────────────────────────────────────────────── */
.site-footer {
  border-top: 1px solid var(--border-light);
  padding-block: 2rem;
}
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
}
.footer-links {
  display: flex;
  gap: 1.25rem;
}
.footer-links a {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.875rem;
  color: var(--text-muted);
}
.footer-links a:hover { color: var(--text); }
.footer-copy {
  font-size: 0.8rem;
  color: var(--text-dim);
}

/* ── Responsive ─────────────────────────────────────────────── */
@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 3.75rem;
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--bg-card);
    border-bottom: 1px solid var(--border);
    padding: 1rem 1.5rem;
    gap: 0.25rem;
  }
  .nav-links.open { display: flex; }
  .nav-toggle { display: flex; }
  .hero-inner {
    grid-template-columns: 1fr;
    text-align: center;
  }
  .hero-photo-wrap { order: -1; margin-inline: auto; }
  .hero-ctas { justify-content: center; }
  .hero-tagline { margin-inline: auto; }
  .experience-item {
    grid-template-columns: 1fr;
    gap: 0.5rem;
  }
  .experience-list::before { display: none; }
  .experience-item::before { display: none; }
  .experience-item { padding-left: 0; }
  .article-item {
    grid-template-columns: 1fr;
    gap: 0.25rem;
  }
  .knowledge-card { flex-direction: column; gap: 1rem; }
  .footer-inner { flex-direction: column; text-align: center; }
  .profile-photo { width: 160px; height: 160px; }
}

@media (max-width: 480px) {
  .projects-grid { grid-template-columns: 1fr; }
  .hero { padding-block: 4rem 3rem; }
  .section { padding-block: 3.5rem; }
}