/* ===================================
   CSS Variables & Reset
   =================================== */
:root {
  --primary-color: #2563eb;
  --primary-dark: #1d4ed8;
  --primary-light: #60a5fa;
  --secondary-color: #64748b;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-light: #64748b;
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --surface: #ffffff;
  --surface-2: #f8fafc;
  --border-color: #e2e8f0;
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.08);
  --shadow-md: 0 10px 25px rgba(15, 23, 42, 0.10);
  --shadow-lg: 0 18px 40px rgba(15, 23, 42, 0.12);
  --font-family: 'Inter', sans-serif;
  --font-size-base: 16px;
  --line-height-base: 1.65;
  --spacing-xs: 0.5rem;
  --spacing-sm: 0.75rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2.5rem;
  --spacing-2xl: 4rem;
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --container-width: 1200px;
  --border-radius: 0.75rem;
  --border-radius-lg: 1.25rem;
}

html.dark {
  --primary-color: #7dd3fc;
  --primary-dark: #38bdf8;
  --primary-light: #bae6fd;
  --text-primary: #e6eef8;
  --text-secondary: #cbd5e1;
  --text-light: #94a3b8;
  --bg-primary: #0b1220;
  --bg-secondary: #071127;
  --surface: #111c31;
  --surface-2: #16233d;
  --border-color: #23304a;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.35);
  --shadow-md: 0 10px 25px rgba(0, 0, 0, 0.35);
  --shadow-lg: 0 18px 40px rgba(0, 0, 0, 0.45);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; font-size: var(--font-size-base); }
body { font-family: var(--font-family); line-height: var(--line-height-base); color: var(--text-primary); background-color: var(--bg-primary); }
a { text-decoration: none; color: inherit; }
ul { list-style: none; }
.container { max-width: var(--container-width); margin: 0 auto; padding: 0 var(--spacing-md); }

.section { padding: var(--spacing-2xl) 0; }
.section-alt { background-color: var(--bg-secondary); }
.section-header { text-align: center; margin-bottom: var(--spacing-xl); }
.section-title { text-align: center; margin-bottom: var(--spacing-md); color: var(--text-primary); position: relative; font-size: clamp(2rem, 4vw, 3rem); }
.section-title::after { content: ''; display: block; width: 72px; height: 4px; background: linear-gradient(90deg, var(--primary-color), var(--primary-light)); margin: var(--spacing-sm) auto 0; border-radius: 999px; }
.section-subtitle { text-align: center; color: var(--text-secondary); font-size: 1.1rem; max-width: 760px; margin: 0 auto; }
.section-badge { display: inline-flex; align-items: center; justify-content: center; padding: 0.45rem 0.9rem; border-radius: 999px; background: rgba(37,99,235,0.12); color: var(--primary-color); font-weight: 700; margin-bottom: var(--spacing-sm); }

.btn { display: inline-flex; align-items: center; justify-content: center; gap: 0.5rem; padding: 0.9rem 1.25rem; border-radius: 0.85rem; border: 1px solid transparent; cursor: pointer; font-weight: 600; transition: transform var(--transition-fast), background-color var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast), box-shadow var(--transition-fast); }
.btn:hover { transform: translateY(-1px); }
.btn-primary { background: linear-gradient(135deg, var(--primary-color), var(--primary-dark)); color: #ffffff; box-shadow: var(--shadow-sm); }
.btn-secondary { background-color: transparent; color: var(--primary-color); border-color: rgba(37,99,235,0.35); }
.btn-ghost { background-color: transparent; color: var(--text-primary); border: 1px solid var(--border-color); min-width: 48px; }

.navbar { position: sticky; top: 0; z-index: 1000; padding: var(--spacing-sm) 0; border-bottom: 1px solid var(--border-color); backdrop-filter: blur(12px); background-color: rgba(255,255,255,0.88); transition: background-color var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast); }
html.dark .navbar { background-color: rgba(11,18,32,0.88); }
.navbar.scrolled { box-shadow: var(--shadow-sm); }
.navbar .container { display: flex; align-items: center; justify-content: space-between; gap: var(--spacing-lg); }
.nav-brand a { font-size: 1.45rem; font-weight: 800; color: var(--text-primary); letter-spacing: -0.03em; }
.nav-menu { display: flex; align-items: center; gap: var(--spacing-lg); }
.nav-link { position: relative; color: var(--text-secondary); font-weight: 500; transition: color var(--transition-fast); }
.nav-link:hover, .nav-link.active { color: var(--primary-color); }
.nav-link::after { content: ''; position: absolute; left: 0; bottom: -0.45rem; width: 100%; height: 2px; border-radius: 999px; background-color: var(--primary-color); transform: scaleX(0); transform-origin: left center; transition: transform var(--transition-base); }
.nav-link:hover::after, .nav-link.active::after { transform: scaleX(1); }
.nav-actions { display: flex; align-items: center; gap: var(--spacing-sm); }
.nav-toggle { display: none; flex-direction: column; gap: 4px; background: none; border: 0; cursor: pointer; }
.nav-toggle span { width: 24px; height: 3px; border-radius: 999px; background-color: var(--text-primary); transition: transform var(--transition-fast), opacity var(--transition-fast); }

.hero { min-height: 88vh; display: flex; align-items: center; justify-content: center; background: linear-gradient(180deg, var(--bg-secondary), var(--bg-primary)); }
.hero-content { text-align: center; max-width: 860px; margin: 0 auto; }
.hero-title { font-size: clamp(2.6rem, 6vw, 4.8rem); margin-bottom: var(--spacing-md); letter-spacing: -0.04em; color: var(--text-primary); }
.highlight { color: var(--primary-color); }
.hero-subtitle { font-size: clamp(1.15rem, 2.5vw, 1.5rem); color: var(--text-secondary); margin-bottom: var(--spacing-xl); }
.hero-cta { display: flex; align-items: center; justify-content: center; gap: var(--spacing-md); flex-wrap: wrap; }

.about-content { max-width: 850px; margin: 0 auto; }
.about-text { display: grid; gap: var(--spacing-md); }
.about-text p, p { color: var(--text-secondary); }

.expertise-grid, .hobbies-grid, .blog-grid, .projects-grid { display: grid; gap: var(--spacing-lg); }
.expertise-grid, .hobbies-grid { grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); margin-top: var(--spacing-xl); }
.expertise-card, .hobby-card, .blog-card, .project-card { background-color: var(--surface); border: 1px solid var(--border-color); border-radius: var(--border-radius-lg); box-shadow: var(--shadow-sm); }
.expertise-card, .hobby-card { padding: var(--spacing-lg); transition: transform var(--transition-fast), box-shadow var(--transition-fast); }
.expertise-card:hover, .hobby-card:hover, .blog-card:hover, .project-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); }
.expertise-icon, .hobby-icon { width: 56px; height: 56px; display: inline-flex; align-items: center; justify-content: center; border-radius: 1rem; font-size: 1.6rem; margin-bottom: var(--spacing-md); background-color: rgba(37,99,235,0.12); }
.tech-list { display: flex; gap: 0.6rem; flex-wrap: wrap; margin-top: var(--spacing-md); }
.tech-list li, .project-tech, .project-metric { padding: 0.4rem 0.7rem; border-radius: 999px; background-color: var(--surface-2); color: var(--text-secondary); font-size: 0.9rem; border: 1px solid var(--border-color); }

.projects-section { background: linear-gradient(180deg, var(--bg-primary), var(--bg-secondary)); }
.projects-grid { grid-template-columns: minmax(0, 860px); justify-content: center; margin-top: var(--spacing-xl); }
.project-card { overflow: hidden; }
.project-card-content { display: grid; gap: var(--spacing-md); padding: clamp(1.25rem, 3vw, 2rem); }
.project-card-header { display: grid; gap: 0.55rem; }
.project-category { justify-self: start; display: inline-flex; align-items: center; border-radius: 999px; padding: 0.45rem 0.8rem; font-size: 0.9rem; font-weight: 700; color: var(--primary-color); background-color: rgba(37,99,235,0.12); }
.project-title { margin: 0; font-size: clamp(1.5rem, 3vw, 2rem); color: var(--text-primary); }
.project-excerpt { margin: 0; color: var(--text-secondary); font-size: 1rem; line-height: 1.75; }
.project-tech-list, .project-metrics { display: flex; flex-wrap: wrap; gap: 0.65rem; }
.project-actions { display: flex; flex-wrap: wrap; gap: var(--spacing-sm); margin-top: var(--spacing-xs); }
.loading, .loading-text { text-align: center; padding: var(--spacing-xl); color: var(--text-secondary); grid-column: 1 / -1; }

.blog-grid { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); margin-top: var(--spacing-xl); }
.blog-card { padding: var(--spacing-lg); display: flex; flex-direction: column; gap: 0.9rem; }
.blog-meta { display: flex; gap: var(--spacing-sm); flex-wrap: wrap; font-size: 0.9rem; color: var(--text-light); }
.blog-card-excerpt { flex-grow: 1; }
.blog-card-link { display: inline-flex; align-items: center; gap: 0.4rem; color: var(--primary-color); font-weight: 600; }

.contact-links { display: flex; justify-content: center; flex-wrap: wrap; gap: var(--spacing-md); margin-top: var(--spacing-xl); }
.contact-link { display: inline-flex; align-items: center; gap: 0.7rem; padding: 0.95rem 1.15rem; border-radius: 1rem; background-color: var(--surface); border: 1px solid var(--border-color); color: var(--text-primary); box-shadow: var(--shadow-sm); transition: transform var(--transition-fast), box-shadow var(--transition-fast); }
.contact-link:hover { transform: translateY(-2px); box-shadow: var(--shadow-md); }

.footer { padding: var(--spacing-xl) 0; border-top: 1px solid var(--border-color); background-color: var(--bg-secondary); text-align: center; }
.footer .container { display: grid; gap: 0.35rem; }
.footer-note { color: var(--text-light); }

@media (max-width: 980px) {
  .navbar .container { flex-wrap: wrap; }
  .nav-toggle { display: flex; margin-left: auto; }
  .nav-menu { display: none; width: 100%; flex-direction: column; align-items: flex-start; gap: var(--spacing-md); padding-top: var(--spacing-md); }
  .nav-menu.active { display: flex; }
  .nav-actions { margin-left: auto; }
}
@media (max-width: 768px) {
  .section { padding: 3.25rem 0; }
  .hero { min-height: 78vh; }
  .hero-cta, .project-actions, .contact-links { flex-direction: column; align-items: stretch; }
  .btn, .contact-link { width: 100%; }
}
@media (max-width: 520px) {
  .container { padding: 0 0.9rem; }
  .section-title { font-size: 2rem; }
  .blog-grid, .expertise-grid, .hobbies-grid { grid-template-columns: 1fr; }
}


/* ===================================
   Contact compact icons
   =================================== */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.contact-links-compact {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.95rem;
}

.contact-link-icon {
  width: 72px;
  height: 72px;
  padding: 0;
  border-radius: 999px;
  justify-content: center;
  background: var(--surface);
  border: 1px solid var(--border-color);
}

.contact-link-icon .icon {
  width: 28px;
  height: 28px;
}

/* ===================================
   Project detail page
   =================================== */
.project-detail-page {
  min-height: 100vh;
  background: linear-gradient(180deg, var(--bg-primary), var(--bg-secondary));
}

.project-detail-shell {
  padding: 2rem 0 4rem;
}

.project-detail-topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  margin-bottom: 2rem;
}

.project-detail-actions {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  color: var(--primary-color);
  font-weight: 700;
}

.project-detail-hero {
  display: grid;
  gap: 1.5rem;
  margin-bottom: 2rem;
}

.project-detail-title {
  font-size: clamp(2rem, 5vw, 3.25rem);
  line-height: 1.15;
  color: var(--text-primary);
}

.project-detail-subtitle {
  max-width: 850px;
}

.project-hero-media {
  overflow: hidden;
  border-radius: var(--border-radius-lg);
  border: 1px solid var(--border-color);
  background: var(--surface);
  box-shadow: var(--shadow-md);
}

.project-hero-media img {
  display: block;
  width: 100%;
  height: auto;
}

.project-meta-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 1rem;
  margin: 2rem 0;
}

.project-meta-card,
.project-section {
  background: var(--surface);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  box-shadow: var(--shadow-sm);
}

.project-meta-card {
  padding: 1.15rem 1.25rem;
}

.project-meta-card strong {
  display: block;
  margin-bottom: 0.4rem;
  color: var(--text-primary);
}

.project-meta-card p,
.project-meta-card a {
  color: var(--text-secondary);
}

.project-content-grid {
  display: grid;
  gap: 1.25rem;
}

.project-section {
  padding: 1.4rem 1.45rem;
}

.project-section h2 {
  margin-bottom: 0.85rem;
  color: var(--text-primary);
  font-size: 1.35rem;
}

.project-list {
  display: grid;
  gap: 0.75rem;
  padding-left: 1.2rem;
  color: var(--text-secondary);
}

.project-gallery {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1rem;
}

.project-gallery img {
  width: 100%;
  height: 240px;
  object-fit: cover;
  border-radius: 1rem;
  border: 1px solid var(--border-color);
  background: var(--surface-2);
}

.project-footer-actions {
  display: flex;
  gap: 0.85rem;
  flex-wrap: wrap;
  margin-top: 2rem;
}

@media (max-width: 768px) {
  .project-detail-topbar {
    flex-direction: column;
    align-items: stretch;
  }

  .project-detail-actions {
    justify-content: space-between;
  }

  .contact-links-compact {
    gap: 0.85rem;
  }

  .contact-link-icon {
    width: 64px;
    height: 64px;
  }

  .project-footer-actions {
    flex-direction: column;
  }
}