/* ============================================
   Responsive Layout — Tech Blog + Gallery
   Full-bleed hero + warm/cool alternating sections
   Flexbox for alignment, Grid for structure
   ============================================ */

:root {
  --color-bg: #0f1419;
  --color-bg-warm: #141210;
  --color-bg-cool: #0d1117;
  --color-surface: rgba(20, 26, 35, 0.85);
  --color-surface-warm: rgba(25, 22, 18, 0.85);
  --color-primary: #3b82f6;
  --color-primary-glow: rgba(59, 130, 246, 0.2);
  --color-accent-warm: #f59e0b;
  --color-accent-red: #ef4444;
  --color-text: #e2e8f0;
  --color-text-secondary: #94a3b8;
  --color-text-muted: #64748b;
  --color-border: rgba(148, 163, 184, 0.1);
  --color-white: #ffffff;

  --font-body: 'Inter', system-ui, sans-serif;
  --radius-md: 12px;
  --radius-lg: 16px;
  --transition-smooth: 300ms cubic-bezier(0.25, 0.46, 0.45, 0.94);
  --container-max: 1200px;
  --container-padding: 1.5rem;
}

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

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

img { max-width: 100%; height: auto; display: block; }
a { color: var(--color-primary); text-decoration: none; transition: color var(--transition-smooth); }
a:hover { color: var(--color-accent-warm); }

.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0,0,0,0); border: 0;
}
.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

/* ============ Navigation ============ */
.site-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  background: rgba(15, 20, 25, 0.9);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  padding: 0.875rem 0;
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-logo {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-white);
  text-decoration: none;
}
.nav-logo span { color: var(--color-primary); }
.nav-links { display: flex; gap: 2rem; }
.nav-links a {
  color: var(--color-text-secondary);
  font-size: 0.85rem;
  font-weight: 500;
  text-decoration: none;
  transition: color var(--transition-smooth);
}
.nav-links a:hover,
.nav-links a.active { color: var(--color-white); }

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
}
.hamburger span {
  width: 22px; height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: var(--transition-smooth);
}
.hamburger.active span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.hamburger.active span:nth-child(2) { opacity: 0; }
.hamburger.active span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

.mobile-overlay { display: none; position: fixed; inset: 0; background: rgba(0,0,0,0.6); z-index: 998; }
.mobile-overlay.active { display: block; }
.mobile-menu {
  display: none; position: fixed; top: 0; right: -280px;
  width: 280px; height: 100vh; background: var(--color-bg);
  border-left: 1px solid var(--color-border);
  padding: 5rem 2rem; z-index: 999;
  transition: right var(--transition-smooth);
  flex-direction: column; gap: 1.5rem;
}
.mobile-menu.active { right: 0; }
.mobile-menu a { color: var(--color-text-secondary); font-size: 1rem; text-decoration: none; }

@media (max-width: 768px) {
  .nav-links { display: none; }
  .hamburger { display: flex; }
  .mobile-menu { display: flex; }
}

/* ============ Hero ============ */
.hero-banner {
  position: relative;
  padding: 10rem 0 5rem;
  overflow: hidden;
}
.hero-banner::before {
  content: '';
  position: absolute;
  inset: 0;
  background: url('https://images.unsplash.com/photo-1451187580459-43490279c0fa?w=1600&h=600&fit=crop') center/cover no-repeat;
  filter: brightness(0.3);
  z-index: -2;
}
.hero-banner::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(to bottom, transparent 40%, var(--color-bg) 100%);
  z-index: -1;
}
.hero-banner h1 {
  font-size: clamp(2.5rem, 5vw, 4rem);
  font-weight: 800;
  color: var(--color-white);
  letter-spacing: -1px;
  margin-bottom: 0.75rem;
}
.hero-banner p {
  font-size: 1.1rem;
  color: var(--color-text-secondary);
  max-width: 600px;
  line-height: 1.7;
}
.hero-badge {
  display: inline-block;
  margin-top: 1.5rem;
  padding: 0.4rem 1rem;
  background: rgba(59, 130, 246, 0.1);
  border: 1px solid rgba(59, 130, 246, 0.2);
  border-radius: 20px;
  font-size: 0.8rem;
  color: var(--color-primary);
  font-weight: 500;
}

/* ============ Page Layout (2-col with sidebar) ============ */
.page-layout {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 2.5rem;
  padding: 4rem 0;
}
@media (max-width: 1024px) {
  .page-layout { grid-template-columns: 1fr; }
}

/* ============ Blog Grid ============ */
.section-heading {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 0.5rem;
}
.section-desc {
  color: var(--color-text-secondary);
  margin-bottom: 2rem;
  font-size: 0.95rem;
}

.blog-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}
@media (max-width: 1024px) {
  .blog-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 600px) {
  .blog-grid { grid-template-columns: 1fr; }
}

.blog-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: all var(--transition-smooth);
  display: flex;
  flex-direction: column;
}
.blog-card:hover {
  transform: translateY(-4px);
  border-color: var(--color-primary-glow);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.3);
}
.blog-card a.card-link {
  display: flex;
  flex-direction: column;
  height: 100%;
  color: inherit;
  text-decoration: none;
}
.blog-card .card-image-wrap {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16/9;
}
.blog-card .card-image-wrap img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}
.blog-card:hover .card-image-wrap img {
  transform: scale(1.05);
}
.blog-card .card-body {
  padding: 1.5rem;
  flex: 1;
  display: flex;
  flex-direction: column;
}
.blog-card .card-category {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 0.5rem;
}
.blog-card h3 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 0.5rem;
  line-height: 1.4;
}
.blog-card .card-excerpt {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
  flex: 1;
}
.blog-card .card-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--color-border);
  font-size: 0.8rem;
  color: var(--color-text-muted);
}
.blog-card .read-more {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-primary);
  opacity: 0;
  transform: translateY(4px);
  transition: all var(--transition-smooth);
}
.blog-card:hover .read-more {
  opacity: 1;
  transform: translateY(0);
}

.blog-card.featured {
  grid-column: 1 / -1;
}
.blog-card.featured a.card-link {
  flex-direction: row;
}
.blog-card.featured .card-image-wrap {
  width: 50%;
  aspect-ratio: auto;
  min-height: 280px;
}
.blog-card.featured .card-body {
  padding: 2rem;
  justify-content: center;
}
.blog-card.featured h3 { font-size: 1.4rem; }
@media (max-width: 768px) {
  .blog-card.featured a.card-link { flex-direction: column; }
  .blog-card.featured .card-image-wrap { width: 100%; aspect-ratio: 16/9; min-height: auto; }
}

/* ============ Gallery Grid ============ */
.gallery-section {
  padding: 4rem 0;
  background: var(--color-bg-warm);
  border-top: 1px solid var(--color-border);
}

.gallery-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
}
@media (max-width: 768px) {
  .gallery-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 480px) {
  .gallery-grid { grid-template-columns: 1fr; }
}

.gallery-item {
  position: relative;
  border-radius: var(--radius-md);
  overflow: hidden;
  cursor: pointer;
  aspect-ratio: 4/3;
}
.gallery-item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}
.gallery-item:hover img {
  transform: scale(1.08);
}
.gallery-item .overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(to top, rgba(0,0,0,0.7) 0%, transparent 60%);
  display: flex;
  align-items: flex-end;
  padding: 1rem;
  opacity: 0;
  transition: opacity var(--transition-smooth);
}
.gallery-item:hover .overlay { opacity: 1; }
.gallery-item .overlay span {
  font-size: 0.85rem;
  color: var(--color-white);
  font-weight: 500;
}

/* ============ Lightbox ============ */
.lightbox {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.92);
  backdrop-filter: blur(8px);
  z-index: 3000;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
}
.lightbox.active {
  opacity: 1;
  pointer-events: auto;
}
.lightbox img {
  max-width: 90vw;
  max-height: 85vh;
  border-radius: var(--radius-md);
  object-fit: contain;
}
.lightbox-close {
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  background: rgba(255,255,255,0.1);
  border: 1px solid rgba(255,255,255,0.2);
  border-radius: 50%;
  width: 40px; height: 40px;
  display: flex; align-items: center; justify-content: center;
  color: var(--color-white);
  font-size: 1.25rem;
  cursor: pointer;
  transition: background var(--transition-smooth);
}
.lightbox-close:hover { background: rgba(255,255,255,0.2); }
.lightbox-nav {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: 50%;
  width: 44px; height: 44px;
  display: flex; align-items: center; justify-content: center;
  color: var(--color-white);
  font-size: 1.25rem;
  cursor: pointer;
  transition: background var(--transition-smooth);
}
.lightbox-nav:hover { background: rgba(255,255,255,0.15); }
.lightbox-prev { left: 1.5rem; }
.lightbox-next { right: 1.5rem; }

/* ============ Sidebar ============ */
.sidebar {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}
.sidebar-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  backdrop-filter: blur(8px);
}
.sidebar-card h3 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 1rem;
}
.sidebar-card .tag-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}
.sidebar-card .tag-pill {
  padding: 0.3rem 0.7rem;
  background: rgba(59, 130, 246, 0.08);
  border: 1px solid rgba(59, 130, 246, 0.15);
  border-radius: 16px;
  font-size: 0.75rem;
  color: var(--color-primary);
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-smooth);
}
.sidebar-card .tag-pill:hover {
  background: rgba(59, 130, 246, 0.15);
  border-color: rgba(59, 130, 246, 0.3);
}
.sidebar-card .newsletter-input {
  width: 100%;
  padding: 0.7rem 1rem;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  color: var(--color-text);
  font-size: 0.875rem;
  margin-bottom: 0.75rem;
  transition: border-color var(--transition-smooth);
}
.sidebar-card .newsletter-input:focus {
  outline: none;
  border-color: var(--color-primary);
}
.sidebar-card .newsletter-btn {
  width: 100%;
  padding: 0.7rem;
  background: linear-gradient(135deg, var(--color-primary), #6366f1);
  color: var(--color-white);
  border: none;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.85rem;
  cursor: pointer;
  transition: all var(--transition-smooth);
}
.sidebar-card .newsletter-btn:hover {
  box-shadow: 0 4px 20px rgba(59, 130, 246, 0.3);
}

/* ============ Article Page ============ */
.article-hero {
  position: relative;
  padding: 10rem 0 3rem;
  overflow: hidden;
}
.article-hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--article-hero-bg, #1a1a2e) center/cover no-repeat;
  filter: brightness(0.25);
  z-index: -2;
}
.article-hero::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(to bottom, transparent 50%, var(--color-bg) 100%);
  z-index: -1;
}
.article-hero .breadcrumb {
  font-size: 0.8rem;
  color: var(--color-text-muted);
  margin-bottom: 1rem;
}
.article-hero .breadcrumb a { color: var(--color-primary); }
.article-hero h1 {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 800;
  color: var(--color-white);
  letter-spacing: -0.5px;
  margin-bottom: 1rem;
  max-width: 700px;
}
.article-meta {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  flex-wrap: wrap;
}
.article-meta span {
  font-size: 0.8rem;
  color: var(--color-text-muted);
}
.reading-badge {
  padding: 0.25rem 0.6rem;
  background: rgba(59, 130, 246, 0.1);
  border: 1px solid rgba(59, 130, 246, 0.2);
  border-radius: 12px;
  font-size: 0.75rem;
  color: var(--color-primary);
}

.article-content {
  max-width: 740px;
  padding: 3rem 0 5rem;
}
.article-content h2 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-white);
  margin: 2.5rem 0 1rem;
}
.article-content h3 {
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--color-white);
  margin: 2rem 0 0.75rem;
}
.article-content p {
  color: var(--color-text-secondary);
  line-height: 1.8;
  margin-bottom: 1.25rem;
}
.article-content code {
  background: rgba(59, 130, 246, 0.08);
  padding: 0.2rem 0.4rem;
  border-radius: 4px;
  font-size: 0.85em;
  color: var(--color-primary);
}
.article-content pre {
  background: rgba(0, 0, 0, 0.4);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  overflow-x: auto;
  margin: 1.5rem 0;
}
.article-content pre code {
  background: none;
  padding: 0;
  font-size: 0.85rem;
  color: var(--color-text);
  line-height: 1.7;
}
.article-content blockquote {
  border-left: 3px solid var(--color-primary);
  padding: 1rem 1.5rem;
  margin: 1.5rem 0;
  background: rgba(59, 130, 246, 0.04);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
}
.article-content blockquote p {
  color: var(--color-text);
  font-style: italic;
}

.related-articles {
  border-top: 1px solid var(--color-border);
  padding-top: 3rem;
  margin-top: 3rem;
}
.related-articles h2 {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 1.5rem;
}
.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1rem;
}

/* ============ Footer ============ */
.site-footer {
  padding: 2rem 0;
  border-top: 1px solid var(--color-border);
  text-align: center;
}
.site-footer p {
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

/* ============ Scroll Reveal ============ */
.reveal {
  opacity: 0; transform: translateY(20px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}
.reveal.visible { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
  .reveal { opacity: 1; transform: none; }
}