/* ===== Base & Variables ===== */
:root {
  --bg-primary: #ffffff;
  --text-primary: #0f172a;
  --text-secondary: #334155;
  --text-muted: #64748b;
  --border-light: #e2e8f0;
  --accent-light: #dbeafe;
  --accent-dark: #1e3a8a;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1);
  --transition: 0.2s ease;
  --font-base: 1.05rem;
  --focus-outline: 2px solid #2563eb;
  --focus-offset: 2px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg-primary: #0f172a;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --border-light: #334155;
    --accent-light: #1e3a8a;
    --accent-dark: #dbeafe;
  }
}

/* ===== Global ===== */
*:focus-visible {
  outline: var(--focus-outline);
  outline-offset: var(--focus-offset);
}

/* ===== Blog Post Shell ===== */
.blog-post-shell {
  padding: 2rem 1rem;
  min-height: 60vh;
  max-width: 1060px;
  margin: 0 auto;
}

/* ===== Progress Bar ===== */
.blog-read-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0;
  z-index: 60;
  background: linear-gradient(90deg, #16a34a 0%, #22c55e 100%);
}

/* ===== Breadcrumb ===== */
.blog-post-breadcrumb {
  margin-bottom: 0;
  display: flex;
  gap: 0.45rem;
  align-items: center;
  flex-wrap: wrap;
  color: var(--text-muted);
  font-size: 0.85rem;
}

.blog-post-topbar {
  margin-bottom: 0.85rem;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.8rem;
}
.blog-post-breadcrumb a {
  color: #1d4ed8;
  text-decoration: none;
}
.blog-post-breadcrumb a:hover {
  text-decoration: underline;
}

/* ===== Back Button ===== */
.blog-back-btn {
  margin-bottom: 0;
  margin-left: 0;
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}

.blog-back-link {
  font-size: 0.85rem;
  font-weight: 600;
  color: #1d4ed8;
  text-decoration: none;
  padding: 0;
  border: none;
  background: transparent;
  line-height: 1.2;
}

.blog-back-link::before {
  content: "<";
  margin-right: 0.2rem;
}

.blog-back-link:hover {
  text-decoration: underline;
}

/* ===== Article Card ===== */
.blog-post-article {
  border: 1px solid var(--border-light);
  border-radius: 14px;
  background: var(--bg-primary);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  transition: box-shadow var(--transition);
}
.blog-post-article:hover {
  box-shadow: 0 10px 28px rgba(15, 23, 42, 0.12);
}
.blog-post-article > img {
  width: 100%;
  max-height: 430px;
  object-fit: cover;
  border-top: 1px solid var(--border-light);
}

/* ===== Hero Section ===== */
.blog-post-hero {
  padding: 1.05rem 1.15rem 0.95rem;
  background: linear-gradient(180deg, #f8fafc 0%, var(--bg-primary) 100%);
}
.blog-post-hero h1 {
  margin: 0.5rem 0 0.45rem;
  line-height: 1.2;
  font-size: clamp(1.8rem, 5vw, 2.5rem);
}
.blog-category-chip {
  display: inline-flex;
  align-items: center;
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  font-weight: 700;
  padding: 0.22rem 0.62rem;
  border-radius: 999px;
  color: var(--accent-dark);
  background: var(--accent-light);
}
.blog-post-excerpt {
  margin: 0 0 0.55rem;
  color: var(--text-secondary);
  font-size: 1rem;
}
.blog-post-submeta {
  margin: 0;
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* ===== Share Row & Icons ===== */
.blog-share-row {
  margin-top: 0.75rem;
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}
.btn-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  padding: 0;
  border: 1px solid var(--border-light);
  border-radius: 999px;
  background: var(--bg-primary);
  color: var(--text-primary);
  transition: all var(--transition);
}
.btn-icon:hover {
  background: var(--accent-light);
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}
.btn-icon i {
  width: 18px;
  height: 18px;
}
/* Toast */
.toast {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  background: var(--accent-dark);
  color: white;
  padding: 0.75rem 1.5rem;
  border-radius: 999px;
  font-size: 0.9rem;
  z-index: 100;
  box-shadow: var(--shadow-md);
  animation: fadeInOut 2s ease forwards;
}
@keyframes fadeInOut {
  0% { opacity: 0; transform: translateX(-50%) translateY(10px); }
  15% { opacity: 1; transform: translateX(-50%) translateY(0); }
  85% { opacity: 1; transform: translateX(-50%) translateY(0); }
  100% { opacity: 0; transform: translateX(-50%) translateY(-10px); }
}
.hidden {
  display: none !important;
}

/* ===== Layout ===== */
.blog-post-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(240px, 280px);
  gap: 1.1rem;
  padding: 1rem 1.15rem 1.2rem;
  align-items: start;
}
.blog-post-body {
  min-width: 0;
  order: 1;
  border: 1px solid var(--border-light);
  border-radius: 12px;
  background: var(--bg-primary);
  box-shadow: var(--shadow-sm);
  padding: 1rem 1.05rem;
}

/* ===== Table of Contents (Desktop) ===== */
.blog-post-toc-card.desktop-only {
  display: block;
  order: 2;
}
.blog-post-toc-card {
  position: sticky;
  top: 90px;
  align-self: start;
  border: 1px solid var(--border-light);
  border-radius: 10px;
  padding: 1rem 1.05rem;
  background: color-mix(in srgb, var(--bg-primary) 98%, var(--text-primary));
  box-shadow: var(--shadow-sm);
}
.blog-post-toc-card h4 {
  margin: 0 0 0.55rem;
  font-size: 1rem;
}
.blog-post-toc-card ul {
  margin: 0;
  padding-left: 1rem;
  display: grid;
  gap: 0.3rem;
}
.blog-post-toc-card li {
  color: var(--text-secondary);
  list-style: disc;
}
.blog-post-toc-card li.toc-sub {
  margin-left: 0.6rem;
  list-style-type: circle;
}
.blog-post-toc-card a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.9rem;
}
.blog-post-toc-card a:hover {
  text-decoration: underline;
  color: var(--accent-dark);
}
.blog-post-toc-card a[aria-current="location"] {
  font-weight: 600;
  color: var(--accent-dark);
  border-left: 2px solid var(--accent-dark);
  padding-left: 0.5rem;
  margin-left: -0.5rem;
}
/* Mobile TOC (collapsible) */
.blog-post-toc-mobile {
  display: none;
  margin-bottom: 1rem;
  border: 1px solid var(--border-light);
  border-radius: 10px;
  background: var(--bg-primary);
}
.blog-post-toc-mobile summary {
  padding: 0.7rem 0.8rem;
  font-weight: 600;
  cursor: pointer;
  list-style: none;
}
.blog-post-toc-mobile summary::-webkit-details-marker {
  display: none;
}
.blog-post-toc-mobile summary::after {
  content: '▼';
  float: right;
  font-size: 0.8rem;
  transition: transform var(--transition);
}
.blog-post-toc-mobile[open] summary::after {
  transform: rotate(180deg);
}
.blog-post-toc-mobile .blog-post-toc-card {
  border: none;
  box-shadow: none;
  padding-top: 0;
}

/* ===== Content Styling ===== */
.blog-content {
  max-width: 70ch;
  line-height: 1.78;
  color: var(--text-primary);
  font-size: var(--font-base);
}
.blog-content h2 {
  margin-top: 1.7rem;
  margin-bottom: 0.55rem;
  line-height: 1.28;
  scroll-margin-top: 80px; /* for smooth scroll offset */
}
.blog-content h3 {
  margin-top: 1.25rem;
  margin-bottom: 0.45rem;
  line-height: 1.3;
  scroll-margin-top: 80px;
}
.blog-content p {
  margin: 0.65rem 0;
}
.blog-content ul,
.blog-content ol {
  margin: 0.55rem 0 0.8rem;
  padding-left: 1.2rem;
}
.blog-content blockquote {
  margin: 0.9rem 0;
  padding: 0.55rem 0.8rem;
  border-left: 4px solid #93c5fd;
  background: #eff6ff;
  color: #1e3a8a;
}
.blog-content a {
  color: #1d4ed8;
  text-decoration: underline;
}

/* ===== Tags ===== */
.blog-tag-list {
  margin-top: 1rem;
}
.blog-tag {
  display: inline-block;
  padding: 0.25rem 0.55rem;
  margin-right: 0.35rem;
  margin-bottom: 0.35rem;
  border: 1px solid var(--border-light);
  border-radius: 999px;
  font-size: 0.8rem;
  background: var(--bg-primary);
  transition: background var(--transition);
}
.blog-tag:hover {
  background: var(--accent-light);
}

/* ===== Author Box ===== */
.blog-author-box {
  margin-top: 1.05rem;
  border-top: 1px solid var(--border-light);
  padding-top: 0.9rem;
  display: flex;
  gap: 1rem;
  align-items: flex-start;
}
.author-avatar {
  flex-shrink: 0;
  width: 60px;
  height: 60px;
  border-radius: 50%;
  overflow: hidden;
  background: var(--accent-light);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  font-size: 1.5rem;
  color: var(--accent-dark);
}
.author-avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.author-details h4 {
  margin: 0 0 0.25rem;
}
.author-bio {
  margin: 0 0 0.5rem;
  color: var(--text-secondary);
}
.author-more-posts {
  color: #1d4ed8;
  text-decoration: none;
  font-size: 0.9rem;
}
.author-more-posts:hover {
  text-decoration: underline;
}

/* ===== Gallery ===== */
.blog-gallery {
  margin-top: 1.05rem;
  border-top: 1px solid var(--border-light);
  padding-top: 0.9rem;
}
.blog-gallery h3 {
  margin-bottom: 0.65rem;
}
.blog-gallery-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.6rem;
}
.blog-gallery-item {
  border: 1px solid var(--border-light);
  border-radius: 10px;
  padding: 0;
  overflow: hidden;
  cursor: pointer;
  background: var(--bg-primary);
  transition: transform var(--transition), box-shadow var(--transition);
}
.blog-gallery-item:hover {
  transform: scale(1.02);
  box-shadow: var(--shadow-md);
}
.blog-gallery-item img {
  width: 100%;
  height: 120px;
  object-fit: cover;
  display: block;
}

/* Gallery Modal */
.blog-gallery-modal {
  position: fixed;
  inset: 0;
  z-index: 110;
  display: grid;
  place-items: center;
}
.blog-gallery-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(2, 6, 23, 0.85);
}
.blog-gallery-dialog {
  position: relative;
  z-index: 1;
  width: min(96vw, 980px);
  max-height: 90vh;
  padding: 0.8rem;
  border-radius: 12px;
  background: #0f172a;
  display: flex;
  flex-direction: column;
  align-items: center;
}
.gallery-image-container {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
}
.blog-gallery-dialog img {
  max-width: 100%;
  max-height: 70vh;
  border-radius: 8px;
  object-fit: contain;
}
.gallery-spinner {
  position: absolute;
  width: 40px;
  height: 40px;
  border: 4px solid #e2e8f0;
  border-top-color: #1d4ed8;
  border-radius: 50%;
  animation: spin 1s linear infinite;
}
@keyframes spin {
  to { transform: rotate(360deg); }
}
.blog-gallery-close,
.blog-gallery-nav {
  position: absolute;
  border: none;
  width: 44px;
  height: 44px;
  border-radius: 999px;
  cursor: pointer;
  font-size: 2rem;
  line-height: 1;
  color: #e2e8f0;
  background: rgba(15, 23, 42, 0.75);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition);
  z-index: 2;
}
.blog-gallery-close:hover,
.blog-gallery-nav:hover {
  background: rgba(15, 23, 42, 0.95);
}
.blog-gallery-close {
  top: 0.55rem;
  right: 0.55rem;
}
.blog-gallery-nav.prev {
  left: 0.55rem;
  top: 50%;
  transform: translateY(-50%);
}
.blog-gallery-nav.next {
  right: 0.55rem;
  top: 50%;
  transform: translateY(-50%);
}
.blog-gallery-counter {
  margin-top: 0.55rem;
  font-size: 0.85rem;
  color: #cbd5e1;
}
.blog-gallery-caption {
  margin-top: 0.3rem;
  font-size: 0.9rem;
  color: #cbd5e1;
  text-align: center;
  max-width: 80%;
}

/* ===== Related Posts ===== */
.blog-related {
  margin-top: 1.2rem;
}
.blog-related-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.75rem;
}
.blog-related-card {
  display: block;
  border: 1px solid var(--border-light);
  border-radius: 10px;
  overflow: hidden;
  text-decoration: none;
  color: inherit;
  background: var(--bg-primary);
  transition: transform var(--transition), box-shadow var(--transition);
}
.blog-related-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}
.blog-related-card img {
  width: 100%;
  height: 145px;
  object-fit: cover;
}
.blog-related-card-body {
  padding: 0.65rem;
}
.related-meta {
  margin: 0.2rem 0 0;
  color: var(--text-muted);
  font-size: 0.85rem;
}
.related-excerpt {
  margin: 0.5rem 0 0;
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.4;
}

/* ===== Back to Top Button ===== */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 48px;
  height: 48px;
  border-radius: 999px;
  background: var(--accent-dark);
  color: white;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition), visibility var(--transition), transform var(--transition);
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-md);
}
.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}
.back-to-top:hover {
  transform: scale(1.1);
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .blog-post-layout {
    grid-template-columns: 1fr;
  }
  .blog-post-topbar {
    flex-wrap: wrap;
    align-items: flex-start;
  }
  .blog-post-toc-card.desktop-only {
    display: none;
  }
  .blog-post-toc-mobile {
    display: block;
  }
  .blog-post-body {
    order: initial;
    padding: 0.9rem 0.85rem;
  }
  .blog-related-grid {
    grid-template-columns: 1fr;
  }
  .blog-gallery-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .back-to-top {
    bottom: 1rem;
    right: 1rem;
  }
  .btn-icon {
    width: 44px;
    height: 44px;
  }
}

/* ===== Utilities ===== */
.no-scroll {
  overflow: hidden;
}