/* ==========================================================================
   blog.css — Shared stylesheet for jaykoh.pages.dev blog articles
   Design tokens imported from /tokens.css (single source of truth).
   ========================================================================== */
@import url('/tokens.css');

/* --- Reset --- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-font-smoothing: antialiased; }
body {
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text-secondary);
  line-height: 1.7;
}
a { color: var(--color-accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* --- Reading Progress Bar --- */
.reading-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 0%;
  height: 3px;
  background: linear-gradient(90deg, var(--color-accent), #059669);
  z-index: 100;
  border-radius: 0 2px 2px 0;
  transition: width 50ms linear;
}

/* --- Breadcrumb --- */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.8125rem;
  color: var(--color-text-tertiary);
  padding: 1rem 0 0;
  flex-wrap: wrap;
}
.breadcrumb a {
  color: var(--color-text-tertiary);
  transition: color 150ms ease;
}
.breadcrumb a:hover {
  color: var(--color-accent);
  text-decoration: none;
}
.breadcrumb-sep {
  color: var(--color-border);
  font-size: 0.75rem;
}
.breadcrumb-current {
  color: var(--color-text-secondary);
  font-weight: 500;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  max-width: 400px;
}

/* --- Navigation --- */
.blog-nav {
  padding: 1.5rem 0;
  border-bottom: 1px solid var(--color-border);
  background: rgba(245,247,246,0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  position: sticky;
  top: 0;
  z-index: 10;
}
@media (prefers-color-scheme: dark) {
  .blog-nav { background: rgba(15,26,20,0.92); }
}
[data-theme="dark"] .blog-nav { background: rgba(15,26,20,0.92); }
[data-theme="light"] .blog-nav { background: rgba(245,247,246,0.95); }
.blog-nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.blog-nav-logo {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-text-primary);
  letter-spacing: -0.02em;
}
.blog-nav-logo span { color: var(--color-accent); }
.blog-nav-back {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-tertiary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transition: color 150ms ease;
}
.blog-nav-back:hover {
  color: var(--color-text-primary);
  text-decoration: none;
}

/* --- Container --- */
.container {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 0 2rem;
}

/* --- Category Tag --- */
.blog-category-tag {
  display: inline-block;
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--color-accent);
  background: var(--color-accent-dim);
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
  margin-bottom: 0.75rem;
}

/* --- Header --- */
.blog-header {
  padding: 4rem 0 2rem;
  border-bottom: 1px solid var(--color-border);
}
.blog-meta {
  font-size: 0.8125rem;
  color: var(--color-text-tertiary);
  margin-bottom: 1rem;
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
}
.blog-header h1 {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  color: var(--color-text-primary);
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin-bottom: 1rem;
}
.blog-header .lead {
  font-size: 1.1rem;
  color: var(--color-text-tertiary);
  line-height: 1.7;
}

/* --- Table of Contents --- */
.toc {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: 10px;
  padding: 1.5rem;
  margin: 2rem 0;
}
.toc-title {
  font-size: 0.8125rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-primary);
  margin-bottom: 0.75rem;
}
.toc ol {
  list-style: none;
  counter-reset: toc-counter;
  margin: 0;
  padding: 0;
}
.toc li {
  counter-increment: toc-counter;
  margin-bottom: 0.375rem;
}
.toc li::before {
  content: counter(toc-counter) ".";
  color: var(--color-accent);
  font-weight: 600;
  font-size: 0.8125rem;
  margin-right: 0.5rem;
  display: inline-block;
  min-width: 1.25rem;
}
.toc a {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  transition: color 150ms ease;
}
.toc a:hover {
  color: var(--color-accent);
  text-decoration: none;
}

/* Sticky TOC (sidebar on wide screens) */
@media (min-width: 1200px) {
  .toc-sticky {
    position: fixed;
    top: 100px;
    left: calc(50% + 400px);
    width: 220px;
    background: transparent;
    border: none;
    padding: 0;
    margin: 0;
  }
  .toc-sticky .toc-title {
    font-size: 0.75rem;
  }
  .toc-sticky a {
    font-size: 0.8125rem;
  }
}

/* --- Article Content --- */
.blog-content {
  padding: 3rem 0;
}
.blog-content h2 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-text-primary);
  margin: 2.5rem 0 1rem;
  letter-spacing: -0.01em;
  scroll-margin-top: 80px;
}
.blog-content h3 {
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--color-text-primary);
  margin: 2rem 0 0.75rem;
  scroll-margin-top: 80px;
}
.blog-content p {
  margin-bottom: 1.25rem;
  color: var(--color-text-secondary);
  line-height: 1.8;
}
.blog-content ul, .blog-content ol {
  margin: 0 0 1.25rem 1.5rem;
  color: var(--color-text-secondary);
}
.blog-content li {
  margin-bottom: 0.5rem;
  line-height: 1.7;
}
.blog-content ul { list-style: disc; }
.blog-content ol { list-style: decimal; }

/* Inline code */
.blog-content code {
  background: var(--color-bg-elevated);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  font-size: 0.875rem;
  font-family: var(--font-mono);
  color: var(--color-accent);
}

/* Code blocks */
.blog-content pre {
  background: #1a2e22;
  color: #e4e8e5;
  padding: 1.5rem;
  border-radius: 10px;
  overflow-x: auto;
  margin: 1.5rem 0;
  font-size: 0.85rem;
  line-height: 1.6;
  position: relative;
  border: 1px solid rgba(255,255,255,0.06);
}
@media (prefers-color-scheme: dark) {
  .blog-content pre {
    background: #0d1a12;
    border-color: var(--color-border);
  }
}
[data-theme="dark"] .blog-content pre {
  background: #0d1a12;
  border-color: var(--color-border);
}
.blog-content pre code {
  background: none;
  padding: 0;
  color: inherit;
  font-size: inherit;
  font-family: var(--font-mono);
}

/* Code block language label */
.code-label {
  position: absolute;
  top: 0;
  right: 0;
  padding: 0.25rem 0.75rem;
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: rgba(228,232,229,0.4);
  background: rgba(255,255,255,0.05);
  border-radius: 0 10px 0 6px;
  pointer-events: none;
}

/* Copy button for code blocks */
.code-copy {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  padding: 0.35rem 0.6rem;
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: 6px;
  color: rgba(228,232,229,0.5);
  font-size: 0.75rem;
  font-family: var(--font-sans);
  cursor: pointer;
  transition: all 150ms ease;
  opacity: 0;
}
pre:hover .code-copy { opacity: 1; }
.code-copy:hover {
  background: rgba(255,255,255,0.15);
  color: rgba(228,232,229,0.9);
}
.code-copy.copied {
  color: #22c55e;
  border-color: rgba(34,197,94,0.3);
}

/* --- Syntax Highlighting (CSS-only dark theme) --- */
.blog-content pre .kw { color: #7dd3fc; }       /* keywords */
.blog-content pre .fn { color: #86efac; }       /* functions */
.blog-content pre .str { color: #fde68a; }      /* strings */
.blog-content pre .num { color: #c4b5fd; }      /* numbers */
.blog-content pre .cm { color: #5e7568; font-style: italic; } /* comments */
.blog-content pre .op { color: #f0abfc; }       /* operators */
.blog-content pre .tp { color: #67e8f9; }       /* types */

/* --- Callout Boxes --- */
.callout {
  background: var(--color-accent-dim);
  border-left: 3px solid var(--color-accent);
  padding: 1rem 1.25rem;
  border-radius: 0 8px 8px 0;
  margin: 1.5rem 0;
}
.callout p {
  margin-bottom: 0;
  font-size: 0.95rem;
}
.callout-warn {
  background: rgba(239,68,68,0.05);
  border-left-color: #ef4444;
}
@media (prefers-color-scheme: dark) {
  .callout { background: rgba(45,212,191,0.06); }
  .callout-warn { background: rgba(239,68,68,0.08); }
}
[data-theme="dark"] .callout { background: rgba(45,212,191,0.06); }
[data-theme="dark"] .callout-warn { background: rgba(239,68,68,0.08); }

/* --- Tables --- */
.blog-content table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
  background: var(--color-bg-card);
  border-radius: 10px;
  overflow: hidden;
  border: 1px solid var(--color-border);
  margin: 1.5rem 0;
}
.blog-content thead tr {
  background: var(--color-bg-alt);
}
.blog-content th {
  padding: 0.75rem 1rem;
  text-align: left;
  font-weight: 700;
  color: var(--color-text-primary);
  border-bottom: 2px solid var(--color-accent);
}
.blog-content td {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--color-border);
  color: var(--color-text-secondary);
}
.blog-content tbody tr:last-child td {
  border-bottom: none;
}

/* --- Images --- */
.blog-content img {
  max-width: 100%;
  height: auto;
  border-radius: 10px;
  margin: 1.5rem 0;
}

/* --- Blockquote --- */
.blog-content blockquote {
  border-left: 3px solid var(--color-accent);
  padding: 0.5rem 1.25rem;
  margin: 1.5rem 0;
  color: var(--color-text-tertiary);
  font-style: italic;
}

/* --- Horizontal Rule --- */
.blog-content hr {
  border: none;
  height: 1px;
  background: var(--color-border);
  margin: 2.5rem 0;
}

/* --- Related Articles --- */
.related-articles {
  padding: 2.5rem 0;
  border-top: 1px solid var(--color-border);
  margin-top: 1rem;
}
.related-articles h2 {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--color-text-primary);
  margin-bottom: 1.25rem;
}
.related-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
}
.related-card {
  padding: 1.25rem;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: 10px;
  transition: border-color 200ms ease, box-shadow 200ms ease;
  display: flex;
  flex-direction: column;
}
.related-card:hover {
  border-color: var(--color-border-hover);
  box-shadow: 0 2px 12px rgba(26,46,34,0.06);
  text-decoration: none;
}
.related-card-tag {
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--color-accent);
  margin-bottom: 0.5rem;
}
.related-card-title {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-text-primary);
  line-height: 1.4;
  margin-bottom: 0.5rem;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.related-card-meta {
  font-size: 0.75rem;
  color: var(--color-text-tertiary);
  margin-top: auto;
}

/* --- Footer --- */
.blog-footer {
  padding: 3rem 0;
  border-top: 1px solid var(--color-border);
  text-align: center;
}
.blog-footer p {
  color: var(--color-text-tertiary);
  font-size: 0.9rem;
  margin-bottom: 1rem;
}
.blog-cta {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  background: var(--color-accent);
  color: #fff;
  font-weight: 600;
  font-size: 0.9rem;
  border-radius: 6px;
  text-decoration: none;
  transition: opacity 150ms ease;
}
.blog-cta:hover {
  opacity: 0.9;
  text-decoration: none;
}

/* --- Back to Top Button --- */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  color: var(--color-text-tertiary);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: all 200ms ease;
  z-index: 50;
  box-shadow: 0 2px 8px rgba(26,46,34,0.08);
}
.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}
.back-to-top:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
}
.back-to-top:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

/* --- Responsive --- */
@media (max-width: 768px) {
  .related-grid {
    grid-template-columns: 1fr;
  }
}
@media (max-width: 640px) {
  .container { padding: 0 1.25rem; }
  .blog-header { padding: 2.5rem 0 1.5rem; }
  .blog-content h2 { font-size: 1.3rem; }
  .breadcrumb-current { max-width: 200px; }
}

/* --- Reduced Motion --- */
@media (prefers-reduced-motion: reduce) {
  .reading-progress { display: none; }
  .back-to-top { transition: none; }
  .blog-card, .related-card { transition: none; }
}

/* --- Print --- */
@media print {
  .blog-nav, .reading-progress, .back-to-top, .blog-footer, .related-articles, .toc { display: none; }
  .blog-content pre { white-space: pre-wrap; word-wrap: break-word; }
  body { background: #fff; color: #000; }
  .blog-content h2, .blog-content h3, .blog-header h1 { color: #000; }
}