/* ============================================================
   knowledge.css — Shared styles for DataLakehouse101 Knowledge Base
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=Roboto:wght@400;500;700;900&display=swap');

/* ── Design Tokens ─────────────────────────────────────────── */
:root {
  --color-primary:       #052c65;
  --color-primary-dark:  #001240;
  --color-primary-light: #1a4fa0;
  --color-accent-orange: #ff6f00;
  --color-accent-yellow: #ffca28;
  --color-teal:          #00b4d8;
  --color-teal-dark:     #0077a8;
  --color-text-main:     #1a1a2e;
  --color-text-muted:    #5a6478;
  --color-text-light:    #ffffff;
  --color-bg-page:       #f7f9fc;
  --color-bg-white:      #ffffff;
  --color-bg-dark:       #0d1b3e;
  --color-border:        #e2e8f0;
  --color-code-bg:       #f0f4f8;
  --font-body:           'Inter', sans-serif;
  --font-heading:        'Roboto', sans-serif;
  --container-max:       1280px;
  --article-max:         760px;
  --toc-width:           260px;
  --radius-sm:           6px;
  --radius-md:           10px;
  --radius-lg:           16px;
  --shadow-sm:           0 1px 3px rgba(0,0,0,.08);
  --shadow-md:           0 4px 16px rgba(0,0,0,.10);
  --shadow-lg:           0 8px 32px rgba(0,0,0,.14);
  --transition:          all .2s ease;
}

/* ── Reset ─────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-body);
  color: var(--color-text-main);
  background: var(--color-bg-page);
  line-height: 1.7;
  font-size: 1rem;
}
img { max-width: 100%; display: block; }
a { color: var(--color-primary); text-decoration: none; transition: var(--transition); }
a:hover { color: var(--color-accent-orange); }

/* ── Reading Progress Bar ──────────────────────────────────── */
#reading-progress {
  position: fixed;
  top: 0; left: 0;
  height: 3px;
  width: 0%;
  background: linear-gradient(90deg, var(--color-accent-orange), var(--color-accent-yellow));
  z-index: 9999;
  transition: width .1s linear;
}

/* ── Site Nav ──────────────────────────────────────────────── */
.site-nav {
  background: var(--color-primary-dark);
  position: sticky;
  top: 3px;
  z-index: 100;
  border-bottom: 1px solid rgba(255,255,255,.08);
}
.site-nav .nav-inner {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}
.site-nav .nav-logo {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.1rem;
  color: #fff;
  letter-spacing: -.3px;
}
.site-nav .nav-logo span { color: var(--color-accent-yellow); }
.site-nav .nav-links {
  display: flex;
  gap: 2rem;
  list-style: none;
}
.site-nav .nav-links a {
  color: rgba(255,255,255,.8);
  font-size: .875rem;
  font-weight: 500;
  letter-spacing: .3px;
}
.site-nav .nav-links a:hover,
.site-nav .nav-links a.active { color: var(--color-accent-yellow); }

/* ── Breadcrumb ────────────────────────────────────────────── */
.breadcrumb {
  background: var(--color-bg-white);
  border-bottom: 1px solid var(--color-border);
  padding: .75rem 0;
}
.breadcrumb .container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 1.5rem;
}
.breadcrumb ol {
  list-style: none;
  display: flex;
  align-items: center;
  gap: .5rem;
  flex-wrap: wrap;
}
.breadcrumb li { font-size: .825rem; color: var(--color-text-muted); }
.breadcrumb li + li::before { content: '›'; margin-right: .5rem; color: #bbb; }
.breadcrumb li a { color: var(--color-primary); }
.breadcrumb li.current { color: var(--color-text-muted); font-weight: 500; }

/* ── Article Hero ──────────────────────────────────────────── */
.article-hero {
  background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 60%, var(--color-primary-light) 100%);
  color: #fff;
  padding: 4rem 1.5rem 3rem;
  text-align: center;
}
.article-hero .hero-inner {
  max-width: var(--article-max);
  margin: 0 auto;
}
.article-hero .hero-category {
  display: inline-block;
  background: rgba(255,202,40,.2);
  color: var(--color-accent-yellow);
  font-size: .75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  padding: .35rem .85rem;
  border-radius: 999px;
  margin-bottom: 1.25rem;
}
.article-hero h1 {
  font-family: var(--font-heading);
  font-size: clamp(1.75rem, 4vw, 2.75rem);
  font-weight: 900;
  line-height: 1.15;
  margin-bottom: 1.25rem;
  letter-spacing: -.5px;
}
.article-hero .hero-lede {
  font-size: 1.125rem;
  line-height: 1.7;
  opacity: .9;
  margin-bottom: 1.5rem;
  max-width: 680px;
  margin-left: auto;
  margin-right: auto;
}
.article-hero .hero-meta {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  flex-wrap: wrap;
  font-size: .825rem;
  opacity: .75;
}
.article-hero .hero-meta span::before { margin-right: .35rem; }

/* ── Page Layout (sidebar TOC + article) ───────────────────── */
.page-layout {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 3rem 1.5rem;
  display: grid;
  grid-template-columns: var(--toc-width) 1fr;
  gap: 3rem;
  align-items: start;
}

/* ── TOC Sidebar ───────────────────────────────────────────── */
.toc-sidebar {
  position: sticky;
  top: 80px;
  background: var(--color-bg-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
}
.toc-sidebar h2 {
  font-family: var(--font-heading);
  font-size: .7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--color-text-muted);
  margin-bottom: 1rem;
}
.toc-sidebar ol {
  list-style: none;
  counter-reset: toc-counter;
}
.toc-sidebar ol li {
  counter-increment: toc-counter;
  margin-bottom: .35rem;
}
.toc-sidebar ol li a {
  display: flex;
  align-items: flex-start;
  gap: .5rem;
  font-size: .825rem;
  color: var(--color-text-muted);
  line-height: 1.4;
  padding: .3rem .5rem;
  border-radius: var(--radius-sm);
  transition: var(--transition);
}
.toc-sidebar ol li a::before {
  content: counter(toc-counter, decimal-leading-zero);
  font-size: .7rem;
  font-weight: 700;
  color: #bbb;
  min-width: 20px;
  margin-top: .1rem;
}
.toc-sidebar ol li a:hover,
.toc-sidebar ol li a.active {
  background: rgba(5,44,101,.06);
  color: var(--color-primary);
}
.toc-sidebar ol li a.active::before { color: var(--color-accent-orange); }

/* ── Article Body ──────────────────────────────────────────── */
.article-body {
  min-width: 0;
  background: var(--color-bg-white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  padding: 3rem;
}
.article-body section {
  padding-top: 2.5rem;
  margin-bottom: 2.5rem;
  border-top: 1px solid var(--color-border);
}
.article-body section:first-child { border-top: none; padding-top: 0; }
.article-body h2 {
  font-family: var(--font-heading);
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 1.25rem;
  line-height: 1.25;
  letter-spacing: -.3px;
}
.article-body h3 {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--color-text-main);
  margin: 1.75rem 0 .75rem;
}
.article-body h4 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-text-main);
  margin: 1.25rem 0 .5rem;
}
.article-body p { margin-bottom: 1.25rem; }
.article-body p:last-child { margin-bottom: 0; }
.article-body ul, .article-body ol {
  padding-left: 1.5rem;
  margin-bottom: 1.25rem;
}
.article-body li { margin-bottom: .5rem; }
.article-body strong { color: var(--color-primary); font-weight: 600; }
.article-body a {
  color: var(--color-primary);
  text-decoration: underline;
  text-underline-offset: 3px;
}
.article-body a:hover { color: var(--color-accent-orange); }
.article-body code {
  background: var(--color-code-bg);
  padding: .15em .45em;
  border-radius: 4px;
  font-size: .875em;
  font-family: 'Courier New', monospace;
  color: var(--color-primary);
}
.article-body pre {
  background: var(--color-bg-dark);
  color: #e2e8f0;
  padding: 1.5rem;
  border-radius: var(--radius-md);
  overflow-x: auto;
  font-size: .875rem;
  margin: 1.5rem 0;
  line-height: 1.6;
}
.article-body pre code { background: none; color: inherit; padding: 0; font-size: inherit; }
.article-body blockquote {
  border-left: 4px solid var(--color-accent-orange);
  background: rgba(255,111,0,.05);
  padding: 1rem 1.5rem;
  margin: 1.5rem 0;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-style: italic;
  color: var(--color-text-muted);
}

/* ── Callout / Info Boxes ──────────────────────────────────── */
.callout {
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
  margin: 1.5rem 0;
  display: flex;
  gap: 1rem;
  align-items: flex-start;
}
.callout-icon { font-size: 1.25rem; flex-shrink: 0; margin-top: .1rem; }
.callout-body h4 { margin-top: 0; margin-bottom: .35rem; font-size: .95rem; }
.callout-body p { margin-bottom: 0; font-size: .9rem; }
.callout-info { background: rgba(0,180,216,.08); border: 1px solid rgba(0,180,216,.25); }
.callout-info .callout-body h4 { color: var(--color-teal-dark); }
.callout-tip { background: rgba(255,202,40,.1); border: 1px solid rgba(255,202,40,.35); }
.callout-tip .callout-body h4 { color: #8a6800; }
.callout-warning { background: rgba(255,111,0,.08); border: 1px solid rgba(255,111,0,.3); }
.callout-warning .callout-body h4 { color: #b34f00; }

/* ── Diagrams ──────────────────────────────────────────────── */
.diagram-block {
  margin: 2.5rem 0;
  text-align: center;
}
.diagram-block img {
  width: 100%;
  max-width: 720px;
  margin: 0 auto 1rem;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--color-border);
}
.diagram-block figcaption {
  font-size: .825rem;
  color: var(--color-text-muted);
  font-style: italic;
}

/* ── Comparison Table ──────────────────────────────────────── */
.comparison-table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  font-size: .9rem;
}
.comparison-table th {
  background: var(--color-primary);
  color: #fff;
  font-family: var(--font-heading);
  font-size: .8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .5px;
  padding: .85rem 1rem;
  text-align: left;
}
.comparison-table td {
  padding: .85rem 1rem;
  border-bottom: 1px solid var(--color-border);
  vertical-align: top;
}
.comparison-table tr:nth-child(even) td { background: #f9fbff; }
.comparison-table tr:hover td { background: rgba(5,44,101,.04); }

/* ── Related Concepts ──────────────────────────────────────── */
.related-concepts {
  background: var(--color-bg-page);
  border-top: 1px solid var(--color-border);
  padding: 3rem 1.5rem;
}
.related-concepts .container {
  max-width: var(--container-max);
  margin: 0 auto;
}
.related-concepts h2 {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 1.75rem;
  text-align: center;
}
.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 1rem;
}
.related-card {
  background: var(--color-bg-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: .5rem;
  transition: var(--transition);
  text-decoration: none;
  color: inherit;
  box-shadow: var(--shadow-sm);
}
.related-card:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
  color: inherit;
}
.related-card .related-label {
  font-size: .7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--color-accent-orange);
}
.related-card .related-term {
  font-size: .95rem;
  font-weight: 600;
  color: var(--color-primary);
  line-height: 1.3;
}
.related-card .related-desc {
  font-size: .8rem;
  color: var(--color-text-muted);
  line-height: 1.4;
}

/* ── CTA Section ───────────────────────────────────────────── */
.cta-section {
  background: linear-gradient(135deg, var(--color-primary-dark) 0%, #0a3d7a 100%);
  padding: 4rem 1.5rem;
  color: #fff;
}
.cta-section .container {
  max-width: var(--container-max);
  margin: 0 auto;
}
.cta-section .cta-heading {
  font-family: var(--font-heading);
  font-size: 1.75rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: .75rem;
}
.cta-section .cta-sub {
  text-align: center;
  opacity: .8;
  margin-bottom: 2.5rem;
  font-size: 1rem;
}
.cta-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1.25rem;
}
.cta-card {
  background: rgba(255,255,255,.07);
  border: 1px solid rgba(255,255,255,.15);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: .75rem;
  transition: var(--transition);
  text-decoration: none;
}
.cta-card:hover {
  background: rgba(255,255,255,.12);
  border-color: var(--color-accent-yellow);
  transform: translateY(-3px);
  color: inherit;
}
.cta-card .cta-type {
  font-size: .7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--color-accent-yellow);
}
.cta-card .cta-title {
  font-family: var(--font-heading);
  font-size: .975rem;
  font-weight: 700;
  color: #fff;
  line-height: 1.4;
}
.cta-card .cta-publisher {
  font-size: .8rem;
  color: rgba(255,255,255,.6);
}
.cta-card .cta-btn {
  margin-top: auto;
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  font-size: .825rem;
  font-weight: 700;
  color: var(--color-accent-yellow);
  letter-spacing: .3px;
}
.cta-card .cta-btn::after { content: '→'; transition: transform .2s ease; }
.cta-card:hover .cta-btn::after { transform: translateX(4px); }

/* ── Footer ────────────────────────────────────────────────── */
.site-footer {
  background: var(--color-primary-dark);
  color: rgba(255,255,255,.7);
  text-align: center;
  padding: 2rem 1.5rem;
  font-size: .85rem;
}
.site-footer a { color: var(--color-accent-yellow); }
.site-footer a:hover { color: #fff; }

/* ── Responsive ────────────────────────────────────────────── */
@media (max-width: 1024px) {
  .page-layout {
    grid-template-columns: 1fr;
    padding: 2rem 1.25rem;
  }
  .toc-sidebar {
    position: static;
    order: -1;
  }
  .toc-sidebar ol { columns: 2; gap: 1rem; }
  .toc-sidebar ol li { break-inside: avoid; }
}
@media (max-width: 768px) {
  .article-body { padding: 1.75rem 1.25rem; }
  .article-hero { padding: 2.5rem 1.25rem 2rem; }
  .site-nav .nav-links { display: none; }
  .toc-sidebar ol { columns: 1; }
  .cta-grid { grid-template-columns: 1fr; }
  .related-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 480px) {
  .related-grid { grid-template-columns: 1fr; }
}