/* ============================================================
   PRASHANT PANDEY — MAIN CSS
   Design System · Layout · Utilities · Animations
   ============================================================ */

/* ---------- Google Fonts ---------- */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=JetBrains+Mono:wght@400;500&family=Syne:wght@700;800&display=swap');

/* ---------- Design Tokens ---------- */
:root {
  /* Colors */
  --bg-root:        #07070f;
  --bg-surface:     #0e0e1a;
  --bg-elevated:    #141424;
  --bg-card:        rgba(255,255,255,0.04);
  --bg-card-hover:  rgba(255,255,255,0.07);

  --accent-1:       #6366f1;   /* indigo */
  --accent-2:       #8b5cf6;   /* violet */
  --accent-teal:    #14b8a6;
  --accent-amber:   #f59e0b;
  --gradient:       linear-gradient(135deg, #6366f1, #8b5cf6);
  --gradient-text:  linear-gradient(135deg, #818cf8, #a78bfa, #14b8a6);

  --text-primary:   #e8e8f0;
  --text-secondary: #9898b0;
  --text-muted:     #5a5a78;
  --text-inverse:   #07070f;

  --border:         rgba(255,255,255,0.08);
  --border-accent:  rgba(99,102,241,0.4);
  --border-hover:   rgba(255,255,255,0.15);

  /* Typography */
  --font-sans:  'Inter', system-ui, sans-serif;
  --font-mono:  'JetBrains Mono', monospace;
  --font-display: 'Syne', 'Inter', sans-serif;

  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;

  /* Radii */
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-xl: 24px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm:   0 2px 8px rgba(0,0,0,0.4);
  --shadow-md:   0 4px 24px rgba(0,0,0,0.5);
  --shadow-lg:   0 8px 48px rgba(0,0,0,0.6);
  --shadow-glow: 0 0 40px rgba(99,102,241,0.15);
  --shadow-card: 0 4px 32px rgba(0,0,0,0.5), inset 0 1px 0 rgba(255,255,255,0.06);

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4,0,0.2,1);
  --transition-base: 250ms cubic-bezier(0.4,0,0.2,1);
  --transition-slow: 400ms cubic-bezier(0.4,0,0.2,1);

  /* Layout */
  --max-w-content: 780px;
  --max-w-wide:    1100px;
  --max-w-full:    1400px;
  --nav-h:         68px;
}

/* ---------- 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(--bg-root);
  color: var(--text-primary);
  line-height: 1.7;
  min-height: 100vh;
}
img, video { max-width: 100%; height: auto; display: block; }
a { color: var(--accent-1); text-decoration: none; transition: color var(--transition-fast); }
a:hover { color: var(--accent-2); }
ul, ol { list-style: none; }
button { cursor: pointer; border: none; background: none; font-family: inherit; }
input, textarea, select { font-family: inherit; }

/* ---------- Layout ---------- */
.container {
  width: 100%;
  max-width: var(--max-w-wide);
  margin-inline: auto;
  padding-inline: var(--space-6);
}
.container--content {
  max-width: var(--max-w-content);
  margin-inline: auto;
  padding-inline: var(--space-6);
}
.container--full {
  max-width: var(--max-w-full);
  margin-inline: auto;
  padding-inline: var(--space-6);
}

.page-wrapper {
  padding-top: var(--nav-h);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}
.page-main { flex: 1; }

/* ---------- Grid ---------- */
.grid { display: grid; }
.grid-2 { grid-template-columns: repeat(2, 1fr); gap: var(--space-6); }
.grid-3 { grid-template-columns: repeat(3, 1fr); gap: var(--space-6); }
.grid-4 { grid-template-columns: repeat(4, 1fr); gap: var(--space-5); }

/* ---------- Section ---------- */
.section {
  padding-block: var(--space-20);
}
.section--sm { padding-block: var(--space-12); }
.section--lg { padding-block: var(--space-24); }

.section-label {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent-1);
  margin-bottom: var(--space-4);
}
.section-label::before {
  content: '';
  display: inline-block;
  width: 18px; height: 2px;
  background: var(--gradient);
  border-radius: 2px;
}
.section-title {
  font-family: var(--font-display);
  font-size: clamp(1.8rem, 4vw, 2.8rem);
  font-weight: 800;
  line-height: 1.15;
  color: var(--text-primary);
  margin-bottom: var(--space-4);
}
.section-desc {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 560px;
  line-height: 1.75;
}
.section-header {
  margin-bottom: var(--space-12);
}
.section-header--row {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-4);
}

/* ---------- Gradient Text ---------- */
.gradient-text {
  background: var(--gradient-text);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ---------- Noise Overlay ---------- */
.noise-bg {
  position: relative;
}
.noise-bg::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='200' height='200'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.75' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='200' height='200' filter='url(%23n)' opacity='0.035'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: 0;
}

/* ---------- Glow Orbs ---------- */
.orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  pointer-events: none;
  z-index: 0;
  opacity: 0.35;
}
.orb--indigo  { background: radial-gradient(circle, #6366f1, transparent 70%); }
.orb--violet  { background: radial-gradient(circle, #8b5cf6, transparent 70%); }
.orb--teal    { background: radial-gradient(circle, #14b8a6, transparent 70%); }

/* ---------- Divider ---------- */
.divider {
  border: none;
  border-top: 1px solid var(--border);
  margin-block: var(--space-8);
}

/* ---------- Badge ---------- */
.badge {
  display: inline-flex;
  align-items: center;
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  background: rgba(99,102,241,0.12);
  color: #a5b4fc;
  border: 1px solid rgba(99,102,241,0.25);
  transition: all var(--transition-fast);
}
.badge:hover { background: rgba(99,102,241,0.22); border-color: rgba(99,102,241,0.5); }
.badge--teal  { background: rgba(20,184,166,0.12); color: #5eead4; border-color: rgba(20,184,166,0.25); }
.badge--amber { background: rgba(245,158,11,0.12); color: #fcd34d; border-color: rgba(245,158,11,0.25); }

/* ---------- Tag Chip ---------- */
.tag-chip {
  display: inline-flex;
  align-items: center;
  padding: 3px 10px;
  border-radius: var(--radius-full);
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  background: var(--bg-elevated);
  color: var(--text-secondary);
  border: 1px solid var(--border);
  transition: all var(--transition-fast);
}
.tag-chip:hover { border-color: var(--accent-1); color: #a5b4fc; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  border-radius: var(--radius-md);
  font-size: 0.9rem;
  font-weight: 600;
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}
.btn--primary {
  background: var(--gradient);
  color: #fff;
  box-shadow: 0 4px 20px rgba(99,102,241,0.35);
}
.btn--primary:hover {
  color: #fff;
  transform: translateY(-1px);
  box-shadow: 0 6px 28px rgba(99,102,241,0.5);
}
.btn--secondary {
  background: var(--bg-elevated);
  color: var(--text-primary);
  border: 1px solid var(--border);
}
.btn--secondary:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-hover);
  color: var(--text-primary);
  transform: translateY(-1px);
}
.btn--ghost {
  color: var(--accent-1);
  padding-inline: var(--space-4);
}
.btn--ghost:hover { color: var(--accent-2); background: rgba(99,102,241,0.08); }

/* ---------- Card ---------- */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-card);
  transition: all var(--transition-base);
  backdrop-filter: blur(12px);
  position: relative;
  overflow: hidden;
}
.card::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: linear-gradient(135deg, rgba(255,255,255,0.04), transparent 60%);
  pointer-events: none;
}
.card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-hover);
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg), var(--shadow-glow);
}
.card--link { cursor: pointer; }

/* ---------- Content Card ---------- */
.content-card {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}
.content-card__type {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent-1);
}
.content-card__title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.35;
  transition: color var(--transition-fast);
}
.card:hover .content-card__title { color: #a5b4fc; }
.content-card__desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.7;
}
.content-card__meta {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-top: auto;
}
.content-card__tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}
.content-card__arrow {
  margin-left: auto;
  color: var(--text-muted);
  transition: all var(--transition-fast);
}
.card:hover .content-card__arrow { color: var(--accent-1); transform: translateX(3px); }

/* ---------- Scroll Progress ---------- */
.scroll-progress {
  position: fixed;
  top: 0; left: 0;
  width: 0%;
  height: 2px;
  background: var(--gradient);
  z-index: 1000;
  transition: width 50ms linear;
}

/* ---------- Back to Top ---------- */
.back-to-top {
  position: fixed;
  bottom: var(--space-6);
  right: var(--space-6);
  width: 44px;
  height: 44px;
  border-radius: var(--radius-full);
  background: var(--gradient);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-md);
  opacity: 0;
  transform: translateY(10px);
  transition: all var(--transition-base);
  pointer-events: none;
  z-index: 99;
}
.back-to-top.visible {
  opacity: 1;
  transform: translateY(0);
  pointer-events: all;
}
.back-to-top:hover { transform: translateY(-3px); color: #fff; }

/* ---------- Hero Separator Line ---------- */
.hero-line {
  display: block;
  width: 64px;
  height: 3px;
  background: var(--gradient);
  border-radius: var(--radius-full);
  margin-block: var(--space-6);
}

/* ---------- Reading Progress & TOC ---------- */
.toc-sidebar {
  position: sticky;
  top: calc(var(--nav-h) + var(--space-8));
  max-height: calc(100vh - var(--nav-h) - var(--space-16));
  overflow-y: auto;
  padding: var(--space-5);
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
}
.toc-sidebar h3 {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: var(--space-4);
}
.toc-list { display: flex; flex-direction: column; gap: var(--space-2); }
.toc-list a {
  font-size: 0.82rem;
  color: var(--text-secondary);
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  display: block;
}
.toc-list a:hover, .toc-list a.active {
  color: var(--accent-1);
  background: rgba(99,102,241,0.1);
}
.toc-list .toc-h3 { padding-left: var(--space-4); }

/* ---------- Article Layout ---------- */
.article-layout {
  display: grid;
  grid-template-columns: 1fr 220px;
  gap: var(--space-12);
  align-items: start;
}
.article-content {
  min-width: 0;
  width: 100%;
}
.article-content h2 {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-top: var(--space-12);
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-3);
  border-bottom: 1px solid var(--border);
}
.article-content h3 {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-top: var(--space-8);
  margin-bottom: var(--space-3);
}
.article-content p {
  margin-bottom: var(--space-5);
  color: var(--text-secondary);
  font-size: 1rem;
  line-height: 1.8;
}
.article-content ul, .article-content ol {
  list-style: disc;
  padding-left: var(--space-6);
  margin-bottom: var(--space-5);
  color: var(--text-secondary);
}
.article-content ul li, .article-content ol li {
  margin-bottom: var(--space-2);
  line-height: 1.75;
}
.article-content code {
  font-family: var(--font-mono);
  font-size: 0.85em;
  background: rgba(99,102,241,0.12);
  color: #a5b4fc;
  padding: 2px 6px;
  border-radius: 4px;
  border: 1px solid rgba(99,102,241,0.2);
}
.article-content pre {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: var(--space-5);
  overflow-x: auto;
  margin-bottom: var(--space-6);
  max-width: 100%;
  width: 100%;
}
.article-content pre code {
  background: none;
  border: none;
  padding: 0;
  font-size: 0.85rem;
  color: #c4b5fd;
}
.article-content blockquote {
  border-left: 3px solid var(--accent-1);
  padding-left: var(--space-5);
  margin: var(--space-6) 0;
  color: var(--text-secondary);
  font-style: italic;
}
.article-content strong { color: var(--text-primary); font-weight: 700; }
.article-content a { color: var(--accent-1); }
.article-content a:hover { color: var(--accent-2); text-decoration: underline; }
.article-content table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: var(--space-6);
  font-size: 0.88rem;
}
.article-content table th,
.article-content table td {
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--border);
  text-align: left;
  line-height: 1.6;
}
.article-content table th {
  background: var(--bg-elevated);
  font-weight: 700;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  white-space: nowrap;
}
.article-content table tr:nth-child(even) td {
  background: rgba(255,255,255,0.02);
}
/* Scrollable table wrapper for mobile */
.table-wrapper {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  margin-bottom: var(--space-6);
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
}
.table-wrapper table { margin-bottom: 0; border: none; width: 100%; min-width: 480px; }

/* ---------- Article Header ---------- */
.article-header {
  padding-block: var(--space-16) var(--space-10);
  border-bottom: 1px solid var(--border);
  margin-bottom: var(--space-10);
}
.article-meta-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-4);
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-bottom: var(--space-5);
}
.article-meta-row span { display: flex; align-items: center; gap: var(--space-2); }

/* ---------- Related Content ---------- */
.related-section {
  padding-block: var(--space-12);
  border-top: 1px solid var(--border);
  margin-top: var(--space-12);
}
.related-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-5);
  margin-top: var(--space-6);
}

/* ---------- Breadcrumbs ---------- */
.breadcrumbs {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-2);
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: var(--space-6);
}
.breadcrumbs a { color: var(--text-muted); }
.breadcrumbs a:hover { color: var(--accent-1); }
.breadcrumbs span { color: var(--text-muted); }
.breadcrumbs .current { color: var(--text-secondary); }

/* ---------- Responsive ---------- */
@media (max-width: 1024px) {
  .article-layout { grid-template-columns: 1fr; }
  .toc-sidebar { display: none; }
  .related-grid { grid-template-columns: repeat(2, 1fr); }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 768px) {
  :root { --nav-h: 60px; }
  .container, .container--content, .container--full { padding-inline: var(--space-4); }
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .related-grid { grid-template-columns: 1fr; }
  .section { padding-block: var(--space-12); }
  .section--lg { padding-block: var(--space-16); }
  /* Reduce section--sm so article content isn't buried under a huge dark gap */
  .section--sm { padding-block: var(--space-8); }
  .section-header--row { flex-direction: column; align-items: flex-start; }
  /* Article pages: reduce large padding on mobile */
  .article-header { padding-block: var(--space-8) var(--space-5) !important; margin-bottom: var(--space-2) !important; }
  .page-hero { padding-block: var(--space-10) var(--space-6) !important; }
  /* Ensure pre code blocks scroll on mobile */
  .article-content pre { font-size: 0.78rem; padding: var(--space-4); }
  /* Article meta row: stack on very small screens */
  .article-meta-row { gap: var(--space-3); font-size: 0.78rem; }
}
@media (max-width: 480px) {
  .btn { padding: var(--space-3) var(--space-4); font-size: 0.85rem; }
  /* Filter buttons on very small phones */
  .filter-btn { font-size: 0.75rem; padding: var(--space-2) var(--space-3); }
  .filter-bar { gap: var(--space-2); margin-bottom: var(--space-8); }
  /* Even tighter spacing on small phones */
  .section--sm { padding-block: var(--space-6); }
  .article-header { padding-block: var(--space-6) var(--space-4) !important; margin-bottom: 0 !important; }
  .page-hero { padding-block: var(--space-8) var(--space-4) !important; }
  /* h1 lead paragraph font size on mobile */
  .lead { font-size: 0.95rem !important; }
}