/* ========================================
   ShallowSpeed Visual Guide — Styles
   Dark theme inspired by VizuaraAI design
   ======================================== */

/* --- CSS Variables --- */
:root {
  --bg: #0a0a0a;
  --bg-card: #121212;
  --bg-card-hover: #1a1a1a;
  --bg-section-alt: #0f0f0f;
  --fg: #f2f2f2;
  --fg-muted: #a3a3a3;
  --border: #262626;
  --border-light: #333;
  --primary: #00d46a;
  --primary-dim: #00a854;
  --secondary: #00c8e6;
  --accent: #a78bfa;
  --red: #FF7043;
  --orange: #FF9800;
  --yellow: #FFCA28;
  --blue: #42A5F5;
  --green: #66BB6A;
  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  --font-serif: 'Instrument Serif', Georgia, serif;
  --max-w: 1280px;
  --glow-opacity: 0.15;
}

/* --- Reset & Base --- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-sans);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

code, pre { font-family: var(--font-mono); }

.container { max-width: var(--max-w); margin: 0 auto; padding: 0 24px; }

.gradient-text {
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}


/* ========================================
   NAVBAR
   ======================================== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(10,10,10,0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 12px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
  font-size: 1.1rem;
}

.brand-icon { font-size: 1.3rem; }

.brand-tag {
  font-size: 0.7rem;
  background: var(--primary);
  color: #000;
  padding: 2px 8px;
  border-radius: 9999px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.nav-links {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
}

.nav-links a {
  color: var(--fg-muted);
  font-size: 0.82rem;
  font-weight: 500;
  transition: color 0.2s;
}

.nav-links a:hover {
  color: var(--primary);
  text-decoration: none;
}


/* ========================================
   HERO
   ======================================== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 120px 24px 80px;
  overflow: hidden;
}

.hero-bg-orbs {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(120px);
  opacity: 0.12;
}

.orb-green {
  width: 500px; height: 500px;
  background: var(--primary);
  top: 10%; left: 10%;
  animation: float-slow 20s ease-in-out infinite;
}

.orb-cyan {
  width: 400px; height: 400px;
  background: var(--secondary);
  top: 40%; right: 5%;
  animation: float-slow 25s ease-in-out infinite reverse;
}

.orb-purple {
  width: 350px; height: 350px;
  background: var(--accent);
  bottom: 10%; left: 30%;
  animation: float-slow 22s ease-in-out infinite;
}

@keyframes float-slow {
  0%, 100% { transform: translate(0, 0); }
  25% { transform: translate(30px, -20px); }
  50% { transform: translate(-20px, 30px); }
  75% { transform: translate(20px, 20px); }
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 800px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(0, 212, 106, 0.1);
  border: 1px solid rgba(0, 212, 106, 0.3);
  border-radius: 9999px;
  padding: 6px 18px;
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--primary);
  margin-bottom: 24px;
}

.pulse-dot {
  width: 8px; height: 8px;
  background: var(--primary);
  border-radius: 50%;
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(1.4); }
}

.hero h1 {
  font-family: var(--font-serif);
  font-style: italic;
  font-size: clamp(2.5rem, 7vw, 5rem);
  font-weight: 400;
  line-height: 1.1;
  margin-bottom: 20px;
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--fg-muted);
  line-height: 1.7;
  max-width: 600px;
  margin: 0 auto 40px;
}

/* --- Colab CTA Buttons --- */
.colab-cta-row {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 36px;
}

.colab-cta {
  display: inline-block;
  text-decoration: none;
  border-radius: 16px;
  background: linear-gradient(135deg, rgba(249,171,0,0.12) 0%, rgba(232,113,10,0.10) 100%);
  border: 1px solid rgba(249,171,0,0.25);
  padding: 3px;
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
}

.colab-cta::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: 16px;
  background: linear-gradient(135deg, rgba(249,171,0,0.08), rgba(232,113,10,0.04));
  opacity: 0;
  transition: opacity 0.3s ease;
}

.colab-cta:hover {
  text-decoration: none;
  border-color: rgba(249,171,0,0.5);
  transform: translateY(-2px);
  box-shadow: 0 8px 32px rgba(249,171,0,0.15), 0 0 0 1px rgba(249,171,0,0.1);
}

.colab-cta:hover::before {
  opacity: 1;
}

.colab-cta-inner {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 16px 24px;
  border-radius: 13px;
  background: rgba(10,10,10,0.7);
  backdrop-filter: blur(8px);
  position: relative;
  z-index: 1;
}

.colab-icon {
  flex-shrink: 0;
  width: 52px;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(249,171,0,0.1);
  border-radius: 12px;
  border: 1px solid rgba(249,171,0,0.15);
}

.colab-cta-text {
  display: flex;
  flex-direction: column;
  gap: 2px;
  text-align: left;
}

.colab-cta-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: #F9AB00;
  letter-spacing: -0.01em;
}

.colab-cta-desc {
  font-size: 0.8rem;
  color: var(--fg-muted);
  line-height: 1.4;
}

.colab-arrow {
  flex-shrink: 0;
  color: rgba(249,171,0,0.6);
  transition: all 0.3s ease;
}

.colab-cta:hover .colab-arrow {
  color: #F9AB00;
  transform: translate(2px, -2px);
}

.colab-cta-advanced {
  background: linear-gradient(135deg, rgba(0,212,106,0.12) 0%, rgba(0,200,230,0.10) 100%);
  border-color: rgba(0,212,106,0.25);
}

.colab-cta-advanced:hover {
  border-color: rgba(0,212,106,0.5);
  box-shadow: 0 8px 32px rgba(0,212,106,0.15), 0 0 0 1px rgba(0,212,106,0.1);
}

.colab-cta-advanced .colab-icon {
  background: rgba(0,212,106,0.1);
  border-color: rgba(0,212,106,0.15);
}

.colab-cta-advanced .colab-cta-title {
  color: var(--primary);
}

.colab-cta-advanced .colab-arrow {
  color: rgba(0,212,106,0.6);
}

.colab-cta-advanced:hover .colab-arrow {
  color: var(--primary);
}

.hero-cards {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

.hero-stat-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px 12px;
  transition: border-color 0.3s, transform 0.2s;
}

.hero-stat-card:hover {
  border-color: rgba(0, 212, 106, 0.3);
  transform: translateY(-2px);
}

.stat-number {
  font-size: 1.8rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.stat-label {
  font-size: 0.78rem;
  color: var(--fg-muted);
  margin-top: 4px;
}


/* ========================================
   SECTIONS
   ======================================== */
.section {
  padding: 100px 0;
  position: relative;
}

.section-dark {
  background: var(--bg-section-alt);
}

.section-heading {
  text-align: center;
  margin-bottom: 60px;
}

.section-label {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--primary);
  margin-bottom: 12px;
}

.section-heading h2 {
  font-family: var(--font-serif);
  font-style: italic;
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 400;
  line-height: 1.2;
  margin-bottom: 16px;
}

.section-subtitle {
  color: var(--fg-muted);
  font-size: 1.05rem;
  max-width: 650px;
  margin: 0 auto;
}


/* ========================================
   4-MODES GRID
   ======================================== */
.four-modes-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
}

.mode-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 28px 24px;
  position: relative;
  transition: border-color 0.3s, transform 0.2s;
}

.mode-card:hover {
  border-color: rgba(0, 212, 106, 0.3);
  transform: translateY(-3px);
}

.mode-number {
  position: absolute;
  top: 16px;
  right: 16px;
  font-size: 2.5rem;
  font-weight: 800;
  color: rgba(255,255,255,0.04);
  line-height: 1;
}

.mode-icon {
  font-size: 2rem;
  margin-bottom: 12px;
}

.mode-card h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.mode-desc {
  font-size: 0.88rem;
  color: var(--fg-muted);
  margin-bottom: 16px;
  line-height: 1.6;
}

.mode-timeline {
  display: flex;
  gap: 2px;
  border-radius: 6px;
  overflow: hidden;
  margin-bottom: 14px;
}

.tl-bar {
  padding: 6px 4px;
  font-size: 0.65rem;
  font-weight: 600;
  text-align: center;
  white-space: nowrap;
  overflow: hidden;
}

.tl-compute { background: #2196F3; color: #fff; }
.tl-comm { background: #FF5722; color: #fff; }
.tl-update { background: #9E9E9E; color: #fff; }
.tl-overlap { background: linear-gradient(90deg, #2196F3, #00c8e6); color: #fff; }
.tl-ddp { background: linear-gradient(90deg, #2196F3, #66BB6A); color: #fff; }

.mode-tag {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: 9999px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.tag-baseline { background: rgba(255,255,255,0.1); color: var(--fg-muted); }
.tag-naive { background: rgba(255,112,67,0.15); color: var(--red); }
.tag-interleaved { background: rgba(66,165,245,0.15); color: var(--blue); }
.tag-ddp { background: rgba(102,187,106,0.15); color: var(--green); }


/* ========================================
   FIRST PRINCIPLES
   ======================================== */
.principles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
}

.principle-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 28px 24px;
  position: relative;
}

.principle-step {
  width: 32px; height: 32px;
  border-radius: 50%;
  background: var(--primary);
  color: #000;
  font-weight: 700;
  font-size: 0.85rem;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 14px;
}

.principle-card h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 12px;
}

.principle-card p {
  font-size: 0.88rem;
  color: var(--fg-muted);
  line-height: 1.6;
}

.principle-visual {
  background: rgba(0,0,0,0.3);
  border-radius: 10px;
  padding: 16px;
  margin-bottom: 14px;
}

.gpu-box {
  background: rgba(33,150,243,0.12);
  border: 1px solid rgba(33,150,243,0.3);
  border-radius: 8px;
  padding: 8px 12px;
  margin-bottom: 8px;
  font-size: 0.8rem;
  font-weight: 600;
}

.gpu-box span { display: block; font-size: 0.72rem; color: var(--blue); margin-bottom: 4px; }

.data-bar {
  border-radius: 4px;
  padding: 4px 8px;
  font-size: 0.7rem;
  font-weight: 500;
  text-align: center;
}

.data-bar.full { background: rgba(33,150,243,0.3); }
.data-bar.half-a { background: rgba(0,212,106,0.25); }
.data-bar.half-b { background: rgba(0,200,230,0.25); }

.sync-diagram {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  margin-bottom: 10px;
}

.gpu-node {
  background: rgba(33,150,243,0.15);
  border: 1px solid rgba(33,150,243,0.3);
  border-radius: 8px;
  padding: 10px 14px;
  font-size: 0.78rem;
  font-weight: 600;
  text-align: center;
}

.gpu-node small { color: var(--fg-muted); }

.sync-arrows {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
}

.arrow-lr { font-size: 1.5rem; color: var(--primary); }
.arrow-label { font-size: 0.65rem; color: var(--primary); font-weight: 600; text-transform: uppercase; }

.sync-result {
  text-align: center;
  font-size: 0.78rem;
  color: var(--fg-muted);
  padding: 6px;
  background: rgba(0,212,106,0.08);
  border-radius: 6px;
}

.sync-result code {
  color: var(--primary);
  font-size: 0.75rem;
}

.question-box {
  display: flex;
  align-items: center;
  gap: 12px;
  justify-content: center;
  font-size: 0.92rem;
  font-weight: 500;
}

.question-mark {
  width: 40px; height: 40px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  font-weight: 800;
  color: #000;
}


/* ========================================
   ALLREDUCE VISUAL
   ======================================== */
.allreduce-visual {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 24px;
  flex-wrap: wrap;
  margin-bottom: 20px;
}

.ar-step h4 {
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 12px;
  text-align: center;
}

.ar-gpus { display: flex; flex-direction: column; gap: 10px; }

.ar-gpu {
  display: flex;
  align-items: center;
  gap: 10px;
}

.ar-gpu span {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--fg-muted);
  width: 50px;
}

.ar-val {
  padding: 8px 16px;
  border-radius: 8px;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  font-weight: 500;
  color: #fff;
}

.ar-arrow {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}

.ar-arrow small {
  font-size: 0.72rem;
  color: var(--fg-muted);
}

.ar-caption {
  text-align: center;
  font-size: 0.92rem;
  color: var(--fg-muted);
  max-width: 600px;
  margin: 0 auto;
}


/* ========================================
   CODE + EXPLAIN ROWS
   ======================================== */
.code-explain-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  align-items: start;
}

@media (max-width: 900px) {
  .code-explain-row { grid-template-columns: 1fr; }
}

/* Code Panel */
.code-panel {
  position: sticky;
  top: 80px;
}

.code-header {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 10px 16px;
  background: #1a1a2e;
  border-radius: 12px 12px 0 0;
  border: 1px solid var(--border);
  border-bottom: none;
}

.code-header + pre { border-radius: 0 0 12px 12px; }

.dot {
  width: 10px; height: 10px;
  border-radius: 50%;
}
.dot.red { background: #ff5f57; }
.dot.yellow { background: #febc2e; }
.dot.green { background: #28c840; }

.code-filename {
  margin-left: 10px;
  font-size: 0.75rem;
  color: var(--fg-muted);
  font-family: var(--font-mono);
}

pre {
  background: #0d0d1a;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px;
  overflow-x: auto;
  font-size: 0.82rem;
  line-height: 1.7;
  tab-size: 4;
}

pre code {
  color: #e0e0e0;
}

.code-output {
  margin-top: 8px;
  border-radius: 10px;
  overflow: hidden;
  border: 1px solid var(--border);
}

.output-header {
  background: #1a2332;
  padding: 6px 14px;
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--secondary);
  text-transform: uppercase;
  letter-spacing: 1px;
}

.code-output pre {
  border: none;
  border-radius: 0;
  background: #0a1520;
  font-size: 0.78rem;
  color: var(--primary);
  padding: 14px;
}

/* Syntax highlighting */
.kw { color: #c792ea; }
.fn { color: #82aaff; }
.str { color: #c3e88d; }
.num { color: #f78c6c; }
.cmt { color: #546e7a; font-style: italic; }
.mod { color: #ffcb6b; }
.hl { background: rgba(0,212,106,0.15); padding: 1px 4px; border-radius: 3px; }

/* Explain Panel */
.explain-panel {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.explain-block {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px;
}

.explain-block.highlight-bad {
  border-color: rgba(255,112,67,0.4);
  background: rgba(255,112,67,0.05);
}

.explain-block.highlight-good {
  border-color: rgba(0,212,106,0.4);
  background: rgba(0,212,106,0.05);
}

.explain-icon {
  font-size: 1.3rem;
  margin-bottom: 8px;
}

.explain-block h4 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.explain-block p {
  font-size: 0.88rem;
  color: var(--fg-muted);
  line-height: 1.65;
}

.explain-block code {
  background: rgba(0,0,0,0.3);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.82rem;
  color: var(--secondary);
}

.step-list {
  list-style: none;
  counter-reset: step;
  padding: 0;
  margin-top: 8px;
}

.step-list li {
  counter-increment: step;
  font-size: 0.85rem;
  color: var(--fg-muted);
  padding: 6px 0 6px 32px;
  position: relative;
  line-height: 1.5;
}

.step-list li::before {
  content: counter(step);
  position: absolute;
  left: 0;
  width: 22px; height: 22px;
  border-radius: 50%;
  background: rgba(0,212,106,0.15);
  color: var(--primary);
  font-size: 0.72rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  top: 6px;
}

.callout {
  border-radius: 10px;
  padding: 16px 20px;
  font-size: 0.85rem;
  line-height: 1.6;
}

.callout-info {
  background: rgba(66,165,245,0.08);
  border: 1px solid rgba(66,165,245,0.2);
  color: var(--fg-muted);
}

.callout-green {
  background: rgba(0,212,106,0.08);
  border: 1px solid rgba(0,212,106,0.2);
  color: var(--fg-muted);
}

.callout-warn {
  background: rgba(255,112,67,0.08);
  border: 1px solid rgba(255,112,67,0.2);
  color: var(--fg-muted);
}

.callout strong {
  color: var(--fg);
}

.inline-code {
  display: block;
  margin-top: 8px;
  background: rgba(0,0,0,0.3);
  padding: 6px 10px;
  border-radius: 6px;
  font-size: 0.78rem;
  color: var(--secondary);
}


/* ========================================
   MODEL ARCHITECTURE VISUAL
   ======================================== */
.model-arch-visual {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px;
}

.model-arch-visual h4 {
  font-size: 0.88rem;
  font-weight: 600;
  margin-bottom: 14px;
  text-align: center;
}

.layer-stack {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
}

.layer-box {
  background: linear-gradient(90deg, rgba(33,150,243,0.15), rgba(33,150,243,0.08));
  border: 1px solid rgba(33,150,243,0.3);
  border-radius: 8px;
  padding: 8px 12px;
  text-align: center;
  min-width: 80px;
  transition: transform 0.2s;
}

.layer-box:hover { transform: scale(1.03); }

.layer-box span {
  font-weight: 700;
  font-size: 0.92rem;
}

.layer-box small {
  display: block;
  font-size: 0.68rem;
  color: var(--fg-muted);
}

.layer-box.output {
  background: linear-gradient(90deg, rgba(0,212,106,0.15), rgba(0,212,106,0.08));
  border-color: rgba(0,212,106,0.3);
}

.layer-arrow {
  font-size: 0.7rem;
  color: var(--fg-muted);
  padding: 2px 0;
}

.model-sizes-table {
  margin-top: 16px;
}

.model-sizes-table table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.82rem;
}

.model-sizes-table th {
  text-align: left;
  padding: 8px 12px;
  color: var(--fg-muted);
  font-weight: 600;
  border-bottom: 1px solid var(--border);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.model-sizes-table td {
  padding: 8px 12px;
  border-bottom: 1px solid rgba(38,38,38,0.5);
  color: var(--fg-muted);
}

.model-sizes-table tr.highlight td {
  color: var(--fg);
  background: rgba(0,212,106,0.05);
}


/* ========================================
   TIMELINE DIAGRAMS
   ======================================== */
.timeline-diagram {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 24px;
  margin-bottom: 32px;
  overflow-x: auto;
}

.timeline-diagram.warn {
  border-color: rgba(255,112,67,0.3);
}

.timeline-diagram.good {
  border-color: rgba(0,212,106,0.3);
}

.timeline-diagram h4 {
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: 16px;
  text-align: center;
}

.timeline-row {
  display: flex;
  align-items: center;
  gap: 3px;
  margin-bottom: 6px;
  min-width: 600px;
}

.tl-label {
  width: 70px;
  min-width: 70px;
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--fg-muted);
  text-align: right;
  padding-right: 10px;
}

.tl-block {
  padding: 8px 6px;
  font-size: 0.68rem;
  font-weight: 600;
  text-align: center;
  border-radius: 4px;
  white-space: nowrap;
  overflow: hidden;
}

.tl-fwd { background: #1565C0; color: #fff; width: 25%; }
.tl-bwd { background: #2196F3; color: #fff; width: 30%; }
.tl-upd { background: #607D8B; color: #fff; width: 10%; }
.tl-idle { background: rgba(255,255,255,0.03); color: var(--fg-muted); }
.tl-idle-bad { background: rgba(255,112,67,0.12); color: var(--red); border: 1px dashed rgba(255,112,67,0.3); }
.tl-comm-bar { background: #FF5722; color: #fff; }
.tl-overlap-block { background: linear-gradient(180deg, #1565C0, #0288D1); color: #fff; }
.tl-comm-good { background: rgba(0,212,106,0.2); color: var(--primary); border: 1px solid rgba(0,212,106,0.3); }

.overlap-label {
  text-align: center;
  font-size: 0.78rem;
  color: var(--fg-muted);
  margin-top: 10px;
  padding: 8px;
  background: rgba(0,212,106,0.05);
  border-radius: 6px;
}


/* ========================================
   COMPARISON BOX
   ======================================== */
.comparison-box {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px;
}

.comparison-box h4 {
  font-size: 0.88rem;
  font-weight: 600;
  margin-bottom: 14px;
}

.comp-row { margin-bottom: 10px; }

.comp-timeline {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-top: 6px;
}

.ct-compute {
  background: #2196F3;
  color: #fff;
  padding: 6px 14px;
  border-radius: 4px;
  font-size: 0.75rem;
  font-weight: 600;
}

.ct-then { color: var(--fg-muted); font-size: 0.8rem; }

.ct-comm {
  background: #FF5722;
  color: #fff;
  padding: 6px 14px;
  border-radius: 4px;
  font-size: 0.75rem;
  font-weight: 600;
}

.ct-overlap {
  background: linear-gradient(90deg, #1565C0, #00c8e6);
  color: #fff;
  padding: 6px 14px;
  border-radius: 4px;
  font-size: 0.75rem;
  font-weight: 600;
  flex: 1;
  text-align: center;
}


/* ========================================
   BUCKETING VISUAL
   ======================================== */
.bucketing-visual {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 28px;
  margin-bottom: 32px;
}

.bucketing-visual h4 {
  text-align: center;
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 20px;
}

.bucket-compare {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

@media (max-width: 700px) {
  .bucket-compare { grid-template-columns: 1fr; }
}

.bucket-side h5 {
  font-size: 0.82rem;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--fg-muted);
}

.bucket-params {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
}

.bp {
  background: rgba(33,150,243,0.15);
  border: 1px solid rgba(33,150,243,0.3);
  border-radius: 6px;
  padding: 6px 10px;
  font-size: 0.72rem;
  font-weight: 600;
  text-align: center;
}

.bp.small { padding: 4px 6px; font-size: 0.65rem; }

.bp-arrow {
  font-size: 0.7rem;
  color: var(--red);
  font-weight: 600;
}

.bp-bucket {
  display: flex;
  align-items: center;
  gap: 4px;
  background: rgba(0,212,106,0.06);
  border: 1px dashed rgba(0,212,106,0.3);
  border-radius: 8px;
  padding: 8px;
  margin-bottom: 8px;
  width: 100%;
}

.bp-bucket .bp-arrow { color: var(--primary); }

.bp-count {
  width: 100%;
  text-align: center;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--fg-muted);
  margin-top: 6px;
}

.bp small { display: block; font-size: 0.6rem; color: var(--fg-muted); }


/* ========================================
   RESULTS TABLE
   ======================================== */
.results-table-wrapper {
  overflow-x: auto;
  margin-bottom: 40px;
  border-radius: 16px;
  border: 1px solid var(--border);
}

.results-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
}

.results-table thead {
  background: #1a1a2e;
}

.results-table th {
  padding: 14px 16px;
  text-align: left;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--fg-muted);
  border-bottom: 1px solid var(--border);
}

.results-table td {
  padding: 12px 16px;
  border-bottom: 1px solid rgba(38,38,38,0.5);
  color: var(--fg-muted);
  font-family: var(--font-mono);
  font-size: 0.82rem;
}

.row-sep td { border-top: 2px solid var(--border); }

.badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 9999px;
  font-size: 0.72rem;
  font-weight: 600;
  font-family: var(--font-sans);
}

.badge-base { background: rgba(255,255,255,0.1); color: var(--fg); }
.badge-naive { background: rgba(255,112,67,0.15); color: var(--red); }
.badge-inter { background: rgba(66,165,245,0.15); color: var(--blue); }
.badge-ddp { background: rgba(102,187,106,0.15); color: var(--green); }

.val-bad { color: var(--red) !important; font-weight: 600; }
.val-ok { color: var(--orange) !important; font-weight: 600; }
.val-good { color: var(--blue) !important; font-weight: 600; }
.val-great { color: var(--primary) !important; font-weight: 600; }


/* ========================================
   INSIGHTS GRID
   ======================================== */
.insights-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
}

.insight-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 24px;
  transition: border-color 0.3s, transform 0.2s;
}

.insight-card:hover {
  border-color: rgba(0,212,106,0.3);
  transform: translateY(-2px);
}

.insight-icon {
  font-size: 1.5rem;
  margin-bottom: 10px;
}

.insight-card h4 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.insight-card p {
  font-size: 0.85rem;
  color: var(--fg-muted);
  line-height: 1.6;
}


/* ========================================
   CHART EXPLANATION GRID
   ======================================== */
.chart-explain-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: 20px;
}

.chart-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 24px;
  transition: border-color 0.3s;
}

.chart-card:hover {
  border-color: rgba(0,212,106,0.2);
}

.chart-num {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--primary);
  margin-bottom: 6px;
}

.chart-card h4 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 12px;
}

.chart-card p {
  font-size: 0.85rem;
  color: var(--fg-muted);
  line-height: 1.7;
}

.chart-card code {
  background: rgba(0,0,0,0.3);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.78rem;
  color: var(--secondary);
}

/* Mock chart containers */
.chart-mock {
  background: rgba(0,0,0,0.3);
  border-radius: 10px;
  padding: 16px;
  margin-bottom: 14px;
  height: 180px;
  position: relative;
  overflow: visible;
}

.mock-bars {
  display: flex;
  align-items: flex-end;
  justify-content: center;
  gap: 10px;
  height: 100%;
}

.mock-bar-group {
  display: flex;
  align-items: flex-end;
  gap: 2px;
  position: relative;
  flex: 1;
  height: 100%;
  padding-bottom: 22px;
}

.mock-bar {
  flex: 1;
  border-radius: 3px 3px 0 0;
  min-width: 6px;
  transition: height 0.5s ease;
}

.mock-label {
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  font-size: 0.6rem;
  color: var(--fg-muted);
  white-space: nowrap;
}

/* Line chart mock */
.mock-line-area {
  height: 100%;
  position: relative;
}

.mock-line-area svg {
  width: 100%;
  height: 100%;
}

.mock-y-label, .mock-x-label {
  position: absolute;
  font-size: 0.6rem;
  color: var(--fg-muted);
}
.mock-y-label { left: 0; top: 0; }
.mock-x-label { right: 0; bottom: 0; }

.mock-ideal {
  position: absolute;
  top: 8px;
  right: 8px;
  font-size: 0.6rem;
  color: #666;
}

/* Stacked chart mock */
.mock-stacked {
  display: flex;
  align-items: flex-end;
  justify-content: center;
  gap: 6px;
  height: 100%;
  padding-bottom: 22px;
  padding-top: 22px;
}

.mock-stack-bar {
  min-width: 36px;
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  position: relative;
  height: 100%;
}

.ms-compute {
  background: #42A5F5;
  border-radius: 3px 3px 0 0;
  font-size: 0.55rem;
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  min-height: 20px;
}

.ms-comm {
  background: #FF7043;
  font-size: 0.55rem;
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  min-height: 14px;
  border-radius: 0 0 0 0;
}

.ms-compute:first-child { border-radius: 3px 3px 0 0; }

.ms-pct {
  position: absolute;
  top: -20px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 0.65rem;
  font-weight: 700;
  color: var(--red);
  white-space: nowrap;
}

/* Compare chart mock */
.mock-compare {
  display: flex;
  align-items: flex-end;
  justify-content: center;
  gap: 8px;
  height: 100%;
  padding-bottom: 22px;
  padding-top: 22px;
}

.mc-group {
  display: flex;
  align-items: flex-end;
  gap: 3px;
  flex: 1;
  position: relative;
  height: 100%;
}

.mc-bar {
  flex: 1;
  min-width: 10px;
  border-radius: 3px 3px 0 0;
}
.mc-bar.naive { background: #FF7043; }
.mc-bar.inter { background: #42A5F5; }
.mc-bar.ddp { background: #66BB6A; }

.mc-save {
  position: absolute;
  top: -20px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 0.65rem;
  font-weight: 700;
  color: var(--blue);
  white-space: nowrap;
}


/* ========================================
   TAKEAWAYS
   ======================================== */
.takeaways-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 20px;
}

.takeaway-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 24px;
  position: relative;
  overflow: hidden;
}

.takeaway-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--primary), var(--secondary));
}

.takeaway-num {
  width: 28px; height: 28px;
  border-radius: 50%;
  background: rgba(0,212,106,0.12);
  color: var(--primary);
  font-weight: 700;
  font-size: 0.8rem;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 12px;
}

.takeaway-card h4 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.takeaway-card p {
  font-size: 0.85rem;
  color: var(--fg-muted);
  line-height: 1.6;
}


/* ========================================
   FOOTER
   ======================================== */
.footer {
  border-top: 1px solid var(--border);
  padding: 40px 0;
  text-align: center;
}

.footer-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
}

.footer-brand {
  font-size: 1.1rem;
  font-weight: 600;
}

.footer p {
  font-size: 0.85rem;
  color: var(--fg-muted);
}

.footer-muted {
  font-size: 0.78rem !important;
  color: rgba(163,163,163,0.5) !important;
}


/* ========================================
   RESPONSIVE
   ======================================== */
@media (max-width: 768px) {
  .hero-cards { grid-template-columns: repeat(2, 1fr); }
  .nav-links { display: none; }
  .hero h1 { font-size: 2.2rem; }
  .section { padding: 60px 0; }
  .four-modes-grid { grid-template-columns: 1fr; }
  .principles-grid { grid-template-columns: 1fr; }
  .chart-explain-grid { grid-template-columns: 1fr; }
  .bucket-compare { grid-template-columns: 1fr; }
  .takeaways-grid { grid-template-columns: 1fr; }
  .insights-grid { grid-template-columns: 1fr; }
  .code-panel { position: static; }
  .speedup-panels { grid-template-columns: repeat(2, 1fr); }
  .chart-bar-viz { height: 240px; }
  .colab-cta-inner { padding: 12px 16px; gap: 12px; }
  .colab-cta-title { font-size: 0.85rem; }
  .colab-cta-desc { font-size: 0.75rem; }
  .colab-icon { width: 44px; height: 44px; }
  .colab-icon svg { width: 28px; height: 28px; }
  .colab-arrow { display: none; }
}

@media (max-width: 480px) {
  .hero-cards { grid-template-columns: 1fr 1fr; }
}


/* ========================================
   SCROLL ANIMATION (CSS-only)
   ======================================== */
.mode-card,
.principle-card,
.insight-card,
.takeaway-card,
.chart-card {
  opacity: 0;
  transform: translateY(20px);
  animation: fadeInUp 0.6s ease forwards;
}

@keyframes fadeInUp {
  to { opacity: 1; transform: translateY(0); }
}

/* Stagger delays for cards */
.four-modes-grid .mode-card:nth-child(1) { animation-delay: 0.1s; }
.four-modes-grid .mode-card:nth-child(2) { animation-delay: 0.2s; }
.four-modes-grid .mode-card:nth-child(3) { animation-delay: 0.3s; }
.four-modes-grid .mode-card:nth-child(4) { animation-delay: 0.4s; }

.principles-grid .principle-card:nth-child(1) { animation-delay: 0.1s; }
.principles-grid .principle-card:nth-child(2) { animation-delay: 0.2s; }
.principles-grid .principle-card:nth-child(3) { animation-delay: 0.3s; }
.principles-grid .principle-card:nth-child(4) { animation-delay: 0.4s; }

.insights-grid .insight-card:nth-child(1) { animation-delay: 0.1s; }
.insights-grid .insight-card:nth-child(2) { animation-delay: 0.2s; }
.insights-grid .insight-card:nth-child(3) { animation-delay: 0.3s; }
.insights-grid .insight-card:nth-child(4) { animation-delay: 0.4s; }

.takeaways-grid .takeaway-card:nth-child(1) { animation-delay: 0.1s; }
.takeaways-grid .takeaway-card:nth-child(2) { animation-delay: 0.2s; }
.takeaways-grid .takeaway-card:nth-child(3) { animation-delay: 0.3s; }
.takeaways-grid .takeaway-card:nth-child(4) { animation-delay: 0.4s; }
.takeaways-grid .takeaway-card:nth-child(5) { animation-delay: 0.5s; }
.takeaways-grid .takeaway-card:nth-child(6) { animation-delay: 0.6s; }

/* ========================================
   FULL-WIDTH CHART CARDS
   ======================================== */
.chart-full-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
  margin-bottom: 24px;
}

.chart-full-header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 20px 24px 12px;
}

.chart-full-header h4 {
  font-size: 1rem;
  font-weight: 600;
}

.chart-full-body {
  padding: 0 24px 16px;
}

.chart-full-explain {
  padding: 20px 24px 24px;
  background: rgba(0,212,106,0.04);
  border-top: 1px solid var(--border);
}

.chart-full-explain p {
  font-size: 0.88rem;
  color: var(--fg-muted);
  line-height: 1.7;
  margin-bottom: 10px;
}

.chart-full-explain p:last-child {
  margin-bottom: 0;
}

.chart-full-explain p:first-child {
  font-size: 0.95rem;
  color: var(--primary);
  font-weight: 600;
  margin-bottom: 12px;
  letter-spacing: 0.3px;
}

.chart-full-explain code {
  background: rgba(0,0,0,0.3);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.82rem;
  color: var(--secondary);
}

/* Bar chart visualization */
.chart-bar-viz {
  display: flex;
  gap: 16px;
  align-items: flex-end;
  height: 320px;
  padding: 20px 0;
}

.cbv-group {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  height: 100%;
}

.cbv-bars {
  display: flex;
  align-items: flex-end;
  gap: 2px;
  flex: 1;
  width: 100%;
}

.cbv-bar {
  flex: 1;
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  min-width: 12px;
}

.cbv-fill {
  width: 100%;
  height: 100%;
  border-radius: 3px 3px 0 0;
  transition: height 0.5s ease;
}

.cbv-val {
  position: absolute;
  top: -18px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 0.55rem;
  font-family: var(--font-mono);
  color: var(--fg-muted);
  white-space: nowrap;
}

.cbv-label {
  margin-top: 8px;
  font-size: 0.75rem;
  font-weight: 600;
  text-align: center;
  color: var(--fg-muted);
  line-height: 1.3;
}

/* Legend */
.chart-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: center;
  padding: 12px 0 0;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 5px;
  font-size: 0.72rem;
  color: var(--fg-muted);
}

.lg-swatch {
  width: 12px;
  height: 12px;
  border-radius: 3px;
  display: inline-block;
}

/* Speedup panels */
.speedup-panels {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
}

@media (max-width: 768px) {
  .speedup-panels { grid-template-columns: repeat(2, 1fr); }
}

.speedup-panel {
  background: rgba(0,0,0,0.3);
  border-radius: 10px;
  padding: 12px;
}

.speedup-panel h5 {
  font-size: 0.78rem;
  font-weight: 600;
  text-align: center;
  margin-bottom: 8px;
}

.speedup-chart-area {
  position: relative;
}

.speedup-svg {
  width: 100%;
  height: auto;
}

.sp-verdict {
  display: block;
  text-align: center;
  font-size: 0.68rem;
  font-weight: 600;
  margin-top: 4px;
  padding: 3px 6px;
  border-radius: 4px;
}

.sp-verdict.bad { color: var(--red); background: rgba(255,112,67,0.1); }
.sp-verdict.ok { color: var(--orange); background: rgba(255,152,0,0.1); }
.sp-verdict.good { color: var(--blue); background: rgba(66,165,245,0.1); }
.sp-verdict.great { color: var(--primary); background: rgba(0,212,106,0.1); }

/* ========================================
   RING ALLREDUCE SECTION
   ======================================== */
.ring-intro-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-bottom: 40px;
}

@media (max-width: 768px) {
  .ring-intro-grid { grid-template-columns: 1fr; }
}

.ring-intro-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 24px;
}

.ring-intro-card.bad { border-color: rgba(255,112,67,0.3); }
.ring-intro-card.good { border-color: rgba(0,212,106,0.3); }

.ring-intro-card h4 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 14px;
}

.ring-intro-card p {
  font-size: 0.85rem;
  color: var(--fg-muted);
  line-height: 1.6;
  margin-top: 14px;
}

.ring-intro-card code {
  background: rgba(0,0,0,0.3);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.8rem;
  color: var(--secondary);
}

.ring-diagram {
  background: rgba(0,0,0,0.3);
  border-radius: 10px;
  padding: 16px;
  min-height: 160px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.ring-visual-naive {
  display: grid;
  grid-template-columns: auto auto auto;
  grid-template-rows: auto auto;
  gap: 10px;
  align-items: center;
  justify-items: center;
  position: relative;
}

.rn-gpu {
  background: rgba(33,150,243,0.12);
  border: 1px solid rgba(33,150,243,0.3);
  border-radius: 8px;
  padding: 8px 12px;
  font-size: 0.78rem;
  font-weight: 600;
  text-align: center;
}

.rn-gpu.center {
  grid-column: 2;
  grid-row: 1 / 3;
  background: rgba(255,112,67,0.12);
  border-color: rgba(255,112,67,0.4);
  padding: 16px;
}

.rn-gpu.center small { color: var(--red); display: block; font-size: 0.68rem; }

.rn-arrows { display: none; }

.ring-visual-ring {
  width: 100%;
  max-width: 220px;
}

.ring-svg {
  width: 100%;
  height: auto;
}

/* Ring step visualization */
.ring-steps-section {
  margin-bottom: 20px;
}

.ring-steps-title {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.ring-steps-subtitle {
  font-size: 0.9rem;
  color: var(--fg-muted);
  margin-bottom: 24px;
}

.ring-phase {
  margin-bottom: 32px;
}

.ring-phase-header {
  border-radius: 12px;
  padding: 18px 22px;
  margin-bottom: 16px;
}

.ring-phase-header.phase-1 {
  background: rgba(33,150,243,0.08);
  border: 1px solid rgba(33,150,243,0.2);
}

.ring-phase-header.phase-2 {
  background: rgba(0,212,106,0.08);
  border: 1px solid rgba(0,212,106,0.2);
}

.ring-phase-header h4 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 6px;
}

.ring-phase-header p {
  font-size: 0.85rem;
  color: var(--fg-muted);
  line-height: 1.6;
}

.ring-step-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 14px;
}

.ring-step-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px;
}

.ring-step-card.final {
  border-color: rgba(0,212,106,0.3);
  background: rgba(0,212,106,0.03);
}

.rs-label {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--primary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 10px;
}

.rs-gpus {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 8px;
}

.rs-gpu {
  display: flex;
  align-items: center;
  gap: 8px;
  position: relative;
}

.rs-name {
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--fg-muted);
  min-width: 42px;
}

.rs-chunks {
  display: flex;
  gap: 3px;
  flex: 1;
}

.rs-chunk {
  flex: 1;
  padding: 4px 2px;
  font-size: 0.6rem;
  font-family: var(--font-mono);
  font-weight: 600;
  text-align: center;
  border-radius: 4px;
  background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.08);
  white-space: nowrap;
  overflow: hidden;
}

.rs-chunk.c0 { background: rgba(0,212,106,0.08); border-color: rgba(0,212,106,0.2); }
.rs-chunk.c1 { background: rgba(66,165,245,0.08); border-color: rgba(66,165,245,0.2); }
.rs-chunk.c2 { background: rgba(167,139,250,0.08); border-color: rgba(167,139,250,0.2); }
.rs-chunk.c3 { background: rgba(255,152,0,0.08); border-color: rgba(255,152,0,0.2); }

.rs-chunk.hl-add {
  background: rgba(255,193,7,0.15) !important;
  border-color: rgba(255,193,7,0.4) !important;
  color: #FFCA28;
}

.rs-chunk.hl-done {
  background: rgba(0,212,106,0.15) !important;
  border-color: rgba(0,212,106,0.4) !important;
  color: var(--primary);
}

.rs-send {
  position: absolute;
  right: -2px;
  top: -10px;
  font-size: 0.55rem;
  color: var(--fg-muted);
  font-style: italic;
}

.rs-note {
  font-size: 0.78rem;
  color: var(--fg-muted);
  line-height: 1.5;
}

/* Ring Math card */
.ring-math-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 28px;
  margin-top: 24px;
}

.ring-math-card h4 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 18px;
  text-align: center;
}

.ring-math-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 14px;
  margin-bottom: 20px;
}

.rm-block {
  background: rgba(0,0,0,0.2);
  border-radius: 10px;
  padding: 16px;
}

.rm-block h5 {
  font-size: 0.82rem;
  font-weight: 600;
  margin-bottom: 6px;
  color: var(--fg);
}

.rm-block p {
  font-size: 0.82rem;
  color: var(--fg-muted);
  line-height: 1.6;
}

.rm-block code {
  background: rgba(0,0,0,0.3);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.8rem;
  color: var(--secondary);
}

.rm-block.highlight-math {
  background: rgba(0,212,106,0.06);
  border: 1px solid rgba(0,212,106,0.2);
}

.rm-block.highlight-math code {
  font-size: 0.9rem;
  color: var(--primary);
  display: block;
  margin-bottom: 8px;
}

.ring-math-insight {
  background: rgba(0,212,106,0.04);
  border: 1px solid rgba(0,212,106,0.15);
  border-radius: 10px;
  padding: 18px 22px;
}

.ring-math-insight p {
  font-size: 0.88rem;
  color: var(--fg-muted);
  line-height: 1.7;
  margin-bottom: 10px;
}

.ring-math-insight p:last-child { margin-bottom: 0; }

.ring-math-insight code {
  background: rgba(0,0,0,0.3);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.82rem;
  color: var(--secondary);
}


/* ========================================
   RING ALLREDUCE — NEW EXPLAINER STYLES
   ======================================== */
.ring-explainer-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 28px 28px 24px;
  margin-bottom: 24px;
  position: relative;
}

.ring-explainer-num {
  position: absolute;
  top: -14px;
  left: 24px;
  width: 28px;
  height: 28px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  font-weight: 700;
  color: #000;
}

.ring-explainer-card h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 16px;
  padding-left: 20px;
}

.ring-explainer-body {
  font-size: 0.88rem;
  color: var(--fg-muted);
  line-height: 1.75;
}

.ring-explainer-body p {
  margin-bottom: 14px;
}

.ring-explainer-body strong {
  color: var(--fg);
}

.ring-explainer-body ul,
.ring-explainer-body ol {
  padding-left: 20px;
  margin-bottom: 14px;
}

.ring-explainer-body li {
  margin-bottom: 4px;
  line-height: 1.75;
}

.ring-explainer-body code {
  background: rgba(0,0,0,0.3);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.82rem;
  color: var(--secondary);
}

/* Scenario visual: before → after */
.ring-scenario-visual {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  margin: 20px 0;
}

.ring-scenario-box {
  background: rgba(0,0,0,0.25);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 18px 20px;
  width: 100%;
}

.ring-scenario-box.goal-box {
  border-color: rgba(0,212,106,0.3);
  background: rgba(0,212,106,0.04);
}

.rsb-title {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--fg);
  margin-bottom: 12px;
  text-align: center;
}

.rsb-gpus {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
}

@media (max-width: 640px) {
  .rsb-gpus { grid-template-columns: repeat(2, 1fr); }
}

.rsb-gpu {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}

.rsb-label {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--fg-muted);
}

.rsb-grad {
  padding: 8px 6px;
  border-radius: 8px;
  font-size: 0.72rem;
  font-family: var(--font-mono);
  font-weight: 600;
  text-align: center;
  border: 1px solid;
  width: 100%;
}

.rsb-grad.hl-done {
  background: rgba(0,212,106,0.12) !important;
  border-color: rgba(0,212,106,0.4) !important;
  color: var(--primary);
  font-size: 0.65rem;
}

.rsb-desc {
  font-size: 0.62rem;
  color: var(--fg-muted);
  text-align: center;
  opacity: 0.7;
}

.ring-scenario-arrow {
  opacity: 0.5;
}

/* Naive approach timeline */
.ring-naive-timeline {
  display: flex;
  flex-direction: column;
  gap: 0;
  margin: 16px 0;
  border-left: 3px solid var(--red);
  padding-left: 16px;
}

.rnt-step {
  display: flex;
  gap: 12px;
  padding: 12px 0;
  border-bottom: 1px solid rgba(255,255,255,0.05);
}

.rnt-step:last-child { border-bottom: none; }

.rnt-step-num {
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--red);
  text-transform: uppercase;
  min-width: 48px;
  padding-top: 2px;
}

.rnt-step-desc {
  font-size: 0.85rem;
  color: var(--fg-muted);
  line-height: 1.6;
}

.rnt-step-desc strong { color: var(--fg); }

.rnt-detail {
  font-size: 0.8rem;
  color: var(--fg-muted);
  opacity: 0.8;
  margin-top: 4px;
  font-family: var(--font-mono);
}

/* Problem callout */
.ring-problem-callout {
  background: rgba(255,112,67,0.06);
  border: 1px solid rgba(255,112,67,0.2);
  border-radius: 12px;
  padding: 18px 22px;
  margin-top: 16px;
}

.ring-problem-callout h4 {
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--red);
  margin-bottom: 8px;
}

.ring-problem-callout p {
  font-size: 0.85rem;
  color: var(--fg-muted);
  line-height: 1.7;
  margin-bottom: 8px;
}

.ring-problem-callout p:last-child { margin-bottom: 0; }

.ring-problem-callout code {
  background: rgba(0,0,0,0.3);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.8rem;
  color: var(--secondary);
}

/* Chunk visual */
.ring-chunk-visual {
  margin: 16px 0;
}

.rcv-label {
  font-size: 0.78rem;
  color: var(--fg-muted);
  margin-bottom: 8px;
}

.rcv-bar {
  display: flex;
  gap: 3px;
  border-radius: 8px;
  overflow: hidden;
}

.rcv-chunk {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 12px 4px;
  border-radius: 6px;
  text-align: center;
}

.rcv-chunk span {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--fg);
}

.rcv-chunk small {
  font-size: 0.62rem;
  color: var(--fg-muted);
  opacity: 0.7;
  margin-top: 2px;
}

.rcv-chunk.c0 { background: rgba(0,212,106,0.12); border: 1px solid rgba(0,212,106,0.25); }
.rcv-chunk.c1 { background: rgba(66,165,245,0.12); border: 1px solid rgba(66,165,245,0.25); }
.rcv-chunk.c2 { background: rgba(167,139,250,0.12); border: 1px solid rgba(167,139,250,0.25); }
.rcv-chunk.c3 { background: rgba(255,152,0,0.12); border: 1px solid rgba(255,152,0,0.25); }

/* Ring topology large SVG */
.ring-topo-visual {
  display: flex;
  justify-content: center;
  margin: 16px 0;
}

.ring-svg-large {
  width: 100%;
  max-width: 320px;
  height: auto;
}

/* Step action text */
.rs-action {
  font-size: 0.78rem;
  color: var(--secondary);
  margin-bottom: 10px;
  padding: 8px 10px;
  background: rgba(0,200,230,0.06);
  border-radius: 6px;
  border-left: 3px solid var(--secondary);
  line-height: 1.6;
}

.c0-text { color: #00d46a; font-weight: 600; }
.c1-text { color: #42A5F5; font-weight: 600; }
.c2-text { color: #a78bfa; font-weight: 600; }
.c3-text { color: #FF9800; font-weight: 600; }

.rs-detail {
  font-size: 0.62rem;
  color: var(--fg-muted);
  opacity: 0.7;
  margin-top: 2px;
  font-style: italic;
}

/* Comparison table */
.ring-compare-table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0;
  font-size: 0.82rem;
}

.ring-compare-table th {
  padding: 10px 12px;
  text-align: left;
  font-weight: 600;
  color: var(--fg);
  border-bottom: 2px solid var(--border);
  font-size: 0.8rem;
}

.ring-compare-table td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  color: var(--fg-muted);
  vertical-align: top;
  line-height: 1.5;
}

.ring-compare-table td:first-child {
  color: var(--fg);
  font-weight: 500;
  min-width: 150px;
}

.ring-compare-table td.val-bad { color: var(--red); }
.ring-compare-table td.val-good { color: var(--primary); }

.ring-compare-table code {
  background: rgba(0,0,0,0.3);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.78rem;
  color: var(--secondary);
}

/* Step 3 trace blocks */
.rs-trace-block {
  margin: 14px 0 10px;
}

.rs-trace-header {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--fg);
  margin-bottom: 8px;
}

.rs-trace-sends {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding-left: 12px;
  border-left: 3px solid var(--secondary);
  margin-bottom: 14px;
}

.rs-trace-send {
  font-size: 0.78rem;
  color: var(--fg-muted);
  line-height: 1.6;
  padding: 4px 0;
}

.rs-trace-send code {
  background: rgba(0,0,0,0.3);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.72rem;
  color: var(--secondary);
}

.rs-trace-send strong { color: var(--fg); }

.rs-trace-detail-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 10px;
  margin-bottom: 14px;
}

.rs-trace-detail-card {
  background: rgba(0,0,0,0.2);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px 14px;
}

.rs-trace-gpu-label {
  font-size: 0.78rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.rs-trace-math {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.rs-trace-line {
  font-size: 0.75rem;
  color: var(--fg-muted);
  line-height: 1.5;
}

.rs-trace-line code {
  background: rgba(0,0,0,0.3);
  padding: 1px 5px;
  border-radius: 3px;
  font-size: 0.7rem;
  color: var(--secondary);
}

.rs-trace-result {
  margin-top: 4px;
  padding-top: 6px;
  border-top: 1px solid rgba(0,212,106,0.2);
  color: var(--primary) !important;
  font-weight: 600;
}

.rs-trace-result strong {
  color: var(--primary);
}

.rs-insight-box {
  background: rgba(0,212,106,0.04);
  border: 1px solid rgba(0,212,106,0.15);
  border-radius: 10px;
  padding: 16px 18px;
  margin-top: 14px;
}

.rs-insight-box p {
  font-size: 0.82rem;
  color: var(--fg-muted);
  line-height: 1.7;
  margin-bottom: 8px;
}

.rs-insight-box p:last-child { margin-bottom: 0; }
.rs-insight-box strong { color: var(--fg); }

.rs-insight-box ul {
  padding-left: 18px;
  margin: 6px 0;
}

.rs-insight-box li {
  font-size: 0.78rem;
  color: var(--fg-muted);
  line-height: 1.6;
  margin-bottom: 2px;
}

/* Math examples grid */
.ring-math-examples {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 8px;
  margin: 12px 0;
}

.rme {
  font-size: 0.82rem;
  color: var(--fg-muted);
  padding: 6px 10px;
  background: rgba(0,0,0,0.2);
  border-radius: 6px;
}

.rme strong { color: var(--fg); }

/* ========================================
   DETAILED CHART EXPLANATIONS
   ======================================== */
.chart-explanation-detailed {
  margin-top: 14px;
}

.chart-explanation-detailed p {
  font-size: 0.85rem;
  color: var(--fg-muted);
  line-height: 1.75;
  margin-bottom: 12px;
}

.chart-explanation-detailed strong {
  color: var(--fg);
}

.chart-explanation-detailed ul,
.chart-explanation-detailed ol {
  padding-left: 20px;
  margin-bottom: 12px;
}

.chart-explanation-detailed li {
  font-size: 0.85rem;
  color: var(--fg-muted);
  line-height: 1.75;
  margin-bottom: 4px;
}

.chart-explanation-detailed li strong {
  color: var(--fg);
}

.chart-explanation-detailed code {
  background: rgba(0,0,0,0.3);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.78rem;
  color: var(--secondary);
}

.chart-explanation-detailed h5 {
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: 8px;
}

/* Throughput detail table */
.throughput-detail-table {
  width: 100%;
  border-collapse: collapse;
  margin: 8px 0 16px 0;
  font-size: 0.8rem;
}

.throughput-detail-table td {
  padding: 6px 10px;
  border-bottom: 1px solid var(--border);
  color: var(--fg-muted);
  vertical-align: top;
}

.throughput-detail-table td:first-child {
  color: var(--fg);
  font-weight: 500;
  white-space: nowrap;
  width: 140px;
}

.throughput-detail-table td:nth-child(2) {
  font-family: var(--font-mono);
  color: var(--secondary);
  white-space: nowrap;
  width: 160px;
}

.throughput-detail-table tr:last-child td {
  border-bottom: none;
}

/* Selection styling */
::selection {
  background: rgba(0,212,106,0.3);
  color: #fff;
}