/* ═══════════════════════════════════════════════════════════
   CASE STUDY 02 — FACELESS STARTUP EXPLAINER
   Theme: High-End Tech Infographic / Documentary
   Palette: Dark Charcoal + Teal-Mint + Amber accents
   ═══════════════════════════════════════════════════════════ */

/* ─── Design Tokens ─── */
:root {
  --cs2-bg-deep: #0b0d11;
  --cs2-bg-primary: #111318;
  --cs2-bg-card: #161920;
  --cs2-bg-elevated: #1c1f28;

  --cs2-text-primary: #e2e6ed;
  --cs2-text-secondary: #8b93a1;
  --cs2-text-dim: #5c6370;

  --cs2-accent: #64FFDA;
  --cs2-accent-rgb: 100, 255, 218;
  --cs2-accent-warm: #FFB347;
  --cs2-accent-warm-rgb: 255, 179, 71;

  --cs2-border: #1e2230;
  --cs2-border-light: #2a2f3d;

  --cs2-font-display: 'Sora', -apple-system, BlinkMacSystemFont, sans-serif;
  --cs2-font-sans: 'Outfit', -apple-system, BlinkMacSystemFont, sans-serif;
  --cs2-font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  --cs2-radius-sm: 6px;
  --cs2-radius-md: 10px;
  --cs2-radius-lg: 14px;
  --cs2-radius-xl: 20px;
}

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

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  background-color: var(--cs2-bg-deep);
  color: var(--cs2-text-primary);
  font-family: var(--cs2-font-sans);
  font-weight: 400;
  line-height: 1.7;
  overflow-x: hidden;
  position: relative;
}

/* ─── Ambient Particle Canvas ─── */
#cs2-ambient-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  z-index: 0;
  pointer-events: none;
  background: transparent;
  display: block;
}

/* ─── Typography Base ─── */
h1, h2, h3, h4, h5 {
  font-family: var(--cs2-font-display);
  font-weight: 800;
  color: #ffffff;
  letter-spacing: -0.03em;
  line-height: 1.15;
}

p {
  color: var(--cs2-text-secondary);
  font-size: 16px;
  line-height: 1.75;
}

a {
  text-decoration: none;
  color: inherit;
}

/* ─── Layout Containers ─── */
.cs2-container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 28px;
  position: relative;
  z-index: 1;
}

.cs2-container-narrow {
  max-width: 780px;
  margin: 0 auto;
  padding: 0 28px;
  position: relative;
  z-index: 1;
}

/* ─── Section Spacing ─── */
.cs2-section {
  margin-bottom: 140px;
}

@media (max-width: 768px) {
  .cs2-section {
    margin-bottom: 90px;
  }
}

/* ═══════════════════════════════════════
   TOP NAVIGATION BAR
   ═══════════════════════════════════════ */
.cs2-topnav {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 100;
  background: rgba(11, 13, 17, 0.85);
  backdrop-filter: blur(20px) saturate(1.3);
  -webkit-backdrop-filter: blur(20px) saturate(1.3);
  border-bottom: 1px solid var(--cs2-border);
  padding: 0 28px;
  transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1);
}

.cs2-topnav-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}

.cs2-nav-back {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--cs2-font-sans);
  font-size: 13px;
  font-weight: 500;
  color: var(--cs2-text-secondary);
  transition: color 0.25s ease;
}

.cs2-nav-back svg {
  width: 18px;
  height: 18px;
  transition: transform 0.25s ease;
}

.cs2-nav-back:hover {
  color: #ffffff;
}

.cs2-nav-back:hover svg {
  transform: translateX(-4px);
}

.cs2-nav-label {
  font-family: var(--cs2-font-mono);
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.2em;
  color: var(--cs2-accent);
  text-transform: uppercase;
}

/* ═══════════════════════════════════════
   HERO SECTION (Title + Video Placeholder)
   ═══════════════════════════════════════ */
.cs2-hero {
  padding-top: 120px;
  margin-bottom: 100px;
}

.cs2-eyebrow-wrap {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 28px;
}

.cs2-eyebrow {
  font-family: var(--cs2-font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.22em;
  color: var(--cs2-accent);
  text-transform: uppercase;
}

.cs2-eyebrow-badge {
  background: rgba(var(--cs2-accent-rgb), 0.08);
  border: 1px solid rgba(var(--cs2-accent-rgb), 0.3);
  color: var(--cs2-accent);
  font-family: var(--cs2-font-mono);
  font-size: 9px;
  font-weight: 700;
  padding: 3px 10px;
  border-radius: 4px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.cs2-hero-title {
  font-size: clamp(32px, 4.5vw, 54px);
  line-height: 1.15;
  font-weight: 400; /* Minimal premium lighter weight */
  letter-spacing: -0.02em;
  color: #ffffff;
  margin-bottom: 30px;
  max-width: 900px;
}

/* Word-inner gradient for text mask reveal */
.cs2-hero-title .word-inner,
.cs2-section-heading .word-inner {
  background: linear-gradient(180deg, #ffffff 40%, var(--cs2-text-secondary) 100%) !important;
  -webkit-background-clip: text !important;
  -webkit-text-fill-color: transparent !important;
  background-clip: text !important;
  color: transparent !important;
}

.cs2-hero-subtitle {
  font-family: var(--cs2-font-sans);
  font-size: clamp(15px, 2vw, 18px);
  color: var(--cs2-text-dim);
  line-height: 1.6;
  max-width: 720px;
  margin-bottom: 0;
}

/* ─── Video Grid & Placeholder Frame ─── */
.cs2-video-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
  width: 100%;
}
@media (min-width: 992px) {
  .cs2-video-grid {
    grid-template-columns: 1fr 1fr;
  }
}

.cs2-video-placeholder {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  background: var(--cs2-bg-card);
  border: 2px dashed var(--cs2-border-light);
  border-radius: var(--cs2-radius-lg);
  margin-top: 48px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 20px;
  overflow: hidden;
  transition: border-color 0.35s ease, background 0.35s ease;
}

.cs2-video-placeholder::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at 50% 50%, rgba(var(--cs2-accent-rgb), 0.03) 0%, transparent 70%);
  pointer-events: none;
}

.cs2-video-placeholder:hover {
  border-color: rgba(var(--cs2-accent-rgb), 0.3);
  background: var(--cs2-bg-elevated);
}

.cs2-video-play-icon {
  width: 72px;
  height: 72px;
  border-radius: 50%;
  background: rgba(var(--cs2-accent-rgb), 0.1);
  border: 2px solid rgba(var(--cs2-accent-rgb), 0.25);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275), 
              background 0.3s ease,
              border-color 0.3s ease;
}

.cs2-video-placeholder:hover .cs2-video-play-icon {
  transform: scale(1.08);
  background: rgba(var(--cs2-accent-rgb), 0.15);
  border-color: rgba(var(--cs2-accent-rgb), 0.5);
}

.cs2-video-play-icon svg {
  width: 28px;
  height: 28px;
  color: var(--cs2-accent);
  margin-left: 3px;
}

.cs2-video-label {
  font-family: var(--cs2-font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.15em;
  color: var(--cs2-text-dim);
  text-transform: uppercase;
}

/* When video is actually embedded */
.cs2-video-placeholder.has-video {
  border: none;
  background-color: #000;
}

.cs2-video-placeholder.has-video iframe,
.cs2-video-placeholder.has-video video {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: none;
  border-radius: var(--cs2-radius-lg);
  object-fit: cover;
}

/* ═══════════════════════════════════════
   METADATA LABEL (Module Tags)
   ═══════════════════════════════════════ */
.cs2-meta-label {
  font-family: var(--cs2-font-mono);
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.18em;
  color: var(--cs2-accent);
  text-transform: uppercase;
  margin-bottom: 16px;
  opacity: 0.85;
}

/* ═══════════════════════════════════════
   SECTION HEADINGS
   ═══════════════════════════════════════ */
.cs2-section-header {
  margin-bottom: 36px;
}

.cs2-section-heading {
  font-size: clamp(26px, 3.5vw, 42px);
  line-height: 1.15;
  color: #ffffff;
  margin-bottom: 10px;
}

.cs2-section-rule {
  width: 60px;
  height: 3px;
  background: linear-gradient(90deg, var(--cs2-accent), rgba(var(--cs2-accent-rgb), 0.2));
  border-radius: 2px;
  margin-bottom: 24px;
  border: none;
}

/* ═══════════════════════════════════════
   PROJECT OVERVIEW SECTION
   ═══════════════════════════════════════ */
.cs2-overview {
  margin-bottom: 140px;
}

.cs2-overview-text {
  font-size: 18px;
  color: var(--cs2-text-primary);
  font-weight: 300;
  line-height: 1.8;
  letter-spacing: -0.005em;
}

/* ═══════════════════════════════════════
   CREATIVE CHALLENGE SECTION
   ═══════════════════════════════════════ */
.cs2-challenge-intro {
  font-size: 16px;
  margin-bottom: 48px;
  max-width: 800px;
}

/* Bottleneck Cards Grid */
.cs2-bottleneck-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

@media (max-width: 768px) {
  .cs2-bottleneck-grid {
    grid-template-columns: 1fr;
    gap: 18px;
  }
}

.cs2-bottleneck-card {
  background: var(--cs2-bg-card);
  border: 1px solid var(--cs2-border);
  border-radius: var(--cs2-radius-md);
  padding: 28px 24px;
  position: relative;
  overflow: hidden;
  transition: border-color 0.35s ease, transform 0.3s ease;
}

.cs2-bottleneck-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 4px;
  height: 100%;
  background: var(--cs2-accent);
  border-radius: 4px 0 0 4px;
  opacity: 0.7;
  transition: opacity 0.3s ease;
}

.cs2-bottleneck-card:hover {
  border-color: rgba(var(--cs2-accent-rgb), 0.2);
  transform: translateY(-2px);
}

.cs2-bottleneck-card:hover::before {
  opacity: 1;
}

.cs2-bottleneck-card:nth-child(2)::before {
  background: var(--cs2-accent-warm);
}

.cs2-bottleneck-card:nth-child(3)::before {
  background: #a78bfa;
}

.cs2-bottleneck-title {
  font-family: var(--cs2-font-display);
  font-size: 15px;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 10px;
  letter-spacing: -0.01em;
}

.cs2-bottleneck-desc {
  font-size: 13.5px;
  color: var(--cs2-text-secondary);
  line-height: 1.6;
}

/* ═══════════════════════════════════════
   STRATEGY & WORKFLOW SECTION
   ═══════════════════════════════════════ */
.cs2-workflow-steps {
  display: flex;
  flex-direction: column;
  gap: 100px;
}

@media (max-width: 768px) {
  .cs2-workflow-steps {
    gap: 70px;
  }
}

/* Individual Workflow Step */
.cs2-workflow-step {
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: 40px;
  align-items: start;
}

@media (max-width: 768px) {
  .cs2-workflow-step {
    grid-template-columns: 1fr;
    gap: 16px;
  }
}

.cs2-step-number {
  font-family: var(--cs2-font-mono);
  font-size: 48px;
  font-weight: 800;
  color: rgba(var(--cs2-accent-rgb), 0.12);
  line-height: 1;
  letter-spacing: -0.04em;
  position: relative;
  user-select: none;
}

.cs2-step-number::after {
  content: '';
  position: absolute;
  bottom: -8px;
  left: 0;
  width: 32px;
  height: 2px;
  background: var(--cs2-accent);
  opacity: 0.3;
  border-radius: 2px;
}

.cs2-step-content {
  display: flex;
  flex-direction: column;
}

.cs2-step-title {
  font-family: var(--cs2-font-display);
  font-size: clamp(20px, 2.5vw, 28px);
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 18px;
  line-height: 1.25;
}

.cs2-step-body {
  font-size: 15.5px;
  color: var(--cs2-text-secondary);
  line-height: 1.75;
  margin-bottom: 12px;
}

/* Sub-bullet Technique Cards */
.cs2-technique-list {
  display: flex;
  flex-direction: column;
  gap: 20px;
  margin-top: 28px;
}

.cs2-technique-item {
  background: var(--cs2-bg-card);
  border: 1px solid var(--cs2-border);
  border-radius: var(--cs2-radius-md);
  padding: 24px;
  position: relative;
  overflow: hidden;
  transition: border-color 0.3s ease;
}

.cs2-technique-item:hover {
  border-color: rgba(var(--cs2-accent-rgb), 0.2);
}

.cs2-technique-item::after {
  content: '';
  position: absolute;
  top: 0;
  right: 0;
  width: 120px;
  height: 120px;
  background: radial-gradient(circle, rgba(var(--cs2-accent-rgb), 0.03) 0%, transparent 70%);
  pointer-events: none;
}

.cs2-technique-name {
  font-family: var(--cs2-font-display);
  font-size: 14px;
  font-weight: 700;
  color: var(--cs2-accent);
  margin-bottom: 8px;
  letter-spacing: 0.01em;
}

.cs2-technique-desc {
  font-size: 14px;
  color: var(--cs2-text-secondary);
  line-height: 1.6;
}

/* ═══════════════════════════════════════
   HORIZONTAL DIVIDER
   ═══════════════════════════════════════ */
.cs2-divider {
  width: 100%;
  max-width: 600px;
  margin: 0 auto 100px auto;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  padding: 0 28px;
  position: relative;
  z-index: 1;
}

.cs2-divider-line {
  flex: 1;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--cs2-border-light), transparent);
}

.cs2-divider-dot {
  width: 6px;
  height: 6px;
  background: var(--cs2-accent);
  border-radius: 50%;
  opacity: 0.5;
  box-shadow: 0 0 10px rgba(var(--cs2-accent-rgb), 0.3);
}

/* ═══════════════════════════════════════
   KEY TAKEAWAYS SECTION
   ═══════════════════════════════════════ */
.cs2-takeaways {
  margin-bottom: 120px;
}

.cs2-takeaway-text {
  font-size: 17px;
  color: var(--cs2-text-primary);
  font-weight: 300;
  line-height: 1.85;
  letter-spacing: -0.005em;
  position: relative;
  padding-left: 24px;
  border-left: 3px solid rgba(var(--cs2-accent-rgb), 0.25);
}

/* ═══════════════════════════════════════
   FOOTER
   ═══════════════════════════════════════ */
.cs2-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-top: 1px solid var(--cs2-border);
  padding-top: 48px;
  margin-top: 60px;
  padding-bottom: 80px;
}

@media (max-width: 576px) {
  .cs2-footer {
    flex-direction: column;
    gap: 24px;
    text-align: center;
  }
}

.cs2-footer-back {
  font-size: 14px;
  color: var(--cs2-text-secondary);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  transition: color 0.25s ease;
}

.cs2-footer-back svg {
  width: 16px;
  height: 16px;
  transition: transform 0.25s ease;
}

.cs2-footer-back:hover {
  color: #fff;
}

.cs2-footer-back:hover svg {
  transform: translateX(-4px);
}

.cs2-footer-cta {
  font-family: var(--cs2-font-display);
  font-size: 14px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  background-color: #ffffff;
  color: #0a0a0a;
  padding: 14px 28px;
  border-radius: 4px;
  transition: transform 0.25s cubic-bezier(0.175, 0.885, 0.32, 1.275), 
              background-color 0.25s ease,
              color 0.25s ease;
}

.cs2-footer-cta:hover {
  transform: scale(1.05);
  background-color: var(--cs2-accent);
  color: var(--cs2-bg-deep);
}

/* ═══════════════════════════════════════
   SCROLL REVEAL ANIMATIONS
   ═══════════════════════════════════════ */
.fade-slide-up {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s cubic-bezier(0.16, 1, 0.3, 1), 
              transform 0.7s cubic-bezier(0.16, 1, 0.3, 1);
}

.fade-slide-up.revealed {
  opacity: 1;
  transform: translateY(0);
}

/* Staggered children reveal */
.fade-slide-up.revealed .cs2-bottleneck-card,
.fade-slide-up.revealed .cs2-technique-item {
  opacity: 1;
  transform: translateY(0);
}

.cs2-bottleneck-card,
.cs2-technique-item {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.5s cubic-bezier(0.16, 1, 0.3, 1),
              transform 0.5s cubic-bezier(0.16, 1, 0.3, 1);
}

.fade-slide-up.revealed .cs2-bottleneck-card:nth-child(1),
.fade-slide-up.revealed .cs2-technique-item:nth-child(1) { transition-delay: 0.1s; }
.fade-slide-up.revealed .cs2-bottleneck-card:nth-child(2),
.fade-slide-up.revealed .cs2-technique-item:nth-child(2) { transition-delay: 0.2s; }
.fade-slide-up.revealed .cs2-bottleneck-card:nth-child(3),
.fade-slide-up.revealed .cs2-technique-item:nth-child(3) { transition-delay: 0.3s; }

/* Text Mask Reveal */
.text-mask-reveal .word-mask {
  display: inline-block;
  overflow: hidden;
  vertical-align: bottom;
  margin-right: 0.22em;
}

.text-mask-reveal .word-inner {
  display: inline-block;
  transform: translateY(110%);
  transition: transform 0.85s cubic-bezier(0.16, 1, 0.3, 1);
  transition-delay: inherit;
}

.text-mask-reveal.revealed .word-inner {
  transform: translateY(0);
}

/* ═══════════════════════════════════════
   RESPONSIVE REFINEMENTS
   ═══════════════════════════════════════ */
@media (max-width: 992px) {
  .cs2-hero-title {
    font-size: clamp(28px, 5vw, 44px);
  }
}

@media (max-width: 768px) {
  .cs2-container {
    padding: 0 20px;
  }
  .cs2-container-narrow {
    padding: 0 20px;
  }
  .cs2-hero {
    padding-top: 100px;
    margin-bottom: 70px;
  }
  .cs2-video-placeholder {
    margin-top: 32px;
  }
  .cs2-overview {
    margin-bottom: 100px;
  }
  .cs2-workflow-step {
    grid-template-columns: 1fr;
    gap: 12px;
  }
  .cs2-step-number {
    font-size: 36px;
  }
  .cs2-step-number::after {
    bottom: -4px;
    width: 24px;
  }
}

@media (max-width: 576px) {
  .cs2-hero-title {
    font-size: 26px;
  }
  .cs2-section-heading {
    font-size: 24px;
  }
  .cs2-eyebrow-wrap {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
  }
  .cs2-video-play-icon {
    width: 56px;
    height: 56px;
  }
  .cs2-video-play-icon svg {
    width: 22px;
    height: 22px;
  }
}