/* Case Study Pages */
:root {
  --bg: #0a0c0f;
  --bg-soft: #101318;
  --surface: #151922;
  --surface-raised: #1a1f29;
  --line: #2a303b;
  --line-soft: #202631;
  --text: #f4f7fb;
  --text-muted: #a7b0bf;
  --text-subtle: #778294;
  --accent: #7dd3fc;
  --accent-strong: #38bdf8;
  --accent-warm: #f4c95d;
  --success: #6ee7b7;
  --shadow: 0 24px 70px rgba(0, 0, 0, 0.32);
  --radius: 8px;
  --radius-sm: 6px;
  --container: 860px;
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --transition: 170ms ease;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Nav */
.cs-nav {
  padding: 1.1rem 0;
  background: rgba(10, 12, 15, 0.94);
  border-bottom: 1px solid var(--line-soft);
  backdrop-filter: blur(14px);
  position: sticky;
  top: 0;
  z-index: 100;
}

.cs-nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.cs-nav-brand {
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 700;
  text-decoration: none;
}

.cs-nav-brand::before {
  content: "~/";
  color: var(--accent);
}

.cs-nav-back {
  color: var(--text-muted);
  font-size: 0.9rem;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  transition: color var(--transition);
}

.cs-nav-back:hover { color: var(--accent); }

/* Hero */
.cs-hero {
  padding: 80px 0 48px;
}

.cs-breadcrumb {
  color: var(--text-subtle);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  margin-bottom: 1rem;
}

.cs-breadcrumb a {
  color: var(--text-muted);
  text-decoration: none;
}

.cs-breadcrumb a:hover { color: var(--accent); }

.cs-title {
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 800;
  margin: 0 0 0.75rem;
  line-height: 1.08;
}

.cs-subtitle {
  color: var(--text-muted);
  font-size: 1.1rem;
  max-width: 640px;
  margin-bottom: 1.5rem;
}

.cs-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
}

.cs-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: #10151d;
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  padding: 0.4rem 0.6rem;
}

.cs-links {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin-top: 1.5rem;
}

.cs-link {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.65rem 1rem;
  border-radius: var(--radius-sm);
  font-weight: 700;
  font-size: 0.9rem;
  text-decoration: none;
  transition: background var(--transition), border-color var(--transition), color var(--transition), transform var(--transition);
}

.cs-link-primary {
  background: var(--text);
  border: 1px solid var(--text);
  color: #080a0d;
}

.cs-link-primary:hover {
  background: var(--accent);
  border-color: var(--accent);
  color: #071018;
  transform: translateY(-2px);
}

.cs-link-secondary {
  background: transparent;
  border: 1px solid var(--line);
  color: var(--text);
}

.cs-link-secondary:hover {
  border-color: var(--accent);
  color: var(--accent);
  transform: translateY(-2px);
}

/* Section */
.cs-section {
  padding: 56px 0;
  border-top: 1px solid var(--line-soft);
}

.cs-section:first-of-type {
  border-top: none;
}

.cs-section-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin: 0 0 1.25rem;
}

.cs-section-title::after {
  content: "";
  display: block;
  width: 36px;
  height: 2px;
  margin-top: 12px;
  background: linear-gradient(90deg, var(--accent), var(--accent-warm));
}

.cs-text {
  color: var(--text-muted);
  line-height: 1.75;
  margin: 0 0 1rem;
}

.cs-text:last-child { margin-bottom: 0; }

.cs-grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}

.cs-card {
  background: var(--surface);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  padding: 1.5rem;
}

.cs-card-title {
  font-size: 1.05rem;
  font-weight: 700;
  margin: 0 0 0.75rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.cs-card-title i { color: var(--accent); }

.cs-card-text {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.65;
  margin: 0;
}

/* Architecture Diagram */
.cs-diagram {
  background: var(--surface);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  padding: 2rem;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  line-height: 1.6;
  white-space: pre;
  color: var(--text-muted);
}

.cs-diagram .highlight {
  color: var(--accent);
}

.cs-diagram .success {
  color: var(--success);
}

.cs-diagram .warm {
  color: var(--accent-warm);
}

/* Tech Stack List */
.cs-tech-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 1rem;
}

.cs-tech-item {
  background: var(--surface);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  padding: 1.25rem;
}

.cs-tech-name {
  font-weight: 700;
  margin-bottom: 0.35rem;
}

.cs-tech-desc {
  color: var(--text-muted);
  font-size: 0.88rem;
  margin: 0;
}

/* Results */
.cs-results-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
}

.cs-result-card {
  background: var(--surface);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  padding: 1.5rem;
  text-align: center;
}

.cs-result-value {
  font-size: 2rem;
  font-weight: 800;
  color: var(--accent);
  font-family: var(--font-mono);
  margin-bottom: 0.35rem;
}

.cs-result-label {
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* Challenge */
.cs-challenge {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.cs-challenge-card {
  background: var(--surface);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  padding: 1.25rem;
}

.cs-challenge-card.cs-solution {
  border-color: var(--accent);
}

.cs-challenge-label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-subtle);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
}

.cs-challenge-text {
  color: var(--text-muted);
  font-size: 0.92rem;
  margin: 0;
}

/* Footer */
.cs-footer {
  padding: 32px 0;
  border-top: 1px solid var(--line-soft);
  text-align: center;
  color: var(--text-subtle);
  font-size: 0.88rem;
}

.cs-footer a {
  color: var(--text-muted);
  text-decoration: none;
}

.cs-footer a:hover { color: var(--accent); }

/* Responsive */
@media (max-width: 767px) {
  .cs-grid-2,
  .cs-results-grid,
  .cs-challenge {
    grid-template-columns: 1fr;
  }

  .cs-tech-list {
    grid-template-columns: 1fr;
  }

  .cs-hero {
    padding: 48px 0 32px;
  }
}