:root {
  --void: #06080f;
  --bg: #0c1020;
  --surface: #121830;
  --surface-2: #1a2142;
  --border: rgba(255,255,255,0.07);
  --border-strong: rgba(255,255,255,0.14);
  --text: #eef3fb;
  --text-muted: #8c97b3;
  --text-dim: #5a648a;
  --signal: #1aa8e2;
  --signal-2: #4fc3f7;
  --accent: #00bcd4;
  --display: 'Geist', system-ui, -apple-system, 'Segoe UI', sans-serif;
  --sans: 'Geist', system-ui, -apple-system, 'Segoe UI', sans-serif;
  --mono: 'Geist Mono', ui-monospace, 'SF Mono', Menlo, monospace;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  background: var(--void);
  color: var(--text);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

body::before {
  content: "";
  position: fixed; inset: 0;
  background-image:
    linear-gradient(rgba(26,168,226,0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(26,168,226,0.04) 1px, transparent 1px);
  background-size: 64px 64px;
  pointer-events: none;
  z-index: 0;
  mask-image: radial-gradient(ellipse at top, black 30%, transparent 75%);
}
body::after {
  content: "";
  position: fixed; top: -20%; left: 50%;
  width: 1200px; height: 800px;
  transform: translateX(-50%);
  background: radial-gradient(ellipse at center, rgba(26,168,226,0.10), transparent 60%);
  pointer-events: none;
  z-index: 0;
}

a { color: inherit; text-decoration: none; }
img, svg { display: block; max-width: 100%; }

/* ---------- PAGE LAYOUT ---------- */
.page {
  position: relative;
  z-index: 1;
  max-width: 1100px;
  margin: 0 auto;
  padding: 80px 32px 120px;
}

.page-head {
  margin-bottom: 56px;
}
.kicker {
  display: inline-block;
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--signal);
  margin-bottom: 16px;
}
.page-head h1 {
  font-family: var(--display);
  font-weight: 300;
  font-size: clamp(1.8rem, 4vw, 3rem);
  letter-spacing: -0.025em;
  line-height: 1.12;
  margin-bottom: 14px;
}
.page-head h1 em {
  font-style: normal;
  font-weight: 500;
  background: linear-gradient(120deg, var(--signal), var(--signal-2));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}
.page-head .subtitle {
  color: var(--text-muted);
  font-size: 1rem;
  line-height: 1.6;
}

/* ---------- SECTION CARDS ---------- */
.section {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 32px 36px;
  margin-bottom: 20px;
}
.section h2 {
  font-family: var(--display);
  font-weight: 500;
  font-size: 1.15rem;
  color: var(--text);
  margin-bottom: 16px;
  letter-spacing: -0.01em;
}
.section h2::before {
  content: "▸ ";
  color: var(--signal);
}
.section p {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.65;
  margin-bottom: 14px;
}
.section p:last-child { margin-bottom: 0; }

/* ---------- ARCHITECTURE IMAGE ---------- */
.arch-image {
  width: 100%;
  border-radius: 10px;
  margin-top: 8px;
}

/* ---------- METRICS ---------- */
.metric-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 12px;
}
.metric {
  background: rgba(26,168,226,0.06);
  border: 1px solid rgba(26,168,226,0.12);
  border-radius: 10px;
  padding: 18px 20px;
}
.metric .label {
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.06em;
  color: #fff;
  text-transform: uppercase;
  margin-bottom: 6px;
}
.metric .value {
  font-family: var(--display);
  font-size: 1.35rem;
  font-weight: 600;
  color: var(--signal);
  letter-spacing: -0.02em;
}

/* ---------- CHALLENGE CARDS ---------- */
.challenge-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 14px;
}
.challenge-card {
  background: rgba(234,179,8,0.08);
  border-left: 3px solid rgba(234,179,8,0.6);
  padding: 16px 18px;
  border-radius: 0 8px 8px 0;
  font-size: 0.9rem;
  color: rgba(250,204,21,0.85);
  line-height: 1.55;
}
.challenge-card strong {
  display: block;
  color: rgba(250,204,21,0.95);
  margin-bottom: 6px;
  font-size: 0.92rem;
}

/* ---------- HIGHLIGHT ---------- */
.highlight {
  background: rgba(26,168,226,0.08);
  border: 1px solid rgba(26,168,226,0.15);
  border-radius: 10px;
  padding: 16px 20px;
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-top: 14px;
}

/* ---------- FOOTER NOTE ---------- */
.footer-note {
  padding: 28px 0 0;
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.04em;
  color: var(--text-dim);
}

/* ---------- SCREENSHOT FLOW (case3) ---------- */
.flow-step {
  margin-bottom: 20px;
}
.flow-step .step-label {
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--signal);
  margin-bottom: 8px;
}
.flow-step p {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.65;
  margin-bottom: 14px;
}
.flow-step .step-img {
  width: 100%;
  border-radius: 10px;
  border: 1px solid var(--border);
}

/* ---------- RESPONSIVE ---------- */
@media (max-width: 768px) {
  .page { padding: 48px 20px 80px; }
  .section { padding: 24px 24px; }
  .metric-grid { grid-template-columns: repeat(2, 1fr); }
  .challenge-grid { grid-template-columns: 1fr; }
}
@media (max-width: 480px) {
  .metric-grid { grid-template-columns: 1fr; }
}