/* ==========================================================
   nslabs — How the Ecosystem Operates
   Pure CSS. No frameworks.
   ========================================================== */

:root {
  --bg-deep: #0a0e1a;
  --bg-surface: #111728;
  --bg-elevated: #161d33;
  --bg-elevated-2: #1a2342;

  --accent: #4f7df5;
  --accent-2: #22d3a7;
  --accent-glow: rgba(79, 125, 245, 0.35);

  --text-primary: #e8ecf4;
  --text-secondary: #8a93ad;
  --text-dim: #5b6480;

  --border: rgba(140, 160, 220, 0.10);
  --border-strong: rgba(140, 160, 220, 0.18);

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;

  --shadow-lg: 0 24px 60px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 0 1px rgba(79,125,245,0.35), 0 8px 28px rgba(79,125,245,0.25);

  --font-mono: ui-monospace, "JetBrains Mono", "SF Mono", Menlo, monospace;
  --font-sans: -apple-system, BlinkMacSystemFont, "Inter", "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }

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

/* ===== SECTION SHELL ===== */
.interaction-model {
  position: relative;
  padding: 120px 24px;
  background:
    radial-gradient(900px 500px at 15% 0%, rgba(79, 125, 245, 0.10), transparent 60%),
    radial-gradient(900px 500px at 100% 100%, rgba(34, 211, 167, 0.07), transparent 60%),
    var(--bg-deep);
  overflow: hidden;
}

/* radial dot pattern */
.interaction-model::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: radial-gradient(circle, rgba(140,160,220,0.10) 1px, transparent 1.4px);
  background-size: 28px 28px;
  mask-image: radial-gradient(ellipse at center, #000 25%, transparent 75%);
  opacity: 0.55;
  pointer-events: none;
}

.interact-container {
  position: relative;
  max-width: 1280px;
  margin: 0 auto;
}

/* ===== HEADER ===== */
.interact-header {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  margin-bottom: 84px;
}

.interact-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  border: 1px solid var(--border-strong);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.02);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--text-secondary);
  margin-bottom: 22px;
}
.interact-badge .pulse {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 12px var(--accent);
  animation: ping 2.4s ease-in-out infinite;
}
@keyframes ping {
  0%, 100% { opacity: 1; transform: scale(1); }
  50%      { opacity: 0.4; transform: scale(1.4); }
}

.interact-header h2 {
  font-size: clamp(34px, 5vw, 54px);
  font-weight: 600;
  letter-spacing: -0.02em;
  margin: 0 0 18px;
  line-height: 1.05;
}
.interact-header h2 .grad {
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.interact-header p {
  max-width: 580px;
  color: var(--text-secondary);
  font-size: 17px;
  line-height: 1.55;
  margin: 0;
}

/* ===== ORBITAL FLOW LAYOUT =====
   2x2 grid orbiting a central core
   ============================== */
.interact-flow {
  position: relative;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 28px 220px;
  align-items: stretch;
  padding: 40px 0;
}

/* central core */
.interact-core {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  width: 180px; height: 180px;
  border-radius: 50%;
  background:
    radial-gradient(circle at 50% 40%, rgba(79,125,245,0.55), rgba(79,125,245,0) 65%),
    radial-gradient(circle at 50% 60%, rgba(34,211,167,0.30), rgba(34,211,167,0) 65%),
    var(--bg-elevated-2);
  border: 1px solid var(--border-strong);
  box-shadow:
    inset 0 0 30px rgba(79,125,245,0.25),
    0 0 60px rgba(79,125,245,0.20),
    var(--shadow-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 3;
}

/* rotating ring */
.interact-core::before,
.interact-core::after {
  content: "";
  position: absolute;
  inset: -22px;
  border-radius: 50%;
  border: 1px dashed rgba(140,160,220,0.25);
  animation: spin 28s linear infinite;
}
.interact-core::after {
  inset: -50px;
  border: 1px dashed rgba(34,211,167,0.18);
  animation: spin 50s linear infinite reverse;
}
@keyframes spin { to { transform: rotate(360deg); } }

.core-label {
  position: relative;
  z-index: 2;
  text-align: center;
  font-family: var(--font-mono);
}
.core-label .core-name {
  display: block;
  font-size: 14px;
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: 0.02em;
}
.core-label .core-tag {
  display: block;
  margin-top: 6px;
  font-size: 10px;
  letter-spacing: 0.25em;
  text-transform: uppercase;
  color: var(--accent-2);
}

/* ===== INTERACTION BLOCK ===== */
.interact-block {
  position: relative;
  background: linear-gradient(180deg, var(--bg-elevated) 0%, var(--bg-surface) 100%);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px 28px 26px;
  box-shadow: var(--shadow-lg);
  transition: transform 0.4s ease, border-color 0.4s ease, box-shadow 0.4s ease;
  overflow: hidden;
  min-height: 200px;
}

.interact-block:hover {
  transform: translateY(-3px);
  border-color: var(--border-strong);
  box-shadow: var(--shadow-glow);
}

/* corner index */
.block-index {
  position: absolute;
  top: 18px;
  right: 22px;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-dim);
  letter-spacing: 0.18em;
}

/* icon plate */
.block-icon {
  width: 44px; height: 44px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, rgba(79,125,245,0.18), rgba(79,125,245,0.04));
  border: 1px solid rgba(79,125,245,0.28);
  color: var(--accent);
  margin-bottom: 18px;
  position: relative;
}
.block-icon svg { width: 20px; height: 20px; }

.interact-block.alt .block-icon {
  background: linear-gradient(135deg, rgba(34,211,167,0.18), rgba(34,211,167,0.04));
  border-color: rgba(34,211,167,0.30);
  color: var(--accent-2);
}

.block-title {
  font-size: 19px;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--text-primary);
  margin-bottom: 10px;
}

.interact-block p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.6;
  color: var(--text-secondary);
}

/* connection lines from each block to center (decorative) */
.interact-block::after {
  content: "";
  position: absolute;
  width: 110px; height: 1px;
  opacity: 0.35;
  top: 50%;
  pointer-events: none;
}
.interact-block.left::after  { right: -110px; background: linear-gradient(90deg, var(--accent), transparent); }
.interact-block.right::after { left: -110px;  background: linear-gradient(-90deg, var(--accent-2), transparent); }

/* corner endpoint dot */
.interact-block::before {
  content: "";
  position: absolute;
  width: 8px; height: 8px;
  border-radius: 50%;
  top: calc(50% - 4px);
  z-index: 2;
}
.interact-block.left::before  { right: -4px; background: var(--accent);  box-shadow: 0 0 10px var(--accent); }
.interact-block.right::before { left: -4px;  background: var(--accent-2); box-shadow: 0 0 10px var(--accent-2); }

/* ===== FOOTER STRIP ===== */
.interact-footer {
  margin-top: 80px;
  display: flex;
  justify-content: center;
  gap: 18px;
  flex-wrap: wrap;
}
.foot-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 14px;
  border: 1px solid var(--border-strong);
  border-radius: 999px;
  background: rgba(255,255,255,0.015);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--text-secondary);
}
.foot-chip .d {
  width: 6px; height: 6px; border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 8px var(--accent);
}
.foot-chip.alt .d { background: var(--accent-2); box-shadow: 0 0 8px var(--accent-2); }

/* ===== RESPONSIVE ===== */
@media (max-width: 960px) {
  .interact-flow {
    grid-template-columns: 1fr;
    gap: 22px;
    padding: 0;
  }
  .interact-core {
    position: relative;
    left: auto; top: auto;
    transform: none;
    margin: 10px auto 18px;
    width: 150px; height: 150px;
    grid-column: 1;
    order: 0;
  }
  .interact-block::before,
  .interact-block::after { display: none; }
}

@media (max-width: 600px) {
  .interaction-model { padding: 80px 18px; }
  .interact-block { padding: 22px 20px; }
}