/* css/layout.css
   ─────────────────────────────────────
   Page structure, grid, topbar, panels.
   ───────────────────────────────────── */

/* ── Body & Background ──────────────── */

/* orbs only — transitions and padding-right handled above */

/* Ambient background orbs */
body::before,
body::after {
  content: '';
  position: fixed;
  border-radius: 50%;
  filter: blur(100px);
  pointer-events: none;
  z-index: 0;
  transition: opacity var(--dur-slow);
}

body::before {
  width: 700px; height: 700px;
  top: -200px; left: -150px;
  background: radial-gradient(circle, rgba(0,240,255,.1) 0%, transparent 70%);
  animation: orb-a 20s ease-in-out infinite alternate;
}

body::after {
  width: 500px; height: 500px;
  bottom: -100px; right: -100px;
  background: radial-gradient(circle, rgba(167,139,250,.1) 0%, transparent 70%);
  animation: orb-b 25s ease-in-out infinite alternate;
}

[data-theme="light"] body::before { opacity: .4; }
[data-theme="light"] body::after  { opacity: .3; }

/* ── Top Bar ─────────────────────────── */

.topbar {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
  padding: 0 var(--sp-6);
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border-bottom: 1px solid var(--glass-border);
  transition: background var(--dur-slow) var(--ease-out);
}

.topbar__brand {
  display: flex;
  align-items: baseline;
  gap: var(--sp-3);
}

.brand-name {
  font-family: var(--font-display);
  font-size: 1.65rem;
  letter-spacing: .16em;
  line-height: 1;
  color: var(--text-1);
}

.brand-accent { color: var(--accent); }

.brand-tagline {
  font-family: var(--font-mono);
  font-size: .5rem;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--text-3);
}

.topbar__actions {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
}

/* ── Main Shell ──────────────────────── */

:root { --network-panel-w: 300px; }

.app-shell {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1fr;
  grid-template-areas:
    "hero"
    "canvas"
    "result"
    "train";
  gap: var(--sp-6);
  max-width: 580px;
  /* Centre in the available space — body padding handles the panel offset */
  margin: 0 auto;
  padding: var(--sp-8) var(--sp-6) var(--sp-12);
}

/* When panel is open: add right padding to body so the
   auto-margin still centres content in the REMAINING space */
body.network-open {
  padding-right: var(--network-panel-w);
  transition: padding-right var(--dur-slow) var(--ease-spring);
}

body {
  transition:
    background     var(--dur-slow) var(--ease-out),
    color          var(--dur-slow) var(--ease-out),
    padding-right  var(--dur-slow) var(--ease-spring);
}

/* Grid areas */
.hero-section  { grid-area: hero;   }
.canvas-section{ grid-area: canvas; display: flex; flex-direction: column; align-items: center; gap: var(--sp-4); }
.result-section{ grid-area: result; }
.train-panel   { grid-area: train;  }

/* ── Network Side Panel ──────────────── */

.network-panel {
  position: fixed;
  top: 56px;
  right: 0;
  bottom: 0;
  width: var(--network-panel-w);
  z-index: 50;

  display: flex;
  flex-direction: column;
  padding: var(--sp-5);
  gap: var(--sp-4);

  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border-left: 1px solid var(--glass-border);

  /* Hidden by default — slides in */
  transform: translateX(100%);
  transition: transform var(--dur-slow) var(--ease-spring);
}

.network-panel.is-open {
  transform: translateX(0);
}

.network-panel__header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  padding-bottom: var(--sp-3);
  border-bottom: 1px solid var(--glass-border);
}

.network-panel__title {
  font-weight: 700;
  font-size: .88rem;
  color: var(--text-1);
}

.network-panel__sub {
  font-family: var(--font-mono);
  font-size: .52rem;
  color: var(--text-3);
  letter-spacing: .1em;
}

#netCanvas {
  flex: 1;
  width: 100%;
  min-height: 0;
  border-radius: var(--radius-sm);
}

.network-panel__legend {
  display: flex;
  flex-direction: column;
  gap: var(--sp-2);
}

/* ── Responsive ──────────────────────── */
@media (max-width: 760px) {
  :root { --network-panel-w: 260px; }
  .app-shell { padding: var(--sp-5) var(--sp-4) var(--sp-10); }
  /* On mobile, panel overlays rather than shifting content */
  body.network-open .app-shell { transform: none; }
}