/* ─────────────────────────────────────────────────────────
   layout.css — Grid, flex, responsive page containers
   ───────────────────────────────────────────────────────── */

/* ---------- App Root ---------- */
#app {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  position: relative;
  overflow: hidden;
}

/* ---------- Scene Container ---------- */
.scene {
  display: none;
  flex-direction: column;
  min-height: 100vh;
  width: 100%;
  position: relative;
  animation: sceneIn var(--transition-slow) ease both;
}

.scene.active {
  display: flex;
}

@keyframes sceneIn {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ---------- Page Containers ---------- */
.container {
  width: 100%;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 var(--sp-6);
}

.container--narrow {
  max-width: 760px;
}

.container--wide {
  max-width: 1400px;
}

/* ---------- Flexbox Utilities ---------- */
.flex         { display: flex; }
.flex-col     { flex-direction: column; }
.flex-wrap    { flex-wrap: wrap; }
.items-center { align-items: center; }
.items-start  { align-items: flex-start; }
.justify-center  { justify-content: center; }
.justify-between { justify-content: space-between; }
.justify-end     { justify-content: flex-end; }
.gap-2  { gap: var(--sp-2); }
.gap-4  { gap: var(--sp-4); }
.gap-6  { gap: var(--sp-6); }
.gap-8  { gap: var(--sp-8); }
.flex-1 { flex: 1; }

/* ---------- Grid Utilities ---------- */
.grid          { display: grid; }
.grid-2        { grid-template-columns: repeat(2, 1fr); }
.grid-3        { grid-template-columns: repeat(3, 1fr); }
.grid-auto-fit { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }

/* ---------- Section / Panels ---------- */
.panel {
  background: var(--bg-card);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-xl);
  padding: var(--sp-6);
}

.panel--surface {
  background: var(--bg-surface);
}

.panel--glow {
  border-color: var(--clr-border-mid);
  box-shadow: var(--glow-primary);
}

/* ---------- Top Navigation Bar ---------- */
.top-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--sp-4) var(--sp-6);
  background: rgba(7, 9, 15, 0.8);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--clr-border);
  position: sticky;
  top: 0;
  z-index: var(--z-overlay);
}

.top-bar__logo {
  font-family: var(--font-title);
  font-size: 1.1rem;
  color: var(--clr-primary);
  display: flex;
  align-items: center;
  gap: var(--sp-2);
}

.top-bar__logo span { font-size: 1.3rem; }

.top-bar__actions {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
}

/* ---------- XP Badge in nav ---------- */
.xp-badge {
  display: flex;
  align-items: center;
  gap: var(--sp-1);
  background: rgba(245, 158, 11, 0.15);
  border: 1px solid rgba(245, 158, 11, 0.35);
  color: var(--clr-accent);
  border-radius: var(--radius-xl);
  padding: var(--sp-1) var(--sp-3);
  font-size: 0.85rem;
  font-weight: 600;
}

/* ---------- Chapter Layout (two-pane) ---------- */
.chapter-layout {
  display: grid;
  grid-template-columns: 1fr 400px;
  gap: var(--sp-6);
  padding: var(--sp-6);
  flex: 1;
  min-height: 0;
}

.chapter-main {
  display: flex;
  flex-direction: column;
  gap: var(--sp-5);
  min-height: 0;
}

.chapter-sidebar {
  display: flex;
  flex-direction: column;
  gap: var(--sp-5);
  min-height: 0;
}

/* ---------- Section headers ---------- */
.section-title {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--clr-text-muted);
  margin-bottom: var(--sp-3);
}

/* ---------- Dividers ---------- */
.divider {
  height: 1px;
  background: var(--clr-border);
  margin: var(--sp-6) 0;
}

/* ---------- Centering helper ---------- */
.center-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--sp-8) var(--sp-6);
  flex: 1;
}

/* ---------- Responsive breakpoints ---------- */
@media (max-width: 960px) {
  .chapter-layout {
    grid-template-columns: 1fr;
    padding: var(--sp-4);
  }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 640px) {
  .container { padding: 0 var(--sp-4); }
  .grid-2, .grid-3 { grid-template-columns: 1fr; }
  .top-bar { padding: var(--sp-3) var(--sp-4); }
  .chapter-layout { padding: var(--sp-3); gap: var(--sp-4); }
  h1 { font-size: 1.8rem; }
}