/* ============================================================
   layout-app.css — App Shell Layout (Shared)
   ─────────────────────────────────────────
   PURPOSE : Global page structure shared between both simulators:
             body reset, .app wrapper, .brand header, .tab-bar.
   SCOPE   : Used by index.html AND visual_pathway.html.
   NOTE    : Do NOT add simulator-specific rules here.
   ============================================================ */

/* ── Reset & Box Model ── */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  overflow-x: hidden;
}

/* ── App Wrapper ── */
.app {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: var(--bg);
}

/* ── Brand Header ── */
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 24px 12px;
  border-bottom: 1px solid var(--border-soft);
  flex-shrink: 0;
  background: var(--surface);
}

.brand-mark {
  width: 36px;
  height: 36px;
  flex-shrink: 0;
}

.brand-text h1 {
  font-family: 'Source Serif 4', Georgia, serif;
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text);
  line-height: 1.2;
  letter-spacing: -0.01em;
}

.brand-text p {
  font-size: 0.75rem;
  color: var(--text-soft);
  margin: 1px 0 0;
}

/* ── Tab Bar ── */
.tab-bar {
  display: flex;
  gap: 4px;
  padding: 8px 24px 0;
  border-bottom: 1px solid var(--border-soft);
  flex-shrink: 0;
  background: var(--surface);
}

.tab-btn {
  font-family: 'Inter', sans-serif;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-soft);
  background: transparent;
  border: none;
  border-bottom: 2px solid transparent;
  padding: 6px 14px 8px;
  cursor: pointer;
  border-radius: 6px 6px 0 0;
  transition: color 0.18s ease, border-color 0.18s ease;
  text-decoration: none;
}

.tab-btn:hover { color: var(--accent); }

.tab-btn.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}