/* App shell: 3-pane CSS grid (sidebar | chat | preview).
 * Preview pane is hidden by default and animates in on first preview_update. */

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg-base);
  color: var(--fg-primary);
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow: hidden;
  height: 100vh;
}

#app {
  display: grid;
  grid-template-columns: 60px 1fr 0;
  grid-template-rows: 100vh;
  background: var(--bg-base);
  overflow: hidden;
  transition: grid-template-columns var(--duration-slow) var(--easing);
}

#app.preview-open {
  grid-template-columns: 60px 1fr minmax(420px, 45vw);
}

#sidebar {
  grid-column: 1;
  background: var(--bg-elevated);
  border-right: 1px solid var(--border-soft);
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 18px 0 16px;
}

#chat-panel {
  grid-column: 2;
  display: flex;
  flex-direction: column;
  background: var(--bg-base);
  overflow: hidden;
}

#preview-panel {
  grid-column: 3;
  background: var(--bg-preview);
  display: flex;
  flex-direction: column;
  border-left: 1px solid var(--border-soft);
  overflow: hidden;
}

#preview-panel.collapsed { display: none; }

/* ── Session overlay (slides over the chat) ──────────────────── */
#session-overlay {
  position: fixed;
  top: 0; left: 60px;
  width: 280px;
  height: 100vh;
  background: var(--bg-elevated);
  border-right: 1px solid var(--border-soft);
  z-index: 30;
  padding: 16px;
  overflow-y: auto;
  transform: translateX(0);
  transition: transform var(--duration) var(--easing);
}
#session-overlay.hidden {
  transform: translateX(calc(-100% - 60px));
  pointer-events: none;
}

/* ── Artifacts overlay — same layout as session overlay ─────── */
#artifacts-overlay {
  position: fixed;
  top: 0; left: 60px;
  width: 320px;
  height: 100vh;
  background: var(--bg-elevated);
  border-right: 1px solid var(--border-soft);
  z-index: 30;
  padding: 16px;
  overflow-y: auto;
  transform: translateX(0);
  transition: transform var(--duration) var(--easing);
}
#artifacts-overlay.hidden {
  transform: translateX(calc(-100% - 60px));
  pointer-events: none;
}

/* ── Responsive ─────────────────────────────────────────────── */

@media (max-width: 1023px) {
  #app, #app.preview-open { grid-template-columns: 60px 1fr 0; }
  #preview-panel {
    position: fixed;
    inset: 0;
    z-index: 50;
    transform: translateY(100%);
    transition: transform var(--duration-slow) var(--easing);
  }
  #app.preview-open #preview-panel {
    transform: translateY(0);
  }
}

@media (max-width: 767px) {
  #app, #app.preview-open { grid-template-columns: 1fr; }
  #sidebar {
    position: fixed; inset: 0 auto 0 0;
    width: 60px;
    transform: translateX(-100%);
    transition: transform var(--duration) var(--easing);
    z-index: 40;
  }
  #app.sidebar-open #sidebar { transform: translateX(0); }
}