.app-header {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 24px;
  min-height: 76px;
  padding: 14px 32px;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  line-height: 1.5;
}
.back-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 0;
  color: var(--secondary);
  font-size: 14px;
  text-decoration: none;
  white-space: nowrap;
}
.back-link:hover { color: var(--mint); }
.app-identity { display: flex; align-items: center; gap: 12px; min-width: 0; }
.app-mark { color: var(--mint); font: 32px/1 Georgia, serif; }
.app-name { color: var(--text); font-size: 21px; font-weight: 600; letter-spacing: -.5px; }
.quiet-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  padding: 8px 0;
  border: 0;
  background: none;
  color: var(--secondary);
  font-size: 14px;
  white-space: nowrap;
}
.quiet-button:hover { color: var(--mint); }
.app-header a:focus-visible, .app-header button:focus-visible { outline: 2px solid var(--mint); outline-offset: 5px; border-radius: 3px; }
.explore-guide {
  width: calc(100% - 32px);
  max-width: 560px;
  max-height: calc(100% - 32px);
  overflow: auto;
  padding: 28px;
  border: 1px solid var(--border-strong);
  border-radius: 13px;
  background: var(--panel);
  color: var(--text);
  box-shadow: var(--dialog-shadow);
}
.explore-guide::backdrop { background: var(--dialog-backdrop); backdrop-filter: blur(5px); }
.guide-heading { display: flex; justify-content: space-between; align-items: center; gap: 16px; margin-bottom: 16px; }
.explore-guide h2 { margin: 0; font-size: 22px; font-weight: 600; line-height: 1.3; }
.explore-guide p, .explore-guide li { font-size: 15px; line-height: 1.7; color: var(--secondary); }
.explore-guide li { margin-bottom: 12px; }
.explore-guide ul { padding-left: 20px; }
.guide-close { flex: none; width: 32px; height: 32px; padding: 0; border: 0; border-radius: 4px; background: none; color: var(--muted); font-size: 24px; }
.guide-close:hover { background: var(--hover-bg); }
.primary-button { background: var(--mint); border: 0; color: var(--on-accent); border-radius: 6px; padding: 10px 20px; margin-top: 12px; font-weight: 600; }
@media (max-width: 620px) {
  .app-header { grid-template-columns: auto minmax(0, 1fr); gap: 2px 20px; padding: 10px 18px; }
  .app-name { font-size: 19px; }
  .app-identity { justify-self: end; gap: 8px; }
  .app-header .quiet-button { grid-column: 2; justify-self: end; }
  .explore-guide { padding: 22px; }
}