.portal-surface { position: fixed; inset: 0; width: 100%; height: 100%; border: 0; z-index: 1000; background: #edf4f7; }
.portal-surface[hidden], .portal-navigation-notice[hidden] { display: none; }
body.portal-child-active { overflow: hidden; }
body.portal-child-active > :not(.portal-surface):not(.portal-navigation-notice) { visibility: hidden; }
.portal-navigation-notice { position: fixed; right: 16px; bottom: 16px; max-width: calc(100vw - 32px); padding: 12px 18px; background: #fff; color: #223947; border: 1px solid #cedce3; border-radius: 10px; box-shadow: 0 4px 18px #20304018; z-index: 2000; }