Extract the "preserved" content from inside the legacy <header> — everything that is NOT site-header-nav, NOT site-language-switcher, NOT the legacy theme-toggle button, and NOT the hero-banner div. This keeps page-specific hero blocks (hero-header-text, election-countdown, hero-stats, politician-dashboard's logo+ul secondary nav) intact and re-inserts them between the modern chrome and the page's <main>.
Extract the "preserved" content from inside the legacy
<header>— everything that is NOT site-header-nav, NOT site-language-switcher, NOT the legacy theme-toggle button, and NOT the hero-banner div. This keeps page-specific hero blocks (hero-header-text, election-countdown, hero-stats, politician-dashboard's logo+ul secondary nav) intact and re-inserts them between the modern chrome and the page's<main>.