What first seemed like a luxury = The thing that first seemed like a luxury ，后面的 crawling from bed to computer, not worrying about hair and clothes and face 表示 a luxury 的具体情况。 that first seemed like a luxury 是定语从句，修饰 The thing。可以把 What first seemed like a luxury 看作主语从句，在该主语从句中， What 是主语，seemed 是系动词， like a luxury 是介词短语作表语。