Lenition: an stéig vs. an tseacláid
First I didn't understand why there is no lenition happening in "an stéig". But then I remembered the rule that if a word starts with d,t or s and the word before it ends with d,n,t,l or s, there is no lenition. Ok, great.
I looked up seacláid expecting to find the same.
But in the example sentences (e.g. "d'ith sí an tseacláid go han-chúramach" and several others) seacláid is lenited behind an and becomes "an tseacláid".