Case C-26/13: Judgment of the Court (Fourth Chamber) of 30 April 2014 (request for a preliminary ruling from the Kúria — Hungary) — Árpád Kásler, Hajnalka Káslerné Rábai v OTP Jelzálogbank Zrt (Directive 93/13/EEC — Unfair terms in a contract concluded between a seller or supplier and a consumer — Articles 4(2) and 6(1) — Assessment of the unfairness of the contractual terms — Exclusion of terms relating to the main subjectmatter of the contract or the adequacy of the price and the remuneration provided they are drafted in plain intelligible language — Consumer credit contracts denominated in foreign currency — Terms relating to the exchange rate — Difference between the buying rate of exchange applicable to the advance of the loan and the selling rate of exchange applicable to its repayment — Powers of the national court when dealing with a term considered to be unfair — Substitution of the unfair term by a supplementary provision of national law — Whether lawful)