You're helping me lay out a set of exterior deck stairs. Use...

Prompt

You're helping me lay out a set of exterior deck stairs. Use residential code limits (CRC/IRC): riser max 7-3/4", finished tread min 10", and no two risers in the flight may differ by more than 3/8". Total rise from landing pad to deck surface: 45 3/8". Treads are 10" — don't factor nosing into the run. Stringers are 2x12, and I want the fewest risers that keeps every riser legal. 1. Give me: number of risers, exact riser height to the 1/16", total run, and rough uncut stringer length. Fractions only in this section — zero decimals. 2. The pad ended up 5/8" higher than planned. What's my bottom riser now? Is the flight still legal? Give me my fixes ranked cheapest first, and the point at which re-pouring beats any recut. 3. What's the single layout mistake that ruins the most 2x12s, and the habit that prevents it? Rules: commit to one riser count. No "it depends." Under 350 words.