I create epubs from usually ocr-ed sources, currently a dichotomous key for plant identification, which involves many lines similar to these:
Code:
10a Stipules about equal to leaflets; leaflets 6-12; flowers purple
<a href="#japonicus">L. japonicus</a>
10b Stipules less than 1/2 as long as leaflets; leaflets typically 6,
(4-8); flowers pinkish-purple or rarely white <a href="#palustris">L. palustris</a>
8b Not sea-beach or coastal marsh plants
11a Peduncles 1-2-flowered; leaflets 8-16,1-2 cm long; legumes
1.5-2.5 cm long <a href="#torreyi">L. torreyi</a>
11b Peduncles more than 2-flowered or leaflets or legumes longer
12a Stipules 1 cm wide or more; leaflets 10-16 <a href="#polyphyllus">L. polyphyllus</a>
12b Stipules less than 1 cm wide; leaflets 12 or less
13a Corollas white <a href="#vestitus">L. vestitus</a>
13b Corollas purple to lavender or pink <a href="#nevadensis">L. nevadensis</a></pre>
I cannot find any practical way to achieve multi-space indentation. Using <pre>...</pre> means that links within them are not encoded; using nothing loses all indentation completely; and alternating spaces with produced no progress after an hour's run time (otherwise calibre completes this in < 2 minutes.
What would be the best method of multiple space indenting?