LIbreOffice Witer in web mode is just the same as the usual Writer with its styles (but for page styles which do not make sense in HTML) when it comes to type your text. The only difference appears when the document is saved as HTML. The Writer styles are converted into CSS styles.
In Writer tables, you have no provision to constrain cells or rows to a fixed size with a scroll slider; Consequently, there will be no translation to the appropriate CSS attributes.
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