Text won't align right when output to xhtml

If I create a paragraph or table cell with content aligned right it is not reflected correctly in the html output.

To illustrate, here’s a simple document with one paragraph that is aligned right in writer, but in html is given left alignment.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1 plus MathML 2.0//EN" "http://www.w3.org/Math/DTD/mathml2/xhtml-math11-f.dtd"><html xmlns="http://www.w3.org/1999/xhtml" lang="en-US"><!--This file was converted to xhtml by LibreOffice - see https://cgit.freedesktop.org/libreoffice/core/tree/filter/source/xslt for the code.--><head profile="http://dublincore.org/documents/dcmi-terms/"><meta http-equiv="Content-Type" content="application/xhtml+xml; charset=utf-8"/><title xml:lang="en-US">- no title specified</title><meta name="DCTERMS.title" content="" xml:lang="en-US"/><meta name="DCTERMS.language" content="en-US" scheme="DCTERMS.RFC4646"/><meta name="DCTERMS.source" content="http://xml.openoffice.org/odf2xhtml"/><meta name="DCTERMS.issued" content="2022-08-12T15:55:52.672138273" scheme="DCTERMS.W3CDTF"/><meta name="DCTERMS.modified" content="2022-08-12T15:56:18.602828935" scheme="DCTERMS.W3CDTF"/><meta name="xsl:vendor" content="libxslt"/><link rel="schema.DC" href="http://purl.org/dc/elements/1.1/" hreflang="en"/><link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" hreflang="en"/><link rel="schema.DCTYPE" href="http://purl.org/dc/dcmitype/" hreflang="en"/><link rel="schema.DCAM" href="http://purl.org/dc/dcam/" hreflang="en"/><style>
    table { border-collapse:collapse; border-spacing:0; empty-cells:show }
    td, th { vertical-align:top; font-size:12pt;}
    h1, h2, h3, h4, h5, h6 { clear:both;}
    ol, ul { margin:0; padding:0;}
    li { list-style: none; margin:0; padding:0;}
    span.footnodeNumber { padding-right:1em; }
    span.annotation_style_by_filter { font-size:95%; font-family:Arial; background-color:#fff000;  margin:0; border:0; padding:0;  }
    span.heading_numbering { margin-right: 0.8rem; }* { margin:0;}
    .P1 { font-size:12pt; font-family:'Liberation Serif'; writing-mode:horizontal-tb; direction:ltr;text-align:left ! important; }
    /* ODF styles with no properties representable as CSS:
     { } */
</style></head>

<body dir="ltr" style="max-width:21.001cm;margin-top:2cm; margin-bottom:2cm; margin-left:2cm; margin-right:2cm; ">

<p class="P1">This is aligned right</p>

</body></html>

As you can see, its given class P1, which has text-align:left and is even marked !important.

Without the original Writer file, we can’t tell anything except some paragraph style with internal name P1 was created and used. For better help, edit your question to attach the original file and mention OS name and LO version.