basta che lo metti in head! come faresti normalmente in un file html
codice:
<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<html>
<head>
<style type="text/css">
</style>
</head>
<body>
<table border="2">
<th align="center" colspan="5"><xsl:value-of select="//nome_scuola"/><xsl:value-of select="//indirizzo_scuola"/></th>
<tr>
<td><primo>classe</primo></td>
<td>sezione</td>
<td>sperimentazione</td>
<td>indirizzo</td>
<td>nr. studenti</td>
</tr>
<xsl:for-each select="scrutinio/classe">
<tr>
<td><xsl:value-of select="@classe"/></td>
<td><xsl:value-of select="@sezione"/></td>
<td><xsl:value-of select="@sperimentazione"/></td>
<xsl:choose>
<xsl:when test="@indirizzo = 'informatico'">
<td bgcolor ="green"><xsl:value-of select="@indirizzo"/>
</td>
</xsl:when>
<xsl:otherwise>
<td bgcolor ="yellow"><xsl:value-of select="@indirizzo"/>
</td>
</xsl:otherwise>
</xsl:choose>
<td><xsl:value-of select="count(studente)"/></td>
</tr>
</xsl:for-each>
</table>
<table border="2">
<tr>
<td>nome</td>
<td>cognome</td>
<td>data nascita</td>
<td>classe</td>
<td>italiano</td>
<td>matematica</td>
<td>caratterizzante</td>
<td>condotta</td>
<td>sezione</td>
<td>esito</td>
</tr>
<xsl:for-each select="scrutinio/classe">
<xsl:for-each select="studente">
<tr>
<td><xsl:value-of select="nome"/></td>
<td><xsl:value-of select="cognome"/></td>
<td><xsl:value-of select="datanascita"/></td>
<td><xsl:value-of select="../@classe"/></td>
<td><xsl:value-of select="@italiano"/></td>
<td><xsl:value-of select="@matematica"/></td>
<td><xsl:value-of select="@caratterizzante"/></td>
<td><xsl:value-of select="@condotta"/></td>
<td><xsl:value-of select="../@sezione"/></td>
<xsl:variable name="media"><xsl:value-of select="(@italiano+@matematica+@caratterizzante+@condotta) div 4"/></xsl:variable>
<xsl:value-of select="$media"/>
<xsl:choose>
<xsl:when test="$media >= '6'">
<td bgcolor ="green"><xsl:value-of select="$media"/>
</td>
</xsl:when>
<xsl:otherwise>
<td bgcolor ="red"><xsl:value-of select="$media"/>
</td>
</xsl:otherwise>
</xsl:choose>
</tr>
</xsl:for-each>
</xsl:for-each>
</table>
</body>
</html>
</xsl:template>
</xsl:stylesheet>