set termout off
alter session set nls_date_format='yyyy-mm-dd hh24:mi:ss';

set markup HTML ON HEAD " -
<style type='text/css'> - 
  body {font:10pt Arial,Helvetica,sans-serif; color:black; background:White;} -
  p {   font:10pt Arial,Helvetica,sans-serif; color:black; background:White;} -
        table,tr,td {font:10pt Arial,Helvetica,sans-serif; color:Black; background:#f7f7e7; -
        padding:0px 0px 0px 0px; margin:0px 0px 0px 0px; white-space:nowrap;} -
  th {  font:bold 10pt Arial,Helvetica,sans-serif; color:#336699; background:#cccc99; -
        padding:0px 0px 0px 0px;} -
  h1 {  font:16pt Arial,Helvetica,Geneva,sans-serif; color:#336699; background-color:White; -
        border-bottom:1px solid #cccc99; margin-top:0pt; margin-bottom:0pt; padding:0px 0px 0px 0px;} -
  h2 {  font:bold 10pt Arial,Helvetica,Geneva,sans-serif; color:#336699; background-color:White; -
        margin-top:4pt; margin-bottom:0pt;} a {font:9pt Arial,Helvetica,sans-serif; color:#663300; -
        background:#ffffff; margin-top:0pt; margin-bottom:0pt; vertical-align:top;} -
</style> -
<title>SQL*Plus HTML Report: Audit</title>" -
BODY "" -
TABLE "title='Audit' border='1' align='center' summary='Audit script output'" -
SPOOL ON ENTMAP ON PREFORMAT OFF

--можно выключить замену ENTMAP для отдельных колонок
--или выше для всего текста
col os     HEADING 'Os_Username' ENTMAP OFF
col action HEADING 'Action_name' ENTMAP OFF

spool rep.html

select * from (
	select timestamp
              ,username
              ,decode(os_username,'oracle12','<b>oracle12</b>',os_username) os
              ,userhost
              ,terminal
              ,decode(action_name,'LOGON','<b>LOGON</b>', action_name) action
	from dba_audit_session
	order by timestamp desc
)
where rownum <= 20;

spool off
set markup html off spool off
host start rep.html
set termout on