Hi Zdenka,
Here are your answers.
1. To make all links in the main content area underlined use the following CSS .
article.page a, article.post a {
text-decoration: underline;
}
2. Insert margin to each paragraph and list item in main content area. Here are the selector for it.
article.page p, article.post p {
article.page li, article.post li {
3. You mean table like this : http://demo.styledthemes.com/preferential/table-styles/ . We will add it new version.
4. Note down custom 404 page like others will be added too in next version.
