getting only column borders using CSS

Question 1

You can achieve that by setting the border on the td and th cells, but making the border-top and border-bottom none for the td, but then setting surrounding border of the entire table as well.

The following css is an example:

table {
    border-collapse:collapse;
    border: 1px solid #000;
}

th {
    background-color: #ccc;
    border-left: 1px solid #000;
    border-bottom: 1px solid #000;
    padding: 5px;
}

td {
    border-left: 1px solid #000;
    padding: 5px;
}

Link to JS Fiddle

Question 2

table {
    border-top: 1px Solid Black;
    border-left: 1px Solid Black;
    border-bottom: 1px Solid Black;
    border-spacing: 0;
}
th, td {
    border-right: 1px Solid Black;
}
th {
    background-color: lightgrey;
    border-bottom: 1px Solid Black;
}

Question 3

You can use pseudo classes here:

As your table has th for table headers then you can try this:

table.topbotcol tr:first-of-type{
     border-bottom:1px solid #ccc;   // Will apply border to first row
}
table.topbotcol tr:first-of-type td{
     border:none;  // will not apply border to tds of first row, and continue after first row
}

You haven't provided detailed description, i think this might help you!

Pseudo-Classes

Docs

:first-of-type

Question 4

What you need to do is set a border and set the table border to collapse. This will merge the cell borders. Then remove the unwanted top and bottom borders.

table, th, td{
    border: 1px solid #000;
}    
table {
    border-collapse: collapse;
}
td {
    border-bottom: none;
    border-top: none;
}

Here's a JSFiddle with a fuller example as well as some more optimizations.

Link to JS Fiddle

Suggestions:

don't use valign or align on table cells, use CSS vertical-align and text-align instead
use paragraph tags instead of <div class="para">
use class names that are descriptive of the content, not its style. This helps with maintenance later when you decide that you do not want something to be font-style-bold anymore. It is easier to change <th> in the CSS than it is to change it in the CSS and THEN go back and change ALL font-style-bold to font-style-normal in your HTML.

Question 5

Try this

http://jsfiddle.net/aYCjA/

.tbl {
    border: 1px solid black;
    border-collapse: collapse;
    min-width: 300px;
    text-align: center;
}
.tbl th, .tbl td {
    padding: 2px 5px;
}
.tbl td {
    border-left: 1px solid black;
    border-right: 1px solid black;
}
.tbl th {
    border: 1px solid black;
}

The important thing here is border-collapse: collapse. This attribute prevents showing duplicate borders in sibling cells.