Where are the themes?

here -> system/application/views/themes

Copy the Sandbox Theme

The best method for creating a new theme is to make a duplicate of the sandbox folder inside system/application/views/themes and to rename the duplicate to your desired theme name. Folder names cannot contain spaces. Once you create a new folder in the themes folder, it becomes available as a selectable theme in the admin panel. Use your new theme to edit and experiment with.

Theme Contents

A theme folder should always contain these components:

_activity_feed.php //the main activity list of your theme 
_header.php //the header of your site 
_footer.php //the footer of your site 
_sidebar.php //the sidebar of your site 
home.php //the index page of your site
items.php //the item page of your site (search / tag results)
single.php //the single item view page
rss_feed.php //formatting for the rss feed
main.css //the css for your site

Sweetcron allows for a lot of customisation beyond this. You can put any files you want into your theme folder and include them like you would using regular php / html in your theme templates. For example, the sandbox theme also contains an images folder.

The Item Loop

View _activity_feed.php for an example of the item loop. For your site's index page and item pages, an $items object is provided to the theme templates. You can use this to loop through available items like so:

<!-- some html -->
<?php foreach ($items as $item): ?>
<?php echo $item->get_title()?>
<?php endforeach; ?>
<!-- some html -->

For the full API reference detailing what you can do with the $item objects and other variables that are available to theme files, please see the API page.

http://code.google.com/p/sweetcron/wiki/API

Creating different styles for different types of items

Is very easy. To understand this fully, you will need to read the API documentation: http://code.google.com/p/sweetcron/wiki/API

Here's one basic method you could try. Loop through your items like so:

<?php foreach ($items as $item): ?>
<div class="<?php echo $item->get_feed_class()?>">

<?php echo $item->get_title()?>

</div>
<?php endforeach; ?>

get_feed_class() will return the domain name of your item in a "css-safe" manner. For example, youtube.com would become youtube_com. Then it would simply be up to you to create styles associated with the websites you are pulling data from, e.g.

div.youtube_com {
   background: red;
}

div.flickr_com {
   background: blue;
}

and so on.

When you want to get more specific, you can start using conditional tags. For example:

<?php foreach ($items as $item): ?>
<div class="<?php echo $item->get_feed_class()?>">

<?php echo $item->get_title()?>

<?php if ($item->get_feed_domain() == 'youtube.com'): ?>
Hey! this is from youtube!
<?php echo $item->get_video()?>
<?php endif; ?>

<?php if ($item->get_feed_domain() == 'flickr.com'): ?>
Hey! this is from flickr!
<img src="<?php echo $item->image()?>" alt="" />
<?php endif; ?>

</div>
<?php endforeach; ?>

See the _activity_feed.php file in the sandbox and boxy but good themes for more examples. But...most importantly...read the API! http://code.google.com/p/sweetcron/wiki/API

The possibilities are endless once you learn how to control the API :)