To change your style system options, go to https://www.insanejournal.com/customize/. Select either S1 or S2 from the drop-down box, and hit the "Change" button.
If you want to customize your journal using S2, you can do so at https://www.insanejournal.com/customize/ as well. Once you have selected a S2 layout to use, you will see the customization options offered by that layout.
You can switch your journal between S1 and S2, and each style system's settings will be saved. This means that you can choose the other style system, and if you decide that you don't like it, you can switch back and your previous customizations will be visible again.
Only Early Inmates, "Self-committed" [paid] and Permanently Insane account holders can create custom styles. If you are a Free Patient and would like to create your own style, you will first need to get a Self-committed account (https://www.insanejournal.com/support/faqbrowse.bml?faqid=8).
In order to edit a custom style, you will need to first create a style to work from, which can be done at the Create a Style page (https://www.insanejournal.com/styles/create.bml). You can either start from a blank style, or base your style off an existing system style template. Once you have done this, you can then edit your style (https://www.insanejournal.com/styles/edit.bml) to your liking.
The default name for a new style is <username>-<view type>-new.
Since the style creation page will not overwrite an existing style, you will need to change the name of your new style if you would like to create additional styles for that view. Until you change the name of the style from the default name, you will be unable to create new styles for that view.
You can change the name of your style on the Edit Style page (https://www.insanejournal.com/styles/edit.bml), under "Style Description". Under "Style Options", you can choose to make the style Public, which affects whether or not another InsaneJournal user can see the coding that makes up your style (and possibly use it).
You will need to save your style for any changes to take effect.
Once you have created a custom style, you will first need to select that style for your journal. Go to https://www.insanejournal.com/modify.bml and under whatever view you made it for, choose the style from the drop-down menu and Save Changes.
By using overrides, there are a number of things that Free Patients can change about their journal appearance. (Early Inmates, "Self-committed" [paid] or Permanently Insane account holders can use the style system, detailed in https://www.insanejournal.com/support/faqbrowse.bml?faqid=43 , as well as using overrides.)
The "HowTo" journal (https://www.insanejournal.com/userinfo.bml?user=howto) have a number of tutorials detailing common override requests. The memories of HowTo (https://www.insanejournal.com/tools/memories.bml?user=howto) are categorized based on which system style they are intended to override. Please make sure that you choose an override intended for the style you are currently using. If you change system styles in the future, you may need to change your overrides.
Please note that detailed customization support is outside the realm of InsaneJournal Support. If you require further assistance in using HTML or CSS to customize your journal, you can search for "HTML tutorial" in your favorite search engine.
Last Updated: February 10th, 2021 (squeaky)
» Why is my Modify Journal page missing some options?
You have selected the S2 style system, which is not completely controlled by the Modify Journal page (https://www.insanejournal.com/modify.bml). Some options, such as the ability to enter overrides, do not exist when using the S2 style system.