Here's exactly what to fill in at Admin > Posts and Topics > Custom BBCodes:
Tag name
icode
Tag Description
Inline Code
Tag type
Parsed Content
Format
<code class="icode">{content}</code>
Block level
No
Trim whitespace
No trim
Assume URL
No
Leave the button fields blank unless you want a toolbar button.
Then add the CSS to your theme:
nano /var/www/html/Themes/default/css/index.css
code.icode {
font-family: monospace;
font-size: 0.9em;
background-color: #f0f0f0;
border: 1px solid #ccc;
border-radius: 3px;
padding: 1px 4px;
color: #c7254e;
white-space: nowrap;
}
Usage:
[icode]inline code[/icode]
gives:
inline code