Hello markroll,
You did not tell us whether you uploaded the font using section 1 “Add Fonts” or section 2 “Custom Fonts”, so I will answer for both.
First of all make sure you have our latest version of the plugin ??
Also note there is no need to use the custom elements section of the plugin in this case.
1st step is to upload the font:
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The font Open Sans is already in our system, which means you can simply click on it in section 1 “Add Fonts” and press “Use this font”. When you do that you will automatically have all of the font weights of open sans available to use instantly.
A second option is to manually upload the files of the Open Sans light weight.
You simply go to section 2 “Custom Fonts” add the light weight of Open Sans under the same name as the regular font, and on the “Font Weight” field you choose light.
2nd step is to assign the font to the correct elements you want:
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In section 3 “Known Elements Settings” you can choose the font you want to use on each element, in your case that would be “Open Sans”, and after choosing it there will open a select menu “Font Weight” right under, and there you choose “Light”.
After it you only need to save the changes and that is all ??
For your last question about tinyMCE:
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While bold and italic are integral part of HTML text formatting, “light” is not.
That is why on the text editor there is not straight forward way to “light” text.
This is not a plugin related issue but simply how the web world works.
You have 2 choices:
1. Target the elements you want to “light” in the plugin settings page, such as <p> for example, then assign it Open Sans Light.
or
2. If you need to “light” specific text in text editor, use CSS code to manipulate the specific text locally. If you don’t have any knowledge on CSS you should contact a webmaster or maybe try an online guide about “Css font weight”.
That said we have taken into consideration the fact that such a formatting feature might be useful to our users and we will work on adding it into next versions of the plugin so our users will have easier time formatting their text in non-standard ways.
If you need any further help, let us know, we are at your service!