Why aren't my base styles updating in the preview?
If you're removing styling from a base style, those styles still apply until you have saved the base style.
Acquia Cohesion renames to Site Studio from version 6.2. Tell me more.
Base styles are CSS styles for HTML elements.
No. Component content entities do not have view modes.
Style guides provide site builders with the tools to create theme-specific settings which affect the style and layout of a website.
Yes. You can use style guides to create theme-specific styles.
The 'Edited' tag shows that the value of the field has been edited.
To create style guides go to Acquia Cohesion > Style guides
The Youtube video embed is responsive so it should expand to the width of its parent. If you do need to set a width you can apply the Width CSS property through the Style Builder.