To illustrate the question: I want to get the full list of values without pressing this “i” as in picture provided. There many
hidden CSS values to be experimented upon. 
Please help me configure Sublime if there is any hidden feature in it! I couldn’t understand all those complex codes in Settings. If this can’t be done, I request Sublime Text makers to get this feature in a update.
Thank you!
in a CSS context you can use whatever keyboard shortcut that is assigned to the Edit menu -> Show Completions (normally Ctrl+Space or Alt+/), and it will list all available values for the current property.
For HTML, the plugin (which comes with ST) that offers the completions needs to be modified if you want it to show all tags when typing < - currently you have to type at least one letter before it will suggest anything:
Thank you for the reply!
It really solved my CSS problem. Though I couldn’t understand the HTML part. Didn’t think anyone would solve it. But how did you solve it. Where did you find that Ctrl+Space works such an operation? (Alt+/ didn’t work) I really wanna know how do you people find such answers. Where do you get such knowledge?