I grasped the concept of CSS almost immediately after reading about it 7 years ago, but I am still learning every day. I think it was a couple of days for me to get my first layout coded. and then a few weeks to have the basics memorized. Now when I'm coding a layout it's a combination of memory and quick referencing to the w3school's website.
fortunately it's a relatively easy syntax to learn. I still look most of the details up online though. learned it in about 3 months I guess.
I think it was about a month before I was using it comfortably. The biggest hurdle for me was dealing with the difference between inline styling and using an external style sheet. Frankly I find the external style sheet approach the least confusing and makes it clearer what you're doing in the beginning. Also Using Visual Studio is a great help with the learning curve. VS's "Intella Sense" feature is a big help when learning all the different elements that are available to you.
CSS (Cascading Style Sheets) are the most fundamental technologies of the web. They are the language of all web pages on the Internet and sometimes they are also used to write documents and help files in your local computer. Learning CSS is the first step to be a web developer. There are many online tutorial sites that may help you to learn CSS step by step systematically.
Not true. HTML is "the language of all web pages on the Internet". CSS is not needed to make a webpage. HTML is needed (every browser has it's own "iplemented" CSS). You will never know CSS up to 100% (I mean correct CSS). For me it is still an ongoing process.
Like with most things, "learning" CSS can take many years or one day, since you don't define "learn". If you want to be able to do some basic text formatting you can learn to do this in an hour or two with css. To be well educated in CSS and all its cababilities, exceptions and browser compability issues it would probably take several months of real study to achieve. I've used CSS for many years, and I'm still learning new things! But then I don't "study", per se.