I know the SF style for riding is wearing dark clothing, dark skinny jeans, and a hoodie but i prefer a dress or skirt. It’s so much more comfortable, you have plenty of room to move your hips, and you don’t need to worry about getting your pants stuck in the chains. if the skirt is fitted well with a good outfit, you also reduce your chance of showing bicycle crack, not a pretty sight. It’s always a good idea to wear leggings just in case of a fall or your skirt flows up. You can color coordinate them with your outfit too. Places I like to shop are at H&M or online at modcloth.com.