The information here should answer most of your questions about the seasons. If it doesn't, don't hesitate to send us your question, using the Ask Jack a question form. Depending on where you are on Earth, a few days before and after the solstices will be the same length as the actual solstice.
Day is slightly longer than night at the equinoxes.
This is because sunrise and sunset are based on when the top of the sun touches the horizon as it rises or sets. But, since the Earth's atmosphere bends light rays, we see the top of the sun when it's still below the horizon. Our sunrise and sunset page has links to the U.S. Naval Observatory site. Here you can find sunrise and sunset times for anywhere in the world. It also has links to detailed information explaining sunrise, sunset, the solstices and equinoxes.