Describing Atmosphere in a Park Scene

In the following passage, a young girl reflects on her experiences in a vibrant city park. She describes the various activities she observed and the joy they brought to the visitors.

As the sun set over the park, children laughed and played on the swings. Families gathered for picnics, their laughter mingling with the cheerful barks of dogs darting to and fro. A street performer captivated the audience, twirling and juggling with an air of grace that enchanted all who watched. It was a day that felt alive with energy and excitement, each moment bursting with color.

In this context, which word best describes the atmosphere conveyed in the description?