Fire plays different roles throughout the story, but most often it represents Katniss. Her first dress is covered in synthetic flames, while later outfits use fire more subtly. Katniss’s fire dress earns her the epithet “the girl who was on fire,” and this title comes to mean more than just her dress. Cinna calls her “the girl who was on fire” again, this time using “fire” to refer to Katniss’s spirit and temperament. During the Games, the phrase takes on a literal meaning after Katniss is struck in the leg by a fireball and thinks the Gamemakers must be laughing at “the girl who was on fire.”
https://www.sparknotes.com/lit/the-hunger-games/motifs/
The novel is full of acts of Defiance against the Capitol, despite its control over the people of Panem. Katniss’s and Gale’s illegal hunting is an act of defiance, since they’re willfully violating the Capitol’s rules. The mockingjay, which appears throughout the novel, represents defiance because it recalls the Capitol’s failures. The most significant acts of defiance come from Katniss. Decorating Rue’s body after her death directly violates the spirit of the Hunger Games, which demand that tributes show no mercy for one another, and Katniss’s idea for her and Peeta to threaten suicide with the berries shows that they will not accept the Gamemakers’ rules.
https://www.sparknotes.com/lit/the-hunger-games/motifs/
Katniss is the sixteen-year-old protagonist of The Hunger Games, and the story is told from her perspective. She is practical and fiercely protective of her family, having learned to care for her mother and little sister after their father died in a mining accident when Katniss was eleven.
Katniss is tough, independent, resourceful, fiery, and skilled with a bow and arrow, and yet she also has a compassionate side and a deep loyalty to those she loves. This combination of traits turns out to be dangerous for the Capitol and President Snow, as it inspires others and serves as a catalyst that creates bonds among people.
https://www.litcharts.com/lit/the-hunger-games/characters/katniss-everdeen
The Hunger Games features several themes of dystopia, the most prominent being the bread and circuses, a concept originating in ancient Rome, describing government control via the providing of enough food and entertainment for the people to be content in passive obedience. The author seems to be warning young people not to rely on the government for handouts and Hollywood for entertainment—because otherwise, the population will become too corrupt and the Empire will fall.
There is also a separation of class, with sharp divisions between the Capitol versus the rest, and the subdivision of the rest into twelve districts of decreasing living standards and government favour. In District 12, there is a further separation between the merchants and the workers due to the perception of the other class by each. The residents of the Capitol are kept apathetic to the conditions of the rest of Panem by their extravagant lifestyles, their viewing of the games as entertainment, and ignorance of the outside world. The districts, (particularly Districts 1 & 2), are forced to provide specialised labour for the Capitol or risk brutal punishment, and, in watching their children murder and be murdered each year, are reminded that they are powerless.
The citizens of the Capitol don't think twice about wasting resources, while those of District 12 fear not having enough every day. Furthermore, by the separation and isolation of the different districts, the Capitol keeps them from communicating, organizing, and uniting.