Democratic presidential nominee Hillary Clinton arrives to accept the nomination on the fourth and final night at the Democratic National Convention in Philadelphia, Pennsylvania, US, on July 28, 2016. [Photo/Agencies]

PHILADELPHIA - US presidential candidate Hillary Clinton said on Thursday Americans faced challenges at home and abroad that demand steady leadership and a collective spirit, and attacked Republican Donald Trump for sowing fear and divisiveness.

In the biggest speech of her more than 25-year-old career in the public eye, Clinton accepted the Democratic presidential nomination for the Nov 8 election with a promise to make the United States a country that worked for everyone.

"We are clear-eyed about what our country is up against. But we are not afraid," she said.

She presented a sharply more upbeat view of the country than the dark vision Trump offered at last week's Republican convention, and even turned one of Republican hero Ronald Reagan's signature phrases against the real estate developer.

"He's taken the Republican Party a long way, from 'Morning in America' to 'Midnight in America,'" Clinton said. "He wants to divide us - from the rest of the world, and from each other. He's betting that the perils of today's world will blind us to its unlimited promise."

The speech was Clinton's turn in the spotlight after three days of electrifying appearances by President Barack Obama, Vice President Joe Biden and first lady Michelle Obama, and Clinton acknowledged that some people still do not know her well.