Morgan Long left clear wishes about the dress code for her funeral.

Guests should wear bright and happy colors, please.

Converse tennis shoes are preferred.

And whatever you do: No black.

Long, who died Friday at the age of 19, was born and raised in Duluth. She struggled with brain cancer for most of her life, but was known among peers across three high schools in town for optimism despite a grim prognosis.

Her motto was “believe,” and friends say it inspired others while helping Morgan Long live more than 10 years longer than doctors expected.

“Despite her circumstances, she never complained and was always so positive,” said Anissa Jones, 18, of Duluth. “There was something about her that everybody loved.”

At 17 months of age, Morgan Long was diagnosed with ependymoma, a rare disease in which malignant cells form in the tissues of the brain and spinal cord. After the diagnosis came, Morgan lived for months near the Mayo Clinic in Rochester for surgical and radiation treatments, recalled her mother, Molly Long.

Early on, doctors said she’d be lucky to live to age 5. The condition often sparks recurring brain tumors, but Morgan Long lived without another for eight years.

Life wasn’t perfect, to be sure. She suffered from migraine headaches and painful pressure in her head, plus nausea and vision troubles. Yet at age 10, Morgan Long and her family celebrated a remarkable run of relatively good health with a special meal in Minneapolis and a Twins game.

The next day, doctors said the brain cancer was back.

“From 10 years of age to 19 years of age, it just never stopped,” Molly Long said.

Through a series of surgeries, treatments and rehabilitation, Morgan Long would feel terrible for long periods, her mom said. Yet, whenever she could, she defiantly pushed forward with a life filled with friends, four-wheeling and fishing.

Morgan Long missed her junior year of high school, and relied on a tutor to keep pace with studies. Even with the pain and disruptions, she realized her goals of graduating from high school and attending college. She won two scholarships that helped her enroll last year at Fond du Lac Community College in Cloquet.

Early on, Morgan Long picked up the word “believe” as her motto, and it resonated with people around her.

“She just believed that she was going to keep fighting,” her mother said. “God was going to help keep her alive — she was going to get through all of her surgeries and everything.”

In winter 2014, when the hockey teams from Denfeld, East and Marshall high schools in Duluth met for a tournament, kids from all three schools saluted Morgan. The Denfeld students all wore white T-shirts decorated with Morgan’s “keep believing” motto — a fact that then-Mayor Don Ness noted at the time in his proclamation of Morgan Long Day.

This year, the “believe” motto had to change, after doctors said there were no more treatments that might help. She switched to “hakuna matata,” a Swahili phrase used in Disney’s “The Lion King” — an expression that translates roughly as “no worries” — that she hoped would comfort others.

“She wanted everyone to remember her as the spunky, sassy girl that she was,” Anissa Jones said.

“I definitely think it was hard for her. But she accepted it, and she did it in a way that I don’t think anyone else could have.”

Morgan Long is survived by parents Steve and Molly Long, brother Steve Jr., and grandparents, aunts, uncles and cousins. Visitation is noon until the 2 p.m. mass on Wednesday at St. Lawrence Church, 2404 Morris Thomas Road, Duluth.