Steady in her sneakers and grasping the helpful hand of a colleague, Rep. Gabrielle Giffords walked onto the House floor as colleagues approved her border security bill on the day she retired from elected office.

WASHINGTON — Steady in her sneakers and grasping the helpful hand of a colleague, Rep. Gabrielle Giffords walked onto the House floor as colleagues approved her border security bill on the day she retired from elected office.

Giffords made her way down the center aisle that divides Democrats from Republicans, a distinction the Arizona congresswoman had tried to blur with her moderate politics and good nature. Colleagues quickly enveloped her slight frame, offering an outstretched hand — or, more often, a kiss on the cheek. In ovation, lawmakers stood.

Friends have said the three-term Democrat has never been one to tackle goals halfway. It was fitting, then, that she closed out her career Wednesday with a legislative victory. The House unanimously passed the border security bill she had authored.

House Minority Leader Nancy Pelosi called Giffords "the brightest star that Congress has ever seen. She has brought the word dignity to new heights by her courage. Congresswoman Giffords' message of bipartisanship and civility is one that all in Washington and in the nation should honor and emulate."

The congresswoman was shot in the head a year ago after a gunman opened fire at a public event Giffords hosted for constituents outside a Tucson grocery store. Six people died and 12 others were wounded in a rampage that unsettled lawmakers and brought pleas for civility during an era of heated partisan politics.

Her last day in Congress was bittersweet, as emotional colleagues said farewell to the well-liked 41-year-old, who announced on Sunday that she would step down to focus on her recovery.

Rep. Eric Cantor, R-Va., the majority leader, said that "while Gabby may be leaving Washington today, I know this won't be the last we see of her."

Giffords' mother, Gloria, watched from the House gallery along with the congresswoman's husband, retired astronaut Mark Kelly. Her father watched from Tucson. The chamber was mostly full, and staff members ringed the back rows.

At one point, Rep. Steny Hoyer, D-Md., who called Giffords "an extraordinary daughter of this House," said to her, "We have missed you."

Giffords, who had turned backward in the chair to see her colleague, replied: "And I miss you."

The legislation approved Wednesday would impose tougher penalties on those who use ultralight aircraft to smuggle narcotics. Officials believe the planes are carrying drugs into the U.S. across the southern border with Mexico with increased frequency. The bill, introduced this week with Rep. Jeff Flake, R-Ariz., closes a loophole that imposed lesser penalties on smugglers who use ultralights than autos or planes.

It passed unanimously 408-0, with Giffords casting her final vote.