Twitter is making changes to its new redesign after users complained of headaches and discomfort.
Unveiled only last week, the redesign mainly involved high-contrast colours and a custom-designed font, Chirp.
At the time, the social network said it "might feel weird at first" but would improve content consumption and clean up "visual clutter".
But many, especially with accessibility needs, found it confusing, hard to read and uncomfortably bright.
"It's smaller and denser now, which means I need to strain my eyes more to read," one user wrote.
Another said: "It is just impossible to read if one has a visual and/or processing impairment."
A few days later, a tweet from the technology giant's accessibility account said: "We're making contrast changes on all buttons to make them easier on the eyes because you told us the new look is uncomfortable for people with sensory sensitivities."
And the next day, it said: "We've identified issues with the Chirp font for Windows users and are actively working on a fix."
Many users had also complained about the new font on mobile phones, however.
And, replying to a concerned user asking to be able to choose their own font, Twitter promised future changes and it was "going through everyone's feedback on the font".
Announcing the new font, in January, Twitter head of branding Derrit DeRouen said it had been designed, by Swiss type foundry Grilli, "to improve how we convey emotion and imperfection" - and the widely used standard typeface Helvetica was "not up for the job".
But now, that thread is filled with replies urging Twitter to use Helvetica - or whatever the user's default system font is.
Social-media companies often face a backlash to changes, however.
Twitter users initially railed against a 2014 redesign - and then complained about its 2017 replacement.
Snapchat faced a similar backlash in 2018.
And Facebook users have reacted badly to changes over the years - to both its design and the algorithms that power its news feed and dictate what users see.