Workplace with casual environment usually follows “neither to be overdressed nor to be underdressed” thumb rule.
For example, IT is one of those industries where wearing less formal dress code or business casuals is considered as appropriate.
Similarly, in startup-like environments, casuals or business casuals are mostly preferred.
Leading recruiter watches the dress code selected by the candidate while they enter for the interview.
Shirts: Long-sleeved and button-down shirts in a light color with simple design generally look attractive.
The best colors to choose are white, light blue, light grey, light brown, light pink, mauve, etc.