Some countries have a special dress code. And it is a result of their culture.
If you look at the people from different countries then you can understand the style of their cloth. It is something clear that each country has its own culture and some rules about dress code. But if you take a look at Iran, it is a bit different here. For example, most of the women prefer to wear cloth, which is short, tight, or loose and are of different colours. The men usually wear pants or jeans, a T-shirt, long sleeves shirt and more. Believe me, Hijab in Iran is not a matter of concern as much as you think and you watch. Based on Islamic religion, some would say a girl supposed to be above the age of 9 has to obey the dress code. They should cover all part of their bodies from head to toes except face and hands in public. The clothes they choose should not be papery or skin tight. If the clothes cover up the body, they are appropriate. Wearing a different colour also doesn’t matter and it is completely up to an individual. There aren’t any limits about it. But to participate in the sad national holiday, it is better to put dark garments on. Also, you can have light makeup.
By the way, if you decide to travel to Iran then it might be the best trip of your life. As soon as your plane enters the Iranian air borders, it is needed to put your scarf and Manto on. Watching the flight attendants' dress will help you get an idea. You can get a simple Iranian dress in your own country. A traditional dress has a special design that it is not a thing that everybody can do.
If you travel to different cities in Iran, you can try wearing very beautiful dresses from that city. Don’t miss it if you are crazy about the dress code.