Need help making my WeatherApp responsive

HTML-CSS
6

Since you only have essentially one main div and some stuff inside it. You only need a few lines of CSS to do this. I recommend looking at something like Flex-Box or Grid CSS tutorials I personally like Wes Bos or LevelUpTuts. Just google them.

But for the short answer; I simplified the body to:

body {
    background-color: #1B1D28;
    font-family: 'Roboto', sans-serif;
    color: white;
}

And then you only need two lines of css to fix your .main div.
Play with margin and text-align. that should get it done. You can leave your font-size as is.