how to set margin top to only a div code example

Example 1: css margin top

.yourClass {
  margin-top: 25px;
}

Example 2: css my body have margin top

You probably have an element with margin-top as one of the first children of body.

Read up on collapsing margins.

Purely as a simple test, set padding: 1px on body. If the gap goes away, I'm right.

/* 
from stackoverflow.com ->
css & html5: why does my body have a spacing at the top

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