Changing font-weight to normal in h2 - html

Question

I Want to change font-weight to normal of h2 element. I'm trying to do it by change it in parent directory.
h2 {
margin: 0;
padding: 0;
}
.top, .date {
display: inline-block;
width: 150px;
height: 30px;
border: 2px solid black;
text-align: center;
}
.date {
float: right;
font-size: 16px;
font-weight: normal;
}
<div id="instrument" class="top">
<h2>SP500</h2>
</div>
<div id="date" class="top date">
<h2>Data</h2>
</div>
<div class="date">
<h2>Czas Zamknięcia</h2>
</div>

Answer 1

I have no idea what you mean by parent directory, I guess you mean by selecting it with a parent tag/class/id, in that case, this is how you do it:
parent-tag h2 {
font-weight: normal;
}
or if you want to do it by parent class/id name like this
.className/#idName h2 {
font-weight: normal;
}

Answer 2

h2 {
margin: 0;
padding: 0;
}
.top, .date {
display: inline-block;
width: 150px;
height: 30px;
border: 2px solid black;
text-align: center;
}
.date {
font-size: 16px;
font-weight: normal;
}
.date>h2 {
font-size: 16px;
font-weight: normal !important;
}
<div id="instrument" class="top">
<h2>SP500</h2>
</div>
<div id="date" class="top date">
<h2>Data</h2>
</div>
<div class="date">
<h2>Czas Zamknięcia</h2>
</div>