CSS Rule for the 8th and on element in a div - css

Question

Is it possible to create a CSS rule that applies to the every element except for the first 8 elements? Ie, the 8th plus elements should have a margin top of 65px.
My below less code applies margins to every odd and even button within a menu. Now I want to add a specific margin to the 8th plus buttons. And then ideally apply a specific margin to the 16th plus buttons and so on.
.foo-menu {
.foo-menu-btn {
float: left;
margin: 1px;
}
// Apply specific margin to every second(even) button
.foo-menu-btn:nth-child(even) {
margin-left: -23px;
margin-top: 46px;
}
// Apply specific margin to every odd button
.foo-menu-btn:nth-child(odd) {
margin-left: -23px;
}
// For every button after the 8th one; apply a specific margin
.foo-menu-btn:nth-child( ??? ) {
margin-top: 65px;
}
}
<div class="foo-menu">
<div class="foo-menu-btn"></div>
<div class="foo-menu-btn"></div>
<div class="foo-menu-btn"></div>
<div class="foo-menu-btn"></div>
<div class="foo-menu-btn"></div>
<div class="foo-menu-btn"></div>
<div class="foo-menu-btn"></div>
<div class="foo-menu-btn"></div>
<!-- Now every foo-menu-btn should have a top margin of 65px -->
<div class="foo-menu-btn"></div>
<div class="foo-menu-btn"></div>
<div class="foo-menu-btn"></div>
<div class="foo-menu-btn"></div>
<div class="foo-menu-btn"></div>
<div class="foo-menu-btn"></div>
<div class="foo-menu-btn"></div>
<div class="foo-menu-btn"></div>
</div>

Answer 1

Try below code, i think help full to you.
hr {
display: block; float: left;
width: 50px; height: 50px;
border: solid 2px #aaa; margin: 10px;
}
hr:nth-child(n+9):not(:nth-last-child(-n)) {
background-color: #ddd;
}
<div id=t>
<hr>
<hr>
<hr>
<hr>
<hr>
<hr>
<hr>
<hr>
<hr>
<hr>
<hr>
<hr>
<hr>
<hr>
<hr>
<hr>
<hr>
</div>

Answer 2

You can use the native CSS :nth-child pseudo-class to specify a range. According to the case you specified it might look like this:
div.foo-menu div.foo-menu-btn:nth-child(n+8):nth-child(-n+15) {
margin-left: 50px
}
The downside is that you still have to manually define each range.

Answer 3

To select everything other than the first 8 divs you can use .foo-menu-btn:nth-child(n+9). See it applied to your HTML below (I took out the negative margins so that the divs would be visible for this example):
.foo-menu-btn {
float: left;
margin: 1px;
background-color: #ccc;
height: 1rem;
}
.foo-menu-btn:nth-child(even) {
margin-top: 46px;
}
.foo-menu-btn:nth-child(n+9) {
margin-top: 65px;
}
<div class="foo-menu">
<div class="foo-menu-btn">1</div>
<div class="foo-menu-btn">2</div>
<div class="foo-menu-btn">3</div>
<div class="foo-menu-btn">4</div>
<div class="foo-menu-btn">5</div>
<div class="foo-menu-btn">6</div>
<div class="foo-menu-btn">7</div>
<div class="foo-menu-btn">8</div>
<!-- Now every foo-menu-btn should have a top margin of 65px -->
<div class="foo-menu-btn">9</div>
<div class="foo-menu-btn">10</div>
<div class="foo-menu-btn">11</div>
<div class="foo-menu-btn">12</div>
<div class="foo-menu-btn">13</div>
<div class="foo-menu-btn">14</div>
<div class="foo-menu-btn">15</div>
<div class="foo-menu-btn">16</div>
</div>

Answer 4

Use :
.foo-menu .foo-menu-btn:nth-child(n+9){
color: blue;
}
.foo-menu .foo-menu-btn:nth-child(odd){
color: red;
}
.foo-menu .foo-menu-btn:nth-child(even){
color: green;
}
.foo-menu .foo-menu-btn:nth-child(n+9){
color: blue;
}
<div class="foo-menu">
<div class="foo-menu-btn">1</div>
<div class="foo-menu-btn">2</div>
<div class="foo-menu-btn">3</div>
<div class="foo-menu-btn">4</div>
<div class="foo-menu-btn">5</div>
<div class="foo-menu-btn">6</div>
<div class="foo-menu-btn">7</div>
<div class="foo-menu-btn">8</div>
<!-- Now every foo-menu-btn should have a top margin of 65px -->
<div class="foo-menu-btn">9</div>
<div class="foo-menu-btn">10</div>
<div class="foo-menu-btn">11</div>
<div class="foo-menu-btn">12</div>
<div class="foo-menu-btn">13</div>
<div class="foo-menu-btn">14</div>
<div class="foo-menu-btn">15</div>
<div class="foo-menu-btn">16</div>
</div>