if you give a class 'row' to the first v-main that is wrapping all the elements and a class 'mx-auto' to the div that is wrapping the calculator it may work.
<v-main row>
<div class="col-8 mx-auto">
<h1 pb-1>Calculate stuff</h1>
<p disclaimer pb-10>Hi Lorem ipsum</p>
<v-layout class="layout row">
<v-flex xs8>
<v-form>
<v-layout row wrap>
<v-flex pr-3 xs12 sm6>
<div class="field" mb-3>
<label>Tokens staked</label>
<v-input type="number" />
</div>
<div class="field" mb-3>
<label>Tokens staked</label>
<input type="number" />
</div>
<div class="field" mb-3>
<label>Tokens staked</label>
<input type="number" />
</div>
</v-flex>
<v-flex pr-3 xs12 sm6>
<div class="field" mb-3>
<label>Tokens staked</label>
<input type="number" />
</div>
<div class="field" mb-3>
<label>Tokens staked</label>
<input type="number" />
</div>
<div class="field" mb-3>
<v-btn elevation="2" color="purple"></v-btn>
</div>
</v-flex>
</v-layout>
</v-form>
</v-flex>
<v-flex xs4>
<div class="pl-3">
<h3 subheading mb-3>Random text</h3>
<ul class="rewards mb-5">
<li>Field1</li>
<li>Field2</li>
<li>Field3</li>
</ul>
</div>
</v-flex>
</v-layout>
</div>
</v-main>
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…