h5, .h5{
  font-size: 1rem !important;
}
.post-title h5{
    font-size:0.9rem !important;
}
.btn {
  font-size:0.75rem !important;
}
#app > .mt-4 > .container-lg hr.my-3 {
   display: none;
}
#app > div > .container-lg {
    max-width: 100% !important;
}
#app > nav > .container-lg {
    max-width: 100% !important;
}
.post-listing{
    background-color: rgba(255,255,255,0.04);
    margin: 0.25rem 0 !important;
    padding: 0.25rem 1rem !important;
}
.post-listing picture img.rounded-circle{
    width:1.25rem;
    height:1.25rem;
}
.post-listing .d-none .row .col-sm-2 {
    max-width:150px;
}
.post-listing .d-none .row .col-sm-9 {
    display:flex;
    align-items:center;
}
#app > .mt-4 > .container-lg {
    margin:0;
    padding:0;
}
/* post index layout */
#app > .mt-4 > .container-lg > .row  {
    display: flex;
    flex-wrap:nowrap;
    margin: 0 !important;
}
#app > .mt-4 > .container-lg > .row > main {
    display: flex;
    flex-wrap:wrap;
    flex-basis:calc(100% - 450px);
    max-width:100%;
}
/* post layout */ 
#app > .mt-4 > .container-lg > .row > aside{
    display: flex;
    flex-basis:450px;
    font-size:0.7rem;
}
#app > .mt-4 > .container-lg > .row > .col-md-8 {
    width:calc(100% - 450px);
}
#app > .mt-4 > .container-lg > .row > .col-md-4 {
    width:450px;
}
.comment {
  margin-left: 1rem !important;
}
.comment .details > div > div > .md-div > p {
    font-size:0.9rem;
}

I’ll probably keep tweaking these, stay tuned.