すみません…

以下は見出しリセット&h2~h4コードです。

.entry-content h3 {
    font-size: unset;
    position: unset;
    padding: unset;
    margin: unset;
    text-align: unset;
    box-shadow: unset;
    overflow: unset;
}
.entry-content h3:before {
    content: none;
    position: unset;
    bottom: unset;
    transform: unset;
    height: unset;
    width: unset;
    left: unset;
    top: unset;
}
.entry-content h4 {
    font-size: unset;
    position: unset;
    margin: unset;
    padding: unset;
    border-bottom: unset;
}
.entry-content h4:before {
    content: none;
    position: unset;
    bottom: unset;
    left: unset;
    z-index: unset;
    width: unset;
    height: unset;
}
.entry-content h5 {
position: unset;
padding: unset;
margin: unset;
font-size: unset;
}
.entry-content h5::after, .entry-content h5::before {
    content: none;
    position: unset;
    border-radius: unset;
    top: unset;
    left: unset;
    width: unset;
    height: unset;
    opacity: unset;
}
.entry-content h5::after {
    top: unset;
    left: unset;
    width: unset;
    height: unset;
    opacity: unset;
}


.entry-content h2 {
    font-size: 24px;
    position: relative;
    padding: 14px 12px;
    margin: 3.2em 0 1.8em 0;
    text-align: center;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
    overflow: hidden;
}
.entry-content h2:before {
  content: '';
  position: absolute;
  bottom: 0;
  transform: rotate(90deg);
  height: 8px;
  width: 108px;
  left: -50px;
  top: calc(50% - 4px);
}
.entry-content h3 {
font-size: 21px;
position: relative;
margin: 3rem 0 2rem;
padding: 0 0 0 8px;
border-bottom: 4px solid #ccc;
}
.entry-content h3:before {
    content: "";
    position: absolute;
    bottom: -4px;
    left: 0;
    z-index: 2;
    content: '';
    width: 20%;
    height: 4px;
}
.entry-content h4 {
position: relative;
padding: 0 .5em .1rem 2em;
margin:3em 0 .8em;
font-size: 18px;
}
.entry-content h4::after, .entry-content h4::before {
    content: "";
    position: absolute;
    border-radius: 100%;
    top: -.1em;
    left: -.1em;
    width: 24px;
    height: 24px;
    opacity: .6;
}
.entry-content h4::after {
    top: .7em;
    left: .7em;
    width: 16px;
    height: 16px;
    opacity: .2;
}