<section class="box" data-content="offset-position: auto">
  <svg viewBox="0 0 236 200"><path d="M0,0 C40,240 200,240 240,0" fill="none" stroke="lightgrey"/></svg>
  <div class="offset-path">0</div>
</section>

<section class="box" data-content="offset-position: <position>">
  <svg viewBox="0 0 236 200"><path d="M0,0 C40,240 200,240 240,0" fill="none" stroke="lightgrey"/></svg>
  <div class="offset-path"></div>
</section>

@import url('https://fonts.googleapis.com/css?family=Gochi+Hand');

* {
  box-sizing: border-box;
}


body {
  margin: 0;
  padding: 0;
  background-color: #291642;
  font-family: 'Gochi Hand', sans-serif;
  color: #fff;
  font-size: 130%;
  letter-spacing: 0.1rem;
  display: flex;
  justify-content: center;
  align-items: center;
  width: 100vw;
  min-height: 100vh;
}

.box {
  width: 240px;
  height: 240px;
  border: 1px dashed #f36;
  margin: 2vh;
  position: relative;
  
  &::after {
    content: attr(data-content);
    position: absolute;
    left: 50%;
    top: calc(100% + 2vh);
    white-space: nowrap;
    transform: translate(-50%, 0);
  }
}

.offset-path {
  
  width: 5vh;
  height: 5vh;
  border: 1px solid hsla(343,100%,58%,.3);
  border-right: 5px solid hsl(343,100%,58%);
  background: hsla(343,100%,58%,.3);
  display: flex;
  justify-content: center;
  align-items: center;
  color: rgba(#fff, .5);
  position: absolute;
  
  top: 100px;
  left: 80px;
  
  
  offset-path: path('M0,0 C40,240 200,240 240,0');
  offset-position: auto;
  
  
  &::after {
    content: '';
    position: absolute;
    width: 4px;
    height: 4px;
    background: #fff;
    border-radius: 50%;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
  }
}

svg {
  position: absolute;
  opacity: .3;
}

.box:nth-child(2) {
  .offset-path {
    offset-position: 100px  200px;
  }
}