<h1 class="hero__title">
              <span>Дизайн и верстка</span><br>
              <span><span class="accent">сайтов</span> с нуля</span><br>
              <span>для вас</span>
            </h1>

.hero__title {
 margin-bottom: 1em;
 font-size: 3em;
 font-weight: 900;
 color: #fff;
 line-height: 0.9;
 > span {
  position: relative;
  display: inline-block;
  -webkit-box-decoration-break: clone;
  box-decoration-break: clone;
  &:before {
   content: "";
   position: absolute;
   display: block;
   left: -0.5em;
   bottom: -0.3em;
   width: calc(100% + 0.55em);
   height: 115%;
   background: linear-gradient(0deg, #000 0, #000 90%, rgba(255, 255, 255, 0) 90%);
   z-index: -1;
  }
 }
}

.accent {
  color: aqua;
}