galaxy/Buttons/AqFox_nervous-crab-0.html

<button class="btn btn-1 hover-filled-slide-left">
    <span>hover me</span>
</button>
<style>
/* From Uiverse.io by AqFox - Tags: button */
.btn {
  position: relative;
  display: inline-block;
  width: auto;
  height: auto;
  background-color: transparent;
  border: none;
  cursor: pointer;
  margin: 0px 25px 15px;
  min-width: 150px;
}

.btn span {
  position: relative;
  display: inline-block;
  font-size: 14px;
  font-weight: bold;
  letter-spacing: 2px;
  text-transform: uppercase;
  top: 0;
  left: 0;
  width: 100%;
  padding: 15px 20px;
  transition: 0.3s;
}

.btn-1::before {
  background-color: #004dff;
  transition: 0.3s ease-out;
}

.btn-1 span {
  color: rgb(255,255,255);
  border: 1px solid #004dff;
  transition: 0.2s 0.1s;
}

.btn-1 span:hover {
  color: #004dff;
  transition: 0.2s 0.1s;
}

:active, :hover, :focus {
  outline: 0!important;
  outline-offset: 0;
}

::before,
::after {
  position: absolute;
  content: "";
}

.btn.hover-filled-slide-left::before {
  top: 0;
  bottom: 0;
  left: 0;
  height: 100%;
  width: 100%;
}

.btn.hover-filled-slide-left:hover::before {
  width: 0%;
}
</style>