nelle-observer/frontend/public/styles/css/nav-buttons.css

.custom-btn {
  width: 130px;
  height: 40px;
  color: --text;
  border-radius: 5px;
  padding: 10px 25px;
  font-weight: 500;
  background: transparent;
  cursor: pointer;
  transition: all 0.3s ease;
  position: relative;
  display: inline-block;
  box-shadow:
    inset 2px 2px 2px 0px rgba(255, 255, 255, 0.5),
    7px 7px 20px 0px rgba(0, 0, 0, 0.1),
    4px 4px 5px 0px rgba(0, 0, 0, 0.1);
  outline: none;
  font-size: large;
  -webkit-box-shadow: 0 0 10px var(--accent);
  -moz-box-shadow: 0 0 10px var(--accent);
  box-shadow: 0 0 10px var(--accent);
}

/* 8 */
.btn-1 {
  background-color: var(--background);
  background-image: linear-gradient(315deg, var(--text) 0%, var(--accent) 74%);
  line-height: 42px;
  padding: 0;
  border: none;
}

.btn-1 span {
  position: relative;
  display: block;
  width: 100%;
  height: 100%;
}

.btn-1:before,
.btn-1:after {
  position: absolute;
  content: "";
  right: 0;
  bottom: 0;
  background: var(--accent);
  /*box-shadow:  4px 4px 6px 0 rgba(255,255,255,.5),
                -4px -4px 6px 0 rgba(116, 125, 136, .2), 
      inset -4px -4px 6px 0 rgba(255,255,255,.5),
      inset 4px 4px 6px 0 rgba(116, 125, 136, .3);*/
  transition: all 0.3s ease;
}

.btn-1:before {
  height: 0%;
  width: 2px;
}

.btn-1:after {
  width: 0%;
  height: 2px;
}

.btn-1:hover:before {
  height: 100%;
}

.btn-1:hover:after {
  width: 100%;
}

.btn-1:hover {
  background: transparent;
}

.btn-1 span:hover {
  color: var(--accent);
}

.btn-1 span:before,
.btn-1 span:after {
  position: absolute;
  content: "";
  left: 0;
  top: 0;
  background: var(--accent);
  /*box-shadow:  4px 4px 6px 0 rgba(255,255,255,.5),
                -4px -4px 6px 0 rgba(116, 125, 136, .2), 
      inset -4px -4px 6px 0 rgba(255,255,255,.5),
      inset 4px 4px 6px 0 rgba(116, 125, 136, .3);*/
  transition: all 0.3s ease;
}

.btn-1 span:before {
  width: 2px;
  height: 0%;
}

.btn-1 span:after {
  height: 2px;
  width: 0%;
}

.btn-1 span:hover:before {
  height: 100%;
}

.btn-1 span:hover:after {
  width: 100%;
}