Corner Frame

.btn-corner-frame {
  position: relative;
  display: inline-block;
  padding: 14px 28px;
  border: none;
  background: transparent;
  color: #e2e8f0;
  font-family: inherit;
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.04em;
  cursor: pointer;
}
.btn-corner-frame::before,
.btn-corner-frame::after {
  content: "";
  position: absolute;
  width: 14px;
  height: 14px;
  transition: width 0.3s ease, height 0.3s ease;
}
.btn-corner-frame::before {
  top: 0;
  left: 0;
  border-top: 2px solid #38bdf8;
  border-left: 2px solid #38bdf8;
}
.btn-corner-frame::after {
  bottom: 0;
  right: 0;
  border-bottom: 2px solid #38bdf8;
  border-right: 2px solid #38bdf8;
}
.btn-corner-frame:hover::before,
.btn-corner-frame:hover::after {
  width: 100%;
  height: 100%;
}