input.css

form {
  text-align: center;
}
input[type="number"] {
  font-family: inherit;
}
.value-button {
  font-size: 1.3rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 2.5px solid black;
  margin: 0px;
  width: 40px;
  height: 20px;
  text-align: center;
  vertical-align: middle;
  padding: 11px 0;
  background: #eee;
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  -khtml-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

.value-button:hover {
  cursor: pointer;
}

form #decrease {
  margin-right: -4px;
  border-radius: 8px 0 0 8px;
}

form #increase {
  margin-left: -4px;
  border-radius: 0 8px 8px 0;
}

form #input-wrap {
  margin: 0px;
  padding: 0px;
}

input#number {
  text-align: center;
  border: 2px solid black;
  box-shadow: 0px 2px 2px black;
  border-radius: 5px;
  margin: 0px;
  width: 40px;
  height: 40px;
}

input[type="number"]::-webkit-inner-spin-button,
input[type="number"]::-webkit-outer-spin-button {
  -webkit-appearance: none;
  margin: 0;
}