Styling a input type=number

UPDATE 17/03/2017

Original solution won't work anymore. The spinners are part of shadow dom. For now just to hide in chrome use:

input[type=number]::-webkit-inner-spin-button {
  -webkit-appearance: none;
}

<input type="number" />

or to always show:

input[type=number]::-webkit-inner-spin-button {
  opacity: 1;
}

<input type="number" />

You can try the following but keep in mind that works only for Chrome:

input[type=number]::-webkit-inner-spin-button { 
    -webkit-appearance: none;
    cursor:pointer;
    display:block;
    width:8px;
    color: #333;
    text-align:center;
    position:relative;
}

input[type=number]::-webkit-inner-spin-button:before,
input[type=number]::-webkit-inner-spin-button:after {
    content: "^";
    position:absolute;
    right: 0;
}

input[type=number]::-webkit-inner-spin-button:before {
    top:0px;
}

input[type=number]::-webkit-inner-spin-button:after {
    bottom:0px;
    -webkit-transform: rotate(180deg);
}

<input type="number" />

For Mozilla

input[type=number] { 
    -moz-appearance: textfield;
    appearance: textfield;
    margin: 0; 
}

For Chrome

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

I modified @LcSalazar's answer a bit... it's still not perfect because the background of the default buttons can still be seen in both Firefox, Chrome & Opera (not tested in Safari); but clicking on the arrows still works

Notes:

• Adding pointer-events: none; allows you to click through the overlapping button, but then you can not style the button while hovered.
• The arrows are visible in Edge, but don't work because Edge doesn't use arrows. It only adds an "x" to clear the input.

.number-wrapper {
  position: relative;
}

.number-wrapper:after,
.number-wrapper:before {
  position: absolute;
  right: 5px;
  width: 1.6em;
  height: .9em;
  font-size: 10px;
  pointer-events: none;
  background: #fff;
}

.number-wrapper:after {
  color: blue;
  content: "\25B2";
  margin-top: 1px;
}

.number-wrapper:before {
  color: red;
  content: "\25BC";
  margin-bottom: 5px;
  bottom: -.5em;
}

<span class='number-wrapper'>
    <input type="number" />
</span>