change color / transpanency of spinor of <input type="number">

Question

I have an input field for a number and when hovering over it, it shows those arrows with whome one can change the value by one. I want to adjust them to fit my color shema. I'd like to change the color of the arrows if possible, but for now it would be enought if I could just make the background transparent. And I mean the white background ONLY. I know how to make the arrows transparent but that is not what I want.

For a scrollbar I manged it

/* ----- scrollbar ----- */
#message-input, .edit-input, #messages {
    scrollbar-color: #e4a9c4 transparent;
}

for the number input I tried this but it does not work

input::-webkit-outer-spin-button,
input::-webkit-inner-spin-button {
    color: #e4a9c4 transparent;
}

Answer 1

The styling options for default spin buttons are limited, and not all browsers support them. Instead, I recommend hiding them and manually adding your own buttons.

// For every input number that has the spin-buttons class, add the container and buttons with the proper structure
document.addEventListener("DOMContentLoaded", function() {
  document.querySelectorAll("input[type='number'].spin-buttons").forEach(input => {
    const container = document.createElement("div");
    container.classList.add("spin-container");
    input.parentNode.insertBefore(container, input);
    container.appendChild(input);

    const controls = document.createElement("div");
    controls.classList.add("spin-controls");

    const upButton = document.createElement("button");
    upButton.classList.add("up");
    upButton.textContent = "▲";
    upButton.addEventListener("click", function(event) {
      event.stopPropagation();
      input.value = Number(input.value) + 1;
    });

    const downButton = document.createElement("button");
    downButton.classList.add("down");
    downButton.textContent = "▼";
    downButton.addEventListener("click", function(event) {
      event.stopPropagation();
      input.value = Number(input.value) - 1;
    });

    controls.appendChild(upButton);
    controls.appendChild(downButton);
    container.appendChild(controls);
  });
});

/* Set background-color just for test */
input[type='number'] {
  background-color: #7fb0dc;
}

.spin-container {
  position: relative;
  display: inline-block;
}

/* Providing space for our arrows */
.spin-container > input[type='number'].spin-buttons {
  padding-right: 15px;
}

/* Hiding the default arrows of the number input */
.spin-container > input[type='number'].spin-buttons::-webkit-inner-spin-button,
.spin-container > input[type='number'].spin-buttons::-webkit-outer-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

/* Positioning the buttons to the right */
.spin-container > .spin-controls {
  position: absolute;
  top: 0;
  bottom: 0;
  right: 0;
  width: 20px;
  display: none;
  flex-direction: column;
}
.spin-container .spin-controls button {
  width: 10px;
  height: calc((100% - 1px) / 2);
  font-size: 7px;
  border: none;
  background: transparent;
  color: #555;
  cursor: pointer;
  display: block;
}
.spin-container > .spin-controls > button:hover {
  color: #000;
}
.spin-container:hover > .spin-controls {
  display: flex;
}

Default
<input type="number" />
Improved
<input type="number" class="spin-buttons" />

It's not the most optimal solution I made, I just wanted to demonstrate the approach. I added padding to the right side of the input so that a div with two buttons could fit underneath each other. In these buttons, I displayed two arrows with appropriate sizes for the input.

To avoid code duplication, in the basic HTML, only the input field needs to be declared, and when the spin-buttons class is present, JavaScript places the input field into a container upon DOM load and adds the necessary HTML code and buttons to display the up and down arrows.

The spin-controls only appears when the input field is hovered.