Why is the input bar spilling slightly on the right side of the container?

Question

I made a calculator using HTML, CSS and JavaScript. Everything is working fine but the input bar is slightly overflowing on the right side.

I tried aligning it to center and so many things, but nothing worked.

Here is my code (only the input part):

* {
  margin: 0;
  padding: 0;
}

body {
  min-height: 100vh;
  justify-content: center;
  display: flex;
  align-items: center;
}
.container {
  width: 250px;
  height: 400px;
  background-color: antiquewhite;
  padding: 20px;
  border-radius: 1.5rem;
  outline: 5px solid gray;
}
.container input {
  width: 100%;
  border-style: none;
  height: 50px;
  border-radius: 1rem;
  outline: 2px solid;
  font-size: 20px;
  text-align: right;
  padding-right: 10px;
}

    <div class="container">
      <!--Input-->
      <div class="input">
        <input type="text" placeholder="Write your equation here  " value="" />
      </div>

How can I get the input to fit within the container?

Answer 1

if an element is not defined as box-sizing: border-box the width is not calculated with the padding. meaning it calculates 100% width and added 10px from the padding-right: 10px

* {
  margin: 0;
  padding: 0;
  /* the change */
  box-sizing: border-box;
}

body {
  min-height: 100vh;
  justify-content: center;
  display: flex;
  align-items: center;
}

.container {
  width: 250px;
  height: 400px;
  background-color: antiquewhite;
  padding: 20px;
  border-radius: 1.5rem;
  outline: 5px solid gray;
}

.container input {
  width: 100%;
  border-style: none;
  height: 50px;
  border-radius: 1rem;
  outline: 2px solid;
  font-size: 20px;
  text-align: right;
  padding-right: 10px;
}

<div class="container">
  <!--Input-->
  <div class="input">
    <input type="text" placeholder="Write equation here" value="" />
  </div>