<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <link rel="stylesheet" href="style.css">
</head>
<body>
  <div class="container">
    <div class="calculator">
      <div class="display">
        <span class="calculator__operend--left">0</span>
          <span class="calculator__operator">+</span>
          <span class="calculator__operend--right">0</span>
          <span class="calculator__equal">=</span>
          <span class="calculator__result">1</span>
      </div>
      <div class="inputArea">
        <div class="Button__row">
          <button class="clear">AC</button>
          <button class="enter">=</button>
        </div>
        <div class="Button__row">
          <button class="number">7</button>
          <button class="number">8</button>
          <button class="number">9</button>
          <button class="operator">+</button>
        </div>
        <div class="Button__row">
          <button class="number">4</button>
          <button class="number">5</button>
          <button class="number">6</button>
          <button class="operator">-</button>
        </div>
        <div class="Button__row">
          <button class="number">1</button>
          <button class="number">2</button>
          <button class="number">3</button>
          <button class="operator">*</button>
        </div>
        <div class="Button__row">
          <button class="number wid2">0</button>
          <button class="decimal">.</button>
          <button class="operator">/</button>
        </div>
      </div>
    </div>
  </div>
</body>
</html>
* {
  box-sizing: border-box;
  margin: 0px;
  padding: 0px;
  border: 0px;
  font-family: 'Trebuchet MS', 'Lucida Sans Unicode', 'Lucida Grande', 'Lucida Sans', Arial, sans-serif;
}

.container {
  background-color: gray;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}

.calculator {
  width: 350px;
  height: 520px;
  border: 10px silver;
  border-radius: 20px;
  box-shadow: 0 0 20px 5px skyblue;
  background-color: rgb(96, 96, 96);
  padding: 10px;
}

.display {
  background-color: skyblue;
  height: 100px;
  width: 100%;
  box-shadow: 0 -3px 5px 0 rgb(255, 253, 233) inset;
  border-radius: 10px;
  font-size: 2em;
  color: black;
  text-align:end ;
  padding: 10px 10px;
  overflow: hidden;
  overflow-wrap: break-word;
}

.display > span {
  display: inline-block;
  text-align: center;
  width: 30px;
  height: 100px;
  font-size: 1.3em;
  padding: 30px 5px;
}

.inputArea {
  width: 100%;
  border-radius: 10px;
  margin-top: 50px;
}
.Button__row {
  height: 50px;
  display: flex;
  justify-content: space-between;
  margin: 20px 0px;
  align-items: center;
}
.Button__row > button {
  position: relative;
  height: 50px;
  width: 75px;
  padding: 15px 25px;
  display: inline-block;
  box-shadow:1px 4px 0 rgb(0,0,0,1);
  font-size: 1.2em;
  border: 0;
  border-radius: 10px;
  cursor: pointer;
  outline: none;
}
.Button__row > button:hover {
  opacity: 70%;
}
.Button__row > button:active {
  top: 2px;
  box-shadow: 0 0 0 1px black,
  0 0 0 2px gainsboro inset,
  0 0 0 1px silver;
  background-color: royalblue;
  color: goldenrod;
}
.Button__row > .isPressed {
  color: blue;
}
.Button__row > .number {
  background-color: gray;
}
.Button__row > .operator {
  background-color: ivory;
}
.Button__row > .clear {
  background-color: slategray;
  width: 120px;
}
.Button__row > .enter {
  background-color: slategrey;
  width: 120px;
}
.Button__row > .wid2 {
  width: 160px;
}
.Button__row > .decimal {
  background-color: gray;
}
Run Pen

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.