I'm beginner in web development and I don't understand why there is white space here (check screen capture), I would remove them...
PS:I use electron framework to make an desktop app

[![enter image description here](https://i.stack.imgur.com/0OQda.png)](https://i.stack.imgur.com/0OQda.png)

```css
* {
  border: 2px solid black;
}

#Icon {
  height: 30px;
  width: 30px;
}

.Minimize {
  height: 30px;
  width: 30px;
}

.Close {
  height: 30px;
  width: 30px;
}

#Triangle {
  width: 0;
  height: 0;
  border-left: 50px solid transparent;
  border-right: 50px solid transparent;
  border-bottom: 100px solid #20272F;
  margin: auto;
}

#Titre {
  vertical-align: middle;
  text-align: center;
}
```

```html
<header>
  <img id="Icon" src="Images/icon.png">

  <input type="image" class="Minimize" src="Images/minimize_window_96px.png"></input>
  <input type="image" class="Close" src="Images/close_window_96px.png"></input>
</header>

<head>
  <meta charset="utf-8">
  <link rel="stylesheet" type="text/css" href="Style.css">
</head>

<body>
  <h1 id="Titre">Triangle des equations</h1>
  <div id="Triangle"></div>
  <div id="PartiEquation"></div>
  <script src="code.js"></script>
</body>
```