body {
  margin: 0;
  display: flex;
  flex-direction: row;
  height: 100vh;
  font-family: sans-serif;
}

aside {
  width: 250px;
  background: #1f1f1f;
  color: white;
  padding: 15px;
}

main {
  flex: 1;
  display: flex;
  flex-direction: column;
}

iframe {
  flex: 1;
  width: 100%;
  border: none;
}

header {
  background: #333;
  color: white;
  padding: 10px;
  font-weight: bold;
  align-items: center;
  justify-content: center;
}

input[type="file"], button {
  width: 100%;
  margin-top: 10px;
  padding: 8px;
  font-size: 14px;
}

button {
  background: #4CAF50;
  color: white;
  border: none;
  cursor: pointer;
}

button:hover {
  background: #45a049;
}

.icon {
  color: white;
  width: 20px;
  height: 20px;
}

.selected-tab {
  border: 2px solid chocolate;
}