* {
  margin: 0;
  padding: 0;
}

.app {
  width: 100vw;
  height: 100vh;
  display: flex;
  flex-direction: column;
}

.header {
  height: 48px;
  color: darkred;
  font-size: 38px;
  background-color: lightgreen;
  box-sizing: border-box;
}

.main {
  display: flex;
  flex-direction: row;
  flex-grow: 1;
}

.sidebar {
  width: 96px;
  font-size: 20px;
  background-color: mediumorchid;
  box-sizing: border-box;
}

.content {
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

.flex-content {
  height: 30px;
  font-size: 20px;
  box-sizing: border-box;
}

.fixed-content {
  height: 128px;
  box-sizing: border-box;
}

.btn {
  width: 96px;
}

.btn1 {
  width: 96px;
}