Untitled

<html>
<head>
<style>
  .antraste {
    display: flex;
	flex-direction: column;
	flex-wrap: nowrap;
	justify-content:  center;
	align-items: center;
	align-content: center;
	background-color: coral;
	height: 50px;

  }
.flex-grid {
  display: flex;
}
.col {
  background-color: blue;
  flex: 1;
}
.col1 {
  background-color: blue;
  flex: 1;
}
.col2 {
  background-color: blue;
  flex: 1;
}
.col3 {
  background-color: blue;
  flex: 1;
}
@media (max-width: 400px) {
  .flex-grid {
    display: block;
  }
}
.flex-grid-thirds {
  display: flex;
  justify-content: space-between;
}
.flex-grid-thirds .col {
  width: 32%;
}
</style>
</head>
<body>
<div class="antraste">Antraštė
</div>
<div class="flex-grid-thirds">
  <div class="col">BOX 1.1</div>
  <div class="col1">BOX 1.2</div>
  <div class="col2">BOX 1.3</div>
  <div class="col3">BOX 1.4</div>
</div>
</body>