.cuidemos{
  color:pink;
}

contenedor {
  display:Flex;
  justify-content:Center;
}
video{
  width:300px
  height:300px
  border-radius:25px
}
img{
 width:300px;
  height:200px;
}
<style>
.boton{
  background-color:#ccc;
  padding:10px 20px;
}