Div height 100% excluding header

Question

Ok so I know this topic has many questions, but I still haven\'t been able to figure exactly how to make this work. This is close to the problem, but its not working for m

Answer 1

Use flex:1;

html, body
{
     height: 100%;
     margin: 0px;
}

#page
{
    min-height: 100%;      
    display: flex;
  flex-direction: column;
}

#header
{
display: flex;
    height: 40px;
    background-color:red;
} 

#content
{
    display: flex;
  flex: 1;    
  background-color:blue;
}

     

          

             header
          
          

             content