Body{ width: 80%;
    margin: 0px auto}
.header{ width: 100%;
         height: 200px;
         border: 3px solid red;
         text-align: center;
         color: red;
         line-height: 200px;
         font-size: 50px;
        } 
.menu{  width: 100%;
        height: 100px;
        border: 3px solid red;
        border-bottom: none;
        border-top: none;
        text-align: center;
        color: red;
        line-height: 100px;
        font-size: 30px;
        }   
.main{
        width: 100%;
        height: 500px;
        border: 3px solid red;
        display: flex;
        }
.content{ width: 70%;
        height: 500px;
        border: 1px solid red;
        border-bottom: none;
        border-top: none;
        border-left: none;
        border-right: none;
        text-align: center;
        color: red;
        line-height: 500px;
        font-size: 30px;
        }        
.sidebar{width: 30%;
        height: 500px;
        border: 3px solid red;
        border-top: none;
        border-bottom: none;
        border-right: none;
        text-align: center;
        color: red;
        line-height: 500px;
        font-size: 30px;
        }
.footer{width: 100%;
        height: 150px;
        border: 3px solid red;
        border-top: none;
        text-align: center;
        color: red;
        line-height: 150px;
        font-size: 30px
        }