* { margin: 0; 
    padding: 0; 
    box-sizing: border-box;
    
}

body { font-family: 'Raleway', sans-serif;
    background-color: rgb(222, 222, 222);
    color:#707173;
    font-weight: 400;
   
}

#contenedor {  width: 100%;
               margin: auto;
               text-align: center;
    
}

a {
    text-decoration: none;
    
}

#arriba { display: flex;
              background-image: url(tumblr_nuj9zwCwCd1r6ljjno1_1280.jpg);
              width: 100%;
              align-content: center;
}
header { display: flex;
         justify-content: space-between;
         align-items: center; 
    }
.menu { padding: 25px;
        margin-top: -17px;
   
}

.menu nav ul li a  { font-weight: 600;
    
}     

nav {   margin: auto;
        margin-top: 5%;
        flex-basis: calc(100%-8em);
                
    }
li  {
    display: inline-block;
    margin: 0;
    padding: :60px 60px;
    color: #fff;
    
    
}
nav ul {
    list-style: none;
    border-radius:0px; 
}
nav ul li {
    margin-bottom: 0.5em;
}
nav ul li a {
    
    background-color: #fce5df;
    color: #58585a;
    padding: 10px 20px;
    display: block;
    width: 205px;
    border-radius:0px;
    text-align: center;
    font-size: 15px;
    font-weight: 400;
}
nav ul li a:hover {
    color:#ffffff;
    background-color: gray;
}
nav ul li a:active {
    color:#81878b;
    background-color: #818486;
    
}

#descargar nav ul li a { background-color: #92e2c4;
                         width: 210px;
    
}
#descargar nav ul li a:hover {
    color:#ffffff;
    background-color: gray;
}


.video { margin: auto;
         margin-top: 20px;
         text-align: center;
         align-items: center;
         
         
}

.video video { width: 40em;
               
               

}

.videotexto { display: flex;
    
}

.texto p { font-size: 115%;
           margin-left: 20px;
           margin-right: 20px;
    
}
  
.textodescargar {  max-width: 670px;
                   text-align: center;
                   align-items: center;
                   margin: auto;
                

    } 



#parte2 {
    background-color: whitesmoke;
    max-width: 90%;   
    width: 90%;
    margin: auto;
    margin-top: 10px;
    align-items: center;
    text-align: center;

}

h2  { color: #efa28e;
      text-align: center;
      font-size: 200%; 
      margin-bottom: 25px;
      margin-top: px;
      padding: 30px;
      text-decoration: underline;
}

h3 { color: #707173;
     font-size: 160%;
     margin-top: 30px;
}

.texto2{ text-align: center;
         font-weight: 400; 
    
}

.contenedorgral{ display: flex;
                 padding: 0%;
                 margin: auto;
                 align-items: center;
                 text-align: center;
    
}

    
.texto2 { max-width: 800px; 
          text-align: center;
          margin: auto;
    } 

.texto2 p { padding: 3px;
            max-width: 600px;
            margin-left: 25px;
            margin-right: 25px;
            
}



.clearfix:after {
    content: "";
    display: table;
    clear: both;
}
footer { display: flex;
    background-color: #fce5df;
    text-align: center;
    margin-left: 30px;
    margin-right: 30px;
    align-items: center;
    
    }
footer img { max-width: 70px;
             margin-left: 20px;
    }
footer p { font-size: 8pt;
           align-items: center;
           text-align: center;
           margin-right: 20px;
}




@media only screen and (max-width: 18em){
    #arriba { display: flex;
                flex-wrap: wrap;
                align-items: center;
                }
    
    header { align-items: center;
        
    }  
    
    .menu { align-items: center;
            
    }
    
    .videotexto { display: block;
                 flex-wrap: wrap;
                 align-items: center; 
    }
    
    .video { display: none;
        
    }
    
    #descargar { margin: 0 auto
        
    }
    
    h2 { text-align: center;
        
    }
    
    .contenedorgral { display: block;
                   padding: 5%;
        
    }
        
    #fotocelular2 { align-items: center;
                    margin: 0 auto;
        
    }
    
    footer {display: none;
        
    }
    
}

@media only screen and (max-width: 30em){
    #arriba { display: flex;
                flex-wrap: wrap;
                align-items: center;
                }
    
    header { margin: auto;
             image-orientation: center;
            
    }  
    
    .menu { margin-left: auto;  
            text-align: center;
    }
        
        
    .video { display: none;
        
    }
  
    #descargar { margin: 0 auto;
                 display: block;

    }
    
    h2 { text-align: center;
        
    }
    
    
    .contenedorgral { display: block;
                   padding: 5%;
        
    }
    
    
     .texto2 p { text-align: center;
                margin-left: 7px;
                margin-right: 7px;
        
    }
    
    footer {display: none;
        
    }

}

@media only screen and (max-width: 40em){
    .video { display: none;
        
    }
    
    #descargar { align-items: center;
                 text-align: center; 
                 margin: 0 auto;

                      
        
    }
    
   
    .contenedorgral{ display: flex;
                  flex-wrap: wrap;
                  align-items: center;
                  image-orientation: center;
                  text-align: center;
                  align-content: center;
    }    

    
    .texto2 p { text-align: center;
                margin-left: 7px;
                margin-right: 7px;
        
    }
    
}

@media only screen and (max-width: 45em){
    .textodescargar {                 
    text-align: center;
    align-items: center;
    margin: auto;
        
        
    } 
    
    #descargar { align-items: center;
                 text-align: center; 
                 margin: 0 auto; 
    }
    
    .video { display: none;
        
    }
   
    
    
    h2 { text-align: center;
        
    }
    
     .contenedorgral { display: block;
                   padding: 8%;
        
    }
    
      
    
    .texto2 { text-align: center;
              text-align: center;
              align-items: center;
              margin: auto;
    } 
         

}

@media only screen and (max-width: 55em){

  .textodescargar {
    text-align: center;
    align-items: center;
    margin: auto;
        
        
    }  
    
   
    h2 { text-align: center;
        
    }
    
     .contenedorgral { display: flex;
         
    }    
    
    .texto2 { text-align: center;
              text-align: center;
              align-items: center;
              margin: auto;
    } 
        

    
}  

@media only screen and (max-width: 70em){
    
     .contenedorgral{ padding: 2%;
        
    }
}




 <div class="texto2">
                
             <img src="img/iphone_black_portrait2-fila.png" width="200px" id="fotocelular2" >    
            
                <h3> Personaliza tu inicio </h3>
                <br>
            <p> INSTAFADU te da la posibilidad de personalizar tu inicio, filtrando los contenidos segun tus preferencias de esta manera vas a poder guardar tus favoritos y acceder mas rapido a lo que mas te interesa. </p>
            </div>