Cambios

<div style="box-sizing: border-box; floatclear:left; flex: 1 0 25%both; width:25100%; bordermargin: 25px 0 0 0.2em solid #FAFAFA; paddingdisplay: 1emflex; backgroundflex-colorwrap:#F3F3F3wrap; overflowbox-sizing:hiddenborder-box; min" id="mp-width: 19em;content">1</div>

<div style="box-sizing: border-box; float:left; flex: 1 0 25%; width:25%; border: 0.2em solid #FAFAFA; padding: 1em; background-color:#F3F3F3; overflow:hidden; min-width: 19em;">Hola<youtube width="100%" height="200">https://www.youtube.com/watch?v=2OlQqWRugMo</youtube></div>

<div style="box-sizing: border-box; float:left; flex: 1 0 25%; width:25%; border: 0.2em solid #FAFAFA; padding: 1em; background-color:#F3F3F3; overflow:hidden; min-width: 19em;">Hola2</div>

<div style="box-sizing: border-box; float:left; flex: 1 0 25%; width:25%; border: 0.2em solid #FAFAFA; padding: 1em; background-color:#F3F3F3; overflow:hidden; min-width: 19em;">Hola3</div> <div style="box-sizing: border-box; float:left; flex: 1 0 25%; width:25%; border: 0.2em solid #FAFAFA; padding: 1em; background-color:#F3F3F3; overflow:hidden; min-width: 19em;">4</div>  </div> <div class="nomobile" style="display:flex;flex-wrap: wrap"><youtube width = "396" height = "250">https://www.youtube.com/watch?v=2OlQqWRugMo</youtube><youtube width = "396" height = "250">https://www.youtube.com/watch?v=2OlQqWRugMo</youtube><youtube width = "396" height = "250">https://www.youtube.com/watch?v=2OlQqWRugMo</youtube> </div> __NOTOC__<div class="nomobile" style="display:flex;flex-wrap: wrap">{| style="width:100%; margin-top:2em; vertical-align:top; border-top:3px #5499C7 solid; border-bottom:3px #5499C7 solid; text-align:center"|- valign="top"|style="padding-top:1em; padding-bottom:1em;"| <div style="font-size: 150%; color:#045FB4; line-height: normal; font-weight: bold; text-align:center">'''Videos'''</div><div style="color:#696969; font-weight: bold; text-align:center">[https://www.youtube.com/channel/UCDnxhvMIqbpHJTveoK8sY7A/featured|<span class="plainlinks" style="color:#696969;"><font class="hover-text" style="font-weight: bold; font-size:100%;">Visita nuestro canal en Youtube donde encontraras todos los videos</font></span>]</div>|} <div class="MainPageSisterProjects__wrapper plainlinks" dir="auto"><div class="MainPageSisterProjects__heading"> </div><div class="" style="text-align:left;"><youtube width = "350" height = "250">https://www.youtube.com/watch?v=2OlQqWRugMo</youtube><youtube width = "350" height = "250">https://www.youtube.com/watch?v=2OlQqWRugMo</youtube><youtube width = "350" height = "250">https://www.youtube.com/watch?v=2OlQqWRugMo</youtube><youtube width = "350" height = "250">https://www.youtube.com/watch?v=2OlQqWRugMo</youtube></div> </div></div>