↑　CSS　↑　

            .a{
                border:lightgray 3px solid;
                padding:2px;
                display: grid;
                grid-template-rows: 3fr 3fr 3fr;
            /*    grid-template-columns: 3fr 3fr 3fr;*/
            }
            .b{
                border:grey 2px solid;
                margin: 5px;
                padding:5px;
                display: grid;
            /*    grid-template-rows: 1fr 1fr 1fr;*/
                grid-template-columns: 1fr 1fr 1fr;
            }
            .c{
                border:black 1px solid;
                margin: 10px;
                padding:10px;
            }
            .no1{
                color: red;
            }
            .no2{
                color: green;
            }
            .no3{
                color:blue;
            }            
        

　↑　HTML　↑　

            
                

                    

                        

                            
class="a b no10 c no1"
                        
                        

                            
class="a b no10 c no2"
                        
                        

                            
class="a b no10 c no3"
                        
                    
                    

                        

                            
class="a b no20 c no1"
                        
                        

                            
class="a b no20 c no2"
                        
                        

                            
class="a b no2s0 c no3"
                        
                    
                    

                        

                            
class="a b no30 c no1"
                        
                        

                            
class="a b no30 c no2"
                        
                        

                            
class="a b no30 c no3"