h4{
  padding-top:30px;
  font-size:25px;
  
  
}
  .container{
  text-align:center;
  border: 2px solid red;
  border-radius:10px;
  border-color:green;
  padding:15px;
  margin:15px;
  background-color:yellow;
  background-color:#DBE2E9;
  }
p{
  text-align:center;
  font-size:18px;
  
  }
input{
  width:250px;
  height:25px;
  type-align:center;
  margin:10px;
  height:45px;
  }
input:hover{
  border-color:blue;
}
#a{
  padding:5px;
  background-color:blue;
  width:250px;
  color:white;
  border-radius:5px;
  border-color:blue;
  padding:10px;
  font-size:20px;
 }
 #b{
   width:250px;
   background-color:green;
   color:white;
   font-size:15px;
   border-radius:5px;
   border-color:green;
   margin:20px;
   padding:5px;
 }
 #c{
   width:250px;
   background-color:green;
   color:white;
   font-size:15px;
   border-radius:5px;
   border-color:green;
   padding:5px;
   margin:10px;
 }
 body{
   background-color:white;
 }
 #d{
   background-color:#DBE2E9;
   margin:1px;
   float:right;
   border-radius:5px;
   border-color:green;
   font-size:14px;
}
.dark input::placeholder{
color:white;
opacity:0.8;
} 

.dark{
  background-color:black;
  color:white;
}

.dark .container{
  background-color:#1e1e1e;
  color:white;
  border-color:white;
}

.dark input{
  background-color:#333;
  color:white;
  border:1px solid white;
}

.dark input::placeholder{
  color:white;
  opacity:0.8;
}