W3Schools.com
CSS
The Language for Styling Web Pages
LEARN CSS CSS REFERENCE
body {
   background-color: #d0e4fe;
}
h1 {
   color: orange;
   text-align: center;
}
p {
   font-family: "Times New Roman";
   font-size: 20px;
}
Try it Yourself
JavaScript
The Language for Programming Web Pages
LEARN JS JS REFERENCE
// Click the button to change the color of this paragraph
function myFunction() {
   var x;
   x = document.getElementById("demo");
   x.style.fontSize = "25px";
   x.style.color = "red";
}
Try it Yourself