color

значения свойства:

css/style.css

.a {
 color: navy;
}

.c {
 color: rgba(0, 255, 0, 0.5);
}

.d {
 color: hsl(315, 100%, 50%);
}

.e {
 color: hsla(315, 100%, 50%, 0.5);
}

index.html

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>New Page</title>
<link href="css/style.css" rel="stylesheet" />
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
</head>
<body>
<p class="a">Hello World!</p>
<br />
<p id="p1">To be or not to be?</p>
<br />
<p class="b">Привет Мир!</p>
<br />
<p class="c">I live in Ukraine.</p>
<br />
<p class="d">I develop a software.</p>
<br />
<p class="e">I must write this story.</p>
<script>
/*JavaScript*/
document.getElementById("p1").style.color = "#006400";
/*jQuery*/
$(document).ready(function () {
$(".b").css({ "color": "rgb(255, 0, 0)" });
});
</script>
</body>
</html>

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>New Page</title>
<link href="css/style.css" rel="stylesheet" />
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
</head>
<body>
<p class="a">Hello World!</p>
<br />
<p id="p1">To be or not to be?</p>
<br />
<p class="b">Привет Мир!</p>
<br />
<p class="c">I live in Ukraine.</p>
<br />
<p class="d">I develop a software.</p>
<br />
<p class="e">I must write this story.</p>
<script>
/*JavaScript*/
document.getElementById("p1").style.color = "#006400";
/*jQuery*/
$(document).ready(function () {
$(".b").css({ "color": "rgb(255, 0, 0)" });
});
</script>
</body>
</html>