Rainbow gradient on text in CSS

Here is how you can create basic rainbow linear gradient (without integration with text yet):

#grad1 {
    height: 200px;
    background: red; /* For browsers that do not support gradients */
    background: -webkit-linear-gradient(left, orange , yellow, green, cyan, blue, violet); /* For Safari 5.1 to 6.0 */
    background: -o-linear-gradient(right, orange, yellow, green, cyan, blue, violet); /* For Opera 11.1 to 12.0 */
    background: -moz-linear-gradient(right, orange, yellow, green, cyan, blue, violet); /* For Firefox 3.6 to 15 */
    background: linear-gradient(to right, orange , yellow, green, cyan, blue, violet); /* Standard syntax (must be last) */
}

<div id="grad1"></div>

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Or alternatively, you can use one of the gradient generators (I prefer this one).

And here is the text integration:

#grad1 {
    background: red;
    background: -webkit-linear-gradient(left, orange , yellow, green, cyan, blue, violet);
    background: -o-linear-gradient(right, orange, yellow, green, cyan, blue, violet);
    background: -moz-linear-gradient(right, orange, yellow, green, cyan, blue, violet);
    background: linear-gradient(to right, orange , yellow, green, cyan, blue, violet);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    font-size: 20vw;
}

<h1 id="grad1">Fake Text</h1>

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Main parts here are background-clip and text-fill-color properties, but be ready, that not all browsers will support it. For more info about browser compatibility check sections with the same names near the bottoms of these pages:

background-clip

text-fill-color

P.S. Drawing a line is pretty simple, you just need to use a gradient and define some styles to make this block the right form, for example:

#grad1 {
    background: red; /* For browsers that do not support gradients */
    background: -webkit-linear-gradient(left, orange , yellow, green, cyan, blue, violet); /* For Safari 5.1 to 6.0 */
    background: -o-linear-gradient(right, orange, yellow, green, cyan, blue, violet); /* For Opera 11.1 to 12.0 */
    background: -moz-linear-gradient(right, orange, yellow, green, cyan, blue, violet); /* For Firefox 3.6 to 15 */
    background: linear-gradient(to right, orange , yellow, green, cyan, blue, violet); /* Standard syntax (must be last) */
}

.line {
    height: 6px;
    border-radius: 4px;
}

<div id="grad1" class="line"></div>

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