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HTML 

              
                <!--- This is how I make my "OS window" design on my Neocities site (Credit: WolfKat from wolfkat-webdev.neocities.org) --->
<article class="window window--classic">
    <h1 class="window-title">Page/Window Title</h1>
    <div class="inner-window">
        <span id="article-top"></span>
        <section>
            <h2>Heading</h2>
            <p>Content goes here! Lorem ipsum dolor sit amet, consectetur adipisicing elit. Excepturi non, quo ab iusto amet animi ipsum dolores natus sapiente mollitia temporibus consequatur qui? Laboriosam natus ullam sed! Rerum, perspiciatis laudantium.</p>
            <p class="back-to-top wolfOS-font--classic">
                <a href="#article-top">Back to Top</a>
            </p>
        </section>
    </div>
</article>

<!--- The window classes can be applied to <aside> elements as well for more windows! Be sure the "h1" window title is changed to "h2" as there shoud only be one h1 on an entire page. --->
<aside class="window window--classic">
    <h2 class="window-title">Another Window Title</h2>
    <a href="#" class="exit-button wolfOS-font--classic wolfOS-button--classic">X</a>
    <div class="inner-window">
        <span id="aside1-top"></span>
        <section>
            <h3>Heading</h3>
            <p>Content goes here! Lorem ipsum dolor sit amet, consectetur adipisicing elit. Excepturi non, quo ab iusto amet animi ipsum dolores natus sapiente mollitia temporibus consequatur qui? Laboriosam natus ullam sed! Rerum, perspiciatis laudantium.</p>
            <p class="back-to-top wolfOS-font--classic">
                <a href="#aside1-top">Back to Top</a>
            </p>
        </section>
    </div>
</aside>
!

CSS 

              
                /* This gives the actual visual appearance and functions of my "OS window" design (Credit: WolfKat from wolfkat-webdev.neocities.org) */
*, 
*::before, 
*::after {
    margin: 0;
    padding: 0;
    font: inherit;
    box-sizing: border-box;
}

:root {
    --color-black: #121212;
    --color-white: #ebebeb;
    /* Put in your own colors! */
    --main-color: #323232; /* For backgrounds */
    --aux-color: #232323;
    --contrast-color: #fefefe; /* For text | Should contrast well against the main and aux colors */
    --accent-color: #33ccff; /* Whatever pops out from main and aux! Use --color-white or --color-black for contrast when this is a background color behind text (like in my "window-title" class) */
    --shadow-color: #111111;

    --font-size--base: 20px;
    --font-size--small: 0.9em;
    --font-size--medium: 1.25em;
    --font-size--large: 1.6em;
    --font-size--largest: 2.2em;

    --font-family--general: "Fanwood", Arial, Georgia;
    --font-family--titles: "League Spartan", Helvetica, Tahoma;
    --font-family--bulky-digital: Impact, Haettenschweiler, 'Arial Narrow Bold', sans-serif;
    --font-family--sleek-digital: "Orbitron", "Agency FB Bold", Arial, Helvetica, sans-serif;

    --window-title-height: 1.5em;
}

body {
    background-color: var(--aux-color);
    color: var(--contrast-color);
    font-family: var(--font-family--general);
    font-size: var(--font-size--base);
    line-height: 1.25em;
}

h1, 
h2, 
h3, 
h4, 
h5, 
h6 {
    display: block;
    margin: 1.3em auto 1rem auto;
    width: 90%;
    font-family: var(--font-family--titles);
    line-height: 1em;
    text-wrap: balance;
    text-align: center;
}

h1 {
    margin: 1rem auto;
    font-size: var(--font-size--largest);
}

h2 {
    font-size: var(--font-size--large); 
}

h3, 
h4, 
h5, 
h6 {
    font-size: var(--font-size--medium);
}

article, 
aside {
    display: block;
    position: relative;
    margin: 2rem auto;
    width: 100%;
    min-height: 8em;
    max-height: 90vh;
}

.window {
    overflow: hidden;
    display: flex;
    /* Flex ensures that the inner-window contents aren't cut off from the overflow, as it won't fit into the scroll space without this. */
    flex-direction: column;
    padding: 0;
    min-width: 45ch;
    max-width: 70vw;
    background-color: var(--main-color);
    border-color: var(--accent-color);
    box-shadow: 0px 0px 6px 0px var(--shadow-color);
}

.window p,
.window blockquote {
    display: block;
    width: 98%;
    height: auto;
    margin: 2em auto;
    text-align: left;
}

.window p {
    max-width: 75ch;
}

.window blockquote {
    padding: 1em 0px;
    max-width: 55ch;
    border-width: 1px 0px;
    border-style: solid;
    border-color: var(--accent-color);
    font-size: var(--font-size--medium);
    font-style: italic;
    letter-spacing: 1px;
    line-height: 1.3em;
}

.window ol, 
.window ul {
    display: block;
    margin: 1rem auto;
    max-width: 45ch;
    text-align: left;
}

.window ul {
    list-style-type: none;
}

.window li {
    margin: 0.9rem 0.2rem;
}

/* The "classic" and "modern" classes are modular properties depending on the window styles you want */
.window--classic {
    border-width: 6px;
    border-style: ridge;
}

.window--modern {
    border-width: 1px;
    border-style: solid;
}

.window .window-title {
    position: relative;
    top: 0px;
    left: 0px;
    right: 0px;
    padding: 0 1ch;
    margin: 0px;
    width: 100%;
    height: var(--window-title-height);
    background-color: var(--accent-color);
    color: var(--color-black);
    line-height: var(--window-title-height);
}

@media (prefers-color-scheme: light) {
    .window .window-title {
        color: var(--color-white);
    }
}

.window--classic .window-title {
    border-width: 0px;
    border-style: ridge;
    border-color: var(--accent-color);
    border-bottom-width: 6px;
    font-family: var(--font-family--bulky-digital);
}

/* Other modular style classes */
.wolfOS-font--classic {
    font-family: var(--font-family--bulky-digital);
}

.wolfOS-font--modern {
    font-family: var(--font-family--sleek-digital);
}

.wolfOS-button--classic {
    border-style: outset;
    border-width: 2px;
}

.wolfOS-button--modern {
    border-style: solid;
    border-width: 1px;
}

/* Screen size adjustments */
@media (max-width: 700px) {
    .window {
        margin: 5px auto;
        min-width: 20ch;
        max-width: 70ch;
    }
}

.inner-window {
    overflow: auto;
    display: block;
    position: relative;
    padding: 1em 2em 0px 2em;
    width: 100%;
    height: 100%;
    flex-grow: 1;
}

.window .back-to-top {
    width: 99%;
    height: 3em;
    text-align: center;
}

.window .back-to-top a:link,
.window .back-to-top a:visited {
    margin: 0px auto;
	color: var(--accent-color);
    font-size: var(--font-size--medium);
}

.exit-button:link,
.exit-button:visited {
    display: block;
    position: absolute;
    top: 0px;
    right: 0px;
    padding: 0.5em 0.6em;
    margin: 2px;
    background-color: var(--main-color);
	color: var(--accent-color);
    font-size: var(--font-size--medium);
    line-height: 0.5em;
    text-decoration: none;
    text-align: center;
}
!

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