Aaron Qiu qzm

## dropdown.css
.dropdown {
    position: relative;
    display: inline-block;
}

.dropdown-content {
    display: none;
    position: absolute;
    background-color: #f9f9f9;
    min-width: 160px;

## vertical-navigation-bar.html
<!DOCTYPE html>
<html>
    <head>
        <style>
            ul {
                list-style-type: none;
                margin: 0;
                padding: 0;
                width: 200px;
                background-color: #f1f1f1;

## horizontal-navigation-bar.html
<!DOCTYPE html>
<html>
    <head>
        <style>
            ul {
                list-style-type: none;
                margin: 0;
                padding: 0;
                overflow: hidden;
                background-color: #333;

## link.css
.className {
    /* unvisited link */
    a:link {
        color: red;
    }
    /* visited link */
    a:visited {
        color: green;
    }
    /* mouse over link */

## center.css
.center {
    margin: auto;
    width: 60%;
    border: 3px solid #73AD21;
    padding: 10px;
}

## link-button.html
<!DOCTYPE html>
<html>
    <head>
        <style>
            a:link,
            a:visited {
                background-color: #f44336;
                color: white;
                padding: 14px 25px;
                text-align: center;

## viewport.html
<meta name="viewport" content="width=device-width, initial-scale=1.0">

## columns.css
.col-1 {
    width: 8.33%;
}
.col-2 {
    width: 16.66%;
}
.col-3 {
    width: 25%;
}
.col-4 {

## media-query.html
<!DOCTYPE html>
<html>
    <head>
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <style>
            * {
                box-sizing: border-box;
            }
            .row::after {
                content: "";

## tabs.html
<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Tab</title>
        <style>
            ul {
                text-align: center;
                width: auto;
            }
	.dropdown {
	position: relative;
	display: inline-block;
	}

	.dropdown-content {
	display: none;
	position: absolute;
	background-color: #f9f9f9;
	min-width: 160px;
	<!DOCTYPE html>
	<html>
	<head>
	<style>
	ul {
	list-style-type: none;
	margin: 0;
	padding: 0;
	width: 200px;
	background-color: #f1f1f1;
	.className {
	/* unvisited link */
	a:link {
	color: red;
	}
	/* visited link */
	a:visited {
	color: green;
	}
	/* mouse over link */
	.center {
	margin: auto;
	width: 60%;
	border: 3px solid #73AD21;
	padding: 10px;
	}
	.col-1 {
	width: 8.33%;
	}
	.col-2 {
	width: 16.66%;
	}
	.col-3 {
	width: 25%;
	}
	.col-4 {
	<!DOCTYPE html>
	<html lang="en">
	<head>
	<meta charset="UTF-8">
	<title>Tab</title>
	<style>
	ul {
	text-align: center;
	width: auto;
	}