Weird media query problem technical document

Hello lovelies, please help haha.

I’ve got a few strange problems. I tried modeling my css off of the example for the most part. With the media query i have, when the viewport is made smaller, I can’t use position: relative; like the example does. It results in my nav bar and main doc starting at the same point overlapped with a bunch of white space at the top of the page. Position: absolute; works but I think it’s causing problems.

My main issue is with the #main-doc element. When the viewport is smaller, I can’t get the content to resize and fit within the viewport horizontally without a scrollbar. I’m trying to remove the x-axis scroll bar. On the right of it there’s even a weird vertical gray bar I can’t account for.

Thanks so much random internet peeps.

my code

<html>
    <head>
        <title>Technical Documentation Page</title>
<style>
@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+KR:wght@100;300;400;500;700;900&display=swap');
html {
    font-family: Noto Sans KR;
    max-width: 100%;
    line-height: 1.5;
}
main {
    display: block;
}
nav {
    position: fixed;
    min-width: 290px;
    height: 100%;
    border-right: solid;
    border-color: rgba(0, 22, 22, 0.4);
}
#nav-header {
    text-align: center;
    margin: 10px;
}
nav ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    width: 290px;
    height: 88%;
    overflow-y: auto;
    overflow-x: hidden;
}
nav li {
    border-top: 1px solid;
}
nav a {
    text-decoration: none;
    display: block;
    color: #4d4e53;
    padding: 10px 30px;
    cursor: pointer;
}
#main-doc {
    position: absolute;
    margin-left: 310px;
    padding: 20px;
}
header {
    font-size: 1.8em;
    margin: 0;
    text-align: left;
}
article {
    margin: 15px;
}
p {
    display: block;
}
section li {
    margin: 15px 0 0 20px;
}
code {
    display: block;
    text-align: left;
    line-height: 2;
    margin: 10px;
    padding: 15px;
    border-radius: 5px;
    background-color: #f7f7f7;
}
@media (max-width: 815px) {
    nav {
        position: absolute;
        padding: 0;
        margin: 0;
        width: 100%;
        max-height: 275px;
        border: none;
        z-index: 1;
    }
    nav ul {
        width: 100%;
        border: 1px solid;
        border-bottom: 2px solid;

    }
    #main-doc {
        position: absolute;
        margin-left: 0;
        margin-top: 290px;
        overflow-y: scroll;
        width: 100%;
    }
    
}
</style>
    </head>
    <body>
        <nav id="navbar">
            <header id="nav-header">JS Documentation</header>
            <ul>
                <li><a class="nav-link" href="#Introduction">Introduction</a></li>
                <li><a class="nav-link" href="#What_you_should_already_know">What you should already know</a></li>
                <li><a class="nav-link" href="#JavaScript_and_Java">JavaScript and Java</a></li>
                <li><a class="nav-link" href="#Hello_world">Hello world</a></li>
                <li><a class="nav-link" href="#Variables">Variables</a></li>
                <li><a class="nav-link" href="#Declaring_Variables">Declaring Variables</a></li>
                <li><a class="nav-link" href="#Variable_scope">Variable scope</a></li>
                <li><a class="nav-link" href="#Global_variables">Global variables</a></li>
                <li><a class="nav-link" href="#Constants">Constants</a></li>
                <li><a class="nav-link" href="#Data_types">Data types</a></li>
                <li><a class="nav-link" href="#if...else_statement">if...else statement</a></li>
                <li><a class="nav-link" href="#while_statement">while statement</a></li>
                <li><a class="nav-link" href="#Function_declarations">Function declarations</a></li>
                <li><a class="nav-link" href="#Reference">Reference</a></li>
            </ul>
        </nav>
        <main id="main-doc">
        <section class="main-section" id="Introduction">
            <header>Introduction</header>
            <article>
                <p>JavaScript is a cross-platform, object-oriented scripting language. It is a small and lightweight language. Inside a host environment (for example, a web browser), JavaScript can be connected to the objects of its environment to provide programmatic control over them.</p>
                <p>JavaScript contains a standard library of objects, such as Array, Date, and Math, and a core set of language elements such as operators, control structures, and statements. Core JavaScript can be extended for a variety of purposes by supplementing it with additional objects; for example:</p>
                <ul>
                    <li>Client-side JavaScript extends the core language by supplying objects to control a browser and its Document Object Model (DOM). For example, client-side extensions allow an application to place elements on an HTML form and respond to user events such as mouse clicks, form input, and page navigation.</li>
                    <li>Server-side JavaScript extends the core language by supplying objects relevant to running JavaScript on a server. For example, server-side extensions allow an application to communicate with a database, provide continuity of information from one invocation to another of the application, or perform file manipulations on a server.</li>
                </ul>
            </article>
        </section>
        <section class="main-section" id="What_you_should_already_know">
            <header>What you should already know</header>
            <article>
            <p>This guide assumes you have the following basic background:</p>
            <ul>
                <li>A general understanding of the Internet and the World Wide Web (WWW).</li>
                <li>Good working knowledge of HyperText Markup Language (HTML).</li>
                <li>Some programming experience. If you are new to programming, try one of the tutorials linked on the main page about JavaScript.</li>
            </ul>
            </article>
        </section>
        <section class="main-section" id="JavaScript_and_Java">
            <header>JavaScript and Java</header>
            <article>
            <p>JavaScript and Java are similar in some ways but fundamentally different in some others. The JavaScript language resembles Java but does not have Java's static typing and strong type checking. JavaScript follows most Java expression syntax, naming conventions and basic control-flow constructs which was the reason why it was renamed from LiveScript to JavaScript.</p>
            <p>In contrast to Java's compile-time system of classes built by declarations, JavaScript supports a runtime system based on a small number of data types representing numeric, Boolean, and string values. JavaScript has a prototype-based object model instead of the more common class-based object model. The prototype-based model provides dynamic inheritance; that is, what is inherited can vary for individual objects. JavaScript also supports functions without any special declarative requirements. Functions can be properties of objects, executing as loosely typed methods.</p>
            <p>JavaScript is a very free-form language compared to Java. You do not have to declare all variables, classes, and methods. You do not have to be concerned with whether methods are public, private, or protected, and you do not have to implement interfaces. Variables, parameters, and function return types are not explicitly typed.</p>
            </article>
        </section>
        <section class="main-section" id="Hello_world">
            <header>Hello world</header>
            <article>To get started with writing JavaScript, open the Scratchpad and write your first "Hello world" JavaScript code:        
            <code>function greetMe(yourName) { alert("Hello " + yourName); } greetMe("World");</code>
                Select the code in the pad and hit Ctrl+R to watch it unfold in your browser!</article>
        </section>
        <section class="main-section" id="Variables">
            <header>Variables</header>
            <article>
            <p>You use variables as symbolic names for values in your application. The names of variables, called identifiers, conform to certain rules.</p>
            <p>A JavaScript identifier must start with a letter, underscore (_), or dollar sign ($); subsequent characters can also be digits (0-9). Because JavaScript is case sensitive, letters include the characters "A" through "Z" (uppercase) and the characters "a" through "z" (lowercase).</p>
            <p>You can use ISO 8859-1 or Unicode letters such as å and ü in identifiers. You can also use the Unicode escape sequences as characters in identifiers. Some examples of legal names are Number_hits, temp99, and _name.</p>
            </article>
        </section>
        <section class="main-section" id="Declaring_Variables">
            <header>Declaring Variables</header>
            <article>
                You can declare a variable in three ways:
                <p>With the keyword var. For example,
                    <code>x = 42.</code>
                    This syntax can be used to declare both local and global variables.
                </p>
                <p>By simply assigning it a value. For example,
                    <code>x = 42.</code>
                    This always declares a global variable. It generates a strict JavaScript warning. You shouldn't use this variant.</p>
                    <p>With the keyword let. For example,
                        <code>let y = 13.</code>
                        This syntax can be used to declare a block scope local variable. See Variable scope below.</p>
            </article>
        </section>
        <section class="main-section" id="Variable_scope">
            <header>Variable scope</header>
                <article>
                    <p>When you declare a variable outside of any function, it is called a global variable, because it is available to any other code in the current document. When you declare a variable within a function, it is called a local variable, because it is available only within that function.</p>
                    <p>JavaScript before ECMAScript 2015 does not have block statement scope; rather, a variable declared within a block is local to the function (or global scope) that the block resides within. For example the following code will log 5, because the scope of x is the function (or global context) within which x is declared, not the block, which in this case is an if statement.</p>
                    <code>if (true) { var x = 5; } console.log(x); // 5</code>
                    <p>This behavior changes, when using the let declaration introduced in ECMAScript 2015.</p>
                    <code>if (true) { let y = 5; } console.log(y); // ReferenceError: y is not
                        defined</code>
                </article>
        </section>
        <section class="main-section" id="Global_variables">
            <header>Global variables</header>
            <article>
            <p>Global variables are in fact properties of the global object. In web pages the global object is window, so you can set and access global variables using the window.variable syntax.</p>
            <p>Consequently, you can access global variables declared in one window or frame from another window or frame by specifying the window or frame name. For example, if a variable called phoneNumber is declared in a document, you can refer to this variable from an iframe as parent.phoneNumber.</p>
            </article>
        </section>
        <section class="main-section" id="Constants">
            <header>Constants</header>
            <article>
                <p>You can create a read-only, named constant with the const keyword. The syntax of a constant identifier is the same as for a variable identifier: it must start with a letter, underscore or dollar sign and can contain alphabetic, numeric, or underscore characters.</p>
                <code>const PI = 3.14;</code>
                <p>A constant cannot change value through assignment or be re-declared while the script is running. It has to be initialized to a value.</p>
                <p>The scope rules for constants are the same as those for let block scope variables. If the const keyword is omitted, the identifier is assumed to represent a variable.</p>
                <p>You cannot declare a constant with the same name as a function or variable in the same scope. For example:</p>
                <code>// THIS WILL CAUSE AN ERROR function f() {}; const f = 5; // THIS WILL
                    CAUSE AN ERROR ALSO function f() { const g = 5; var g; //statements
                    }</code>
                However, object attributes are not protected, so the following statement is executed without problems.
                <code>const MY_OBJECT = {"key": "value"}; MY_OBJECT.key = "otherValue";</code>
            </article>
        </section>
        <section class="main-section" id="Data_types">
            <header>Data types</header>
            <article>
            <p>The latest ECMAScript standard defines seven data types:</p>
            <ul>
                <li><p>Six data types that are primitives:</p></li>
                <ul>
                    <li>Boolean. true and false.</li>
                    <li>null. A special keyword denoting a null value. Because JavaScript is case-sensitive, null is not the same as Null, NULL, or any other variant.</li>
                    <li>undefined. A top-level property whose value is undefined.</li>
                    <li>Number. 42 or 3.14159.</li>
                    <li>String. "Howdy"</li>
                    <li>Symbol (new in ECMAScript 2015). A data type whose instances are unique and immutable.</li>
                </ul>
                <li>and Object</li>
            </ul>
            Although these data types are a relatively small amount, they enable you to perform useful functions with your applications. Objects and functions are the other fundamental elements in the language. You can think of objects as named containers for values, and functions as procedures that your application can perform.
            </article>
        </section>
        <section class="main-section" id="if...else_statement">
            <header>if...else statement</header>
            <article>
                Use the if statement to execute a statement if a logical condition is true. Use the optional else clause to execute a statement if the condition is false. An if statement looks as follows:
                <code>if (condition) { statement_1; } else { statement_2; }</code>
                condition can be any expression that evaluates to true or false. See Boolean for an explanation of what evaluates to true and false. If condition evaluates to true, statement_1 is executed; otherwise, statement_2 is executed. statement_1 and statement_2 can be any statement, including further nested if statements.
                <p>You may also compound the statements using else if to have multiple conditions tested in sequence, as follows:</p>
                <code>if (condition_1) { statement_1; } else if (condition_2) { statement_2;
                } else if (condition_n) { statement_n; } else { statement_last; }</code>
                In the case of multiple conditions only the first logical condition which evaluates to true will be executed. To execute multiple statements, group them within a block statement ({ ... }) . In general, it's good practice to always use block statements, especially when nesting if statements:
                <code>if (condition) { statement_1_runs_if_condition_is_true;
                    statement_2_runs_if_condition_is_true; } else {
                    statement_3_runs_if_condition_is_false;
                    statement_4_runs_if_condition_is_false; }</code>
                    It is advisable to not use simple assignments in a conditional expression, because the assignment can be confused with equality when glancing over the code. For example, do not use the following code:
                <code>if (x = y) { /* statements here */ }</code>
                If you need to use an assignment in a conditional expression, a common practice is to put additional parentheses around the assignment. For example:
                <code>if ((x = y)) { /* statements here */ }</code>
            </article>
        </section>
        <section class="main-section" id="while_statement">
            <header>while statement</header>
            <article>
                A while statement executes its statements as long as a specified condition evaluates to true. A while statement looks as follows:
                <code>while (condition) statement</code>
                If the condition becomes false, statement within the loop stops executing and control passes to the statement following the loop.
                <p>The condition test occurs before statement in the loop is executed. If the condition returns true, statement is executed and the condition is tested again. If the condition returns false, execution stops and control is passed to the statement following while.</p>
                <p>To execute multiple statements, use a block statement ({ ... }) to group those statements.</p>
                Example:
                <p>The following while loop iterates as long as n is less than three:</p>
                <code>var n = 0; var x = 0; while (n < 3) { n++; x += n; }</code>
                <p>With each iteration, the loop increments n and adds that value to x. Therefore, x and n take on the following values:</p>
                <ul>
                    <li>After the first pass: n = 1 and x = 1</li>
                    <li>After the second pass: n = 2 and x = 3</li>
                    <li>After the third pass: n = 3 and x = 6</li>
                </ul>
                <p>After completing the third pass, the condition n < 3 is no longer true, so the loop terminates.</p>
            </article>
        </section>
        <section class="main-section" id="Function_declarations">
            <header>Function declarations</header>
        <article>
            A function definition (also called a function declaration, or function statement) consists of the function keyword, followed by:
            <ul>
                <li>The name of the function.</li>
                <li>A list of arguments to the function, enclosed in parentheses and separated by commas.</li>
                <li>The JavaScript statements that define the function, enclosed in curly brackets, { }.</li>
            </ul>
            <p>For example, the following code defines a simple function named square:</p>
            <code>function square(number) { return number * number; }</code>
            <p>The function square takes one argument, called number. The function consists of one statement that says to return the argument of the function (that is, number) multiplied by itself. The return statement specifies the value returned by the function.</p>
            <code>return number * number;</code>
            <p>Primitive parameters (such as a number) are passed to functions by value; the value is passed to the function, but if the function changes the value of the parameter, this change is not reflected globally or in the calling function.</p>
        </article>
        </section>
        <section class="main-section" id="Reference">
            <header>Reference</header>
            <article>
            <ul>
                <li>All the documentation in this page is taken from <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide" target="_blank">MDN</a></li>
            </ul>
            </article>
        </section>
        </body>
    </main>
    <script src="https://cdn.freecodecamp.org/testable-projects-fcc/v1/bundle.js"></script>
</html>

Remove extra padding and margin from html and body elements by giving them value 0 and hide the extra scroll bar from the #main-doc by making its overflow-y property hidden that should fix the issue of extra space on the side.

You’re defining width: 100% on #main-doc. This isn’t necessary as a block-level element will occupy the full width of its parent container automatically.

This is part of your problem as you’re also applying padding to the container. There’s something called box-sizing which determines how the height and width of elements are calculated.

In your case box-sizing isn’t on so your width is being calculated as 100% + 20px padding which is what’s causing your container to breach page width. If you add box-sizing: border-box you’ll see a change in how that’s calculated.

I would also recommend using position: static on both your #main-doc and #navbar

By using position absolute you’re taking these elements out of document flow. If these two elements were static they would naturally sit vertically next to each other.

Both of your suggestions helped. Removing padding and margin from html and body, changing overflow-y to hidden in the media query, and changing the position of the nav and #main-doc to static all worked.

But I have question for each of you.

Why did changing the overflow-y to hidden do what it did? I would have expected it to remove the vertical scroll bar entirely and just hide the rest of the content out of view.

Why did changing the nav and #main-doc elements to static work? I would have expected them to just stack on top of each other like they were before.

And I’m just wondering why there is still a horizontal scroll bar at all. It’s not really a problem, I just want to understand why it’s there when it wasn’t while i was building all of this.

Thanks so much!

my fixed code

<html>
    <head>
        <title>Technical Documentation Page</title>
<style>
@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+KR:wght@100;300;400;500;700;900&display=swap');
html {
    font-family: Noto Sans KR;
    max-width: 100%;
    line-height: 1.5;
    padding: 0;
    margin: 0;
}
body {
    padding: 0;
    margin: 0;
}
main {
    display: block;
}
nav {
    position: fixed;
    min-width: 290px;
    height: 100%;
    border-right: solid;
    border-color: rgba(0, 22, 22, 0.4);
}
#nav-header {
    text-align: center;
    margin: 10px;
}
nav ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    width: 290px;
    height: 88%;
    overflow-y: auto;
    overflow-x: hidden;
}
nav li {
    border-top: 1px solid;
}
nav a {
    text-decoration: none;
    display: block;
    color: #4d4e53;
    padding: 10px 30px;
    cursor: pointer;
}
#main-doc {
    position: absolute;
    margin-left: 310px;
    padding: 20px;
    box-sizing: border-box;
}
header {
    font-size: 1.8em;
    margin: 0;
    text-align: left;
}
article {
    margin: 15px;
}
p {
    display: block;
}
section li {
    margin: 15px 0 0 20px;
}
code {
    display: block;
    text-align: left;
    line-height: 2;
    margin: 10px;
    padding: 15px;
    border-radius: 5px;
    background-color: #f7f7f7;
}
@media (max-width: 815px) {
    nav {
        position: static;
        padding: 0;
        margin: 0;
        width: 100%;
        max-height: 275px;
        border: none;
        z-index: 1;

    }
    nav ul {
        width: 100%;
        border: 1px solid;
        border-bottom: 2px solid;

    }
    #main-doc {
        position: static;
        margin-left: 0;
        margin-top: 20px;
        overflow-y: hidden;
    }
    
}
</style>
    </head>
    <body>
        <nav id="navbar">
            <header id="nav-header">JS Documentation</header>
            <ul>
                <li><a class="nav-link" href="#Introduction">Introduction</a></li>
                <li><a class="nav-link" href="#What_you_should_already_know">What you should already know</a></li>
                <li><a class="nav-link" href="#JavaScript_and_Java">JavaScript and Java</a></li>
                <li><a class="nav-link" href="#Hello_world">Hello world</a></li>
                <li><a class="nav-link" href="#Variables">Variables</a></li>
                <li><a class="nav-link" href="#Declaring_Variables">Declaring Variables</a></li>
                <li><a class="nav-link" href="#Variable_scope">Variable scope</a></li>
                <li><a class="nav-link" href="#Global_variables">Global variables</a></li>
                <li><a class="nav-link" href="#Constants">Constants</a></li>
                <li><a class="nav-link" href="#Data_types">Data types</a></li>
                <li><a class="nav-link" href="#if...else_statement">if...else statement</a></li>
                <li><a class="nav-link" href="#while_statement">while statement</a></li>
                <li><a class="nav-link" href="#Function_declarations">Function declarations</a></li>
                <li><a class="nav-link" href="#Reference">Reference</a></li>
            </ul>
        </nav>
        <main id="main-doc">
        <section class="main-section" id="Introduction">
            <header>Introduction</header>
            <article>
                <p>JavaScript is a cross-platform, object-oriented scripting language. It is a small and lightweight language. Inside a host environment (for example, a web browser), JavaScript can be connected to the objects of its environment to provide programmatic control over them.</p>
                <p>JavaScript contains a standard library of objects, such as Array, Date, and Math, and a core set of language elements such as operators, control structures, and statements. Core JavaScript can be extended for a variety of purposes by supplementing it with additional objects; for example:</p>
                <ul>
                    <li>Client-side JavaScript extends the core language by supplying objects to control a browser and its Document Object Model (DOM). For example, client-side extensions allow an application to place elements on an HTML form and respond to user events such as mouse clicks, form input, and page navigation.</li>
                    <li>Server-side JavaScript extends the core language by supplying objects relevant to running JavaScript on a server. For example, server-side extensions allow an application to communicate with a database, provide continuity of information from one invocation to another of the application, or perform file manipulations on a server.</li>
                </ul>
            </article>
        </section>
        <section class="main-section" id="What_you_should_already_know">
            <header>What you should already know</header>
            <article>
            <p>This guide assumes you have the following basic background:</p>
            <ul>
                <li>A general understanding of the Internet and the World Wide Web (WWW).</li>
                <li>Good working knowledge of HyperText Markup Language (HTML).</li>
                <li>Some programming experience. If you are new to programming, try one of the tutorials linked on the main page about JavaScript.</li>
            </ul>
            </article>
        </section>
        <section class="main-section" id="JavaScript_and_Java">
            <header>JavaScript and Java</header>
            <article>
            <p>JavaScript and Java are similar in some ways but fundamentally different in some others. The JavaScript language resembles Java but does not have Java's static typing and strong type checking. JavaScript follows most Java expression syntax, naming conventions and basic control-flow constructs which was the reason why it was renamed from LiveScript to JavaScript.</p>
            <p>In contrast to Java's compile-time system of classes built by declarations, JavaScript supports a runtime system based on a small number of data types representing numeric, Boolean, and string values. JavaScript has a prototype-based object model instead of the more common class-based object model. The prototype-based model provides dynamic inheritance; that is, what is inherited can vary for individual objects. JavaScript also supports functions without any special declarative requirements. Functions can be properties of objects, executing as loosely typed methods.</p>
            <p>JavaScript is a very free-form language compared to Java. You do not have to declare all variables, classes, and methods. You do not have to be concerned with whether methods are public, private, or protected, and you do not have to implement interfaces. Variables, parameters, and function return types are not explicitly typed.</p>
            </article>
        </section>
        <section class="main-section" id="Hello_world">
            <header>Hello world</header>
            <article>To get started with writing JavaScript, open the Scratchpad and write your first "Hello world" JavaScript code:        
            <code>function greetMe(yourName) { alert("Hello " + yourName); } greetMe("World");</code>
                Select the code in the pad and hit Ctrl+R to watch it unfold in your browser!</article>
        </section>
        <section class="main-section" id="Variables">
            <header>Variables</header>
            <article>
            <p>You use variables as symbolic names for values in your application. The names of variables, called identifiers, conform to certain rules.</p>
            <p>A JavaScript identifier must start with a letter, underscore (_), or dollar sign ($); subsequent characters can also be digits (0-9). Because JavaScript is case sensitive, letters include the characters "A" through "Z" (uppercase) and the characters "a" through "z" (lowercase).</p>
            <p>You can use ISO 8859-1 or Unicode letters such as å and ü in identifiers. You can also use the Unicode escape sequences as characters in identifiers. Some examples of legal names are Number_hits, temp99, and _name.</p>
            </article>
        </section>
        <section class="main-section" id="Declaring_Variables">
            <header>Declaring Variables</header>
            <article>
                You can declare a variable in three ways:
                <p>With the keyword var. For example,
                    <code>x = 42.</code>
                    This syntax can be used to declare both local and global variables.
                </p>
                <p>By simply assigning it a value. For example,
                    <code>x = 42.</code>
                    This always declares a global variable. It generates a strict JavaScript warning. You shouldn't use this variant.</p>
                    <p>With the keyword let. For example,
                        <code>let y = 13.</code>
                        This syntax can be used to declare a block scope local variable. See Variable scope below.</p>
            </article>
        </section>
        <section class="main-section" id="Variable_scope">
            <header>Variable scope</header>
                <article>
                    <p>When you declare a variable outside of any function, it is called a global variable, because it is available to any other code in the current document. When you declare a variable within a function, it is called a local variable, because it is available only within that function.</p>
                    <p>JavaScript before ECMAScript 2015 does not have block statement scope; rather, a variable declared within a block is local to the function (or global scope) that the block resides within. For example the following code will log 5, because the scope of x is the function (or global context) within which x is declared, not the block, which in this case is an if statement.</p>
                    <code>if (true) { var x = 5; } console.log(x); // 5</code>
                    <p>This behavior changes, when using the let declaration introduced in ECMAScript 2015.</p>
                    <code>if (true) { let y = 5; } console.log(y); // ReferenceError: y is not
                        defined</code>
                </article>
        </section>
        <section class="main-section" id="Global_variables">
            <header>Global variables</header>
            <article>
            <p>Global variables are in fact properties of the global object. In web pages the global object is window, so you can set and access global variables using the window.variable syntax.</p>
            <p>Consequently, you can access global variables declared in one window or frame from another window or frame by specifying the window or frame name. For example, if a variable called phoneNumber is declared in a document, you can refer to this variable from an iframe as parent.phoneNumber.</p>
            </article>
        </section>
        <section class="main-section" id="Constants">
            <header>Constants</header>
            <article>
                <p>You can create a read-only, named constant with the const keyword. The syntax of a constant identifier is the same as for a variable identifier: it must start with a letter, underscore or dollar sign and can contain alphabetic, numeric, or underscore characters.</p>
                <code>const PI = 3.14;</code>
                <p>A constant cannot change value through assignment or be re-declared while the script is running. It has to be initialized to a value.</p>
                <p>The scope rules for constants are the same as those for let block scope variables. If the const keyword is omitted, the identifier is assumed to represent a variable.</p>
                <p>You cannot declare a constant with the same name as a function or variable in the same scope. For example:</p>
                <code>// THIS WILL CAUSE AN ERROR function f() {}; const f = 5; // THIS WILL
                    CAUSE AN ERROR ALSO function f() { const g = 5; var g; //statements
                    }</code>
                However, object attributes are not protected, so the following statement is executed without problems.
                <code>const MY_OBJECT = {"key": "value"}; MY_OBJECT.key = "otherValue";</code>
            </article>
        </section>
        <section class="main-section" id="Data_types">
            <header>Data types</header>
            <article>
            <p>The latest ECMAScript standard defines seven data types:</p>
            <ul>
                <li><p>Six data types that are primitives:</p></li>
                <ul>
                    <li>Boolean. true and false.</li>
                    <li>null. A special keyword denoting a null value. Because JavaScript is case-sensitive, null is not the same as Null, NULL, or any other variant.</li>
                    <li>undefined. A top-level property whose value is undefined.</li>
                    <li>Number. 42 or 3.14159.</li>
                    <li>String. "Howdy"</li>
                    <li>Symbol (new in ECMAScript 2015). A data type whose instances are unique and immutable.</li>
                </ul>
                <li>and Object</li>
            </ul>
            Although these data types are a relatively small amount, they enable you to perform useful functions with your applications. Objects and functions are the other fundamental elements in the language. You can think of objects as named containers for values, and functions as procedures that your application can perform.
            </article>
        </section>
        <section class="main-section" id="if...else_statement">
            <header>if...else statement</header>
            <article>
                Use the if statement to execute a statement if a logical condition is true. Use the optional else clause to execute a statement if the condition is false. An if statement looks as follows:
                <code>if (condition) { statement_1; } else { statement_2; }</code>
                condition can be any expression that evaluates to true or false. See Boolean for an explanation of what evaluates to true and false. If condition evaluates to true, statement_1 is executed; otherwise, statement_2 is executed. statement_1 and statement_2 can be any statement, including further nested if statements.
                <p>You may also compound the statements using else if to have multiple conditions tested in sequence, as follows:</p>
                <code>if (condition_1) { statement_1; } else if (condition_2) { statement_2;
                } else if (condition_n) { statement_n; } else { statement_last; }</code>
                In the case of multiple conditions only the first logical condition which evaluates to true will be executed. To execute multiple statements, group them within a block statement ({ ... }) . In general, it's good practice to always use block statements, especially when nesting if statements:
                <code>if (condition) { statement_1_runs_if_condition_is_true;
                    statement_2_runs_if_condition_is_true; } else {
                    statement_3_runs_if_condition_is_false;
                    statement_4_runs_if_condition_is_false; }</code>
                    It is advisable to not use simple assignments in a conditional expression, because the assignment can be confused with equality when glancing over the code. For example, do not use the following code:
                <code>if (x = y) { /* statements here */ }</code>
                If you need to use an assignment in a conditional expression, a common practice is to put additional parentheses around the assignment. For example:
                <code>if ((x = y)) { /* statements here */ }</code>
            </article>
        </section>
        <section class="main-section" id="while_statement">
            <header>while statement</header>
            <article>
                A while statement executes its statements as long as a specified condition evaluates to true. A while statement looks as follows:
                <code>while (condition) statement</code>
                If the condition becomes false, statement within the loop stops executing and control passes to the statement following the loop.
                <p>The condition test occurs before statement in the loop is executed. If the condition returns true, statement is executed and the condition is tested again. If the condition returns false, execution stops and control is passed to the statement following while.</p>
                <p>To execute multiple statements, use a block statement ({ ... }) to group those statements.</p>
                Example:
                <p>The following while loop iterates as long as n is less than three:</p>
                <code>var n = 0; var x = 0; while (n < 3) { n++; x += n; }</code>
                <p>With each iteration, the loop increments n and adds that value to x. Therefore, x and n take on the following values:</p>
                <ul>
                    <li>After the first pass: n = 1 and x = 1</li>
                    <li>After the second pass: n = 2 and x = 3</li>
                    <li>After the third pass: n = 3 and x = 6</li>
                </ul>
                <p>After completing the third pass, the condition n < 3 is no longer true, so the loop terminates.</p>
            </article>
        </section>
        <section class="main-section" id="Function_declarations">
            <header>Function declarations</header>
        <article>
            A function definition (also called a function declaration, or function statement) consists of the function keyword, followed by:
            <ul>
                <li>The name of the function.</li>
                <li>A list of arguments to the function, enclosed in parentheses and separated by commas.</li>
                <li>The JavaScript statements that define the function, enclosed in curly brackets, { }.</li>
            </ul>
            <p>For example, the following code defines a simple function named square:</p>
            <code>function square(number) { return number * number; }</code>
            <p>The function square takes one argument, called number. The function consists of one statement that says to return the argument of the function (that is, number) multiplied by itself. The return statement specifies the value returned by the function.</p>
            <code>return number * number;</code>
            <p>Primitive parameters (such as a number) are passed to functions by value; the value is passed to the function, but if the function changes the value of the parameter, this change is not reflected globally or in the calling function.</p>
        </article>
        </section>
        <section class="main-section" id="Reference">
            <header>Reference</header>
            <article>
            <ul>
                <li>All the documentation in this page is taken from <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide" target="_blank">MDN</a></li>
            </ul>
            </article>
        </section>
        </body>
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The horizontal scroll is caused by one of your <code> blocks exceeding page-width. The text in these blocks only wraps on a line-break, the same as a <pre> tag.

You could use overflow-wrap: anywhere which will allow the text to wrap.

Or alternatively use overflow:auto. This will maintain your code on single lines but will allow users to scroll within the code block to read any hidden content.

As for the static position change, I would recommend reading the link I posted in my previous reply: In Flow and Out of Flow. I suspect this article will do a better job of explaining what’s going on better than I could.