243 lines
7.9 KiB
Markdown
243 lines
7.9 KiB
Markdown
---
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id: 587d778d367417b2b2512aaa
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title: Make Elements Only Visible to a Screen Reader by Using Custom CSS
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challengeType: 0
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videoUrl: 'https://scrimba.com/c/cJ8QGkhJ'
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---
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## Description
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<section id='description'>
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Have you noticed that all of the applied accessibility challenges so far haven't used any CSS? This is to show the importance of a logical document outline, and using semantically meaningful tags around your content before introducing the visual design aspect.
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However, CSS's magic can also improve accessibility on your page when you want to visually hide content meant only for screen readers. This happens when information is in a visual format (like a chart), but screen reader users need an alternative presentation (like a table) to access the data. CSS is used to position the screen reader-only elements off the visual area of the browser window.
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Here's an example of the CSS rules that accomplish this:
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```css
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.sr-only {
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position: absolute;
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left: -10000px;
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width: 1px;
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height: 1px;
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top: auto;
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overflow: hidden;
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}
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```
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<strong>Note:</strong> The following CSS approaches will NOT do the same thing:
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<ul>
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<li><code>display: none;</code> or <code>visibility: hidden;</code> hides content for everyone, including screen reader users</li>
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<li>Zero values for pixel sizes, such as <code>width: 0px; height: 0px;</code> removes that element from the flow of your document, meaning screen readers will ignore it</li>
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</ul>
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</section>
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## Instructions
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<section id='instructions'>
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Camper Cat created a really cool stacked bar chart for his training page, and put the data into a table for his visually impaired users. The table already has an <code>sr-only</code> class, but the CSS rules aren't filled in yet. Give the <code>position</code> an absolute value, the <code>left</code> a -10000px value, and the <code>width</code> and <code>height</code> both 1px values.
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</section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: Your code should set the <code>position</code> property of the <code>sr-only</code> class to a value of absolute.
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testString: assert($('.sr-only').css('position') == 'absolute', 'Your code should set the <code>position</code> property of the <code>sr-only</code> class to a value of absolute.');
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- text: Your code should set the <code>left</code> property of the <code>sr-only</code> class to a value of -10000px.
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testString: assert($('.sr-only').css('left') == '-10000px', 'Your code should set the <code>left</code> property of the <code>sr-only</code> class to a value of -10000px.');
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- text: Your code should set the <code>width</code> property of the <code>sr-only</code> class to a value of 1 pixel.
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testString: assert(code.match(/width:\s*?1px/gi), 'Your code should set the <code>width</code> property of the <code>sr-only</code> class to a value of 1 pixel.');
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- text: Your code should set the <code>height</code> property of the <code>sr-only</code> class to a value of 1 pixel.
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testString: assert(code.match(/height:\s*?1px/gi), 'Your code should set the <code>height</code> property of the <code>sr-only</code> class to a value of 1 pixel.');
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='html-seed'>
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```html
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<head>
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<style>
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.sr-only {
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position: ;
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left: ;
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width: ;
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height: ;
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top: auto;
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overflow: hidden;
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}
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</style>
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</head>
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<body>
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<header>
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<h1>Training</h1>
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<nav>
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<ul>
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<li><a href="#stealth">Stealth & Agility</a></li>
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<li><a href="#combat">Combat</a></li>
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<li><a href="#weapons">Weapons</a></li>
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</ul>
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</nav>
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</header>
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<section>
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<h2>Master Camper Cat's Beginner Three Week Training Program</h2>
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<figure>
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<!-- Stacked bar chart of weekly training-->
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<p>[Stacked bar chart]</p>
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<br />
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<figcaption>Breakdown per week of time to spend training in stealth, combat, and weapons.</figcaption>
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</figure>
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<table class="sr-only">
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<caption>Hours of Weekly Training in Stealth, Combat, and Weapons</caption>
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<thead>
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<tr>
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<th></th>
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<th scope="col">Stealth & Agility</th>
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<th scope="col">Combat</th>
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<th scope="col">Weapons</th>
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<th scope="col">Total</th>
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</tr>
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</thead>
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<tbody>
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<tr>
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<th scope="row">Week One</th>
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<td>3</td>
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<td>5</td>
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<td>2</td>
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<td>10</td>
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</tr>
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<tr>
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<th scope="row">Week Two</th>
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<td>4</td>
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<td>5</td>
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<td>3</td>
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<td>12</td>
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</tr>
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<tr>
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<th scope="row">Week Three</th>
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<td>4</td>
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<td>6</td>
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<td>3</td>
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<td>13</td>
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</tr>
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</tbody>
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</table>
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</section>
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<section id="stealth">
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<h2>Stealth & Agility Training</h2>
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<article><h3>Climb foliage quickly using a minimum spanning tree approach</h3></article>
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<article><h3>No training is NP-complete without parkour</h3></article>
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</section>
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<section id="combat">
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<h2>Combat Training</h2>
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<article><h3>Dispatch multiple enemies with multithreaded tactics</h3></article>
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<article><h3>Goodbye, world: 5 proven ways to knock out an opponent</h3></article>
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</section>
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<section id="weapons">
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<h2>Weapons Training</h2>
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<article><h3>Swords: the best tool to literally divide and conquer</h3></article>
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<article><h3>Breadth-first or depth-first in multi-weapon training?</h3></article>
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</section>
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<footer>© 2018 Camper Cat</footer>
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</body>
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```html
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<head>
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<style>
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.sr-only {
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position: absolute;
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left: -10000px;
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width: 1px;
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height: 1px;
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top: auto;
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overflow: hidden;
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}
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</style>
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</head>
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<body>
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<header>
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<h1>Training</h1>
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<nav>
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<ul>
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<li><a href="#stealth">Stealth & Agility</a></li>
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<li><a href="#combat">Combat</a></li>
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<li><a href="#weapons">Weapons</a></li>
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</ul>
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</nav>
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</header>
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<section>
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<h2>Master Camper Cat's Beginner Three Week Training Program</h2>
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<figure>
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<!-- Stacked bar chart of weekly training-->
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<p>[Stacked bar chart]</p>
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<br />
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<figcaption>Breakdown per week of time to spend training in stealth, combat, and weapons.</figcaption>
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</figure>
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<table class="sr-only">
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<caption>Hours of Weekly Training in Stealth, Combat, and Weapons</caption>
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<thead>
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<tr>
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<th></th>
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<th scope="col">Stealth & Agility</th>
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<th scope="col">Combat</th>
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<th scope="col">Weapons</th>
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<th scope="col">Total</th>
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</tr>
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</thead>
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<tbody>
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<tr>
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<th scope="row">Week One</th>
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<td>3</td>
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<td>5</td>
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<td>2</td>
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<td>10</td>
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</tr>
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<tr>
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<th scope="row">Week Two</th>
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<td>4</td>
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<td>5</td>
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<td>3</td>
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<td>12</td>
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</tr>
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<tr>
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<th scope="row">Week Three</th>
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<td>4</td>
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<td>6</td>
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<td>3</td>
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<td>13</td>
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</tr>
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</tbody>
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</table>
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</section>
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<section id="stealth">
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<h2>Stealth & Agility Training</h2>
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<article><h3>Climb foliage quickly using a minimum spanning tree approach</h3></article>
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<article><h3>No training is NP-complete without parkour</h3></article>
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</section>
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<section id="combat">
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<h2>Combat Training</h2>
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<article><h3>Dispatch multiple enemies with multithreaded tactics</h3></article>
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<article><h3>Goodbye, world: 5 proven ways to knock out an opponent</h3></article>
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</section>
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<section id="weapons">
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<h2>Weapons Training</h2>
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<article><h3>Swords: the best tool to literally divide and conquer</h3></article>
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<article><h3>Breadth-first or depth-first in multi-weapon training?</h3></article>
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</section>
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<footer>© 2018 Camper Cat</footer>
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</body>
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```
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</section>
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