Challenge solutions

This page provides solutions to the challenges posed in the CSS Styling basics module. These are not the only possible solutions. The sections below correspond to the titles of the tutorial sections.

Cascading and inheritance

The challenges on page Handling conflicts are:

Inherited styles

• Challenge

  • : Change your stylesheet so that only the red letters are underlined.

• Solution

  • : Move the declaration for underlining from the rule for {{ HTMLElement("p") }}  to the one for {{ HTMLElement("strong") }} . The resulting file looks like this:

    p {
      color: blue;
    }
    strong {
      color: orange;
      text-decoration: underline;
    }
    

Later sections of this tutorial describe style rules and declarations in greater detail.

Selectors

The challenges on page Basic selectors are:

Second paragraph blue

• Challenge

  • : Without changing your HTML file, add a single rule to your CSS file that keeps all the initial letters the same color as they are now, but makes all the other text in the second paragraph blue.

• Solution

  • : Add a rule with an ID selector of #second and a declaration color: blue;, as shown below:

    #second {
      color: blue;
    }
    

    A more specific selector, p#second also works.

Both paragraphs blue

• Challenge

  • : Now change the rule you have just added (without changing anything else), to make the first paragraph blue too.

• Solution

  • : Change the selector of the new rule to be a tag selector using p:

    p {
      color: blue;
    }
    

The rules for the other colors all have more specific selectors, so they override the blue of the paragraph.

Readable CSS

Commenting out a rule

• Challenge

  • : Comment out part of your stylesheet, without changing anything else, to make the very first letter of your document red.

• Solution

  • : One way to do this is to put comment delimiters around the rule for .carrot:

    /*
    .carrot {
      color: orange;
    }
    */
    

Text styles

Big initial letters

• Challenge

  • : Without changing anything else, make all six initial letters twice the size in the browser’s default serif font.

• Solution

  • : Add the following style declaration to the strong rule:

    font: 200% serif;
    

    If you use separate declarations for font-size and font-family, then the font-style setting on the first paragraph is not overridden.

Color

Three-digit color codes

• Challenge

  • : In your CSS file, change all the color names to 3-digit color codes without affecting the result.

• Solution

  • : The following values are reasonable approximations of the named colors:

    strong {
      color: #f00; /* red */
      background-color: #ddf; /* pale blue */
      font: 200% serif;
    }
    
    .carrot {
      color: #fa0; /* orange */
    }
    
    .spinach {
      color: #080; /* dark green */
    }
    
    p {
      color: #00f; /* blue */
    }
    

Content

The challenges on page are:

Add an image

• Challenge

  • : Add a one rule to your stylesheet so that it displays the image at the start of each line.

• Solution

  • : Add this rule to your stylesheet:

    p::before {
      content: url("yellow-pin.png");
    }
    

Lists

The challenges on page Styling lists are:

Lower Roman numerals

• Challenge

  • : Add a rule to your stylesheet, to number the oceans using Roman numerals from i to v.

• Solution

  • : Define a rule for list items to use the lower-roman list style:

    li {
      list-style: lower-roman;
    }
    

Capital letters

• Challenge

  • : Change your stylesheet to identify the headings with capital letters in parentheses.

• Solution

  • : Add a rule to the body element (parent of the headings) to reset a new counter, and one to display and increment the counter on the headings:

    /* numbered headings */
    body {
      counter-reset: head-num;
    }
    h3::before {
      content: "(" counter(head-num, upper-latin) ") ";
      counter-increment: head-num;
    }
    

Boxes

The challenges on page Boxes are:

Ocean border

• Challenge

  • : Add one rule to your stylesheet, making a wide border all around the oceans in a color that reminds you of the sea.

• Solution

  • : The following rule achieves this effect:

    ul {
      border: 10px solid lightblue;
      width: 100px;
    }
    

Layout

The challenges on page Layout are:

Default image position

Fixed image position

• Challenge

  • : Change your sample document, doc2.html, adding this tag to it near the end, just before </BODY>: <IMG id="fixed-pin" src="Yellow-pin.png" alt="Yellow map pin"> Predict where the image will appear in your document. Then refresh your browser to see if you were correct.

• Solution

  • : The image appears to the right of the second list.

• Challenge

  • : Add a rule to your stylesheet that places the image in the top right of your document.

• Solution

  • : The following rule achieves the desired result:

    #fixed-pin {
      position: fixed;
      top: 3px;
      right: 3px;
    }
    

Tables

The challenges on page Tables are:

Borders on data cells only

• Challenge

  • : Change the stylesheet to make the table have a green border around only the data cells.

• Solution

  • : The following rule puts borders around only {{ HTMLElement("td") }}  elements that are inside the {{ HTMLElement("tbody") }}  element of the table with id=demo-table:

    #demo-table tbody td {
      border: 1px solid #7a7;
    }
    

Media

The challenges on page Media are:

Separate print style file

• Challenge

  • : Move the print-specific style rules to a separate CSS file and import them into your style4.css stylesheet.

• Solution

  • : Cut and paste the lines between /* print only */ and /* end print only */ into a file named style4_print.css. In style4.css, add the following line at the beginning of the file:

    @import url("style4_print.css") print;
    

Heading hover color

• Challenge

  • : Make the headings turn blue when the mouse pointer is over them.

• Solution

  • : The following rule achieves the desired result:

    h1:hover {
      color: blue;
    }
    

JavaScript

Move box to the right

• Challenge

  • : Change the script so that the square jumps to the right by 20 em when its color changes, and jumps back afterwards.

• Solution

  • : Add lines to modify the margin-left property. Be sure to specify it as marginLeft in JavaScript. The following script achieves the desired result:

    // JavaScript demonstration
    function doDemo(button) {
      const square = document.getElementById("square");
      square.style.backgroundColor = "#fa4";
      square.style.marginLeft = "20em";
      button.setAttribute("disabled", "true");
      setTimeout(clearDemo, 2000, button);
    }
    
    function clearDemo(button) {
      const square = document.getElementById("square");
      square.style.backgroundColor = "transparent";
      square.style.marginLeft = "0em";
      button.removeAttribute("disabled");
    }
    

SVG and CSS

Change color of inner petals

• Challenge

  • : Change the stylesheet so that the inner petals all turn pink when the mouse pointer is over any one of them, without changing the way the outer petals work.

• Solution

  • : Move the position of the :hover pseudo-class from a specific petal, to all petals

    #inner-petals {
      --segment-fill-fill-hover: pink;
    }
    
    /* Non-standard way for some older browsers */
    #inner-petals:hover .segment-fill {
      fill: pink;
      stroke: none;
    }