/* RESET */

html, body, div, span, h1, h2, h3, h4, h5, h6, p, ul, ol, li, dl, dt, dd, img, fieldset, form, label, legend, table, caption, tbody, tfoot, thead, tr, th, td, a, article, aside, details, figcaption, figure, footer, header, hgroup, main, menu, nav, section {
    margin: 0;
    padding: 0;
    border: 0;
}
 
* {
    box-sizing: border-box;
}

/* END OF RESET */


/* LAYOUT */

/* Flexboxes */

header {
    display: flex;
    justify-content: space-between;
    
    /* Vertically centre the two flex items - note the vertical alignment of 
       the header text. */
    align-items: center;
}

header > img {
    width: 4rem;
}

/* Margins and padding */

nav, main, aside, footer {
    padding: 1em;
}

header > p {
    margin-right: 1em;
}

aside div {
    margin-bottom: 2em;
    padding: 2em;
}


/* TYPOGRAPHY */

body {
    font-family: Arial, sans-serif;
    line-height: 1.5;
}

h1, h2, h3 {
    font-family: Georgia, "Times New Roman", serif;
    font-weight: bold;
}

h1 {
    font-size: 2rem;
}

h2 {
    font-size: 1.5rem;
}

p {
    margin-bottom: 1em;
}

header > p {
    font-family: Georgia, "Times New Roman", serif;
    font-size: 1.5rem;
    text-align: right;
    margin-bottom: 0;
}

aside {
    text-align: center;
}

aside p {
    font-size: 0.8rem;
    margin-bottom: 0;
}

.instrument-name {
    font-style: italic;
}


/* COLOUR SCHEME & BORDERS */

body {
    color: #444;
}

header {
    background-color: #000;
    color: #fff;
}

aside > div {
    background-color: #e0e0e0;
    
    /* Investigate borders a bit more... */
    border: 1px solid #888;
    border-radius: 0.5em;
}

nav, footer {
    background-color: #444;
}

nav a, footer a {
    color: #fff;
}

.selected, a:hover {
    color: #f00;
}


/* NAVIGATION */

nav ul, footer ul {
    list-style-type: none;
}

nav a, footer a {
    text-decoration: none;
}


/* IMAGES */

/* Don't forget this! */
img {
    width: 100%;
}


/* RESPONSIVENESS */

@media screen and (min-width: 42em) {
    
    /* Page grid */

    body {
        display: grid;
        
        /* One fixed-width central column, with flexible space on either side. */
        grid-template-columns: 1fr 40rem 1fr;
        grid-template-areas: " header header header"
                             " menu menu menu "
                             " . main . "
                             " . aside . "
                             " footer footer footer ";
    }
    
    header {
        grid-area: header;
    }
    
    nav {
        grid-area: menu;
    }
    
    main {
        grid-area: main;
    }
    
    aside {
        grid-area: aside;
    }
    
    footer {
        grid-area: footer;
    }        
    
    /* Flexboxes */
    
    nav ul {
        display: flex;
        justify-content: center;
    }
        
    aside {
        display: flex;
        justify-content: space-between;
        gap: 2em;
    }
    
    aside > div {
        flex-basis: 0;
        flex-grow: 1;
    }
    
    footer ul {
        display: flex;
        justify-content: center;
    }
   
    /* Margins and padding */
    
    nav li {
        /* Push the menu items apart with right and left margins. */
        margin: 0 1em;
    }

    footer li {
        /* Push the list items apart horizontally. We need equal left and right
           margins to keep the centering of the list items. */
        margin: 0 1em;
    }

}

@media screen and (min-width: 62em) {
    
    /* Page grid */

    body {
        /* Two fixed-width central columns, with flexible space on either side. */
        grid-template-columns: 1fr 20rem 40rem 1fr;
        grid-template-areas: " header header header header "
                             " menu   menu   menu   menu "
                             " .      aside  main   . "
                             " footer footer footer footer";
    }


    /* Other layout */
    
    aside {
        /* We don't want this to be a flexbox anymore, so change it back to a block,
           which is its default. */
        display: block;
    }

    
}