/***************************************************************************
 *                              MOBILE                                     *
 * One breakpoint: 767px (aligned with Foundation's grid collapse).        *
 * Below it: hamburger nav, stacked layout, contained overflow, tighter    *
 * whitespace. Above it: the desktop layout, untouched.                     *
 ***************************************************************************/

/* The hamburger is mobile-only. */
.nav-toggle-label,
#nav-toggle {
  display: none;
}

@media only screen and (max-width: 767px) {
  /* Whitespace adapts: smaller gutters than the desktop 20px. */
  .container {
    padding: 0 12px;
  }

  /* Logo and hamburger share one row: logo left, hamburger right. */
  header .row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin: 12px 0;
  }
  header .row > a {
    flex: 1 1 auto;
    min-width: 0;
  }
  /* The 980px logo must never overflow the viewport; leave room for
     the hamburger plus its margin. display: block removes the inline
     baseline gap so align-items: center centers the image itself. */
  header .row img[alt="Logo"] {
    display: block;
    max-width: 100%;
    height: auto;
  }

  /* Hamburger button, fixed at the right of the logo row. */
  #nav-toggle {
    /* Visually hidden but focusable; the label is the visible button. */
    position: absolute;
    opacity: 0;
    width: 30px;
    height: 30px;
    margin: 0;
  }
  /* Flex column so the bars center inside the 30px box. The row's
     align-items: center then puts the bars' center on the logo box's
     center, which is also the visual glyph's center: the logo's baked-in
     white padding is symmetric (~12px top/bottom at 980x84) and scales
     uniformly with the image, so no per-viewport offset is needed. */
  .nav-toggle-label {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    flex: 0 0 30px;
    height: 30px;
    margin: 0 12px 0 12px;
    cursor: pointer;
    z-index: 110;
  }
  .nav-toggle-label span {
    display: block;
    width: 16px;
    height: 4px;
    margin-bottom: 5px;
    background-color: #212121;
    border-radius: 2px;
    transition: transform 0.2s ease, opacity 0.2s ease;
  }
  .nav-toggle-label span:last-child {
    margin-bottom: 0;
  }

  /* Menu closed: the inline nav is hidden on mobile. */
  nav#main .onion ul {
    display: none;
  }

  /* Menu open: full-screen vertical list. */
  #nav-toggle:checked ~ nav#main .onion ul {
    display: flex;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    margin: 0;
    padding: 20% 1em 0 1em;
    flex-direction: column;
    align-items: center;
    background: #fff;
    z-index: 100;
  }
  #nav-toggle:checked ~ nav#main .onion {
    background: none;
  }
  nav#main ul li {
    display: block;
    padding: 0.6em 0;
  }
  nav#main a {
    padding: 0;
    font-size: 1.6em;
  }
  nav#main a.active,
  nav#main a:hover {
    background: none;
    color: #212121;
  }

  /* Hamburger becomes a close button while open. The label is nested
     inside the logo row, the checkbox is its sibling before that row. */
  #nav-toggle:checked ~ .row .nav-toggle-label span:nth-child(1) {
    transform: translateY(9px) rotate(45deg);
  }
  #nav-toggle:checked ~ .row .nav-toggle-label span:nth-child(2) {
    opacity: 0;
  }
  #nav-toggle:checked ~ .row .nav-toggle-label span:nth-child(3) {
    transform: translateY(-9px) rotate(-45deg);
  }

  /* Aside/decorative images drop below the content and fit the screen. */
  article figure.decorative {
    max-width: 100%;
  }
  article figure img,
  article figure img[src*="/images/"] {
    max-width: 100%;
    height: auto;
  }

  /* Nothing may introduce horizontal scrolling. */
  article pre {
    width: auto;
    max-width: 100%;
    overflow-x: scroll;
    -webkit-overflow-scrolling: touch;
  }
  img,
  embed,
  object,
  video {
    max-width: 100%;
    height: auto;
  }
}