body {
    /* try to use systems' UI fonts */
    font-family: system-ui,-apple-system,"Public Sans","Segoe UI","Noto Sans",Oxygen-Sans,Ubuntu,Roboto,Cantarell,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;
}

/* SMALL SCREENS (“mobile first”) */
#wrapper {
    display: grid;
    max-width: 900px;
    margin: 0 auto 0 auto;
    border: 0px solid #000000;
    grid-template-columns: 1fr 1fr;
    grid-template-areas: 
	"lg lg"
	"hd hd"
	"nv nv"
	"ct ct"
	"ft ft";
}
#logo {
    grid-area: lg;
    position: relative;
    height: 36px;
    margin-top: 20px;
    margin-bottom: 20px;
}
#logo-dart img {
    position: absolute;
    left: 0;
    bottom: 0;
    max-width: 47%;
    height: auto;
}
#logo-math img {
    position: absolute;
    right: 0;
    bottom: 0;
    max-width: 47%;
    height: auto;
}

#header {
    grid-area: hd;
    text-align: center;
    color: #666666;
    background-color: #EEEEEE;
}

#navigation {
    grid-area: nv;
    width: 100%;
    background-color: #666666;
    color: white;
}

#content {
    grid-area: ct;
}

#footer {
    grid-area: ft;
}

a {
  color: inherit;
  text-decoration: none;
  border-bottom: 2px solid lightgray;
}

a:hover {
  border-bottom: 2px solid #424141;
}

a.logolink {
  text-decoration: none;
  border: none;
}

table, th, td {
  padding: 7px !important;
  border: 1px solid !important;
  border-collapse: collapse !important;
}

/* navigation */
/* Hamburger */
#navigation label {
    display: inline-block;
    font-style: normal;
    font-size: 1.2em;
    padding: 5px;
}
/* hide checkbox */
#hamburger {
    display: none;
}
/* Toggle show/hide menu on checkbox click */
#navigation ul {
    display: none;
    list-style-type: none;
    padding: 0;
}
/* Break down menu items into vertical */
#navigation ul li {
    display: block;
    padding: 5px;
}
#navigation ul li:hover {
    background-color: #999999;
}
#navigation ul li a {
    text-decoration: none;
    border: none;
}
#navigation input:checked ~ ul {
    display: block;
}

#dropdown1-div ul {
    display: none;
}

.down {
    display: none;
}

/********* BIGGER SCREENS **********/
@media (min-width: 520px) {
  #wrapper {
    grid-template-columns: 1fr 4fr 4fr 1fr;
    grid-template-areas: 
	"lg lg lg lg"
	"hd hd hd hd"
	"nv nv nv nv"
	".  ct ct . "
	"ft ft ft ft";
  }

  #navigation {
    text-align: center;
  }
  /* Hide Hamburger */
  #navigation label {
    display: none;
  }
  /* Menu Items */
  #navigation ul {
    display: flex;
    justify-content: center; /* flexbox align horizontal */
    align-items: center; /* flexbox align vertical */
    margin: 0;
    padding: 0;
  }
  #navigation ul li {
    display: inline-block;
    padding: 10px;
    box-sizing: border-box;
  }

  #dropdown1-div ul {
    display: none;
    position: absolute;
    box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
    z-index: 1;
  }
  #dropdown1-div ul li {
    display: block;
    float: none;
    text-align: left;
  }

  #dropdown1-div ul li:hover {
    background-color: #999999;
  }
  /* Show the dropdown menu on hover */
  #dropdown1:hover #dropdown1-div ul {
    display: block;
    background-color: #666666;
  }

  .down {
    display: inline;
  }

} /* END BIGGER SCREENS */