html {
  background-color: gray;
}

body {
  margin: 0;
  border-width: 0;
  padding: 0;
}

#header {
  display: flex;
  align-items: center;
  column-gap: 2rem;
  padding: 3px;
  background-color: lightgray;
}

#header a > img {
  height: 2em;
  border: none;
  margin: 0;
  margin-bottom: -4px; /* Ugly, ugly hack */
  padding: 0;
}

#header > a {
  display: inline-block;
  text-decoration: none;
  padding: 0;
  margin: 0;
  border: none;
}
#header > a:hover {
  color: white;
}


#main {
  position: relative;
  margin: 1rem;
  padding: 2rem;
  background-color: lightgray;
  background-image: url('math_girl.svg');
  background-repeat: no-repeat;
  background-position: right 1rem top 1rem;
  background-size: 7rem;
  border-radius: 0rem 3rem 3rem 3rem;
}

nav {
  position: absolute;
  top: 0;
  left: 0;
  border-style: solid;
  border-color: gray;
  border-width: 0 0 1px 0;
  background-color: transparent;
}
nav ul
{
  list-style-type: none;
  display: block;
  float: left;
  margin: 0;
  padding: 0;
}
nav ul li {
  float: left;
  margin: 0;
  padding: 0;
}
nav ul li a {
  text-decoration: none;
  display: inline-block;
  margin: 0;
  padding: .5rem;
  padding-left: 1rem;
  padding-right: 1rem;
  color: inherit;
}
nav ul li a:active {
  color: white;
  background-color: black;
}
nav ul li a:hover:not(:active) {
  background-color: darkgray;
}

h1 {
  margin-right: 6rem;
}

h2 {
  margin-top: 2em;
}

h2.separated_header {
  text-align: center;
  text-decoration: underline;
}
h2.separated_header:not(:first-of-type) {
  margin-top: 4em;
}

p {
}

.important {
  background-color: #FAA;
}

p.important, div.important {
  padding: 1em;
  border-radius: 1em;
}

span.important {
  font-weight: 800;
  font-size: 1.1em;
}

emph {
  font-style: italic;
}

code {
  padding: .3em;
  padding-bottom: 1px;
  border-width: 1px;
  border-style: solid;
  border-color: gray;
}

dl {
  margin-left: 10%;
  margin-right: 10%;
}

dt {
  font-weight: 700;
}

table {
  overflow-x: auto;
}

tr {
  background-color: #DDD;
}

tr:nth-child(odd) {
  background-color: #AAA;
}

td, th {
  padding: 2em;
  margin: 2px;
}


@media (width <= 14cm) {
  html {
    margin: 5px;
  }

  .supressible {
    display: none !important;
  }

  #header {
    column-gap: 1rem;
  }

  #main {
    margin: 0;
    margin-top: 2px;
    padding: 10px;
    padding-top: 4rem;
    border-radius: 0;
  }

  nav {
    font-size: 80%;
  }

  nav ul li a {
    padding-top: 3px;
    padding-bottom: 3px;
  }

  h1 {
    font-size: 115%;
  }

  h2, h3, h4 {
    font-size: 110%;
  }

  table {
    font-size: 80%;
  }

  td, th {
    padding: .5em;
  }
}

@media (width >= 56em) {
  #header {
    column-gap: 5rem;
  }

  #main {
    width: 50em;
    margin-left: auto;
    margin-right: auto;
  }
}

.proposta {
  margin: 1rem;
  border-radius: 2rem;
  padding: 1rem;
/*
  border-style: solid;
  border-width: 1px;
  border-color: blue;
*/
  box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2), 0 6px 20px 0 rgba(0, 0, 0, 0.19);
}
.proposta:hover {
  box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2), 0 6px 20px 0 rgba(0, 0, 0, 0.39);
}

.proposta p {
  margin-left: 4rem;
}