:root {
  --background: #fff;
  --text: #333;
  --muted: #6a6a6a;
  --link: #2c5aa0;
  --rule: #d8d8d8;
  --table-stripe: #f7f7f7;
}

html {
  font-size: 16px;
}

body {
  margin: 0;
  background: var(--background);
  color: var(--text);
  font-family: "Open Sans", "Helvetica Neue", Helvetica, Arial, sans-serif;
  line-height: 1.6;
}

.page {
  width: min(920px, calc(100% - 40px));
  margin: 0 auto;
}

.site-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1.5rem;
  padding: 1.5rem 0 0.8rem;
  border-bottom: 1px solid var(--rule);
}

.site-header a {
  text-decoration: none;
}

.course-name {
  color: var(--text);
  font-weight: 700;
}

nav {
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem;
}

a {
  color: var(--link);
}

a:hover,
a:focus {
  text-decoration: underline;
}

main {
  padding: 1.8rem 0 3rem;
}

.announcements {
  margin: 1.7rem 0 2rem;
  padding: 1rem 1.2rem;
  border-left: 4px solid var(--link);
  background: #f1f5fa;
}

.announcements h2 {
  margin-top: 0;
}

.announcements > :last-child {
  margin-bottom: 0;
}

h1,
h2,
h3 {
  line-height: 1.3;
}

h1 {
  margin: 0 0 1rem;
  font-size: 2rem;
}

h2 {
  margin: 2rem 0 0.7rem;
  font-size: 1.35rem;
}

h3 {
  margin: 1.5rem 0 0.5rem;
  font-size: 1.1rem;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
}

th,
td {
  padding: 0.55rem 0.7rem;
  border-bottom: 1px solid var(--rule);
  text-align: left;
  vertical-align: top;
}

tbody tr:nth-child(even) {
  background: var(--table-stripe);
}

pre {
  overflow-x: auto;
  padding: 0.9rem;
  background: var(--table-stripe);
}

code {
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
}

img {
  max-width: 100%;
}

footer {
  padding: 1rem 0 2rem;
  border-top: 1px solid var(--rule);
  color: var(--muted);
  font-size: 0.9rem;
}

@media (max-width: 600px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
    gap: 0.65rem;
  }

  nav {
    gap: 0.8rem;
  }

  table {
    display: block;
    overflow-x: auto;
  }
}