html[data-theme='dark'] {
  --font1: 'Open Sans', sans-serif;
  --background-color: #343a40;
  --header-color: #202225;
  --headings-color: #ffffff;
  --text-color: #eeeeee;
  --border-color: #141414;
  --line-color: #ffffff;
  --link-color: #CC99FF;
  --link-color-hover: #ffffff;
}

body {
  background-color: var(--background-color);
  box-sizing: border-box;
  color: var(--text-color);
  font-family: var(--font1);
  font-display: swap;
  font-size: 1rem;
  line-height: 1.6;
  margin: 0 auto;
}

h1, h2, h3, h4, h5 {
  color: var(--headings-color);
  font-weight: bold;
  line-height: 1.2;
  margin-top: 0;
  margin-bottom: 0.5rem;
}
h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.75rem; }
h4 { font-size: 1.5rem; }
h5 { font-size: 1.25rem; }
h6 { font-size: 1rem; }

hr {
  background-color: var(--line-color);
}

/* Navigation */
header {
  background-color: var(--header-color);
  padding-top: 4px;
  padding-bottom: 4px;
}

a {
  text-decoration: none;
  color: var(--link-color);
  transition: color 0.1s linear;
}

a:hover {
  color: var(--link-color-hover);
  text-decoration: none;
}

/* Banner */
.overlay {
  background-size: cover;
  background-position: center;
  border-top: 2px solid var(--border-color);
  border-bottom: 4px solid var(--border-color);
  display: flex;
  height: 200px;
  text-align: center;
  align-items: center;
  justify-content: center;
}

.title {
  display: inline-block;
  font-size: 3rem;
  text-decoration: none;
}

.container {
  width: 100%;
  padding-right: 15px;
  padding-left: 15px;
  margin-right: auto;
  margin-left: auto;
}
@media (min-width: 576px) {
  .container {
      width: 540px;
  }
}
@media (min-width: 768px) {
  .container {
      width: 720px;
  }
}
@media (min-width: 992px) {
  .container {
      width: 960px;
  }
}
@media (min-width: 1200px) {
  .container {
      width: 1140px;
  }
}

.link {
  text-decoration: none;
  transition: color 0.1s linear;
  padding: 4px 12px;
}

.link:hover {
  border-bottom: 2px solid var(--line-color);
}

/* Content */
main {
  margin-top: 20px;
}

section {
  border-radius: 5px;
  padding: 5px 20px;
}

footer {
  display: flex;
  justify-content: space-between;
  border-top: 3px solid var(--border-color);
  color: var(--text-color);
  font-family: var(--font1);
  margin-top: 30px;
  margin-bottom: 30px;
}

/* Responsive layout - when the screen is less than 700px wide, make the two columns stack on top of each other instead of next to each other */
@media screen and (max-width: 700px) {
  .title {
    display: block;
    text-align: center;
  }
}

@media (max-width: 576px) {
  footer {
    flex-direction: column;
  }
}