* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Trebuchet MS', 'Lucida Sans Unicode', 'Lucida Grande', 'Lucida Sans', Arial, sans-serif;
}

:root {
  --bg-color: #ffffff;
  --text-color: #111111;
  --link-color: #111111;
}

[data-theme="dark"] {
  --bg-color: #111111;
  --text-color: #eeeeee;
  --link-color: #eeeeee;
}

body {
  background-color: var(--bg-color);
  color: var(--text-color);
  transition: background-color 0.3s, color 0.3s;
}

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

a:hover {
  transition: 0.5s;
  color: #21788F;
}
#theme-toggle {
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.3rem;
  border-radius: 50%;
  transition: background 0.2s;
}

main {
  overflow: hidden;
}

#theme-toggle img {
  width: 24px;
  height: 24px;
  transition: transform 0.3s ease;
}

#theme-toggle:hover img {
  transform: rotate(20deg);
}

main {
  padding: 2rem;
}

header {
  justify-content: space-between;
  align-items: center;
  padding: 20px 0;
}
header a {
  font-size: 22px;
}
ul {
  list-style: none;
}
li {
  margin-right: 10px;
}
header,
ul {
  display: flex;
  flex-direction: row;
}