a:link {
  color: blue;
  background-color: transparent;
  text-decoration: underline;
}

a:visited {
  color: blue;
  background-color: transparent;
  text-decoration: underline;
}

a:hover {
  color: black;
  background: linear-gradient(to right, #ff0000, #ff9900, #ffff00, #00ff00, #00ffff, #0000ff, #9900ff, #ff00f6, #ff0000);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  animation: rainbow_animation 6s linear infinite;
  background-size: 400% 100%;
  text-shadow: 0px 0px 0px;
  text-decoration:none;
}

@keyframes rainbow_animation {
 
0%, 100% {
    background-position: 0 0;
}
50% {
    background-position: 100% 0;
}

#hr { 
  border: 0;
    height: 1px;
    margin:3px;
    background-image: linear-gradient(to right, #EE4081, #D4B449, #81EF7C, #48A4DE, #8133E5, #77043E);
}
.flex {
display:flex;
}

header, nav, main, aside {
  border:1px solid white;
}
header, footer, nav {
  max-width:100%;
}
aside {
  width:150px;
}