body {
    text-align: center;
    background-color: rgb(51, 51, 51);
    color: gray;
}

header {
    margin-top: 1.5em;
    margin-bottom: 1.5em;
    font-family: Ubuntu, sans-serif;
}

footer {
    font-size: 1.2em;
    font-family: Cambria, Palatino, Perpetua, serif;
}

header a {
    color: white;
    font-size: 1.5em;
    text-decoration: none;
    text-shadow: 1px 1px 2px silver;
}

img {
    max-width: 90%;
}

hr {
    width: 60%;
    height: 1px;
    border: 0;
    color: silver;
    background:linear-gradient(to right, transparent 0, silver 50%, transparent 100%);
}

.hidden {
    color: gray;
    text-shadow: none;
}

.animation-image {
    transform: rotate(0deg);
    transform-origin: center;
    animation-name: monanimation;
    animation-duration: 6s;
    animation-iteration-count: infinite;
}

@keyframes monanimation {
    0%   {filter: drop-shadow(0 0 0.1rem gray);}
    20%  {filter: drop-shadow(0.5rem 0.2rem 0.1rem gray);}
    40%  {filter: drop-shadow(-0.5rem 0.2rem 0.1rem gray);}
    60%   {filter: drop-shadow(0 0 0.1rem gray);}
    60%  {filter: drop-shadow(-0.5rem -0.2rem 0.1rem gray);}
    80%   {filter: drop-shadow(0.5rem -0.2rem 0.1rem gray);}
    100% {filter: drop-shadow(0 0 0.1rem gray);}
}