body, html {
    background-color: #000;
}
body {
    font-family: sans-serif;
    color: #fff;
}

.scene {
    opacity: 1;
    transition: opacity 1s linear;
}
.scene.hidden {
    opacity: 0;
    pointer-events: none;
}

.start-button {
    z-index:1000; 
    position: fixed;
    top: 50vh;
    left: 50vw;
    transform: translate(-50%, -50%);
    display: block;
    background-color: transparent;
    border: 2px solid #fff;
    border-radius: 0.25rem;
    color: #fff;
    padding: 1rem;
    font-weight: bold;
    font-size: 4rem;
    cursor: pointer;
    transition: 
        background-color 0.25s linear,
        opacity 1s linear;
    opacity: 1;
}
.start-button:hover,
.start-button:focus {
    background-color: rgb(63, 49, 68);
}
.start-button.hidden {
    opacity: 0;
    z-index: -1;
    pointer-events: none;
}

.main-nav {
    position: fixed;
    top: 2rem;
    right: 2rem;
    font-weight: bold;
    font-size: 1.5rem;
    display: flex;
    text-shadow: 0px 0px 5px #000;
}
.main-nav a {
    color: #fff;
    text-decoration: none;
    display: block;
    margin-left: 2rem; 
}
.main-nav a small {
    opacity: 0.5;
    font-size: 1rem;
    font-weight: normal;
}
.main-nav a:hover,
.main-nav a:focus {
    text-decoration: underline;
}
.main {
    padding: 2rem;
    margin: 4rem auto 0;
    max-width: 786px;
    line-height: 1.5;
}
.main a {
    color: #fff;
    text-decoration: underline;
}

.main ul {
    margin: 0 0 4rem 0;
    padding: 0 0 0 1rem;
}

.main ul li {
    margin-bottom: 1rem;
    padding: 0;
    text-indent: 0;
}

.centered {
    text-align: center;
}