main.css

body {
    margin: 0;
    width: 100vw;
    height: 100vh;
}

div {
    margin: 0;
    padding: 0;
}

p {
    margin: 0;
    margin-bottom: 6px;
    padding: 0;
}

.-btn {
    display: inline-block;
    margin: 0;
    padding: 0.3em 1em;
    text-decoration: none;
    background: #454545;
    color: #fff;
    border-bottom: solid 3px #303030;
    border-right: solid 3px #303030;
    border-radius: 3px;
  }
.-btn:active {
    -webkit-transform: translateY(4px);
    transform: translateY(4px);
    border-bottom: none;
    border-right: none;
}


.-bg-container {
    width: 100%;
    height: 100%;
    background-color: black;
    transition: 1s ease 1.5s;
}

.loaded .-bg-container {
    background-color: #c3c3c3;
}

.-bg-container img {
    position: absolute;
    top: 0;
    left: 0;
    opacity: 0;
    z-index: 800;
    transition: opacity 0.25s;
}

.-bg-container img.show {   
    opacity: 1;
    transition: opacity 0.25s;
}

.-section-container {
    position: absolute;
    height: 0;
    color: white;
    z-index: 1200;
}
.-section-container section#top {
    position: fixed;
    top: calc(100vh - 21vmin - 80px);
    transform: translateX(-100%);
    transition: transform 0.2s ease;
    font-family: "Nico Moji";
}
.-section-container section#top h2 {
    margin: 0;
    padding: 0;
    font-size: 6vmin;
}
.-section-container section#top p {
    font-size: 3.7vmin;
    line-height: 3.7vmin;
}

.loaded .-section-container.show section#top:target {
    transform: translateX(0);
}

.-section-container section#challenge {
    position: fixed;
    top: calc(100vh - 30vmin);
    left: calc(100vw - 55vmin);
    transform: translateY(100vh);
    transition: transform 0.2s ease;
    font-family: "Nico Moji";
}
.-section-container section#challenge h2 {
    margin: 0;
    padding: 0;
    font-size: 6vmin;
}
.loaded .-section-container.show section#challenge:target {
    transform: translateY(0);
}

.-container {
    width: 100%;
    height: 100%;
}

.-container img{
    margin: 0;
    padding: 0;
    width: 100vw;
    height: 100vh;
    filter: brightness(0) grayscale(1);
    transition: filter 1s ease 1s;
}

.-container.loaded img{
    filter: brightness(1) grayscale(1);
}

.-big-square {
    display: block;
    position: absolute;
    left: 50%;
    top: 50%;
    background-color: #000;
    transform-origin: center top;
    transform: translateX(-50%);
    transition: transform .2s ease, background-color 1s ease 1s;
}

.loaded .-big-square {
    background-color: #f43e43;
}

.-progress-container {
    position: absolute;
    top: -140px;
    width: 100%;
    height: 0;
    text-align: center;
    transition: opacity 1s ease 1s;
}

.loaded .-progress-container {
    opacity: 0;
}

.-loading-message {
    position: fixed;
    color: white;
    font-size: 20px;
    transform: translateX(-50%) translateY(40px);
    opacity: 0;
    transition: opacity .3s ease;
}

.-loading-message.set {
    opacity: 1;
}

.-title {
    margin: 0;
    background-color: #fff;
    color: transparent;
    width: 0;
    height: 1px;
    text-align: center;
    overflow: hidden;
    transition: width 1s ease, height 1s ease 1s, background-color 0.5s ease 1s, color 0.8s ease 1.2s;
}

.loaded .-title {
    width: 100%;
    font-size: 20px;
    height: 1.5em;
    background-color: #454545;
    color: white;
}

.-copyright {
    position: absolute;
    top: 1.5em;
    margin: 0;
    background-color: white;
    color: #454545;
    width: 0;
    height: 18px;
    text-align: center;
    overflow: hidden;
    transition: width 0.5s ease 0.5s, height 1s ease 1s, background-color 0.5s ease 1s, color 0.8s ease 1.2s;
}
.loaded .-copyright {
    width: 100%;
    font-size: 14px;
    height: 18px;
    background-color: white;
    color: #454545;
}

.-cover {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: 1000;
}