body {
    min-height: 100vh;
    margin: 0;
    font-family: 'Roboto', sans-serif;
    color: white;
}

header {
    margin-bottom: 10px;
}

footer {
    margin-top: 10px;
}

header,
footer {
    display: grid;
    grid-template-columns: 1fr 3fr 1fr;
    background-color: #000;
    padding: 5px;
}

header > *,
footer > * {
    align-self: center;
}

.left {
    justify-self: left;
}

.middle {
    justify-self: center;
}

.right {
    justify-self: right;
}

header > .middle {
    font-size: 25px;
    line-height: 20px;
}

.logo {
    width: 45px;
    height: 45px;
    background-image: url("../images/logo.svg");
    background-repeat: no-repeat;
}

body {
    display: flex;
    flex-direction: column;

    margin: 0;

    background-color: #1a1a1a;
    opacity: 0.8;
    background-image:
        linear-gradient(#161616 2px, transparent 2px),
        linear-gradient(90deg, #161616 2px, transparent 2px),
        linear-gradient(#161616 1px, transparent 1px),
        linear-gradient(90deg, #161616 1px, #1a1a1a 1px);
    background-size:
        50px 50px,
        50px 50px,
        10px 10px,
        10px 10px;
    background-position:
        -2px -2px,
        -2px -2px,
        -1px -1px,
        -1px -1px;

    animation: moveBackground 120s linear infinite alternate;
}

@keyframes moveBackground {
    from {
        background-position: 0% 0%;
    }
    to {
        background-position: 50% 50%;
    }
}

main {
    flex: 1;
    justify-content: center;
    align-items: center;
    display: flex;
    flex-wrap: wrap;
}

.flex-container {
    justify-content: center;
    align-items: center;
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    padding: 50px;
}

.flex-item {
    min-width: 500px;
    flex: 0 0 calc(50% - 20px);
}

@media only screen and (max-width: 600px) {
    .flex-container  {
        max-width: 500px;
        padding: 50px 0 50px 0;
    }
}

@media only screen and (max-width: 1100px) {
    .flex-item  {
        flex: 100%;
    }
}

previewbox-article {
    max-width: 100%;
}