style.css

@media (prefers-color-scheme: light) {
    :root {
        --text: #111;
        --accent: #1688f0;
        --bg-main: #fff;
        --bg-link: #f0f0f0;
        --bg-alt: #f5f5f5;
    }
}

@media (prefers-color-scheme: dark) {
    :root {
        --text: #e5e5e5;
        --accent: #1688f0;
        --bg-main: #000;
        --bg-link: #0f0f1a;
        --bg-alt: #0a0a0f;
    }
}

* {
    box-sizing: border-box;
}

body {
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0;
    font-family: 'Open Sans', sans-serif;
    background-color: var(--bg-main);
    color: var(--text);
    font-size: 16px;
}

.container {
    display: flex;
    justify-content: center;
    flex-direction: row;
    flex-wrap: wrap;
    align-items: center;
    width: 90%;
    max-width: 1280px;
}

.hide {
    /* '!important' is to make sure that when we add the class using JS, it takes precendence */
    display: none !important;
}

h1 {
    color: var(--accent);
    margin-bottom: 4px;
}

small {
    width: 100%;
    text-align: center;
    display: block;
    margin-bottom: 20px;
}

p {
    margin: 0;
    color: var(--text);
}

h2 {
    width: 100%;
    text-align: center;
    color: var(--text);
    margin: 0;
}

img {
    border: 2px solid var(--accent);
    box-shadow:
        0 0px 6px var(--accent),
        0 0px 6px var(--accent);
    max-width: 100%;
    height: auto;
}

a {
    color: var(--accent);
    text-decoration: none;
}

ul {
    list-style: none;
    padding: 0;
}

.filter-links,
input {
    background: var(--bg-alt);
    width: 50%;
    border-radius: 20px;
    min-width: 300px;
    margin-top: 1em;
    padding: 1em;
    margin-bottom: 1em;
    border: 2px solid var(--accent);
    color: var(--text);
    text-align: center;
}

.links {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    background-color: var(--bg-link);
    margin-top: 0;
    padding: 2em;
    border-bottom-left-radius: 20px;
    border-bottom-right-radius: 20px;
    margin-bottom: 4em;
}

h3 {
    margin: 4px;
    width: 100%;
    text-align: center;
    color: var(--accent);
}

.link-list {
    width: 100%;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: flex-start;
}

.link-list li {
    width: 100%;
    min-height: 80px;
    border-radius: 10px;
    margin: 1em 0;
    border: 1px solid var(--accent);
    padding: 1em;
    text-align: center;
    background-color: var(--bg-alt);
}

.link-list li:hover {
    background-color: var(--bg-main);
    box-shadow:
        0 3px 6px var(--accent),
        0 3px 6px var(--accent);
}

@media (min-width: 700px) {
    .link-list {
        justify-content: space-between;
    }

    .link-list li {
        width: 48%;
    }
}

@media (min-width: 1200px) {
    .link-list li {
        width: 30%;
    }
}