:root {
    --clr-title: #252859;
    --clr-text: #252859;
    --clr-outline: #BB0A21;
    --clr-outline-dark: #1D2240;
    --clr-background: rgb(202, 202, 231);
    --clr-cover: #ffffff;
    --weight-normal: normal;
    --weight-bold: bold;
    --font-size-desktop: 1.125rem; /* Desktop font size */
    --font-size-mobile: .875rem; /* Mobile font size */
    --width: 400px;
}

body {
    margin: 0;
    padding: 0;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    font-size: var(--font-size-desktop); /* Set default font size */
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

main {
    width: 100%;
}

section {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}


h1, h2, h3 {
    color: var(--clr-title);
    margin-bottom: 20px;
    font-weight: var(--weight-bold);
}

h1 {
    font-size: 2.25rem; /* 36px */
}

h2 {
    font-size: 1.5rem; /* 24px */
    font-weight: var(--weight-normal);
}

h3 {
    font-size: 1.125rem; /* 18px */
    font-weight: var(--weight-normal);
}

ul {
    list-style-type: none;
}

.background {
    background-color: var(--clr-background);
}

@media (max-width: 768px) {
    /* your code below works, but this file is ment to be for defaults. Lets make this default somehow, no class selectors */
    body {
        font-size: var(--font-size-mobile);
    }

    ul li {
        font-size: var(--font-size-mobile);
    }

    p {
        font-size: var(--font-size-mobile);
    }

    h1 {
        font-size: 1.5rem;
    }

    h2 {
        font-size: 1.25rem;
    }

    h3 {
        font-size: 1rem;
    }
}