@import url('https://fonts.googleapis.com/css2?family=Overpass:wght@400;600;700&display=swap');

html,body {
    margin: 0 auto;
    font-family: 'Overpass', sans-serif;
    font-size: 16px;
    color: #424242;
    min-width: 500px;
}

* { box-sizing: border-box }

a {
    appearance: none;
    text-decoration: none;
    color: rgba(0, 0, 0, 0.8);
    /* font-weight: 400; */
}

h4,p,button {
    font-weight: 400;
}

h1,h2,h3 {
    font-weight: 700 !important;
    border-collapse: collapse;
    tab-size: 2;
    box-sizing: inherit;
    position: relative;
    margin: 0;
    line-height: 1;
    letter-spacing: .05em;
    text-transform: uppercase;
    margin-top: 0;
}


p {
    font-size: 1.2rem;
    border-collapse: collapse;
    tab-size: 2;
    box-sizing: inherit;
    padding: 0;
    margin: 1em 0;
}



a:active {
    color: inherit;
}


.main {
    margin: auto;
    display: grid;
    grid-template: 1fr / 15% 1fr;
    min-height: 100vh;
    letter-spacing: .01em;
}

.nav {
    min-height: 100%;
    color: white !important;
    background: #666678;
    padding: 2rem;
}

.nav .links {
    position: sticky;
    top: 2rem;
    height: 96vh;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.nav .sub {
    margin-left: 2rem;
}

.nav .footer {
    display: flex;
    align-items: center;
    justify-content: space-evenly;
}

.nav .footer .icon {
    width: 40px;
}

.nav h4 {
    border-collapse: collapse;
    line-height: 1.2;
    box-sizing: inherit;
    margin: 0;
    text-decoration: none;
    cursor: pointer;
    user-select: none;
    position: relative;
    padding: 2rem 0 .5rem 0;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    font-weight: 600;
}
.nav a {
    color: white;
    display: block;
    margin: .5rem 0;
    opacity: .7;
}

.intro {
    padding-bottom: 3rem;
}

.chapters {
    padding: 3rem;
    max-width: 60rem;
}

.chapters h1 {
    margin-top: 2rem;
    padding: 2rem 1.6rem 4rem 0.2rem;
    border-top: 4px solid #6767785b;
}

.chapters h2 {
    margin-top: 3rem;
    margin-bottom: 1rem;
    font-size: 1.25rem;
}

.chapters h3 {
    margin-top: 3rem;
    margin-bottom: 1rem;
    font-size: 1rem;
}

.chapters .intro h1 {
    padding: 0;
    border-top: 0;
}