:root {
    --page-background: #f5f6f8;
    --content-background: #ffffff;
    --header-background: #243447;
    --header-text: #ffffff;
    --heading-text: #1f2933;
    --body-text: #303943;
    --muted-text: #303943;
    --border-color: #d7dde3;
    --link-color: #145da0;

    font-family:
            system-ui,
            -apple-system,
            BlinkMacSystemFont,
            "Segoe UI",
            sans-serif;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    color: var(--body-text);
    background: var(--page-background);
    font-size: 17px;
    line-height: 1.6;
}

.container {
    width: min(900px, calc(100% - 40px));
    margin: 0 auto;
}

/* Header */

.site-header {
    padding: 20px 0;
    color: var(--header-text);
    background: var(--header-background);
}

.site-header h1 {
    margin: 0 0 10px;
    font-size: 2.1rem;
    font-weight: 600;
}

nav {
    display: flex;
    gap: 25px;
}

nav a {
    color: var(--header-text);
    font-weight: 600;
    text-decoration: none;
}

nav a:hover,
nav a:focus {
    text-decoration: underline;
}

/* Main */

main {
    padding-top: 10px;
    padding-bottom: 10px;
}

main a {
    color: var(--link-color);
}

/* Small screens */

@media (max-width: 600px) {
    body {
        font-size: 16px;
    }

    .site-header {
        padding-top: 30px;
    }

    .site-header h1 {
        font-size: 1.8rem;
    }

    nav {
        gap: 20px;
    }
}

section {
    margin-bottom: 2.5rem;
}