:root {
    --primary: #2563eb;
    --text: #222;
    --muted: #666;
    --border: #e8e8e8;
    --background: #fff;
    --box: #f7f7f7;

    --max-width: 850px;
}


/* ===== RESET ===== */

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}


/* ===== BODY ===== */

body {
    background: var(--background);
    color: var(--text);

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


/* ===== GENERAL ===== */

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 20px;
}

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

a:hover {
    text-decoration: underline;
}


/* ===== HEADER ===== */

.site-header {
    width: 100%;
    max-width: 1000px;

    margin: 0 auto;

    padding: 28px 20px 22px;

    text-align: center;
}

.site-header .logo {
    display: block;

    width: 320px;
    max-width: 90vw;

    height: auto;

    margin: 0 auto 10px;
}

.site-header .site-description {
    margin: 0;

    color: var(--muted);

    font-size: 15px;
    line-height: 1.5;

    text-align: center;
}


/* ===== NAV ===== */

.nav {
    position: sticky;

    top: 0;

    background: white;

    border-bottom: 1px solid var(--border);

    z-index: 10;
}

.nav-inner {
    max-width: 1000px;

    margin: 0 auto;

    padding: 14px 20px;
}

.menu {
    display: flex;

    justify-content: center;

    gap: 25px;
}

.menu a {
    color: #222;

    font-size: 14px;
}


/* ===== BREADCRUMB ===== */

.breadcrumb {
    padding: 25px 0;

    font-size: 14px;

    color: var(--muted);
}


/* ===== ARTICLE HEADER ===== */

.article-header {
    padding: 20px 0 35px;
}

.article-header h1 {
    font-size: 44px;

    line-height: 1.15;

    letter-spacing: -1px;
}

.excerpt {
    margin-top: 20px;

    font-size: 20px;

    line-height: 1.5;

    color: var(--muted);
}

.article-meta {
    margin-top: 20px;

    font-size: 14px;

    color: var(--muted);
}


/* ===== SUMMARY ===== */

.summary {
    background: var(--box);

    border-left: 4px solid var(--primary);

    padding: 22px;

    margin-bottom: 40px;
}

.summary h2 {
    font-size: 20px;

    margin-bottom: 15px;
}

.summary li {
    margin-left: 20px;

    margin-bottom: 8px;
}


/* ===== CONTENT ===== */

.article-body {
    font-size: 18px;

    line-height: 1.75;
}

.article-body h2 {
    font-size: 30px;

    margin-top: 45px;

    margin-bottom: 15px;
}

.article-body h3 {
    font-size: 24px;

    margin-top: 30px;
}

.article-body p {
    margin-bottom: 22px;
}

.article-body img {
    max-width: 100%;
    height: auto;
}


/* ===== FAQ ===== */

.faq {
    margin-top: 50px;
}

.faq-item {
    border-bottom: 1px solid var(--border);

    padding: 20px 0;
}

.faq-item h3 {
    font-size: 20px;

    margin-bottom: 10px;
}


/* ===== RELATED ===== */

.related {
    margin-top: 50px;
}

.related-grid {
    display: grid;

    grid-template-columns: repeat(3, 1fr);

    gap: 20px;
}

.related-card {
    border: 1px solid var(--border);

    padding: 20px;

    border-radius: 8px;
}


/* ===== FOOTER ===== */

.footer {
    margin-top: 70px;

    border-top: 1px solid var(--border);

    padding-top: 40px;
}

.footer-inner {
    max-width: 1000px;

    margin: 0 auto;

    padding: 0 20px;

    display: flex;

    justify-content: space-between;
}

.bottom-bar {
    margin-top: 40px;

    text-align: center;

    padding: 15px;

    background: #111;

    color: white;

    font-size: 14px;
}


/* ===== MENU TOGGLE ===== */

.menu-toggle {
    display: none;

    cursor: pointer;

    font-size: 24px;
}


/* ===== MOBILE ===== */

@media (max-width: 700px) {

    .article-header h1 {
        font-size: 32px;
    }

    .menu-toggle {
        display: block;
    }

    .menu {
        display: none;

        flex-direction: column;

        align-items: center;

        gap: 15px;
    }

    .menu.active {
        display: flex;
    }

    .related-grid {
        grid-template-columns: 1fr;
    }

    .footer-inner {
        flex-direction: column;

        gap: 30px;
    }

    .site-header {
        width: 100%;

        max-width: 100%;

        padding: 28px 20px 22px;

        text-align: center;
    }

    .site-header .logo {
        display: block;

        width: 320px;

        max-width: 90vw;

        height: auto;

        margin: 0 auto 10px;
    }

    .site-header .site-description {
        text-align: center;
    }

}