```css
* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: Arial, Helvetica, sans-serif;
    color: #222;
    background: #ffffff;
    line-height: 1.75;
}

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

.site-header {
    border-bottom: 1px solid #e8e8e8;
    background: #ffffff;
}

.site-header-inner {
    max-width: 1150px;
    margin: 0 auto;
    padding: 16px 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 25px;
}

.logo {
    text-decoration: none;
    font-size: 25px;
    font-weight: 700;
    color: #1B3FA0;
    white-space: nowrap;
}

.logo span {
    color: #E8440A;
}

.main-nav {
    display: flex;
    gap: 24px;
    flex-wrap: wrap;
}

.main-nav a {
    color: #333;
    text-decoration: none;
    font-size: 15px;
    font-weight: 600;
}

.main-nav a:hover {
    color: #1B3FA0;
}

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

.breadcrumb {
    max-width: 1100px;
    margin: 0 auto;
    padding: 18px 20px 0;
    font-size: 14px;
    color: #777;
}

.breadcrumb a {
    color: #1B3FA0;
    text-decoration: none;
}

/* =========================
   BLOG ARTICLE
   ========================= */

.blog-main {
    width: 100%;
}

.blog-article {
    max-width: 820px;
    margin: 0 auto;
    padding: 35px 20px 70px;
}

.blog-article h1 {
    margin: 0 0 12px;
    font-size: 44px;
    line-height: 1.2;
    color: #1B3FA0;
}

.article-meta {
    color: #777;
    font-size: 14px;
    margin-bottom: 28px;
}

.featured-image {
    display: block;
    width: 100%;
    height: auto;
    margin: 25px 0 38px;
    border-radius: 10px;
}

.article-intro {
    font-size: 21px;
    line-height: 1.65;
    color: #555;
    margin-bottom: 30px;
}

.blog-article p {
    font-size: 18px;
    margin: 0 0 22px;
}

.blog-article h2 {
    margin: 48px 0 18px;
    font-size: 30px;
    line-height: 1.3;
    color: #1B3FA0;
}

.blog-article h3 {
    margin: 32px 0 12px;
    font-size: 22px;
    line-height: 1.4;
    color: #333;
}

.blog-article ul {
    margin: 15px 0 28px;
    padding-left: 28px;
}

.blog-article li {
    font-size: 18px;
    margin-bottom: 9px;
}

.blog-article a {
    color: #1B3FA0;
    font-weight: 600;
}

.blog-article hr {
    border: 0;
    border-top: 1px solid #ddd;
    margin: 55px 0 30px;
}

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

.related-articles {
    max-width: 1000px;
    margin: 0 auto;
    padding: 50px 20px 70px;
    border-top: 1px solid #e5e5e5;
}

.related-articles h2 {
    margin: 0 0 25px;
    color: #1B3FA0;
    font-size: 30px;
}

.related-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 22px;
}

.related-card {
    border: 1px solid #e1e1e1;
    border-radius: 10px;
    padding: 24px;
    background: #fff;
}

.related-category {
    color: #E8440A;
    font-size: 12px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.related-card h3 {
    margin: 9px 0 12px;
    font-size: 21px;
    line-height: 1.4;
}

.related-card h3 a {
    color: #1B3FA0;
    text-decoration: none;
}

.related-card p {
    color: #555;
    font-size: 16px;
    margin-bottom: 15px;
}

.read-more {
    color: #E8440A !important;
    text-decoration: none;
    font-weight: 700;
}

/* =========================
   BLOG INDEX
   ========================= */

.blog-index-header {
    background: #f5f7fb;
    text-align: center;
    padding: 55px 20px;
}

.blog-index-header h1 {
    margin: 0 0 15px;
    font-size: 42px;
    color: #1B3FA0;
    line-height: 1.2;
}

.blog-index-header p {
    max-width: 760px;
    margin: 0 auto;
    font-size: 18px;
    color: #555;
}

.blog-list {
    max-width: 1050px;
    margin: 0 auto;
    padding: 55px 20px 70px;
}

.blog-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 25px;
}

.blog-card {
    border: 1px solid #e2e2e2;
    border-radius: 10px;
    padding: 28px;
    background: #fff;
}

.blog-card h2 {
    margin: 10px 0 12px;
    font-size: 25px;
    line-height: 1.35;
}

.blog-card h2 a {
    color: #1B3FA0;
    text-decoration: none;
}

.blog-card p {
    color: #555;
    font-size: 16px;
}

.blog-category {
    color: #E8440A;
    font-size: 12px;
    font-weight: 700;
    text-transform: uppercase;
}

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

.site-footer {
    background: #f5f7fb;
    border-top: 1px solid #e5e5e5;
    padding: 40px 20px;
    text-align: center;
    color: #666;
}

.footer-inner {
    max-width: 1000px;
    margin: 0 auto;
}

.site-footer a {
    color: #1B3FA0;
    text-decoration: none;
}

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

@media (max-width: 700px) {

    .site-header-inner {
        flex-direction: column;
        align-items: flex-start;
    }

    .main-nav {
        gap: 14px;
    }

    .blog-article {
        padding: 28px 18px 55px;
    }

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

    .blog-article h2 {
        font-size: 26px;
    }

    .blog-article p,
    .blog-article li {
        font-size: 17px;
    }

    .article-intro {
        font-size: 19px;
    }

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

    .blog-index-header h1 {
        font-size: 32px;
    }
}
```