body {
    background-color: #f8f9fa;
    font-family: 'Arial', sans-serif;
    margin: 0;
    padding: 0;
}

.container-fluid {
    max-width: 900px;
    margin: auto;
    padding: 20px;
}

/* Header */
header {
    width: 100%;
    height: 400px;
    text-align: center;
}

.intro {
    width: 900px; 
    background: white;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0px 4px 10px rgba(0, 0, 0, 0.1);
    text-align: center;
    margin: 0 auto 20px auto;
}

.oj-group {
    width: 900px; 
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    justify-content: center;
}

.intro p {
    font-size: 18px;
    line-height: 1.6;
    color: #333;
}

.intro p:first-child {
    font-size: 24px;
    font-weight: bold;
    color: #6c5ce7;
}

article {
    width: 250px;
    padding: 20px;
    background: white;
    border-radius: 10px;
    box-shadow: 0px 4px 8px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s, box-shadow 0.3s;
    text-align: center;
    cursor: pointer;
}

article:hover {
    transform: translateY(-5px);
    box-shadow: 0px 6px 12px rgba(0, 0, 0, 0.15);
}

.b-logo {
    font-size: 22px;
    font-weight: bold;
    color: #6c5ce7;
}

.s-logo {
    font-size: 16px;
    color: #555;
}

.blog-tags {
    margin-top: 10px;
    font-size: 14px;
    color: #666;
}

.tag {
    background: #6c5ce7;
    color: white;
    padding: 4px 10px;
    border-radius: 5px;
    margin-right: 5px;
    font-size: 12px;
}

.blog-content {
    margin-top: 15px;
    font-size: 14px;
    color: #333;
}

/* Footer */
#footer {
    width: 100%;
    margin-top: 20px;
    text-align: center;
    font-size: 14px;
    color: #777;
}

article.codeforces:hover {
    background-color: #d4efdf ;
}

article.leetcode:hover {
    background-color: #f5b7b1;
}

article.spoj:hover {
    background-color: #e8daef;
}

article.cses:hover {
    background-color: #fcf3cf;
}