.announcement-tab {
    width: 80%;
    max-width: 800px;
    margin: 40px auto;
    padding: 20px;
    background-color: #fff;
    border: 1px solid #ddd;
    box-shadow: 0 0 10px rgba(0,0,0,0.1);
}

.announcement-tab h2 {
    margin-top: 0;
}

.announcement-tab ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.announcement-tab li {
    padding: 10px;
    border-bottom: 1px solid #ddd;
}

.announcement-tab li:last-child {
    border-bottom: none;
}

/* Responsive design */

@media only screen and (max-width: 1024px) {
    .announcement-tab {
        width: 90%;
        max-width: 700px;
    }
}

@media only screen and (max-width: 768px) {
    .announcement-tab {
        width: 100%;
        max-width: 600px;
    }
    .announcement-tab li {
        padding: 5px;
    }
}

@media only screen and (max-width: 480px) {
    .announcement-tab {
        width: 100%;
        max-width: 400px;
    }
    .announcement-tab li {
        padding: 5px;
        font-size: 14px;
    }
}