body {
    font-family: Arial, sans-serif;
    font-size: 18px;
    line-height: 1.6;
    color: #243247;
    background-color: #fefefe;
    padding: 24px;
    max-width: 1100px;
    margin: 0 auto;
}

section {
    border: 2px solid #a8b5c6;
    background-color: #ffffff;
    padding: 24px;
    margin-bottom: 20px;
    border-radius: 12px;
}

h2 {
    margin-top: 0;
}

nav ul {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    list-style: none;
    padding: 0;
    margin: 24px 0;
}

nav a {
    display: block;
    padding: 10px 16px;
    background-color: #ffffff;
    color: #243247;
    border: 2px solid #a8b5c6;
    border-radius: 8px;
    text-decoration: none;
}

nav a:hover {
    background-color: #e8edf3;
}

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

    section {
        padding: 16px;
    }

    h1 {
        font-size: 28px;
    }
}

details {
    padding: 12px 0;
    border-bottom: 2px solid #a8b5c6;
}

summary {
    cursor: pointer;
    font-weight: bold;
}

details[open] > summary {
    color: #b32635;
}

header {
    border-bottom: 3px solid #b32635;
    margin-bottom: 24px;
}

footer {
    padding: 16px 0;
    text-align: center;
    font-size: 14px;
}

footer a {
    color: #243247;
}

.announcement {
    border-left: 4px solid #b32635;
    padding-left: 16px;
}

.announcement h3 {
    margin-top: 0;
}

.announcement time {
    display: block;
    margin-bottom: 8px;
    font-size: 14px;
    color: #596579;
}

.important {
    background-color: #fff4f4;
    padding: 16px;
    border-radius: 8px;
}

.badge {
    display: inline-block;
    background-color: #b32635;
    color: #ffffff;
    padding: 4px 10px;
    border-radius: 6px;
    font-size: 14px;
    font-weight: bold;
    margin-bottom: 12px;
}
.announcement + .announcement {
    margin-top: 24px;
}

.site-logo {
    display: block;
    width: 280px;
    max-width: 100%;
    height: auto;
}