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

body {
    background: #fff;
    font-family: '游明朝', 'Yu Mincho', 'Hiragino Mincho ProN', serif;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

main {
    width: 100%;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem;
}

.portal-box {
    width: min(95vw, 80vh);
    max-width: 720px;
    min-height: 540px;
    aspect-ratio: 4 / 3;
    border: 1px solid #c0392b;
    border-radius: 8px;
    padding: 2.5rem;
    display: flex;
}

.left-col {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    padding-right: 2rem;
}

.site-title {
    font-size: clamp(1rem, 3vw, 1.6rem);
    font-weight: 600;
    letter-spacing: 0.05em;
    line-height: 1.8;
    color: #111;
}

.description {
    font-size: 0.82rem;
    color: #666;
    margin-bottom: 0.4rem;
    letter-spacing: 0.08em;
}

.copyright {
    font-size: 0.76rem;
    color: #999;
}

.right-col {
    width: 130px;
    flex-shrink: 0;
    border-left: 1px solid #c0392b;
    padding-left: 1.5rem;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.menu {
    display: flex;
    flex-direction: column;
    gap: 1.2rem;
}

.menu a {
    font-size: 0.92rem;
    color: #222;
    text-decoration: none;
    letter-spacing: 0.12em;
    transition: color 0.2s;
}

.menu a:hover {
    color: #c0392b;
}

.updates {
    border-top: 1px solid #c0392b;
    padding-top: 0.8rem;
}

.update-label {
    font-size: 0.72rem;
    color: #aaa;
    letter-spacing: 0.12em;
    margin-bottom: 0.6rem;
}

.updates ul {
    list-style: none;
    font-size: 0.72rem;
    color: #666;
    line-height: 2;
}

@media (max-width: 480px) {
    .portal-box {
        width: 92vw;
        aspect-ratio: auto;
        min-height: 92vw;
        min-height: 540px;
        flex-direction: column;
    }

    .left-col {
        padding-right: 0;
        padding-bottom: 1.5rem;
    }

    .right-col {
        width: 100%;
        border-left: none;
        border-top: 1px solid #c0392b;
        padding-left: 0;
        padding-top: 1.5rem;
    }
}