:root {
    --color-bg: #f9f9f9; /* 少しグレーを入れて白を目立たせる */
    --color-text: #333333;
    --color-sub-text: #666666;
    --color-card-bg: #ffffff;
    --color-accent: #8dc63f;
    --color-footer-bg: #1a1a1a; /* ダークグレーで引き締める */
    --color-footer-text: #aaaaaa;
    --font-main: 'Noto Sans JP', sans-serif;
    --max-width: 840px;
    --spacing-base: 1rem;
    --spacing-lg: 2rem;
    --spacing-xl: 5rem; /* 余白を広げてモダンに */
}

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

body {
    font-family: var(--font-main);
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.8; /* 行間を広めに */
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased; /* 文字を滑らかに */
}

.container {
    width: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
    flex: 1;
}

/* Header Styles */
.site-header {
    text-align: center;
    padding-top: 6rem;
    padding-bottom: 4rem;
    animation: fadeInDown 1s ease-out;
}

.logo-area {
    margin-bottom: 3rem;
    display: flex;
    justify-content: center;
    align-items: center;
}

.logo {
    margin: 0;
    padding: 0;
    line-height: 0;
    display: inline-block;
    transition: transform 0.3s ease;
}

.logo:hover {
    transform: scale(1.02);
}

.logo-img {
    max-width: 100%;
    width: 220px;
    height: auto;
    display: block;
}

.sub-header-text {
    font-size: 1.05rem;
    line-height: 2.2;
    color: var(--color-text);
    margin-top: var(--spacing-base);
    text-align: left; /* 読みやすさのため左揃え */
    display: inline-block; /* 中央配置のためのブロック化 */
    text-align: justify; /* 両端揃えで整える */
    max-width: 720px;
}

/* Main Content Styles */
.main-content {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
    padding-bottom: 6rem;
    animation: fadeInUp 1s ease-out 0.3s backwards;
}

.content-section {
    background-color: var(--color-card-bg);
    padding: 4rem 3rem; /* 内部の余白もたっぷりと */
    border-radius: 24px; /* 角丸を少し大きめに */
    display: flex;
    flex-direction: column;
    /* モダンなシャドウ: 拡散して柔らかく */
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.04);
    border: 1px solid rgba(255, 255, 255, 0.8);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.content-section:hover {
    transform: translateY(-5px);
    box-shadow: 0 30px 60px rgba(0, 0, 0, 0.08);
}

.content-section h2 {
    font-size: 1.2rem; /* 少し小さく上品に */
    font-weight: 900;
    margin-bottom: 3rem;
    text-transform: uppercase;
    letter-spacing: 0.15em; /* 文字間隔を広げる */
    position: relative;
    display: inline-block;
    color: #000;
}

/* アクセントラインを控えめに */
.content-section h2::after {
    content: '';
    position: absolute;
    bottom: -12px;
    left: 0;
    width: 30px;
    height: 3px;
    background-color: var(--color-accent);
}

.section-body {
    font-size: 1rem;
}

.activity-list {
    list-style-type: none;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.activity-list li {
    position: relative;
    padding-left: 2rem;
    color: var(--color-sub-text); /* 少し色を落として洗練させる */
    font-weight: 500;
}

.activity-list li::before {
    content: "";
    position: absolute;
    left: 0;
    top: 0.7rem;
    width: 8px;
    height: 8px;
    background-color: var(--color-accent);
    border-radius: 50%;
    box-shadow: 0 0 0 4px rgba(141, 198, 63, 0.2); /* 緑の周りに淡い光 */
}

.activity-list a {
    color: var(--color-accent);
    text-decoration: none;
    transition: opacity 0.2s ease;
}

.activity-list a:hover {
    opacity: 0.7;
}

.external-link::after {
    content: " ↗";
    font-size: 0.85em;
}

/* Footer Styles */
.site-footer {
    background-color: var(--color-footer-bg);
    padding: 3rem 0;
    margin-top: auto;
}

.footer-inner {
    max-width: var(--max-width);
    margin: 0 auto;
    font-weight: 400;
    font-size: 0.9rem;
    color: var(--color-footer-text);
    text-align: center;
    letter-spacing: 0.05em;
}

/* Animations */
@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Responsive Adjustments */
@media (max-width: 600px) {
    .site-header {
        padding-top: 4rem;
        padding-bottom: 2rem;
    }

    .logo-img {
        width: 180px;
    }

    .content-section {
        padding: 2.5rem 1.5rem;
        border-radius: 16px;
    }
    
    .sub-header-text {
        text-align: left;
    }
}