/* 基本設定と変数 */
:root {
    --primary-color: #4a0e4e;
    --accent-purple: #a78bfa;
    --accent-light: #d4c6e6;
    --text-primary: #e8e4ef;
    --text-secondary: #b4a4cc;
    --bg-gradient: linear-gradient(135deg, rgba(45, 43, 58, 0.7) 0%, rgba(31, 28, 44, 0.7) 100%);
    --card-gradient: linear-gradient(145deg, rgba(62, 53, 77, 0.75), rgba(45, 40, 58, 0.75));
    --shadow-elegant: 0 10px 30px rgba(167, 139, 250, 0.2);
    --border-accent: rgba(167, 139, 250, 0.3);
    --link-color: #87ceeb;
}

/* 基本要素 */
body {
    margin: 0;
    padding: 0;
    background: var(--bg-gradient);
    color: var(--text-primary);
    font-family: 'Cinzel', 'Yu Mincho', serif;
    line-height: 1.6;
    min-height: 100vh;
    background-attachment: fixed;
}

.outer-container {
    position: relative;
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem;
    box-sizing: border-box;
    z-index: 2;
}

/* ヘッダースタイル */
header {
    text-align: center;
    padding: 2rem;
    margin-bottom: 2rem;
    background: var(--card-gradient);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-accent);
    border-radius: 20px;
    box-shadow: var(--shadow-elegant);
    position: relative;
    height: auto;
}

/* メインコンテンツスタイル */
main {
    background: var(--card-gradient);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-accent);
    padding: 2rem;
    margin: 1.5rem 0;
    border-radius: 20px;
    box-shadow: var(--shadow-elegant);
    max-width: 100%;
}

/* 見出し */
h2 {
    color: var(--accent-purple);
    font-size: 1.8rem;
    margin: 0 0 1rem 0;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--border-accent);
    text-shadow: 0 0 10px rgba(167, 139, 250, 0.3);
    text-align: center;
}

h3 {
    color: var(--accent-light);
    font-size: 1.5rem;
    margin: 1.5rem 0 1rem;
    padding: 0.5rem;
    background: rgba(167, 139, 250, 0.1);
    border-radius: 10px;
    text-align: center;
}

h4 {
    color: var(--accent-purple);
    margin: 1rem 0 0.5rem;
    padding-left: 0;
}

/* 五十音ナビゲーション（kyokurisut.htmlと統一） */
.gojuon {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    margin: 1.5rem 0;
    text-align: center;
    padding: 10px 0;
    width: 100%;
}

.gojuon a {
    display: inline-flex;
    justify-content: center;
    align-items: center;
    margin: 5px;
    background-color: rgba(167, 139, 250, 0.2);
    color: var(--link-color);
    text-decoration: none;
    border-radius: 8px;
    width: 40px;
    height: 40px;
    transition: all 0.3s ease;
    font-size: 1rem;
    flex-shrink: 0;
}

.gojuon a:hover {
    background-color: rgba(167, 139, 250, 0.4);
    color: var(--accent-purple);
    transform: translateY(-2px);
    box-shadow: 0 3px 10px rgba(167, 139, 250, 0.3);
}

/* 曲コンテナスタイル */
.all-songs-container {
    border: 1px solid var(--border-accent);
    border-radius: 15px;
    padding: 20px;
    margin: 20px 0;
}

.song-section {
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 1px dashed var(--border-accent);
}

/* アーティストコンテナ */
.artist-container {
    margin-bottom: 1rem;
}

/* アーティスト名スタイル（元のデザインを維持） */
.artist-name {
    font-weight: bold;
    color: var(--accent-light);
    padding-left: 30px;
    position: relative;
    cursor: pointer;
    transition: color 0.3s ease;
    user-select: none;
}

.artist-name::before {
    content: '▸';
    position: absolute;
    left: 5px;
    color: var(--accent-purple);
    transition: transform 0.3s ease;
}

.artist-name:hover {
    color: var(--accent-purple);
}

.artist-name.expanded::before {
    transform: rotate(90deg);
}

/* 曲リストスタイル */
.song-list {
    list-style-type: none;
    padding-left: 1.5rem;
    margin-top: 0.5rem;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.5s ease-out;
}

.song-list.expanded {
    max-height: 3000px;
}

.song-list li {
    margin-bottom: 0.5rem;
    position: relative;
    padding-left: 1rem;
}

.song-list li::before {
    content: '・';
    position: absolute;
    left: -0.5rem;
    color: var(--accent-purple);
    font-size: 0.9em;
}

/* リンク色を変更 */
.song-list a {
    color: var(--link-color);
    text-decoration: none;
    transition: all 0.3s ease;
    position: relative;
}

.song-list a:hover {
    color: var(--accent-purple);
}

.song-list a::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 100%;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--link-color), transparent);
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.song-list a:hover::after {
    transform: scaleX(1);
}

/* トップに戻るボタン */
.back-to-top {
    display: block;
    text-align: center;
    margin: 2rem auto;
    padding: 10px 20px;
    background: rgba(167, 139, 250, 0.2);
    border: 1px solid var(--border-accent);
    border-radius: 10px;
    color: var(--link-color);
    text-decoration: none;
    width: 200px;
    transition: all 0.3s ease;
}

.back-to-top:hover {
    background: rgba(167, 139, 250, 0.3);
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(167, 139, 250, 0.3);
    text-decoration: none;
}

/* レスポンシブ調整 */
@media (min-width: 768px) {
    .outer-container {
        padding: 3rem;
    }

    h1 {
        font-size: 3.5rem;
    }
}