/* 📱 画面全体の設定 */
html, body { 
    margin: 0; 
    padding: 0; 
    width: 100%; 
    min-height: 100vh; 
    scroll-behavior: smooth; 
}
body { 
    font-family: 'Courier New', 'MS Gothic', sans-serif; 
    color: #e2e8f0; 
    overflow-x: hidden; 
    box-sizing: border-box; 
    background-color: #050608; 
}

/* 🖼️ 固定背景 */
.fixed-bg { 
    position: fixed; 
    top: 0; 
    left: 0; 
    width: 100%; 
    height: 100%; 
    z-index: -1; 
    background: linear-gradient(rgba(8, 10, 13, 0.5), rgba(5, 6, 8, 0.85)), url('../images/S__228139015.png'); 
    background-size: cover; 
    background-position: center; 
    animation: global-glitch 20s infinite linear; 
    pointer-events: none; 
}
@keyframes global-glitch { 
    0%, 93%, 95%, 97%, 100% { transform: none; filter: none; } 
    94% { transform: skewX(1.5deg); filter: hue-rotate(45deg) contrast(1.2); } 
    94.5% { transform: skewX(-1.5deg) translateX(-3px); filter: brightness(1.2); } 
}

/* 🗺️ ナビゲーション */
.site-nav { 
    position: fixed; 
    top: 0; 
    left: 0; 
    width: 100%; 
    z-index: 10000; 
    text-align: center; 
    padding: 12px 0; 
    background: rgba(8, 12, 20, 0.8); 
    backdrop-filter: blur(8px); 
    border-bottom: 1px solid rgba(6, 182, 212, 0.1); 
}
.nav-list { list-style: none; padding: 0; margin: 0; display: inline-flex; justify-content: center; gap: 20px; }
.nav-link { color: #06b6d4; text-decoration: none; font-size: 11px; font-weight: bold; letter-spacing: 1px; cursor: pointer; }
.nav-link:hover { color: #a3e635; }

/* 📦 メインレイアウト */
.page-wrapper { width: 100%; max-width: 1200px; margin: 0 auto; padding: 90px 24px 100px 24px; box-sizing: border-box; position: relative; z-index: 10; }
.disco-index-nav { display: flex; justify-content: center; gap: 40px; margin-bottom: 60px; padding: 10px; }
.index-btn { color: #38bdf8; text-decoration: none; font-size: 13px; font-weight: bold; letter-spacing: 2px; padding: 6px 4px; opacity: 0.7; }
.index-btn.active { color: #ffffff; opacity: 1; }
.section-title { font-size: 14px; color: #38bdf8; font-weight: bold; letter-spacing: 3px; margin: 70px 0 24px 0; padding-left: 12px; border-left: 2px solid #06b6d4; scroll-margin-top: 100px; }

/* 🃏 カード・グリッド */
.disco-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 30px; }
.disco-card { background: rgba(17, 24, 39, 0.4); border: 1px solid rgba(255,255,255,0.1); padding: 16px; transition: 0.3s; }
.disco-thumb-wrapper { position: relative; aspect-ratio: 1/1; overflow: hidden; margin-bottom: 12px; }
.disco-thumb { width: 100%; height: 100%; object-fit: cover; }
.disco-title { font-size: 14px; margin-bottom: 4px; }
.disco-artist { font-size: 12px; color: #94a3b8; margin-bottom: 12px; }
.disco-btn-pair { display: flex; gap: 8px; }
.disco-sub-btn { flex: 1; text-align: center; font-size: 11px; padding: 6px; border: 1px solid #06b6d4; color: #06b6d4; text-decoration: none; }

/* 🔁 フェード演出 */
.has-double-thumb .thumb-vocal, .has-double-thumb .thumb-vocaloid { position: absolute; top: 0; left: 0; width: 100%; height: 100%; transition: opacity 1s ease-in-out; animation: auto-fade 6s infinite; }
.has-double-thumb .thumb-vocaloid { animation-delay: 0s; }
.has-double-thumb .thumb-vocal { animation-delay: 3s; }
.thumb-indicator { position: absolute; bottom: 8px; left: 0; width: 100%; display: flex; justify-content: center; gap: 6px; z-index: 10; }
.dot { width: 6px; height: 6px; border-radius: 50%; background: rgba(255,255,255,0.3); animation: dot-active 6s infinite; }
.dot:nth-child(2) { animation-delay: 3s; }
@keyframes auto-fade { 0%, 45% { opacity: 1; } 50%, 95% { opacity: 0; } 100% { opacity: 1; } }
@keyframes dot-active { 0%, 45% { background: #06b6d4; } 50%, 95% { background: rgba(255,255,255,0.3); } }

/* PCホバー */
@media (min-width: 992px) {
    .disco-card:hover { transform: translateY(-4px); border-color: rgba(6, 182, 212, 0.4); }
    .has-double-thumb .thumb-vocal, .has-double-thumb .thumb-vocaloid, .has-double-thumb .dot { animation: none !important; }
    .thumb-vocal { opacity: 1 !important; } .thumb-vocaloid { opacity: 0 !important; }
    .disco-card:has(.btn-vocaloid:hover) .thumb-vocaloid { opacity: 1 !important; }
    .disco-card:has(.btn-vocaloid:hover) .thumb-vocal { opacity: 0 !important; }
}
/* レスポンシブ */
@media (max-width: 767px) { .disco-grid { display: flex; overflow-x: auto; gap: 16px; } .disco-card { flex: 0 0 75%; } }

/* ボタンのベーススタイル */
.sub-btn {
    display: inline-block;
    padding: 10px 20px;
    border: 1px solid #ffffff; /* 枠線の色 */
    color: #ffffff;           /* 文字の色 */
    text-decoration: none;
    transition: 0.3s;         /* ふわっと色が変わるアニメーション */
    margin: 5px;
}

/* ホバーした時（マウスを乗せた時）の色 */
.sub-btn:hover {
    background-color: #ffffff;
    color: #000000;
}

/* 「Vocal Ver.」用のクラス */
.btn-vocal {
    border-color: #38bdf8; /* 水色系 */
    color: #38bdf8;
}

/* 「花隈千冬 Ver.」用のクラス */
.btn-vocaloid {
    border-color: #fb923c; /* オレンジ系（千冬ちゃんのイメージ） */
    color: #fb923c;
}