/* =========================
   Cromo Dark Navy UI — v1
   ========================= */

/* カラートークン */
:root {
    --bg: #0b1220;                /* 画面全体の濃紺 */
    --bg-soft: #0f172a;           /* セクション背景（やや明るめ） */
    --surface: rgba(18, 27, 48, 0.6); /* カード/パネル（ガラス感） */
    --border: rgba(255, 255, 255, 0.08);
    --text: #e6edf3;              /* メイン文字色 */
    --muted: #97a0af;             /* 補助文字色 */
    --accent: #7aa2ff;            /* アクセント（青） */
    --accent-2: #64ffda;          /* サブアクセント（シアン） */
    --shadow: 0 10px 30px rgba(0,0,0,0.35);
    --radius: 16px;
    --radius-sm: 10px;
    --transition: 180ms ease;
}

/* リセット & 全体 */
* { box-sizing: border-box; }
html, body { height: 100%; }

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Hiragino Kaku Gothic ProN", "Noto Sans JP", "Yu Gothic", "Meiryo", Arial, sans-serif;
    background:
      radial-gradient(1200px 600px at 80% -10%, rgba(122,162,255,0.15), transparent 60%),
      radial-gradient(800px 400px at -10% 20%, rgba(100,255,218,0.10), transparent 60%),
      var(--bg);
    color: var(--text);
    margin: 0;
    padding: 0;
    line-height: 1.7;
    letter-spacing: 0.2px;
}

/* フォーカス可視化 */
:where(a, button):focus-visible {
    outline: 2px solid var(--accent-2);
    outline-offset: 2px;
    border-radius: 8px;
}

/* 言語切り替え */
.language-switch {
    text-align: center;
    padding: 12px 0 0;
}

.language-switch button {
    min-width: 108px;
    height: 40px;
    padding: 0 14px;
    margin: 6px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background: linear-gradient(180deg, rgba(20,32,56,0.9), rgba(14,24,45,0.9));
    color: var(--text);
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 1px 0 rgba(255,255,255,0.05) inset, var(--shadow);
    transition: transform var(--transition), background var(--transition), border-color var(--transition);
}

.language-switch button:hover {
    transform: translateY(-1px);
    border-color: rgba(122,162,255,0.5);
    background: linear-gradient(180deg, rgba(26,44,78,0.95), rgba(16,30,58,0.95));
}

/* ヘッダー */
header {
    background: linear-gradient(135deg, #0d1b2a 0%, #0b1220 40%, #0f1a2f 100%);
    color: var(--text);
    padding: 36px 20px 28px;
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    position: relative;
    overflow: hidden;
}

header::after {
    /* ほんのり薄いグリッドを重ねて未来感を演出 */
    content: "";
    position: absolute;
    inset: 0;
    background-image:
      linear-gradient(transparent 95%, rgba(122,162,255,0.08) 95%),
      linear-gradient(90deg, transparent 95%, rgba(122,162,255,0.08) 95%);
    background-size: 28px 28px;
    opacity: 0.35;
    pointer-events: none;
}

.header-content {
    display: flex;
    align-items: center;
    gap: 18px;
    margin-bottom: 12px;
    z-index: 1;
}

.app-icon {
    width: 92px;
    height: 92px;
    border-radius: 22%;
    object-fit: cover;
    box-shadow: 0 0 0 1px var(--border), 0 12px 30px rgba(0,0,0,0.45);
    background: #0c1528;
}

.header-text {
    display: flex;
    flex-direction: column;
    justify-content: center;
    text-align: left;
}

header h1 {
    font-size: clamp(26px, 4.2vw, 40px);
    line-height: 1.2;
    margin: 0 0 4px;
    letter-spacing: 0.6px;
    background: linear-gradient(90deg, var(--accent), var(--accent-2));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

header p {
    font-size: clamp(13px, 2.4vw, 16px);
    margin: 0;
    color: var(--muted);
}

/* Apple Store / SNS */
.social-links {
    display: flex;
    gap: 12px;
    justify-content: center;
    align-items: center;
    margin-top: 14px;
    z-index: 1;
}

.social-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    transform: translateZ(0);
}

.social-link img,
.store-badge,
#youtubeLink img {
    height: 40px;
    width: auto;
    object-fit: contain;
    border-radius: 8px;
    filter: drop-shadow(0 8px 20px rgba(0,0,0,0.45));
    transition: transform var(--transition), filter var(--transition), opacity var(--transition);
}

.social-link:hover img,
.social-link:hover .store-badge,
.social-link:hover #youtubeLink img {
    transform: translateY(-2px) scale(1.02);
    filter: drop-shadow(0 12px 26px rgba(0,0,0,0.55));
}

/* メイン */
main {
    padding: 28px 20px 40px;
    max-width: 920px;
    margin: 0 auto;
}

/* セクション見出し */
h2 {
    color: var(--text);
    font-size: clamp(18px, 3.2vw, 22px);
    font-weight: 700;
    margin: 24px 0 14px;
    position: relative;
    padding-bottom: 12px;
}

h2::after {
    content: "";
    position: absolute;
    left: 0;
    bottom: 0;
    width: 72px;
    height: 3px;
    border-radius: 3px;
    background: linear-gradient(90deg, var(--accent), transparent 70%);
}

/* リスト（特徴/おすすめ） */
.features ul,
.recommend ul {
    list-style: none;
    margin: 0;
    padding: 0;
    display: grid;
    gap: 10px;
}

.features li,
.recommend li {
    position: relative;
    padding: 12px 14px 12px 34px;
    border: 1px solid var(--border);
    background: var(--surface);
    backdrop-filter: blur(8px);
    border-radius: var(--radius);
    color: var(--text);
    box-shadow: var(--shadow);
    transition: transform var(--transition), border-color var(--transition), background var(--transition);
}

.features li::before,
.recommend li::before {
    content: "";
    position: absolute;
    left: 12px;
    top: 16px;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: radial-gradient(circle at 30% 30%, var(--accent-2), var(--accent));
    box-shadow: 0 0 0 2px rgba(100,255,218,0.15);
}

.features li:hover,
.recommend li:hover {
    transform: translateY(-1px);
    border-color: rgba(122,162,255,0.25);
    background: rgba(18, 27, 48, 0.72);
}

/* セクションカード（Premiumなど） */
.premium {
    background: var(--surface);
    backdrop-filter: blur(10px);
    padding: 22px;
    border-radius: var(--radius);
    margin-top: 24px;
    border: 1px solid var(--border);
    box-shadow: var(--shadow);
}

.premium p {
    margin: 8px 0 0;
    color: var(--muted);
}

/* フッター */
footer {
    background: linear-gradient(180deg, #0c1528, #0b1220);
    color: var(--muted);
    padding: 24px 14px 28px;
    text-align: center;
    margin-top: 46px;
    border-top: 1px solid var(--border);
}

footer p { margin: 6px 0; }

footer a {
    color: var(--accent-2);
    text-decoration: none;
    transition: opacity var(--transition), text-decoration-color var(--transition);
    text-underline-offset: 3px;
}

footer a:hover {
    opacity: 0.9;
    text-decoration: underline;
}

/* モバイル最適化 */
@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        gap: 12px;
        margin-bottom: 6px;
        text-align: center;
    }

    .app-icon {
        width: 84px;
        height: 84px;
        border-radius: 20%;
        margin: 0;
    }

    .header-text { text-align: center; }

    .social-link img,
    .store-badge,
    #youtubeLink img {
        height: 34px;
    }

    main { padding: 18px 14px 28px; }

    .features li,
    .recommend li {
        padding: 12px 12px 12px 32px;
        border-radius: 14px;
    }

    h2 { margin-top: 18px; }
}

/* さらに小さい端末 */
@media (max-width: 380px) {
    .language-switch button { min-width: 96px; height: 38px; }
    .social-link img,
    .store-badge,
    #youtubeLink img { height: 30px; }
}