/* ==========================================================================
   ▼ 個別記事ページ デザイン一括管理CSS (全50種 + ナビ30種)
   ========================================================================== */

/* 共通ベース設定 */
.single-layout-wrapper {
    max-width: 900px;
    margin: 0 auto;
    padding: 60px 20px;
    display: flex;
    flex-direction: column;
}

/* ★ h1とアイキャッチの余白を最小限に詰める設定 ★ */
.entry-header { margin-bottom: 10px; } 
.entry-eye-catch { margin-top: 0; margin-bottom: 30px; width: 100%; overflow: hidden; border-radius: 4px; }

/* メタ情報の縦ズレを防止するための厳密なFlexbox設定 */
.meta-info-wrapper { display: flex; flex-wrap: wrap; gap: 15px; margin-bottom: 15px; font-size: 13px; color: #666; align-items: center; line-height: 1; }
.post-date, .post-author { display: inline-flex; align-items: center; margin: 0; padding: 0; line-height: 1; height: auto; }
.post-categories { display: inline-flex; align-items: center; gap: 5px; margin: 0; padding: 0; }
.post-categories a { text-decoration: none; display: inline-flex; align-items: center; justify-content: center; transition: opacity 0.3s; line-height: 1; box-sizing: border-box; }
.post-categories a:hover { opacity: 0.7; }
.entry-title { font-size: 28px; line-height: 1.5; font-weight: bold; margin: 0; color: #222; font-family: inherit; }
.featured-image-fix { width: 100%; height: auto; display: block; }
.entry-content { line-height: 1.8; font-size: 16px; color: #333; margin-bottom: 60px; }


/* ==========================================================================
   【投稿デザイン 全50パターン】
   ========================================================================== */

/* 01: シンプル。カテゴリはアクセント色下線。 */
.single-design-01 .entry-title { border-bottom: 2px solid var(--single-accent); padding-bottom: 12px; }
.single-design-01 .post-date { color: #888; }
.single-design-01 .post-author { color: #888; font-style: italic; }
.single-design-01 .post-categories a { color: var(--single-accent); font-weight: bold; border-bottom: 1px solid var(--single-accent); }

/* 02: 左ボーダー。カテゴリはアクセント色背景のピル。 */
.single-design-02 .entry-title { border-left: 5px solid var(--single-accent); padding-left: 16px; }
.single-design-02 .post-date { background: #f0f0f0; padding: 4px 8px; border-radius: 4px; font-size: 12px; }
.single-design-02 .post-author { border-left: 2px solid #ccc; padding-left: 8px; }
.single-design-02 .post-categories a { background: var(--single-accent); color: #fff; padding: 5px 12px; border-radius: 20px; font-size: 12px; }

/* 03: 左ボーダー ＋ 薄い背景色。 */
.single-design-03 .entry-title { border-left: 5px solid var(--single-accent); padding: 16px 20px; background-color: #f7f7f7; }
.single-design-03 .post-date, .single-design-03 .post-author { color: #555; }
.single-design-03 .post-categories a { background: #eee; color: var(--single-accent); padding: 5px 10px; border-radius: 4px; font-weight: bold; }

/* 04: タイトル上部にアクセントライン。 */
.single-design-04 .entry-title { border-top: 3px solid var(--single-accent); padding-top: 16px; }
.single-design-04 .post-categories a { color: var(--single-accent); border: 1px solid var(--single-accent); padding: 4px 8px; border-radius: 3px; }

/* 05: タイトル上下に細いボーダー。 */
.single-design-05 .entry-title { border-top: 1px solid #ddd; border-bottom: 1px solid #ddd; padding: 16px 0; }
.single-design-05 .post-date { letter-spacing: 1px; }
.single-design-05 .post-author { font-weight: bold; color: var(--single-accent); }

/* 06: カテゴリータグを先頭に。四角い塗りつぶし。 */
.single-design-06 .meta-info-wrapper { flex-direction: row-reverse; justify-content: flex-end; }
.single-design-06 .post-categories a { background-color: var(--single-accent); color: #fff; padding: 5px 12px; font-size: 12px; }
.single-design-06 .entry-title { border-bottom: 1px solid #eee; padding-bottom: 12px; margin-top: 15px; }

/* 07: カテゴリーを丸枠線。 */
.single-design-07 .post-categories a { border: 1px solid var(--single-accent); color: var(--single-accent); padding: 5px 12px; border-radius: 50px; font-size: 12px; }
.single-design-07 .post-author { opacity: 0.6; }

/* 08: 日付/カテゴリをタイトルの「下」に配置。 */
.single-design-08 .entry-header { display: flex; flex-direction: column; }
.single-design-08 .meta-info-wrapper { order: 2; margin-top: 16px; margin-bottom: 0; padding-top: 16px; border-top: 1px dotted #ccc; }
.single-design-08 .entry-title { order: 1; border-left: 4px solid var(--single-accent); padding-left: 16px; }
.single-design-08 .post-categories a { font-weight: bold; color: #333; }

/* 09: タイトルの文字色をアクセントカラーに。 */
.single-design-09 .entry-title { color: var(--single-accent); border-bottom: 1px dashed #ccc; padding-bottom: 12px; }
.single-design-09 .post-author { color: var(--single-accent); }

/* 10: 破線の下線（ノート風）。 */
.single-design-10 .entry-title { border-bottom: 2px dashed var(--single-accent); padding-bottom: 12px; }
.single-design-10 .meta-info-wrapper { font-family: monospace; }
.single-design-10 .post-categories a { background: #333; color: #fff; padding: 4px 6px; }

/* 11: シンプル中央揃え。 */
.single-design-11 .entry-header { text-align: center; }
.single-design-11 .meta-info-wrapper { justify-content: center; }
.single-design-11 .entry-title { border-bottom: 2px solid var(--single-accent); padding-bottom: 12px; display: inline-block; }
.single-design-11 .post-categories a { color: var(--single-accent); text-decoration: underline; }

/* 12: 中央揃え ＋ 上下ボーダー。 */
.single-design-12 .entry-header { text-align: center; }
.single-design-12 .meta-info-wrapper { justify-content: center; }
.single-design-12 .entry-title { border-top: 1px solid #ddd; border-bottom: 1px solid #ddd; padding: 15px 0; }
.single-design-12 .post-categories a { border: 1px solid #333; color: #333; padding: 4px 10px; }

/* 13: タイトル下にアクセントドット。 */
.single-design-13 .entry-header { text-align: center; }
.single-design-13 .meta-info-wrapper { justify-content: center; text-transform: uppercase; letter-spacing: 1px; }
.single-design-13 .entry-title { position: relative; padding-bottom: 20px; }
.single-design-13 .entry-title::after { content: ''; position: absolute; bottom: 0; left: 50%; transform: translateX(-50%); width: 8px; height: 8px; border-radius: 50%; background-color: var(--single-accent); }

/* 14: 二重線の下線。 */
.single-design-14 .entry-header { text-align: center; }
.single-design-14 .meta-info-wrapper { justify-content: center; }
.single-design-14 .entry-title { border-bottom: 4px double var(--single-accent); padding-bottom: 12px; display: inline-block; }
.single-design-14 .post-date { border-right: 1px solid #ccc; padding-right: 15px; }

/* 15: アイキャッチ画像をタイトルの「上」に配置。 */
.single-design-15 .entry-header { text-align: center; }
.single-design-15 .meta-info-wrapper { justify-content: center; }
.single-design-15 .entry-eye-catch { order: -1; margin-bottom: 20px; }
.single-design-15 .entry-title { font-size: 32px; }
.single-design-15 .post-categories a { background: var(--single-accent); color: #fff; padding: 6px 15px; border-radius: 30px; }

/* 16: メタ情報をタイトルの下に配置。 */
.single-design-16 .entry-header { text-align: center; display: flex; flex-direction: column; }
.single-design-16 .meta-info-wrapper { order: 2; margin-top: 15px; margin-bottom: 0; justify-content: center; }
.single-design-16 .entry-title { order: 1; }
.single-design-16 .post-categories a { border: 1px solid var(--single-accent); color: var(--single-accent); padding: 4px 10px; border-radius: 4px; }

/* 17: 極めてミニマル。 */
.single-design-17 .entry-header { text-align: center; margin-bottom: 40px; }
.single-design-17 .meta-info-wrapper { justify-content: center; font-size: 11px; color: #999; }
.single-design-17 .entry-title { font-size: 36px; font-weight: normal; letter-spacing: 2px; }

/* 18: 背景付きの四角いボックス。 */
.single-design-18 .entry-header { text-align: center; background: #f5f5f5; padding: 30px; border-top: 4px solid var(--single-accent); border-radius: 4px; }
.single-design-18 .meta-info-wrapper { justify-content: center; }
.single-design-18 .post-categories a { background: #fff; border: 1px solid #ddd; color: #333; padding: 5px 12px; }

/* 19: タイトル文字背景をハイライト。 */
.single-design-19 .entry-header { text-align: center; }
.single-design-19 .meta-info-wrapper { justify-content: center; }
.single-design-19 .entry-title { display: inline; background: linear-gradient(transparent 60%, var(--single-accent) 60%); opacity: 0.9; }

/* 20: 雑誌風。 */
.single-design-20 .entry-header { text-align: center; }
.single-design-20 .meta-info-wrapper { justify-content: center; border-bottom: 1px solid #222; padding-bottom: 10px; margin-bottom: 15px; }
.single-design-20 .entry-title { font-weight: normal; }

/* 21: アイキャッチ上が重なるボックス。 */
.single-design-21 .entry-eye-catch { order: -1; margin-bottom: 20px; }
.single-design-21 .entry-header { background: #fff; padding: 20px; box-shadow: 0 2px 10px rgba(0,0,0,0.05); border-left: 4px solid var(--single-accent); transform: translateY(-30px); width: 90%; margin: 0 auto 10px; z-index: 2; position: relative; }
.single-design-21 .post-categories a { color: var(--single-accent); font-weight: bold; }

/* 22: ブラケット装飾 [ Title ]。 */
.single-design-22 .entry-title::before { content: '['; color: var(--single-accent); margin-right: 10px; }
.single-design-22 .entry-title::after { content: ']'; color: var(--single-accent); margin-left: 10px; }

/* 23: メタ右寄せ・タイトル左寄せ分割レイアウト。 */
@media (min-width: 768px) {
    .single-design-23 .entry-header { display: flex; justify-content: space-between; align-items: flex-end; border-bottom: 2px solid #222; padding-bottom: 10px; }
    .single-design-23 .meta-info-wrapper { margin-bottom: 0; flex-direction: column; align-items: flex-end; gap: 5px; }
}
.single-design-23 .entry-title { font-size: 24px; padding: 0; }
.single-design-23 .post-categories a { background: #222; color: #fff; padding: 4px 8px; font-size: 11px; }

/* 24: ソリッドブロック。 */
.single-design-24 .entry-header { background-color: var(--single-accent); padding: 30px; border-radius: 4px; color: #fff; }
.single-design-24 .meta-info-wrapper, .single-design-24 .entry-title, .single-design-24 .post-date, .single-design-24 .post-author { color: #fff; }
.single-design-24 .post-categories a { color: #fff; border: 1px solid #fff; padding: 4px 10px; border-radius: 4px; }

/* 25: インデントライン。 */
.single-design-25 .entry-header { position: relative; padding-left: 20px; }
.single-design-25 .entry-header::before { content: ''; position: absolute; left: 0; top: 0; bottom: 0; width: 2px; background-color: var(--single-accent); }
.single-design-25 .post-author { font-weight: bold; }

/* 26: 論文/レポート風。 */
.single-design-26 .entry-header { border: 1px solid #ddd; padding: 20px; }
.single-design-26 .meta-info-wrapper { border-bottom: 1px solid #ddd; padding-bottom: 15px; margin-bottom: 15px; }

/* 27: ドット区切りのメタ情報 ＋ 大きいタイトル。 */
.single-design-27 .meta-info-wrapper span:not(:last-child)::after { content: '・'; margin-left: 10px; }
.single-design-27 .entry-title { font-size: 32px; letter-spacing: 1px; }

/* 28: アイキャッチなし想定（タイトル領域広く）。 */
.single-design-28 .entry-header { padding: 40px 0; border-bottom: 1px solid #eee; text-align: center; }
.single-design-28 .entry-title { font-size: 34px; }
.single-design-28 .post-categories a { font-size: 14px; color: var(--single-accent); }

/* 29: 左アクセントブロックとタイトルが重なる。 */
.single-design-29 .entry-title { position: relative; z-index: 2; padding-left: 15px; }
.single-design-29 .entry-title::before { content: ''; position: absolute; left: 0; top: -5px; width: 35px; height: 35px; background-color: var(--single-accent); opacity: 0.2; z-index: -1; border-radius: 4px; }
.single-design-29 .post-date { font-weight: bold; color: var(--single-accent); }

/* 30: 究極のミニマル。 */
.single-design-30 .entry-header { margin-bottom: 30px; }
.single-design-30 .meta-info-wrapper { font-size: 11px; text-transform: uppercase; letter-spacing: 2px; }
.single-design-30 .entry-title { font-size: 26px; letter-spacing: 0.05em; font-weight: bold; border: none; }

/* 31: 左右に薄いボーダー */
.single-design-31 .entry-title { border-left: 1px solid #ddd; border-right: 1px solid #ddd; padding: 0 15px; display: inline-block;}
/* 32: タイトル背景に極薄のアクセント色 */
.single-design-32 .entry-title { background: #f9f9f9; border-left: 4px solid var(--single-accent); padding: 12px 15px; }
/* 33: 記号付き ■ */
.single-design-33 .entry-title::before { content: '■'; color: var(--single-accent); margin-right: 8px; font-size: 0.8em; }
/* 34: 英語並記風 */
.single-design-34 .meta-info-wrapper { margin-bottom: 5px; font-weight: bold; color: var(--single-accent); }
/* 35: 下二重線 */
.single-design-35 .entry-title { border-bottom: 3px double var(--single-accent); padding-bottom: 8px; }
/* 36: シャドウボックス */
.single-design-36 .entry-header { padding: 20px; box-shadow: 0 4px 15px rgba(0,0,0,0.05); background:#fff; }
/* 37: 角丸ボックス */
.single-design-37 .entry-header { background: #f0f0f0; border-radius: 15px; padding: 20px; }
/* 38: グラデーションテキスト */
.single-design-38 .entry-title { background: linear-gradient(45deg, #333, var(--single-accent)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
/* 39: アウトラインテキスト */
.single-design-39 .entry-title { -webkit-text-stroke: 1px #333; color: transparent; }
/* 40: アクセントカラー太線下線 */
.single-design-40 .entry-title { border-bottom: 6px solid var(--single-accent); padding-bottom: 5px; display: inline-block; }
/* 41: 左ボーダー ＋ 全体背景 */
.single-design-41 .entry-header { border-left: 4px solid var(--single-accent); padding: 15px; background: #fafafa; }
/* 42: 中央揃え ＋ 全体背景 */
.single-design-42 .entry-header { text-align: center; background: #fafafa; padding: 20px; }
.single-design-42 .meta-info-wrapper { justify-content: center; }
/* 43: 中央揃え ＋ 上下二重線 */
.single-design-43 .entry-header { text-align: center; }
.single-design-43 .meta-info-wrapper { justify-content: center; }
.single-design-43 .entry-title { border-top: 3px double #ddd; border-bottom: 3px double #ddd; padding: 15px 0; }
/* 44: ミニマル・スモールタイトル */
.single-design-44 .entry-title { font-size: 22px; font-weight: 500; }
/* 45: エクストララージ・タイトル */
.single-design-45 .entry-title { font-size: 38px; font-weight: 900; letter-spacing: -1px; }
/* 46: タイトルにクォーテーションマーク */
.single-design-46 .entry-title::before { content: '“'; color: var(--single-accent); font-size: 1.5em; vertical-align: bottom; margin-right: 5px; }
/* 47: タイトル末尾にドット */
.single-design-47 .entry-title::after { content: '.'; color: var(--single-accent); font-size: 1.2em; }
/* 48: ツートーンボーダー */
.single-design-48 .entry-title { border-bottom: 2px solid #ccc; position: relative; padding-bottom: 10px; }
.single-design-48 .entry-title::after { content: ''; position: absolute; left: 0; bottom: -2px; width: 50px; height: 2px; background: var(--single-accent); }
/* 49: インセットシャドウボックス */
.single-design-49 .entry-header { padding: 20px; box-shadow: inset 0 0 10px rgba(0,0,0,0.05); border: 1px solid #eee; }
/* 50: アウトセット太枠 */
.single-design-50 .entry-header { border: 3px solid #222; padding: 20px; }


/* ==========================================================================
   【ナビゲーションデザイン 全30パターン】 ★完全分離・独立化★
   ========================================================================== */

/* 大枠からは背景や枠線を完全に削除し、隙間（gap）を広くとりました */
.post-navigation { border-top: 1px solid #eee; padding-top: 40px; margin-top: 60px; background: transparent !important; }
.nav-links { display: flex; justify-content: space-between; gap: 30px; }
.nav-previous, .nav-next { flex: 1; display: flex; min-width: 0; }
.nav-next { justify-content: flex-end; }

/* 個々のボタン（リンク自体）にスタイルを適用するためのベース */
.nav-btn {
    display: flex; align-items: center; gap: 15px; text-decoration: none; color: #333;
    width: 100%; box-sizing: border-box; transition: all 0.3s ease; background: transparent;
}
.nav-previous .nav-btn { justify-content: flex-start; text-align: left; }
.nav-next .nav-btn { justify-content: flex-end; text-align: right; }

.nav-label { display: block; font-size: 10px; color: #999; margin-bottom: 4px; transition: color 0.3s; }
.nav-post-title { 
    display: block; font-size: 14px; font-weight: bold; line-height: 1.4; transition: color 0.3s;
    white-space: nowrap; overflow: hidden; text-overflow: ellipsis; max-width: 250px; 
}
.arrow-icon { font-size: 18px; transition: transform 0.3s, color 0.3s; display: inline-flex; align-items: center; justify-content: center; }

/* --------------------------------------------------
   01-05: シンプル・ミニマル系
-------------------------------------------------- */
.nav-design-01 .nav-btn:hover .nav-post-title,
.nav-design-01 .nav-btn:hover .arrow-icon { color: var(--single-accent); }

.nav-design-02 .nav-btn:hover .nav-post-title { color: var(--single-accent); text-decoration: underline; }

.nav-design-03 .nav-btn:hover .nav-post-title { color: var(--single-accent); }
.nav-design-03 .nav-previous .nav-btn:hover .arrow-icon { transform: translateX(-8px); color: var(--single-accent); }
.nav-design-03 .nav-next .nav-btn:hover .arrow-icon { transform: translateX(8px); color: var(--single-accent); }

.nav-design-04 .nav-btn { opacity: 0.6; }
.nav-design-04 .nav-btn:hover { opacity: 1; color: var(--single-accent); }
.nav-design-04 .nav-btn:hover * { color: var(--single-accent); }

.nav-design-05 .nav-btn:hover { transform: scale(1.02); }
.nav-design-05 .nav-btn:hover * { color: var(--single-accent); }

/* --------------------------------------------------
   06-10: ボーダー・枠線系
-------------------------------------------------- */
.nav-design-06 .nav-btn { border: 1px solid #ddd; padding: 20px; border-radius: 8px; }
.nav-design-06 .nav-btn:hover { border-color: var(--single-accent); background: #fafafa; }

.nav-design-07 .nav-btn { border-bottom: 2px solid #eee; padding: 15px 0; }
.nav-design-07 .nav-btn:hover { border-bottom-color: var(--single-accent); }

.nav-design-08 .nav-btn { padding: 15px 20px; background: #fcfcfc; border-radius: 4px; }
.nav-design-08 .nav-previous .nav-btn { border-left: 3px solid transparent; }
.nav-design-08 .nav-previous .nav-btn:hover { border-left-color: var(--single-accent); background: #fff; box-shadow: 0 2px 10px rgba(0,0,0,0.05); }
.nav-design-08 .nav-next .nav-btn { border-right: 3px solid transparent; }
.nav-design-08 .nav-next .nav-btn:hover { border-right-color: var(--single-accent); background: #fff; box-shadow: 0 2px 10px rgba(0,0,0,0.05); }

.nav-design-09 .nav-btn { border-top: 2px solid #eee; padding: 15px 0; }
.nav-design-09 .nav-btn:hover { border-top-color: var(--single-accent); background: #fafafa; padding: 15px 10px; }

.nav-design-10 .nav-btn { border: 1px dashed #ccc; padding: 20px; border-radius: 4px; }
.nav-design-10 .nav-btn:hover { border: 1px solid var(--single-accent); background: #fafafa; }

/* --------------------------------------------------
   11-15: ソリッドブロック・背景色系
-------------------------------------------------- */
.nav-design-11 .nav-btn { background: #f5f5f5; padding: 20px; border-radius: 8px; }
.nav-design-11 .nav-btn:hover { background: var(--single-accent); }
.nav-design-11 .nav-btn:hover * { color: #fff; }

.nav-design-12 .nav-btn { background: var(--single-accent); padding: 20px; border-radius: 8px; }
.nav-design-12 .nav-btn * { color: #fff; }
.nav-design-12 .nav-btn:hover { opacity: 0.8; transform: translateY(-3px); box-shadow: 0 5px 15px rgba(0,0,0,0.15); }

.nav-design-13 .nav-btn { background: #222; padding: 20px; border-radius: 8px; }
.nav-design-13 .nav-btn * { color: #fff; }
.nav-design-13 .nav-btn:hover { background: var(--single-accent); }

.nav-design-14 .nav-btn { background: #fff; padding: 20px; border-radius: 12px; box-shadow: 0 4px 15px rgba(0,0,0,0.05); border: 1px solid #f0f0f0; }
.nav-design-14 .nav-btn:hover { box-shadow: 0 8px 25px rgba(0,0,0,0.1); transform: translateY(-3px); border-color: var(--single-accent); }

.nav-design-15 .nav-btn { background: #fafafa; padding: 20px; border-radius: 8px; border: 1px solid #eee; }
.nav-design-15 .nav-btn:hover { border-color: var(--single-accent); }
.nav-design-15 .nav-btn:hover * { color: var(--single-accent); }

/* --------------------------------------------------
   16-20: モダン・シャドウ・形状変化系
-------------------------------------------------- */
.nav-design-16 .nav-btn { background: #fff; padding: 20px; border-radius: 8px; box-shadow: 5px 5px 15px #e6e6e6, -5px -5px 15px #ffffff; }
.nav-design-16 .nav-btn:hover { box-shadow: inset 5px 5px 10px #e6e6e6, inset -5px -5px 10px #ffffff; color: var(--single-accent); }
.nav-design-16 .nav-btn:hover .nav-post-title { color: var(--single-accent); }

.nav-design-17 .nav-btn { border: 2px solid #333; padding: 20px; border-radius: 0; }
.nav-design-17 .nav-btn:hover { background: #333; }
.nav-design-17 .nav-btn:hover * { color: #fff; }

.nav-design-18 .nav-btn { background: #fff; padding: 15px 30px; border-radius: 50px; box-shadow: 0 3px 10px rgba(0,0,0,0.08); border: 1px solid #eee; }
.nav-design-18 .nav-btn:hover { box-shadow: 0 8px 20px rgba(0,0,0,0.12); border-color: var(--single-accent); }

.nav-design-19 .nav-btn { padding: 15px 0; }
.nav-design-19 .arrow-icon { width: 40px; height: 40px; border-radius: 50%; background: #f0f0f0; color: #333; }
.nav-design-19 .nav-btn:hover .arrow-icon { background: var(--single-accent); color: #fff; }
.nav-design-19 .nav-btn:hover .nav-post-title { color: var(--single-accent); }

.nav-design-20 .nav-btn { padding: 15px 0; }
.nav-design-20 .arrow-icon { width: 40px; height: 40px; border-radius: 8px; border: 1px solid #ddd; color: #666; }
.nav-design-20 .nav-btn:hover .arrow-icon { border-color: var(--single-accent); background: var(--single-accent); color: #fff; }

/* --------------------------------------------------
   21-30: ギミック・クリエイティブ系
-------------------------------------------------- */
.nav-design-21 .nav-btn { padding: 15px 0; border-bottom: 1px solid #ddd; }
.nav-design-21 .nav-btn:hover { border-bottom-color: var(--single-accent); }
.nav-design-21 .nav-btn:hover .nav-label { color: var(--single-accent); font-weight: bold; letter-spacing: 1px; }

.nav-design-22 .nav-btn { padding: 20px; border-radius: 8px; border: 1px solid #eee; background: linear-gradient(to right, #f9f9f9 50%, white 50%); background-size: 200% 100%; background-position: right bottom; }
.nav-design-22 .nav-previous .nav-btn:hover { background-position: left bottom; border-color: var(--single-accent); }
.nav-design-22 .nav-next .nav-btn { background: linear-gradient(to left, #f9f9f9 50%, white 50%); background-size: 200% 100%; background-position: right bottom; }
.nav-design-22 .nav-next .nav-btn:hover { background-position: left bottom; border-color: var(--single-accent); }

.nav-design-23 .nav-btn { padding: 15px 0; }
.nav-design-23 .nav-btn:hover .nav-post-title { letter-spacing: 0.5px; color: var(--single-accent); }

.nav-design-24 .nav-btn { filter: grayscale(100%); opacity: 0.7; padding: 15px 0; }
.nav-design-24 .nav-btn:hover { filter: grayscale(0%); opacity: 1; color: var(--single-accent); }
.nav-design-24 .nav-btn:hover * { color: var(--single-accent); }

.nav-design-25 .nav-btn { border: 3px double #ddd; padding: 20px; border-radius: 8px; }
.nav-design-25 .nav-btn:hover { border-color: var(--single-accent); }

@keyframes arrowBounceLeft { 0%, 100% { transform: translateX(0); } 50% { transform: translateX(-5px); } }
@keyframes arrowBounceRight { 0%, 100% { transform: translateX(0); } 50% { transform: translateX(5px); } }
.nav-design-26 .nav-btn { padding: 15px 0; }
.nav-design-26 .nav-previous .nav-btn:hover .arrow-icon { animation: arrowBounceLeft 1s infinite; color: var(--single-accent); }
.nav-design-26 .nav-next .nav-btn:hover .arrow-icon { animation: arrowBounceRight 1s infinite; color: var(--single-accent); }

.nav-design-27 .nav-btn { padding: 20px; border: 1px solid #eee; border-radius: 0; outline: 1px solid transparent; outline-offset: 0; transition: all 0.3s; }
.nav-design-27 .nav-btn:hover { outline: 1px solid var(--single-accent); outline-offset: -5px; border-color: transparent; background: #fafafa; }

.nav-design-28 .nav-btn { position: relative; padding: 20px; background: #fdfdfd; border: 1px solid #f0f0f0; }
.nav-design-28 .nav-previous .nav-btn::before { content: ''; position: absolute; left: 0; top: 0; bottom: 0; width: 4px; background: var(--single-accent); transform: scaleY(0); transition: 0.3s; }
.nav-design-28 .nav-previous .nav-btn:hover::before { transform: scaleY(1); }
.nav-design-28 .nav-next .nav-btn::before { content: ''; position: absolute; right: 0; top: 0; bottom: 0; width: 4px; background: var(--single-accent); transform: scaleY(0); transition: 0.3s; }
.nav-design-28 .nav-next .nav-btn:hover::before { transform: scaleY(1); }

.nav-design-29 .nav-btn { padding: 15px 0; border-bottom: 4px solid #eee; }
.nav-design-29 .nav-btn:hover { border-bottom-color: var(--single-accent); }

.nav-design-30 .nav-btn { padding: 20px; border-radius: 12px; background: rgba(255, 255, 255, 0.5); border: 1px solid rgba(255,255,255,0.8); backdrop-filter: blur(5px); box-shadow: 0 4px 10px rgba(0,0,0,0.03); }
.nav-design-30 .nav-btn:hover { box-shadow: 0 0 15px color-mix(in srgb, var(--single-accent) 40%, transparent); border-color: var(--single-accent); }


/* ==========================================================================
   ▼ レスポンシブ対応（スマホ・タブレット向け）
   ========================================================================== */
@media screen and (max-width: 768px) {
    .single-layout-wrapper {
        padding: 30px 15px;
    }
    .entry-title {
        font-size: 20px !important;
        line-height: 1.4 !important;
        padding: 10px 0 !important;
    }
    .single-design-15 .entry-title, .single-design-17 .entry-title, 
    .single-design-27 .entry-title, .single-design-28 .entry-title,
    .single-design-45 .entry-title { 
        font-size: 24px !important; 
    }
    .single-design-18 .entry-header, .single-design-21 .entry-header, 
    .single-design-24 .entry-header, .single-design-26 .entry-header,
    .single-design-36 .entry-header, .single-design-37 .entry-header,
    .single-design-41 .entry-header, .single-design-42 .entry-header,
    .single-design-49 .entry-header, .single-design-50 .entry-header { 
        padding: 15px !important; 
    }
    .single-design-21 .entry-header { 
        width: 100%; 
        transform: translateY(-15px);
    }
    .meta-info-wrapper { 
        gap: 10px; 
        margin-bottom: 10px; 
    }
    
    /* スマホ時のナビゲーションは縦並びにし、文字の省略を解除 */
    .nav-links { 
        flex-direction: column; 
        gap: 15px;
    }
    .nav-previous, .nav-next { 
        width: 100%; 
    }
    .nav-btn { 
        padding: 15px; 
        border-radius: 8px; 
        border-right: none !important; 
        border-left: none !important; 
    }
    .nav-post-title { 
        max-width: 100%; 
        white-space: normal; 
    }
}