:root {
      --my-clean-bg: #0a0a0a;
      --my-clean-text: #e0e0e0;
      --my-clean-text-light: #c2c2c2;
      --my-clean-border: #333333;
      --my-clean-primary: #ffffff;
      --my-clean-accent-gold: #3ea8ff;
      /* より豪華に輝くリッチゴールドに変更 */
    }

    body {
      background-color: var(--my-clean-bg);
      color: var(--my-clean-text);
      font-family: 'Noto Sans JP', sans-serif;
      margin: 0;
      line-height: 1.8;
      font-weight: 300;
    }

    a {
      color: var(--my-clean-accent-gold);
      text-decoration: none;
    }

    a:hover {
      color: #3ea8ff;
      text-decoration: none;
    }

    h1,
    h2,
    h3,
    h4,
    h5,
    h6 {
      font-family: 'Noto Sans JP', sans-serif;
    }

    p {
      margin-bottom: 1.5rem;
    }

    /*--------------------------------------------------------------
    # Header
    --------------------------------------------------------------*/
    #header {
      position: fixed;
      top: 0;
      left: 0;
      bottom: 0;
      width: 300px;
      z-index: 9997;
      padding: 0 15px;
      overflow-y: auto;
      transition: all ease-in-out 0.5s;
      background: #111111;
      border-right: 1px solid var(--my-clean-border);
      box-shadow: 2px 0 15px rgba(0, 0, 0, 0.5);
    }

    #header .profile img {
      margin: 20px auto 15px auto;
      display: block;
      padding: 5px;
      width: 80%;
      box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    }

    #header .profile h6 {
      color: var(--my-clean-text-light);
      font-weight: 700;
      text-align: center;
      margin-bottom: 20px;
      letter-spacing: 0.1em;
    }

    #header .countdown {
      display: flex;
      justify-content: center;
      gap: 8px;
      margin-bottom: 25px;
    }

    #header .countdown div {
      text-align: center;
      background: #222222;
      border-radius: 8px;
      padding: 10px;
      min-width: 55px;
      border: 1px solid var(--my-clean-border);
      box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
    }

    #header .countdown h3 {
      font-size: 1.2rem;
      color: var(--my-clean-primary);
      font-weight: 700;
      margin: 0;
    }

    #header .countdown h4 {
      font-size: 0.7rem;
      color: var(--my-clean-text-light);
      margin: 2px 0 0 0;
    }

    /*--------------------------------------------------------------
    # Navigation Menu
    --------------------------------------------------------------*/
    .nav-menu {
      padding: 0;
      margin: 0;
    }

    .nav-menu ul {
      list-style: none;
      padding: 0;
      margin: 0;
    }

    .nav-menu li {
      margin-bottom: 8px;
    }

    .nav-menu a {
      display: flex;
      align-items: center;
      color: var(--my-clean-text-light);
      padding: 12px 20px;
      transition: 0.3s;
      font-size: 0.95rem;
      text-decoration: none;
      border-radius: 8px;
      font-weight: 500;
    }

    .nav-menu a i {
      font-size: 20px;
      padding-right: 15px;
      color: #999;
      transition: 0.3s;
    }

    .nav-menu a:hover,
    .nav-menu .active {
      color: #000;
      background: var(--my-clean-accent-gold);
      box-shadow: 0 4px 10px rgba(212, 175, 55, 0.2);
    }

    .nav-menu a:hover i,
    .nav-menu .active i {
      color: #000;
    }

    /* スクロールバーのカスタマイズ (Webkit) */
    #header::-webkit-scrollbar {
      width: 5px;
    }

    #header::-webkit-scrollbar-track {
      background: #111111;
    }

    #header::-webkit-scrollbar-thumb {
      background: var(--my-clean-accent-gold);
      border-radius: 5px;
    }

    /* Mobile Navigation Toggle */
    .mobile-nav-toggle {
      position: fixed;
      right: 15px;
      top: 15px;
      z-index: 9998;
      background-color: var(--my-clean-accent-gold);
      color: #fff;
      border: none;
      width: 45px;
      height: 45px;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 24px;
      cursor: pointer;
      box-shadow: 0 4px 10px rgba(0, 0, 0, 0.5);
      transition: 0.3s;
    }

    .mobile-nav-toggle:hover {
      background-color: var(--my-clean-primary);
      color: #000;
    }

    /*--------------------------------------------------------------
    # Main Content (ELEGANT GOLD ACCENT)
    --------------------------------------------------------------*/
    #main {
      margin-left: 300px;
    }

    .my-s2-wrap {
      padding: 40px 20px;
      min-height: 100vh;
    }

    .my-s2-card {
      background: #111111;
      border: 1px solid rgba(230, 184, 0, 0.3);
      border-radius: 0;
      padding: 60px;
      box-shadow: 0 15px 40px rgba(0, 0, 0, 0.5);
      margin-bottom: 40px;
      position: relative;
    }

    .my-s2-card::after {
      content: '';
      position: absolute;
      top: 10px;
      left: 10px;
      right: 10px;
      bottom: 10px;
      border: 1px solid rgba(230, 184, 0, 0.15);
      pointer-events: none;
    }

    .my-s2-title {
      font-weight: 900;
      font-size: 2.2rem;
      color: #ffffff;
      text-align: center;
      margin-bottom: 40px;
      line-height: 1.3;
      letter-spacing: 0.05em;
    }

    .my-s2-heading {
      font-weight: 500;
      color: var(--my-clean-accent-gold);
      text-align: center;
      letter-spacing: 0.1em;
      margin-bottom: 30px;
    }

    .my-s2-heading span {
      border-bottom: 1px solid var(--my-clean-accent-gold);
      padding-bottom: 5px;
    }

    /* テーブル共通 */
    .my-min-table {
      width: 100%;
      border-collapse: collapse;
      margin-top: 15px;
    }

    .my-min-table th,
    .my-min-table td {
      padding: 15px 10px;
      vertical-align: top;
      text-align: left;
    }

    .my-min-table th {
      width: 30%;
      font-weight: 500;
    }

    .my-s2-table {
      border-top: 1px solid var(--my-clean-accent-gold);
      border-bottom: 1px solid var(--my-clean-accent-gold);
    }

    .my-s2-table th,
    .my-s2-table td {
      border-bottom: 1px dashed var(--my-clean-border);
    }

    .my-s2-table th {
      color: var(--my-clean-accent-gold);
    }

    /* --- ボタンのスタイル追加 --- */
    .my-clean-btn {
      display: inline-block;
      background: #1a1a1a;
      color: var(--my-clean-accent-gold);
      border: 1px solid var(--my-clean-accent-gold);
      padding: 12px 24px;
      text-decoration: none;
      font-weight: 500;
      transition: all 0.3s ease;
      text-align: center;
      width: 100%;
      border-radius: 4px;
    }

    .my-clean-btn:hover {
      background: var(--my-clean-accent-gold);
      color: #000;
      box-shadow: 0 4px 15px rgba(230, 184, 0, 0.3);
    }

    .my-clean-btn i {
      margin-left: 5px;
      font-size: 0.9em;
    }

    /*--------------------------------------------------------------
    # Footer & Back to top
    --------------------------------------------------------------*/
    #footer {
      padding: 15px;
      color: #888;
      font-size: 12px;
      position: fixed;
      left: 0;
      bottom: 0;
      width: 300px;
      z-index: 9999;
      background: #111111;
      border-right: 1px solid var(--my-clean-border);
    }

    #footer .copyright {
      text-align: center;
    }

    .back-to-top {
      position: fixed;
      visibility: hidden;
      opacity: 0;
      right: 15px;
      bottom: 15px;
      z-index: 996;
      background-color: var(--my-clean-accent-gold);
      color: #000;
      width: 40px;
      height: 40px;
      border-radius: 50%;
      transition: all 0.4s;
      display: flex;
      align-items: center;
      justify-content: center;
      text-decoration: none;
    }

    .back-to-top i {
      font-size: 28px;
      line-height: 0;
    }

    .back-to-top:hover {
      background-color: var(--my-clean-primary);
      color: #000;
    }

    .back-to-top.active {
      visibility: visible;
      opacity: 1;
    }

    /*--------------------------------------------------------------
    # Responsive
    --------------------------------------------------------------*/
    @media (max-width: 1199px) {
      #header {
        left: -300px;
      }

      #main {
        margin-left: 0;
      }

      #footer {
        position: static;
        width: auto;
        border-right: none;
        border-top: 1px solid var(--my-clean-border);
      }

      body.mobile-nav-active #header {
        left: 0;
        box-shadow: 5px 0 15px rgba(0, 0, 0, 0.5);
      }
    }

    @media (max-width: 768px) {

      .my-min-table th,
      .my-min-table td {
        display: block;
        width: 100%;
      }

      .my-min-table th {
        padding-bottom: 5px;
      }

      .my-s2-wrap {
        padding: 20px 2px;
      }

      .my-s2-card {
        padding: 30px 20px;
      }

      .my-s2-title {
        font-size: 1.8rem;
      }
    }