:root {
      /* ライトモード */
      --primary-color: #0d6efd;
      --secondary-color: #6c757d;
      --success-color: #198754;
      --danger-color: #dc3545;
      --warning-color: #ffc107;
      --info-color: #17a2b8;
      --bg-color: #f0f2f5;
      --card-bg: #ffffff;
      --border-color: #e0e0e0;
      --text-color: #333;
      --text-muted: #666;
      --shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
      --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    }

    [data-theme="dark"] {
      /* ダークモード */
      --primary-color: #4dabf7;
      --secondary-color: #868e96;
      --success-color: #51cf66;
      --danger-color: #ff6b6b;
      --warning-color: #ffd43b;
      --info-color: #74c0fc;
      --bg-color: #1a1a1a;
      --card-bg: #2d2d2d;
      --border-color: #404040;
      --text-color: #e6e6e6;
      --text-muted: #adb5bd;
      --shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
    }

    * {
      box-sizing: border-box;
    }

    body {
      font-family: var(--font-family);
      margin: 0;
      padding: 2em;
      background: linear-gradient(135deg, var(--bg-color) 0%, var(--bg-color) 100%);
      color: var(--text-color);
      line-height: 1.6;
      min-height: 100vh;
    }

    .container {
      max-width: 800px;
      margin: 2em auto;
      background: var(--card-bg);
      border: 1px solid var(--border-color);
      padding: 2em;
      border-radius: 20px;
      box-shadow: var(--shadow);
      overflow: hidden;
    }

    @keyframes fadeInUp {
      from {
        opacity: 0;
        transform: translateY(30px);
      }
      to {
        opacity: 1;
        transform: translateY(0);
      }
    }

    h1 {
      color: var(--text-color);
      text-align: center;
      margin-bottom: 1.5em;
      font-size: 2.5em;
      font-weight: 700;
      background: linear-gradient(135deg, var(--primary-color) 0%, #0056b3 100%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }

    .theme-toggle {
      position: fixed;
      top: 20px;
      right: 20px;
      background: var(--card-bg);
      border: 1px solid var(--border-color);
      border-radius: 50px;
      padding: 0.5em 1em;
      cursor: pointer;
      transition: all 0.3s ease;
      box-shadow: var(--shadow);
      z-index: 1000;
    }

    .theme-toggle:hover {
      transform: scale(1.05);
    }

    .form-group {
      margin-bottom: 2em;
      position: relative;
    }

    .form-group label {
      display: block;
      margin-bottom: 0.5em;
      font-weight: 600;
      color: var(--text-color);
      transition: color 0.3s ease;
    }

    .form-group p {
      font-size: 0.9em;
      color: var(--text-muted);
      margin-top: -0.2em;
      margin-bottom: 0.5em;
    }

    .form-group input[type="text"],
    .form-group input[type="email"],
    .form-group input[type="number"],
    .form-group input[type="password"],
    .form-group select,
    .form-group textarea {
      width: 100%;
      padding: 1em;
      border: 2px solid var(--border-color);
      border-radius: 12px;
      background: var(--card-bg);
      color: var(--text-color);
      font-size: 1em;
      transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
      max-width: 100%;
      box-sizing: border-box;
    }

    .form-group input:focus,
    .form-group select:focus,
    .form-group textarea:focus {
      border-color: var(--primary-color);
      box-shadow: 0 0 0 3px rgba(13, 110, 253, 0.1);
      transform: translateY(-2px);
      outline: none;
    }

    .button {
      padding: 1em 2em;
      border: none;
      border-radius: 50px;
      cursor: pointer;
      font-weight: 600;
      font-size: 1.1em;
      transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
      text-decoration: none;
      color: white;
      background: linear-gradient(135deg, var(--primary-color) 0%, #0056b3 100%);
      display: inline-block;
      text-align: center;
      position: relative;
      overflow: hidden;
      box-shadow: 0 4px 15px rgba(13, 110, 253, 0.4);
    }

    .button::before {
      content: '';
      position: absolute;
      top: 0;
      left: -100%;
      width: 100%;
      height: 100%;
      background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
      transition: left 0.5s;
    }

    .button:hover::before {
      left: 100%;
    }

    .button:hover {
      transform: translateY(-3px);
      box-shadow: 0 8px 25px rgba(13, 110, 253, 0.3);
    }

    .button:disabled {
      background: var(--secondary-color);
      cursor: not-allowed;
      transform: none;
      box-shadow: none;
    }

    .required-mark {
      color: var(--danger-color);
      margin-left: 4px;
    }

    #drop-zone {
      border: 2px dashed var(--border-color);
      border-radius: 12px;
      padding: 2em;
      text-align: center;
      cursor: pointer;
      transition: all 0.3s ease;
      background: linear-gradient(135deg, rgba(13, 110, 253, 0.05), rgba(13, 110, 253, 0.02));
    }

    #drop-zone.dragover {
      background: linear-gradient(135deg, rgba(13, 110, 253, 0.1), rgba(13, 110, 253, 0.05));
      border-color: var(--primary-color);
      transform: scale(1.02);
    }

    #file-name {
      margin-top: 1em;
      font-weight: 600;
      color: var(--primary-color);
    }

    .consent-group {
      display: flex;
      align-items: flex-start;
      gap: 1em;
    }

    .consent-group input[type="checkbox"] {
      width: 20px;
      height: 20px;
      accent-color: var(--primary-color);
    }

    #form-message {
      margin-top: 1em;
      padding: 1em;
      border-radius: 12px;
      text-align: center;
      display: none;
      animation: slideIn 0.3s ease;
    }

    @keyframes slideIn {
      from {
        opacity: 0;
        transform: translateY(-10px);
      }
      to {
        opacity: 1;
        transform: translateY(0);
      }
    }

    #form-message.success {
      background: linear-gradient(135deg, rgba(25, 135, 84, 0.1), rgba(25, 135, 84, 0.05));
      color: var(--success-color);
      border: 1px solid rgba(25, 135, 84, 0.2);
    }

    #form-message.error {
      background: linear-gradient(135deg, rgba(220, 53, 69, 0.1), rgba(220, 53, 69, 0.05));
      color: var(--danger-color);
      border: 1px solid rgba(220, 53, 69, 0.2);
    }

    .lang-switch {
      display: flex;
      justify-content: flex-end;
      margin-bottom: 1em;
    }

    .lang-switch button {
      background: var(--card-bg);
      color: var(--text-color);
      border: 1px solid var(--border-color);
      border-radius: 25px;
      padding: 0.5em 1.2em;
      font-size: 0.9em;
      cursor: pointer;
      margin-left: 0.5em;
      transition: all 0.3s ease;
    }

    .lang-switch button:hover {
      background: var(--primary-color);
      color: white;
      transform: translateY(-2px);
    }

    .loading {
      position: relative;
      overflow: hidden;
    }

    .loading::after {
      content: '';
      position: absolute;
      top: 0;
      left: -100%;
      width: 100%;
      height: 100%;
      background: linear-gradient(90deg, transparent, rgba(255,255,255,0.4), transparent);
      animation: loading 1.5s infinite;
    }

    @keyframes loading {
      0% { left: -100%; }
      100% { left: 100%; }
    }

    .spinner {
      width: 20px;
      height: 20px;
      border: 2px solid transparent;
      border-top: 2px solid currentColor;
      border-radius: 50%;
      animation: spin 1s linear infinite;
      display: inline-block;
      margin-right: 0.5em;
    }

    @keyframes spin {
      0% { transform: rotate(0deg); }
      100% { transform: rotate(360deg); }
    }

    .toast {
      position: fixed;
      top: 20px;
      right: 20px;
      background: var(--card-bg);
      border: 1px solid var(--border-color);
      border-radius: 12px;
      padding: 1em 1.5em;
      box-shadow: var(--shadow);
      transform: translateX(100%);
      transition: transform 0.3s ease;
      z-index: 1000;
      max-width: 300px;
    }

    .toast.show {
      transform: translateX(0);
    }

    .toast.success {
      border-left: 4px solid var(--success-color);
    }

    .toast.error {
      border-left: 4px solid var(--danger-color);
    }

    /* for admin/settings.html */
    .top-bar { display: flex; justify-content: space-between; align-items: center; margin-bottom: 1em; }
    .actions { display: flex; gap: .6em; margin: 1em 0; }
    .btn-secondary { background: var(--secondary-color); }
    .btn-danger { background: var(--danger-color); }
    table { width: 100%; border-collapse: collapse; }
    th, td { border: 1px solid var(--border-color); padding: 8px; }
    th { background: #fafafa; text-align: left; }
    
    /* for login.html */
    .card { max-width:420px; margin:4em auto; background:var(--card-bg); border-radius:12px; box-shadow:var(--shadow); padding:2em; }
    .h-captcha { margin: 1.5em 0; }

    @media (max-width: 768px) {
      .container {
        margin: 1em;
        padding: 1.5em;
      }
      
      .form-group input,
      .form-group select,
      .form-group textarea {
        font-size: 16px;
      }
      
      .button {
        width: 100%;
        padding: 1em;
      }

      h1 {
        font-size: 2em;
      }
    }

    @media (max-width: 480px) {
      body {
        padding: 0.5em;
      }
      
      .container {
        margin: 0.5em;
        padding: 1em;
      }
    }

    .width-100 { width: 100%; }
    .width-80px { width: 80px; }
    .text-center { text-align: center; }
    .margin-right-1em { margin-right: 1em; }
    .margin-bottom-0-5em { margin-bottom: 0.5em; }
    .display-grid { display: grid; }
    .grid-template-columns-repeat-auto-fill-minmax-250px-1fr { grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); }
    .gap-1em { gap: 1em; }
    .margin-top-2em { margin-top: 2em; }
    .display-flex { display: flex; }
    .border-1px-solid-ddd { border: 1px solid #ddd; }
    .padding-1em { padding: 1em; }
    .border-radius-8px { border-radius: 8px; }
    .text-success { color: var(--success-color); font-weight: bold; }
    .text-danger { color: var(--danger-color); font-weight: bold; }
    .warning-message {
      color: #dc3545;
      background-color: #f8d7da;
      border: 1px solid #f5c6cb;
      padding: .75rem 1.25rem;
      margin-top: 1rem;
      border-radius: .25rem;
    }
    .success-message {
        color: #155724;
        background-color: #d4edda;
        border-color: #c3e6cb;
        padding: .75rem 1.25rem;
        margin-top: 1rem;
        border-radius: .25rem;
    }

/* トーナメントブラケットのスタイル */
.bracket-container {
  overflow-x: auto;
  padding: 20px;
  background: var(--bg-color);
  border-radius: 15px;
  margin-top: 2em;
}

.bracket-scroll-wrapper {
  display: flex;
  gap: 120px;
  padding-bottom: 20px;
}

.round {
  display: flex;
  flex-direction: column;
  justify-content: space-around;
  gap: 30px;
  min-width: 220px;
}

.match-box {
  position: relative;
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 15px;
  box-shadow: var(--shadow);
  transition: all 0.3s ease;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.match-box.current-match {
  border-color: var(--primary-color);
  box-shadow: 0 0 15px rgba(13, 110, 253, 0.3);
}

.slot-name {
  font-weight: 600;
  padding: 8px;
  border-radius: 8px;
  background: var(--bg-color);
  transition: background 0.3s ease;
}

.slot-name.winner {
  background: var(--success-color);
  color: white;
}

.vs {
  text-align: center;
  font-weight: 700;
  color: var(--text-muted);
}

.match-result {
  text-align: center;
  font-size: 0.9em;
  color: var(--primary-color);
  font-weight: bold;
  margin-top: 10px;
}

.connector {
  display: none;
  position: absolute;
  top: 50%;
  right: -22px; /* .round の gap/2 + .connector の width/2 */
  width: 20px;
  height: 2px;
  background-color: #ccc;
  transform: translateY(-50%);
}

/* 最終ラウンドのコネクタは不要 */
.round:last-child .connector {
  display: none;
}

/* イベントバナー */
.event-banners {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 1em;
  margin-bottom: 2em;
}

.event-banner {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1em;
  box-shadow: var(--shadow);
  text-align: center;
}

.event-banner img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
}

.event-banner p {
  margin-top: 0.5em;
  font-weight: 600;
  color: var(--text-color);
}

.event-in-progress {
  background-color: var(--info-color);
  color: white;
  padding: 1em;
  border-radius: 12px;
  margin-bottom: 1em;
  text-align: center;
}