/* === Theme Variables === */
    :root {
      --bg-color: #0c0c10; /* Light mode background */
      --text-color: #eef0f6;
      --header-bg: #0c0c10;
      --header-text: #eef0f6;
      --menu-bg: #0c0c10;
      --menu-text: #eef0f6;
      --menu-hover-bg: rgba(255,46,60,0.12);
      --menu-hover-text: #ff2e3c;
      --footer-bg: #0c0c10;
      --footer-text: #b4b7c9;
    }

    html { scroll-behavior: smooth; }

    body {
      margin: 0;
      font-family: 'Noto Sans JP', sans-serif;
      background-color: var(--bg-color);
      color: var(--text-color);
      transition: background-color 0.6s ease, color 0.6s ease;
      overflow-x: hidden;
    }

    h1, h2, h3 {
      font-family: 'Oswald', sans-serif;
      text-transform: uppercase;
      letter-spacing: 2px;
      transition: color 0.6s ease;
    }

    a { text-decoration: none; color: inherit; transition: color 0.6s ease; }

    /* Header */
    header {
      background-color: var(--header-bg);
      color: var(--header-text);
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 15px 40px;
      box-shadow: 0 2px 10px rgba(0,0,0,0.1);
      position: relative;
      z-index: 100;
      transition: background-color 0.6s ease, color 0.6s ease;
    }

    .left-header {
      display: flex;
      align-items: center;
      gap: 15px;
    }

    .logo { 
      font-size: 32px;
      font-weight: bold;
      letter-spacing: 4px;
      color: #e2e0e0;
      position: relative;
      z-index: 115;
      transition: transform 0.5s ease, left 0.5s ease, top 0.5s ease;
    }

    .menu-button {
      font-size: 28px;
      background: none;
      border: none;
      color: #eef0f6;
      cursor: pointer;
      transition: transform 0.2s;
    }
    .menu-button:hover { transform: scale(1.2); }

    /* Side Menu Panel */
    .menu-box {
      position: fixed;
      top: 0;
      left: -250px;
      width: 250px;
      height: 100vh;
      background: var(--menu-bg);
      color: var(--menu-text);
      box-shadow: 3px 0 15px rgba(0,0,0,0.3);
      display: flex;
      flex-direction: column;
      padding-top: 20px;
      transition: left 0.6s cubic-bezier(0.68, -0.55, 0.27, 1.55), background-color 0.6s ease;
      z-index: 105;
    }
    .menu-box.active { left: 0; }

    .menu-logo-placeholder {
      height: 60px;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .menu-box a {
      padding: 15px 20px;
      font-weight: 600;
      border-bottom: 1px solid rgba(255,255,255,0.2);
      transition: background 0.2s, color 0.2s;
    }

    .menu-box a:hover {
      background: var(--menu-hover-bg);
      color: var(--menu-hover-text);
    }

    /* Contact Section */
    .contact-section {
      text-align: center;
      padding: 80px 20px;
      background-color: var(--bg-color);
      transition: background-color 0.6s ease;
    }

    .contact-section h2 {
      color: #ff2e3c;
      font-size: 36px;
      margin-bottom: 30px;
    }

    form {
      max-width: 500px;
      margin: 0 auto;
      background: var(--panel);
      padding: 30px;
      border-radius: 10px;
      border: 3px solid #ff2e3c;
      box-shadow: 0 4px 15px rgba(0,0,0,0.1);
      opacity: 0;
      transform: translateY(50px);
      transition: 0.6s ease;
    }

    form.visible {
      opacity: 1;
      transform: translateY(0);
    }

    input, textarea {
      width: 100%;
      padding: 10px;
      margin-bottom: 20px;
      border: 1px solid #ccc;
      border-radius: 5px;
      font-family: 'Noto Sans JP', sans-serif;
      font-size: 16px;
    }

    textarea { height: 120px; resize: vertical; }

    button {
      background-color: #ff2e3c;
      color: #eef0f6;
      border: none;
      padding: 12px 25px;
      border-radius: 5px;
      font-size: 16px;
      cursor: pointer;
      transition: 0.3s;
    }

    button:hover { background-color: darkred; transform: scale(1.05); }

    /* Extra Section */
    .extra { 
      background-color: #ff2e3c; 
      color: #eef0f6; 
      padding: 60px 20px; 
      transition: background-color 0.6s ease, color 0.6s ease; 
    }
    .extra h2 { font-size: 26px; margin-bottom: 10px; }
    .extra-columns { display: flex; gap: 20px; justify-content: space-between; align-items: flex-start; flex-wrap: wrap; }
    .extra-left { flex: 2 1 0; min-width: 260px; }
    .extra-right { flex: 1 1 0; min-width: 220px; }

    footer {
      background: #111;
      color: #bbb;
      text-align: center;
      padding: 15px;
      font-size: 14px;
      transition: background-color 0.6s ease, color 0.6s ease;
    }

    /* Dark Mode */
    body.dark-mode {
      --bg-color: #0c0c10; /* grey background in dark mode */
      --text-color: #eef0f6;
      --header-bg: #0c0c10;
      --header-text: #eef0f6;
      --menu-bg: #0c0c10;
      --menu-text: #eef0f6;
      --menu-hover-bg: rgba(255,46,60,0.12);
      --menu-hover-text: #ff2e3c;
      --footer-bg: #0c0c10;
      --footer-text: #b4b7c9;
      --extra-bg: #0c0c10;
      --extra-text: #eef0f6;
    }

    /* Dark/Light Switch */
    .theme-switch {
      position: absolute;
      bottom: 20px;
      right: 20px;
      width: 50px;
      height: 28px;
      background-color: rgba(255,255,255,0.2);
      border-radius: 14px;
      cursor: pointer;
      display: flex;
      align-items: center;
      padding: 2px;
      transition: background-color 0.4s ease;
    }

    .switch-thumb {
      width: 24px;
      height: 24px;
      background-color: var(--panel);
      border-radius: 50%;
      transition: transform 0.4s ease, background-color 0.4s ease;
    }

    body.dark-mode .theme-switch { background-color: rgba(255,255,255,0.4); }
    body.dark-mode .switch-thumb { transform: translateX(22px); background-color: #ffcc00; }

    @media (max-width: 700px) {
      .contact-section h2 { font-size: 28px; }
      form { width: 90%; }
      .extra-columns { flex-direction: column; }
      nav ul { display: none; }
    }