html {
    font-size: 16px;
    scroll-behavior: smooth;
  }
  * {
    box-sizing: border-box;
  }
  body {
    margin: 0;
    padding: 0;
    font-family: 'Noto Sans JP', sans-serif;
    background-color: #1a2e3b;
    color: #fff;
    line-height: 1.8;
    overflow-x: hidden;
    width: 100%;
    min-height: 100vh;
  }
  nav {
    background-color: #101b26;
    padding: 14px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 8px rgba(0,0,0,0.3);
    width: 100%;
    max-width: 100vw;
  }
  .nav-logo {
    display: flex;
    align-items: center;
    font-weight: bold;
    font-size: 1.3em;
    color: #fff;
  }
  .nav-logo-img {
    height: 40px;
    width: auto;
    max-width: 160px;
    transition: transform 0.2s ease;
  }
  .nav-logo-img:hover {
    transform: scale(1.05);
  }
  .nav-menu {
    display: flex;
  }
  .nav-menu a {
    color: #fff;
    text-decoration: none;
    margin-left: 25px;
    font-size: 1em;
    transition: color 0.3s ease;
  }
  .nav-menu a:hover {
    text-decoration: underline;
    color: #fdd835;
  }
  .hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    padding: 5px;
  }
  .hamburger span {
    width: 25px;
    height: 3px;
    background-color: #fff;
    margin: 3px 0;
    transition: 0.3s;
    border-radius: 2px;
  }
  .hamburger.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
  }
  .hamburger.active span:nth-child(2) {
    opacity: 0;
  }
  .hamburger.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -6px);
  }
  header {
    text-align: center;
    padding: 80px 20px 50px;
    background: linear-gradient(to bottom, #24364b, #1a2e3b);
    position: relative;
    overflow: hidden;
    width: 100%;
    box-sizing: border-box;
  }
  header h1 {
    font-size: 2.5em;
    margin-bottom: 25px;
  }
  .title-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 15px;
    margin-bottom: 25px;
  }
  .logo {
    max-width: 300px;
    height: auto;
    filter: drop-shadow(0 4px 8px rgba(0, 0, 0, 0.3));
    transition: transform 0.3s ease;
  }
  .logo:hover {
    transform: scale(1.05);
  }
  .title-container h1 {
    margin: 0;
    font-size: 2.5em;
    text-align: center;
  }
  .cta-button {
    display: inline-block;
    padding: 14px 30px;
    background-color: #5865F2;
    color: white;
    text-decoration: none;
    font-size: 1.1em;
    border-radius: 8px;
    margin-top: 15px;
    transition: background-color 0.3s, transform 0.2s;
  }
  .cta-button:hover {
    background-color: #4752c4;
    transform: scale(1.05);
  }
  .test-period-badge {
    display: inline-block;
    padding: 10px 20px;
    background-color: rgba(253, 216, 53, 0.15);
    color: #fdd835;
    font-size: 1em;
    border-radius: 20px;
    margin: 15px auto 20px auto;
    border: 2px solid #fdd835;
    font-weight: 500;
    box-shadow: 0 2px 8px rgba(253, 216, 53, 0.3);
    backdrop-filter: blur(10px);
    animation: pulse 2s ease-in-out infinite;
  }
  @keyframes pulse {
    0%, 100% {
      box-shadow: 0 2px 8px rgba(253, 216, 53, 0.3);
    }
    50% {
      box-shadow: 0 4px 16px rgba(253, 216, 53, 0.5);
    }
  }
  .bubble {
    background-color: #313338;
    color: #fff;
    padding: 14px 20px;
    border-radius: 14px;
    max-width: 320px;
    margin: 0 auto 25px;
    font-size: 1em;
    text-align: left;
    display: inline-block;
    box-shadow: 0 3px 8px rgba(0,0,0,0.25);
    position: relative;
    animation: fadeInBubble 1s ease-out, bubbleFloat 4s ease-in-out infinite;
    opacity: 1;
    transition: opacity 1s ease-in-out;
  }
  .bubble::after {
    content: "";
    position: absolute;
    bottom: -10px;
    left: 24px;
    width: 0;
    height: 0;
    border: 10px solid transparent;
    border-top-color: #313338;
  }
  @keyframes fadeInBubble {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
  }
  @keyframes bubbleFloat {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-4px); }
  }
  .stars {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
  }
  .stars span {
    position: absolute;
    background: white;
    width: 2px;
    height: 2px;
    border-radius: 50%;
    opacity: 0.6;
    animation: twinkle 2s infinite ease-in-out;
  }
  @keyframes twinkle {
    0%, 100% { opacity: 0.6; }
    50% { opacity: 0.1; }
  }
  .shooting-star {
    position: absolute;
    width: 80px;
    height: 2px;
    background: rgba(255, 255, 255, 0.6);
    transform: rotate(-45deg);
    animation: shooting 8s linear infinite;
  }
  @keyframes shooting {
    0% { transform: translate(100vw, -20vh) rotate(-45deg); opacity: 0; }
    10% { opacity: 1; }
    100% { transform: translate(-10vw, 100vh) rotate(-45deg); opacity: 0; }
  }
  section {
    max-width: 1000px;
    margin: 0 auto;
    padding: 60px 20px;
    width: 100%;
    box-sizing: border-box;
  }
  section h2 {
    border-left: 6px solid #fdd835;
    padding-left: 12px;
    margin-bottom: 24px;
    font-size: 1.7em;
    color: #fdd835;
  }
  ul {
    list-style: none;
    padding: 0;
  }
  li {
    background-color: rgba(255,255,255,0.06);
    margin-bottom: 14px;
    padding: 18px 24px;
    border-radius: 10px;
    font-size: 1.1em;
    display: flex;
    align-items: center;
    box-shadow: 0 2px 4px rgba(0,0,0,0.2);
  }
  li::before {
    margin-right: 14px;
    font-size: 1.5em;
  }
  #features li:nth-child(1)::before { content: "🔒"; }
  #features li:nth-child(2)::before { content: "🎭"; }
  #features li:nth-child(3)::before { content: "⏳"; }
  #features li:nth-child(4)::before { content: "🗣️"; }
  #features li:nth-child(5)::before { content: "💬"; }
  #features li:nth-child(6)::before { content: "📱"; }

  #rules li:nth-child(1)::before { content: "🚫"; }
  #rules li:nth-child(2)::before { content: "❗"; }
  #rules li:nth-child(3)::before { content: "🔞"; }

  footer {
    background: linear-gradient(to bottom, #1a2e3b, #0f1419);
    text-align: center;
    padding: 60px 20px 20px;
    position: relative;
    overflow: hidden;
    margin-top: 0;
    width: 100%;
    box-sizing: border-box;
  }

  footer::before {
    content: '';
    position: absolute;
    top: 20px;
    left: 0;
    width: 100%;
    height: 80px;
    background: linear-gradient(135deg, rgba(26, 46, 59, 0.4), rgba(15, 20, 25, 0.3));
    clip-path: polygon(0 40%, 100% 70%, 100% 100%, 0% 100%);
    z-index: 1;
  }

  footer::after {
    content: '';
    position: absolute;
    top: 30px;
    left: 0;
    width: 100%;
    height: 60px;
    background: linear-gradient(135deg, rgba(36, 54, 75, 0.5), rgba(26, 46, 59, 0.4), rgba(15, 20, 25, 0.3));
    clip-path: polygon(0 20%, 100% 50%, 100% 100%, 0% 100%);
    animation: waveAnimation 6s ease-in-out infinite;
    z-index: 2;
  }

  @keyframes waveAnimation {
    0%, 100% {
      clip-path: polygon(0 30%, 100% 60%, 100% 100%, 0% 100%);
    }
    25% {
      clip-path: polygon(0 60%, 100% 30%, 100% 100%, 0% 100%);
    }
    50% {
      clip-path: polygon(0 40%, 100% 70%, 100% 100%, 0% 100%);
    }
    75% {
      clip-path: polygon(0 70%, 100% 40%, 100% 100%, 0% 100%);
    }
  }

  footer img {
    max-width: 100px;
    margin-bottom: 10px;
    animation: waveHand 3s ease-in-out infinite;
    transform-origin: bottom center;
    position: relative;
    z-index: 10;
  }
  
  @keyframes waveHand {
    0%, 100% {
      transform: rotate(0deg);
    }
    25% {
      transform: rotate(-8deg);
    }
    50% {
      transform: rotate(5deg);
    }
    75% {
      transform: rotate(-3deg);
    }
  }
  
  footer .copyright {
    position: relative;
    z-index: 1;
  }

  .copyright {
    font-size: 0.85em;
    color: #aaa;
  }
  @media (max-width: 900px) and (min-width: 769px) {
    .card-grid {
      grid-template-columns: repeat(2, 1fr);
      gap: 24px;
    }
    .image-card {
      max-width: 320px;
    }
    .character-card {
      flex-direction: column;
      text-align: center;
      padding: 24px;
    }
    .character-avatar {
      align-self: center;
    }
  }
  /* モバイル専用の強制1列レイアウト */
  @media (max-width: 768px) {
    .hamburger {
      display: flex;
    }
    .nav-menu {
      position: fixed;
      top: 70px;
      right: -100%;
      width: 100%;
      height: calc(100vh - 70px);
      background-color: #101b26;
      flex-direction: column;
      justify-content: flex-start;
      align-items: center;
      padding-top: 50px;
      transition: right 0.3s ease;
      box-shadow: 0 2px 8px rgba(0,0,0,0.3);
    }
    .nav-menu.active {
      right: 0;
    }
    .nav-menu a {
      margin: 15px 0;
      font-size: 1.2em;
      padding: 10px 20px;
      border-radius: 8px;
      transition: background-color 0.3s ease;
    }
    .nav-menu a:hover {
      background-color: rgba(253, 216, 53, 0.1);
      text-decoration: none;
    }
    /* 強制的に1列レイアウト */
    .card-grid {
      grid-template-columns: 1fr !important;
      grid-template-rows: repeat(4, auto) !important;
      gap: 20px;
      max-width: 500px;
      margin: 0 auto;
      display: grid !important;
    }
    .image-card {
      max-width: 100%;
      width: 100%;
      margin: 0 auto;
      display: block !important;
    }
  }
  @media (max-width: 600px) {
    nav {
      padding: 14px 20px;
    }
    .nav-logo-img {
      height: 35px;
      max-width: 140px;
    }
    header {
      padding: 60px 15px 40px;
    }
    header h1 {
      font-size: 1.6em;
    }
    .title-container h1 {
      font-size: 1.6em;
    }
    .logo {
      max-width: 100px;
    }
    .cta-button {
      font-size: 1em;
      padding: 10px 16px;
    }
    .test-period-badge {
      font-size: 0.9em;
      padding: 8px 16px;
      margin: 12px auto 16px auto;
    }
    section {
      padding: 40px 20px;
    }
    li {
      font-size: 1em;
      padding: 14px 18px;
    }
    .card-grid {
      grid-template-columns: 1fr !important;
      grid-template-rows: repeat(4, auto) !important;
      gap: 18px;
      max-width: 100%;
      padding: 0 20px;
      display: grid;
    }
    .image-card {
      max-width: 100%;
      width: 100%;
      margin: 0 auto;
    }
    .character-card {
      flex-direction: column;
      text-align: center;
      padding: 20px;
      gap: 16px;
    }
    .character-avatar {
      width: 100px;
      height: 100px;
      align-self: center;
    }
    .use-case-item {
      flex-direction: column;
      text-align: center;
      gap: 12px;
    }
    .use-case-icon {
      align-self: center;
      margin-right: 0;
    }
    .bubble {
      max-width: 280px;
      font-size: 0.9em;
    }
    .tag-row {
      flex-direction: column;
      align-items: flex-start;
      gap: 8px;
    }
    .tag-label {
      align-self: flex-start;
    }
    .modal-content {
      padding: 20px;
      max-height: 60vh;
      margin: 10px;
    }
    .modal-content p {
      font-size: 1em;
      margin: 12px 0;
    }
  }
  @media (max-width: 480px) {
    nav {
      padding: 12px 15px;
    }
    .nav-logo {
      font-size: 1.1em;
    }
    .nav-logo-img {
      height: 30px;
      max-width: 120px;
    }
    header {
      padding: 50px 15px 30px;
    }
    header h1 {
      font-size: 1.4em;
      line-height: 1.3;
      margin-bottom: 20px;
    }
    .title-container h1 {
      font-size: 1.4em;
      line-height: 1.3;
    }
    .title-container {
      gap: 10px;
      margin-bottom: 20px;
    }
    .logo {
      max-width: 0px;
    }
    .cta-button {
      font-size: 0.9em;
      padding: 8px 14px;
    }
    .test-period-badge {
      font-size: 0.8em;
      padding: 6px 12px;
      margin: 10px auto 14px auto;
    }
    section {
      padding: 30px 15px;
    }
    section h2 {
      font-size: 1.4em;
      margin-bottom: 20px;
    }
    li {
      font-size: 0.9em;
      padding: 12px 16px;
      margin-bottom: 10px;
    }
    .bubble {
      max-width: 250px;
      font-size: 0.8em;
      padding: 12px 16px;
    }
    .use-case-item {
      padding: 16px 18px;
    }
    .use-case-icon {
      width: 50px;
      height: 50px;
      min-width: 50px;
      min-height: 50px;
      font-size: 1.4em;
    }
    .use-case-content-title {
      font-size: 1.1em;
    }
    .use-case-content-text {
      font-size: 0.95em;
    }
    .character-card {
      padding: 16px;
    }
    .character-avatar {
      width: 80px;
      height: 80px;
    }
    .character-info h3 {
      font-size: 1.3em;
    }
    .character-info p {
      font-size: 0.95em;
    }
    .tag-label {
      font-size: 0.8em;
      padding: 3px 10px;
    }
    .tag-value {
      font-size: 0.85em;
    }
    .modal-content {
      padding: 15px;
      margin: 5px;
      max-height: 50vh;
    }
    .modal-content p {
      font-size: 0.9em;
      margin: 10px 0;
    }
    .modal-button {
      font-size: 0.9em;
      padding: 10px 20px;
      margin: 10px 5px;
    }
    .card-grid {
      grid-template-columns: 1fr !important;
      grid-template-rows: repeat(4, auto) !important;
      gap: 15px;
      padding: 0 15px;
      max-width: 100%;
      display: grid;
    }
    .image-card {
      max-width: 100%;
      width: 100%;
      margin: 0 auto;
    }
  }
  .modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background-color: rgba(26, 46, 59, 0.9);
    display: flex;
    justify-content: center;
    align-items: center;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
    backdrop-filter: blur(8px);
    z-index: 10000;
  }

  .modal.show {
    opacity: 1;
    visibility: visible;
  }

  .modal-content {
    background: linear-gradient(135deg, #313338, #2b2d31);
    padding: 30px;
    border-radius: 20px;
    text-align: center;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.5);
    animation: scaleIn 0.4s ease;
    color: #fff;
    border: 2px solid rgba(253, 216, 53, 0.3);
    max-width: 400px;
    width: 90%;
    max-height: 70vh;
    overflow: hidden;
    position: relative;
    margin: 20px;
  }

  .modal-content::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><circle cx="20" cy="20" r="1" fill="rgba(255,255,255,0.1)"/><circle cx="80" cy="30" r="0.5" fill="rgba(255,255,255,0.2)"/><circle cx="40" cy="70" r="0.8" fill="rgba(255,255,255,0.15)"/><circle cx="70" cy="80" r="0.6" fill="rgba(255,255,255,0.1)"/></svg>');
    pointer-events: none;
    animation: sparkle 3s ease-in-out infinite;
  }

  .modal-content p {
    margin: 15px 0;
    font-size: 1.1em;
    line-height: 1.6;
  }

  .modal-content img {
    display: none;
  }

  .modal-button {
    margin: 15px 8px;
    padding: 12px 25px;
    background: linear-gradient(135deg, #5865F2, #4752c4);
    color: white;
    border: none;
    border-radius: 25px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 1em;
    font-weight: 500;
    box-shadow: 0 4px 15px rgba(88, 101, 242, 0.3);
  }

  .modal-button:hover {
    background: linear-gradient(135deg, #4752c4, #3c47a0);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(88, 101, 242, 0.4);
  }

  .modal-button:active {
    transform: translateY(0);
  }

  @keyframes scaleIn {
    from {
      transform: scale(0.7) rotate(-5deg);
      opacity: 0;
    }
    to {
      transform: scale(1) rotate(0deg);
      opacity: 1;
    }
  }

  @keyframes sparkle {
    0%, 100% {
      opacity: 0.3;
      transform: scale(1);
    }
    50% {
      opacity: 0.8;
      transform: scale(1.1);
    }
  }
  #use-cases, #image-cards, #character-intro {
    background-color: #1a2e3b;
    padding: 60px 30px;
  }
  .use-cases-title, .section-title {
    font-size: 2em;
    text-align: center;
    color: #fff;
    margin-bottom: 40px;
    position: relative;
  }
  .use-cases-title span, .section-title span {
    background: linear-gradient(to right, #fdd835, #ff8a65);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    font-weight: bold;
  }
  .use-case-list {
    display: flex;
    flex-direction: column;
    gap: 24px;
  }
  .use-case-item {
    display: flex;
    align-items: flex-start;
    background-color: rgba(255, 255, 255, 0.07);
    border-radius: 20px;
    padding: 20px 24px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.3);
  }
  .use-case-icon {
    width: 60px;
    height: 60px;
    min-width: 60px;
    min-height: 60px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.6em;
    color: white;
    margin-right: 20px;
  }
  .use-case-icon.talk { background: #5865F2; }
  .use-case-icon.consult { background: #49964d; }
  .use-case-icon.interview { background: #ffb74d; }
  .use-case-content {
    color: #fff;
  }
  .use-case-content-title {
    font-size: 1.25em;
    font-weight: bold;
    margin-bottom: 6px;
  }
  .use-case-content-text {
    font-size: 1.05em;
    line-height: 1.7;
  }
  .card-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    grid-template-rows: repeat(2, 1fr);
    gap: 30px;
    justify-items: center;
    max-width: 800px;
    margin: 0 auto;
    width: 100%;
    box-sizing: border-box;
  }
  .image-card {
    width: 100%;
    max-width: 380px;
    border-radius: 16px;
    overflow: hidden;
    box-shadow: 0 6px 16px rgba(0,0,0,0.4);
    background-color: #2c3e50;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
  }
  .image-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 20px rgba(0,0,0,0.5);
  }
  .image-card img {
    width: 100%;
    display: block;
  }
  .character-card {
    max-width: 700px;
    margin: 0 auto;
    background-color: rgba(255, 255, 255, 0.05);
    border-radius: 20px;
    padding: 30px;
    color: #fff;
    display: flex;
    align-items: flex-start;
    gap: 24px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.4);
    flex-wrap: wrap;
  }
  .character-avatar {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    background-color: #5865F2;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2em;
    color: white;
    overflow: hidden;
  }
  .character-avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
  }
  .character-info {
    flex: 1;
  }
  .character-info h3 {
    font-size: 1.5em;
    margin-bottom: 10px;
  }
  .character-info p {
    font-size: 1.05em;
    line-height: 1.6;
    margin-bottom: 12px;
  }
  .character-tags {
    display: flex;
    flex-direction: column;
    gap: 10px;
  }
  .tag-row {
    display: flex;
    align-items: center;
    gap: 12px;
  }
  .tag-label {
    background-color: #5865F2;
    padding: 4px 12px;
    border-radius: 999px;
    font-size: 0.9em;
    font-weight: bold;
    white-space: nowrap;
  }
  .tag-value {
    font-size: 0.95em;
  }