:root {
      --bg-main: #ffffff;
      --bg-alt: #f5f5f5;
      --bg-card: #ffffff;
      --text-main: #1e1e2a;
      --text-muted: #4a4a5a;
      --orange-primary: #ff7a00;
      --orange-hover: #e06a00;
      --border-color: #e0e0e0;
      --nav-bg: rgba(255, 255, 255, 0.96);
      --shadow: 0 8px 30px rgba(0, 0, 0, 0.06);
      --card-shadow: 0 12px 28px rgba(0, 0, 0, 0.04);
    }

    /* ---- DARK MODE ---- */
    [data-theme="dark"] {
      --bg-main: #0f0f1a;
      --bg-alt: #191925;
      --bg-card: #1c1c2e;
      --text-main: #f0f0f5;
      --text-muted: #b0b0c8;
      --border-color: #2d2d44;
      --nav-bg: rgba(15, 15, 26, 0.96);
      --shadow: 0 8px 30px rgba(0, 0, 0, 0.6);
      --card-shadow: 0 12px 28px rgba(0, 0, 0, 0.5);
    }

    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
      font-family: 'Poppins', sans-serif;
    }

    html {
      scroll-behavior: smooth;
    }

    body {
      background-color: var(--bg-main);
      color: var(--text-main);
      line-height: 1.6;
      transition: background-color 0.3s ease, color 0.3s ease;
    }

    /* Utility */
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 20px;
    }
    .highlight {
      color: var(--orange-primary);
    }
    .alt-bg {
      background-color: var(--bg-alt);
    }

    .section-title {
      text-align: center;
      font-size: 2.6rem;
      font-weight: 700;
      margin-bottom: 3rem;
    }

    /* Scroll reveal */
    .reveal {
      opacity: 0;
      transform: translateY(40px);
      transition: all 0.8s ease-out;
    }
    .reveal.active {
      opacity: 1;
      transform: translateY(0);
    }

    /* Buttons */
    .btn {
      padding: 12px 32px;
      border-radius: 40px;
      text-decoration: none;
      font-weight: 600;
      transition: all 0.25s ease;
      display: inline-block;
      border: none;
      cursor: pointer;
      font-size: 1rem;
    }
    .btn-primary,
    .btn-register {
      background: var(--orange-primary);
      color: #fff;
      box-shadow: 0 8px 20px rgba(255, 122, 0, 0.3);
    }
    .btn-primary:hover,
    .btn-register:hover {
      background: var(--orange-hover);
      transform: translateY(-3px);
      box-shadow: 0 12px 28px rgba(255, 122, 0, 0.5);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--orange-primary);
      color: var(--orange-primary);
    }
    .btn-outline:hover {
      background: var(--orange-primary);
      color: #fff;
    }

    /* ---- NAVBAR ---- */
    nav {
      position: fixed;
      top: 0;
      width: 100%;
      background: var(--nav-bg);
      backdrop-filter: blur(12px);
      z-index: 999;
      border-bottom: 1px solid var(--border-color);
      transition: box-shadow 0.3s;
    }
    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 12px 5%;
      max-width: 1400px;
      margin: 0 auto;
    }
    .logo {
      font-size: 1.7rem;
      font-weight: 700;
      color: var(--text-main);
    }
    .logo span {
      color: var(--orange-primary);
    }

    .nav-links {
      display: flex;
      list-style: none;
      gap: 28px;
    }
    .nav-links a {
      color: var(--text-main);
      text-decoration: none;
      font-weight: 600;
      transition: color 0.2s;
    }
    .nav-links a:hover {
      color: var(--orange-primary);
    }

    .nav-actions {
      display: flex;
      align-items: center;
      gap: 16px;
    }
    .theme-btn {
      background: transparent;
      border: none;
      color: var(--text-main);
      font-size: 1.5rem;
      cursor: pointer;
      transition: color 0.2s;
      width: 40px;
      height: 40px;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .theme-btn:hover {
      color: var(--orange-primary);
      background: var(--bg-alt);
    }

    .hamburger {
      display: none;
      cursor: pointer;
      flex-direction: column;
      gap: 5px;
    }
    .hamburger div {
      width: 28px;
      height: 3px;
      background: var(--text-main);
      transition: 0.3s;
      border-radius: 4px;
    }

    /* ---- FIXED REGISTER BUTTON (floating) ---- */
    .fixed-register {
      position: fixed;
      bottom: 30px;
      right: 30px;
      z-index: 9999;
      background: var(--orange-primary);
      color: #fff;
      padding: 14px 32px;
      border-radius: 60px;
      font-weight: 700;
      font-size: 1.1rem;
      box-shadow: 0 10px 30px rgba(255, 122, 0, 0.45);
      display: flex;
      align-items: center;
      gap: 12px;
      border: none;
      cursor: pointer;
      transition: all 0.25s ease;
      text-decoration: none;
    }
    .fixed-register i {
      font-size: 1.3rem;
    }
    .fixed-register:hover {
      transform: scale(1.04) translateY(-4px);
      box-shadow: 0 16px 40px rgba(255, 122, 0, 0.6);
      background: var(--orange-hover);
    }
    .fixed-register .price-tag {
      display: flex;
      align-items: center;
      gap: 6px;
      background: rgba(0, 0, 0, 0.1);
      padding: 4px 14px 4px 12px;
      border-radius: 40px;
    }
    .fixed-register .price-tag .strike {
      text-decoration: line-through;
      font-weight: 400;
      opacity: 0.7;
      font-size: 0.9rem;
    }
    .fixed-register .price-tag .offer {
      font-weight: 700;
      font-size: 1.2rem;
    }

    /* ---- HERO / HOME (poster style) ---- */
    #home {
      min-height: 100vh;
      padding: 140px 0 80px;
      display: flex;
      align-items: center;
      background: var(--bg-main);
    }
    .hero-wrapper {
      display: flex;
      flex-wrap: wrap;
      align-items: center;
      gap: 40px;
    }
    .hero-text {
      flex: 1 1 400px;
    }
    .hero-text h1 {
      font-size: 3.4rem;
      font-weight: 800;
      line-height: 1.2;
      margin-bottom: 18px;
    }
    .hero-text h1 .highlight {
      background: linear-gradient(145deg, #ff7a00, #ff9a3c);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }
    .hero-text p {
      font-size: 1.15rem;
      color: var(--text-muted);
      max-width: 550px;
      margin-bottom: 30px;
    }
    .hero-buttons {
      display: flex;
      flex-wrap: wrap;
      gap: 16px;
    }

    /* Poster image */
    .hero-poster {
      flex: 1 1 400px;
      display: flex;
      justify-content: center;
      align-items: center;
    }
    .poster-card {
      background: var(--bg-card);
      border-radius: 28px;
      padding: 20px 20px 25px;
      box-shadow: var(--card-shadow);
      border: 1px solid var(--border-color);
      max-width: 440px;
      width: 100%;
      transition: transform 0.3s ease;
    }
    .poster-card:hover {
      transform: scale(1.01);
    }
    .poster-img {
      width: 100%;
      height: auto;
      border-radius: 20px;
      display: block;
      background: #2a2a3a;
      box-shadow: 0 8px 20px rgba(0, 0, 0, 0.2);
    }
    .poster-badge {
      display: flex;
      justify-content: space-between;
      align-items: center;
      margin-top: 16px;
      padding: 0 6px;
      flex-wrap: wrap;
      gap: 8px;
    }
    .poster-badge .chip {
      background: var(--orange-primary);
      color: #fff;
      font-weight: 600;
      padding: 6px 18px;
      border-radius: 40px;
      font-size: 0.85rem;
    }
    .poster-badge .price-block {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 700;
    }
    .poster-badge .price-block .strike {
      text-decoration: line-through;
      color: var(--text-muted);
      font-weight: 400;
      font-size: 0.95rem;
    }
    .poster-badge .price-block .offer {
      color: var(--orange-primary);
      font-size: 1.4rem;
    }

    /* ---- INFO BADGES (AI specific) ---- */
    .info-badge-grid {
      display: flex;
      flex-wrap: wrap;
      gap: 12px 18px;
      margin-top: 18px;
      justify-content: center;
    }
    .info-badge {
      background: var(--bg-alt);
      padding: 6px 18px;
      border-radius: 40px;
      font-size: 0.9rem;
      font-weight: 500;
      color: var(--text-main);
      border: 1px solid var(--border-color);
      display: inline-flex;
      align-items: center;
      gap: 8px;
    }
    .info-badge i {
      color: var(--orange-primary);
    }

    /* ---- OTHER SECTIONS ---- */
    .page-section {
      padding: 100px 0 80px;
    }

    /* About */
    .about-content {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
      gap: 30px;
    }
    .about-card {
      background: var(--bg-card);
      padding: 40px 30px;
      border-radius: 20px;
      text-align: center;
      box-shadow: var(--card-shadow);
      border: 1px solid var(--border-color);
      transition: transform 0.25s;
    }
    .about-card:hover {
      transform: translateY(-8px);
    }
    .card-icon {
      font-size: 3rem;
      color: var(--orange-primary);
      margin-bottom: 20px;
    }
    .about-card h3 {
      font-size: 1.4rem;
      margin-bottom: 12px;
    }
    .about-card p {
      color: var(--text-muted);
    }

    /* Syllabus */
    .syllabus-header {
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
      margin-bottom: 2rem;
    }
    .syllabus-header .section-title {
      margin-bottom: 0;
    }
    .download-btn {
      background: var(--orange-primary);
      color: #fff;
      padding: 10px 28px;
      border-radius: 40px;
      text-decoration: none;
      font-weight: 600;
      display: inline-flex;
      align-items: center;
      gap: 10px;
      transition: 0.2s;
      border: none;
      cursor: pointer;
      font-size: 1rem;
    }
    .download-btn:hover {
      background: var(--orange-hover);
      transform: scale(1.03);
    }

    .syllabus-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
      gap: 25px;
    }
    .syllabus-card {
      background: var(--bg-card);
      padding: 28px 24px;
      border-radius: 18px;
      box-shadow: var(--card-shadow);
      border-left: 6px solid var(--orange-primary);
      border-top: 1px solid var(--border-color);
      border-right: 1px solid var(--border-color);
      border-bottom: 1px solid var(--border-color);
      transition: transform 0.2s;
    }
    .syllabus-card:hover {
      transform: scale(1.02);
    }
    .chapter-badge {
      background: var(--orange-primary);
      color: #fff;
      padding: 4px 16px;
      border-radius: 40px;
      font-size: 0.75rem;
      font-weight: 700;
      display: inline-block;
      margin-bottom: 12px;
      letter-spacing: 0.5px;
    }
    .syllabus-card h3 {
      margin-bottom: 14px;
      font-size: 1.25rem;
    }
    .syllabus-card ul {
      list-style: none;
    }
    .syllabus-card ul li {
      color: var(--text-muted);
      margin-bottom: 10px;
      display: flex;
      align-items: center;
      gap: 10px;
      font-size: 0.95rem;
    }
    .syllabus-card ul li i {
      color: var(--orange-primary);
    }

    /* Contact */
    .contact-wrapper {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 50px;
      background: var(--bg-card);
      padding: 40px 45px;
      border-radius: 24px;
      box-shadow: var(--card-shadow);
      border: 1px solid var(--border-color);
    }
    .contact-info h3 {
      font-size: 1.6rem;
      margin-bottom: 20px;
    }
    .contact-info p {
      color: var(--text-muted);
      margin-bottom: 16px;
      display: flex;
      align-items: center;
      gap: 14px;
      font-size: 1.05rem;
    }
    .contact-info p i {
      color: var(--orange-primary);
      width: 24px;
    }
    .contact-form {
      display: flex;
      flex-direction: column;
      gap: 16px;
    }
    .contact-form input,
    .contact-form textarea {
      padding: 14px 18px;
      background: var(--bg-main);
      border: 1px solid var(--border-color);
      border-radius: 14px;
      color: var(--text-main);
      font-size: 1rem;
      transition: 0.2s;
    }
    .contact-form input:focus,
    .contact-form textarea:focus {
      outline: none;
      border-color: var(--orange-primary);
      box-shadow: 0 0 0 3px rgba(255, 122, 0, 0.15);
    }

    footer {
      text-align: center;
      padding: 32px;
      background: #0a0a12;
      color: #b0b0c8;
      font-size: 0.95rem;
      border-top: 1px solid #222;
    }

    /* ---- MOBILE ---- */
    @media screen and (max-width: 900px) {
      .nav-links {
        position: absolute;
        top: 70px;
        right: 0;
        width: 100%;
        background: var(--nav-bg);
        flex-direction: column;
        align-items: center;
        padding: 40px 0;
        transform: translateX(100%);
        transition: 0.35s ease;
        backdrop-filter: blur(12px);
        border-bottom: 1px solid var(--border-color);
      }
      .nav-links.nav-active {
        transform: translateX(0);
      }
      .hamburger {
        display: flex;
      }
      .btn-register {
        display: none;
      }

      .hero-text h1 {
        font-size: 2.5rem;
      }
      .hero-wrapper {
        flex-direction: column-reverse;
        text-align: center;
      }
      .hero-text p {
        margin-left: auto;
        margin-right: auto;
      }
      .hero-buttons {
        justify-content: center;
      }

      .contact-wrapper {
        grid-template-columns: 1fr;
        padding: 30px 20px;
      }
      .fixed-register {
        bottom: 20px;
        right: 20px;
        padding: 12px 22px;
        font-size: 0.95rem;
      }
      .fixed-register .price-tag .strike {
        font-size: 0.8rem;
      }
      .fixed-register .price-tag .offer {
        font-size: 1rem;
      }
      .poster-card {
        max-width: 100%;
      }
      .syllabus-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 16px;
      }
    }

    @media screen and (max-width: 480px) {
      .hero-text h1 {
        font-size: 2rem;
      }
      .section-title {
        font-size: 2rem;
      }
    }