/* ===== RESET & BASE ===== */
    *, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
    html { scroll-behavior: smooth; }
    body {
      font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
      color: #333;
      line-height: 1.6;
      overflow-x: hidden;
    }
    a { text-decoration: none; color: inherit; }
    ul { list-style: none; }
    img { max-width: 100%; display: block; }

    /* ===== CSS VARIABLES ===== */
    :root {
      --primary: #4F46E5;
      --primary-dark: #3730A3;
      --primary-light: #818CF8;
      --accent: #EC4899;
      --text: #1e293b;
      --text-light: #64748b;
      --bg: #fff;
      --bg-light: #EEF2FF;
      --bg-dark: #0F172A;
      --border: #e2e8f0;
      --shadow: 0 4px 20px rgba(0,0,0,0.06);
      --shadow-lg: 0 10px 40px rgba(0,0,0,0.1);
      --radius: 12px;
      --transition: 0.3s ease;
    }

    /* ===== NAVBAR ===== */
    .navbar {
      position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
      background: rgba(255,255,255,0.97);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--border);
      padding: 0 60px;
      height: 72px;
      display: flex; align-items: center; justify-content: space-between;
      transition: var(--transition);
    }
    .navbar.scrolled { box-shadow: var(--shadow); }
    .nav-logo {
      display: flex; align-items: center; gap: 10px;
      font-size: 1.4rem; font-weight: 800;
      color: var(--text);
    }
    .nav-logo svg { width: 28px; height: 28px; fill: var(--primary); }
    .nav-links { display: flex; align-items: center; gap: 28px; }
    .nav-links a {
      font-size: 0.9rem; font-weight: 500;
      color: var(--text-light);
      transition: var(--transition);
    }
    .nav-links a:hover { color: var(--primary); }
    .nav-auth { display: flex; align-items: center; gap: 16px; }
    .nav-login {
      font-size: 0.9rem; font-weight: 500;
      color: var(--text);
      transition: var(--transition);
    }
    .nav-login:hover { color: var(--primary); }
    .nav-register {
      padding: 10px 24px;
      background: var(--primary);
      color: #fff;
      font-weight: 600;
      font-size: 0.9rem;
      border-radius: 8px;
      transition: var(--transition);
    }
    .nav-register:hover {
      background: var(--primary-dark);
      transform: translateY(-1px);
    }
    .nav-toggle { display: none; cursor: pointer; font-size: 1.5rem; }

    /* ===== HERO ===== */
    .hero {
      padding: 140px 60px 80px;
      background: var(--bg-light);
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
      max-width: 100%;
    }
    .hero-text h1 {
      font-size: 3.2rem;
      font-weight: 800;
      color: var(--text);
      line-height: 1.2;
      margin-bottom: 20px;
    }
    .hero-text p {
      font-size: 1.1rem;
      color: var(--text-light);
      line-height: 1.7;
      margin-bottom: 32px;
      max-width: 480px;
    }
    .hero-buttons { display: flex; gap: 16px; flex-wrap: wrap; }
    .btn-primary {
      display: inline-block;
      padding: 14px 32px;
      background: var(--primary);
      color: #fff;
      font-weight: 600;
      font-size: 1rem;
      border-radius: 8px;
      border: none;
      cursor: pointer;
      transition: var(--transition);
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      transform: translateY(-2px);
      box-shadow: 0 8px 24px rgba(79,70,229,0.35);
    }
    .btn-outline {
      display: inline-block;
      padding: 14px 32px;
      background: transparent;
      color: var(--primary);
      font-weight: 600;
      font-size: 1rem;
      border-radius: 8px;
      border: 2px solid var(--border);
      cursor: pointer;
      transition: var(--transition);
    }
    .btn-outline:hover {
      border-color: var(--primary);
      color: var(--primary);
    }
    .hero-image {
      position: relative;
      border-radius: 16px;
      overflow: hidden;
    }
    .hero-image img {
      width: 100%;
      height: 400px;
      object-fit: cover;
      border-radius: 16px;
    }

    /* ===== FEATURES ===== */
    .features {
      padding: 100px 60px;
      background: var(--bg);
    }
    .features-header {
      text-align: center;
      margin-bottom: 60px;
    }
    .features-header h2 {
      font-size: 2.4rem;
      font-weight: 800;
      color: var(--text);
      margin-bottom: 12px;
    }
    .features-header p {
      font-size: 1.05rem;
      color: var(--text-light);
      max-width: 560px;
      margin: 0 auto;
    }
    .features-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 28px;
      max-width: 1200px;
      margin: 0 auto;
    }
    .feature-card {
      text-align: center;
      padding: 36px 24px;
      border-radius: var(--radius);
      border: 1px solid var(--border);
      transition: var(--transition);
    }
    .feature-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-lg);
      border-color: transparent;
    }
    .feature-icon {
      width: 64px; height: 64px;
      margin: 0 auto 20px;
      background: var(--bg-light);
      border-radius: 50%;
      display: flex; align-items: center; justify-content: center;
    }
    .feature-icon svg { width: 28px; height: 28px; fill: var(--primary); }
    .feature-card h3 {
      font-size: 1.1rem;
      font-weight: 700;
      margin-bottom: 10px;
      color: var(--text);
    }
    .feature-card p {
      font-size: 0.9rem;
      color: var(--text-light);
      line-height: 1.7;
    }

    /* ===== COURSES ===== */
    .courses {
      padding: 100px 60px;
      background: var(--bg);
    }
    .courses-header {
      display: flex;
      justify-content: space-between;
      align-items: center;
      margin-bottom: 40px;
      max-width: 1200px;
      margin-left: auto;
      margin-right: auto;
      margin-bottom: 40px;
    }
    .courses-header h2 {
      font-size: 2.2rem;
      font-weight: 800;
      color: var(--text);
    }
    .view-all {
      font-size: 0.95rem;
      font-weight: 600;
      color: var(--primary);
      display: flex; align-items: center; gap: 6px;
      transition: var(--transition);
    }
    .view-all:hover { gap: 10px; }
    .courses-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
      max-width: 1200px;
      margin: 0 auto;
    }
    .course-card {
      border-radius: var(--radius);
      overflow: hidden;
      border: 1px solid var(--border);
      transition: var(--transition);
      background: var(--bg);
    }
    .course-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-lg);
    }
    .course-image {
      position: relative;
      height: 200px;
      overflow: hidden;
    }
    .course-image img {
      width: 100%; height: 100%;
      object-fit: cover;
      transition: var(--transition);
    }
    .course-card:hover .course-image img { transform: scale(1.05); }
    .course-badge {
      position: absolute;
      top: 14px; left: 14px;
      padding: 5px 14px;
      border-radius: 20px;
      font-size: 0.78rem;
      font-weight: 600;
      color: #fff;
    }
    .badge-tech { background: var(--primary); }
    .badge-data { background: var(--accent); }
    .badge-design { background: #F59E0B; }
    .course-body { padding: 24px; }
    .course-body h3 {
      font-size: 1.15rem;
      font-weight: 700;
      margin-bottom: 8px;
      color: var(--text);
    }
    .course-body p {
      font-size: 0.88rem;
      color: var(--text-light);
      line-height: 1.6;
      margin-bottom: 16px;
    }
    .course-meta {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding-top: 14px;
      border-top: 1px solid var(--border);
      margin-bottom: 14px;
    }
    .course-meta span {
      font-size: 0.82rem;
      color: var(--text-light);
      display: flex; align-items: center; gap: 5px;
    }
    .course-meta svg { width: 14px; height: 14px; fill: var(--text-light); }
    .course-link {
      font-size: 0.88rem;
      font-weight: 600;
      color: var(--primary);
      transition: var(--transition);
    }
    .course-link:hover { color: var(--primary-dark); }

    /* ===== CTA BANNER ===== */
    .cta {
      padding: 100px 60px;
      background: linear-gradient(135deg, #4F46E5 0%, #7C3AED 50%, #6D28D9 100%);
      text-align: center;
    }
    .cta h2 {
      font-size: 2.6rem;
      font-weight: 800;
      color: #fff;
      margin-bottom: 16px;
    }
    .cta p {
      font-size: 1.1rem;
      color: rgba(255,255,255,0.85);
      max-width: 520px;
      margin: 0 auto 36px;
      line-height: 1.7;
    }
    .btn-cta {
      display: inline-block;
      padding: 16px 40px;
      background: #fff;
      color: var(--primary);
      font-weight: 700;
      font-size: 1.05rem;
      border-radius: 50px;
      border: none;
      cursor: pointer;
      transition: var(--transition);
    }
    .btn-cta:hover {
      transform: translateY(-2px);
      box-shadow: 0 8px 30px rgba(0,0,0,0.2);
    }

    /* ===== FOOTER ===== */
    .footer {
      background: var(--bg-dark);
      color: rgba(255,255,255,0.7);
      padding: 80px 60px 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 40px;
      max-width: 1200px;
      margin: 0 auto;
      padding-bottom: 40px;
      border-bottom: 1px solid rgba(255,255,255,0.1);
    }
    .footer-brand .nav-logo {
      color: #fff;
      margin-bottom: 16px;
    }
    .footer-brand .nav-logo svg { fill: var(--primary-light); }
    .footer-brand p {
      font-size: 0.9rem;
      line-height: 1.7;
      color: rgba(255,255,255,0.5);
      margin-bottom: 20px;
    }
    .social-links { display: flex; gap: 12px; }
    .social-links a {
      width: 38px; height: 38px;
      background: rgba(255,255,255,0.08);
      border-radius: 50%;
      display: flex; align-items: center; justify-content: center;
      transition: var(--transition);
    }
    .social-links a:hover { background: var(--primary); }
    .social-links svg { width: 16px; height: 16px; fill: rgba(255,255,255,0.7); }
    .footer h4 {
      color: #fff;
      font-size: 1.05rem;
      font-weight: 700;
      margin-bottom: 20px;
    }
    .footer ul li { margin-bottom: 10px; }
    .footer ul li a {
      font-size: 0.9rem;
      color: rgba(255,255,255,0.5);
      transition: var(--transition);
    }
    .footer ul li a:hover { color: #fff; }
    .footer-contact-item {
      display: flex; align-items: flex-start; gap: 10px;
      margin-bottom: 14px;
      font-size: 0.9rem;
      color: rgba(255,255,255,0.5);
    }
    .footer-contact-item svg {
      width: 18px; height: 18px; min-width: 18px;
      fill: var(--primary-light);
      margin-top: 2px;
    }
    .footer-bottom {
      max-width: 1200px;
      margin: 0 auto;
      padding-top: 24px;
      text-align: center;
      font-size: 0.85rem;
      color: rgba(255,255,255,0.35);
    }

    /* ===== ANIMATIONS ===== */
    .fade-up {
      opacity: 0;
      transform: translateY(30px);
      transition: opacity 0.6s ease, transform 0.6s ease;
    }
    .fade-up.visible {
      opacity: 1;
      transform: translateY(0);
    }

    /* ===== RESPONSIVE ===== */
    @media (max-width: 1024px) {
      .navbar { padding: 0 30px; }
      .hero { padding: 120px 30px 60px; gap: 40px; }
      .hero-text h1 { font-size: 2.6rem; }
      .features, .courses, .cta { padding: 80px 30px; }
      .features-grid { grid-template-columns: repeat(2, 1fr); }
      .courses-grid { grid-template-columns: repeat(2, 1fr); }
      .footer { padding: 60px 30px 30px; }
      .footer-grid { grid-template-columns: repeat(2, 1fr); }
    }
    @media (max-width: 768px) {
      .nav-links, .nav-auth { display: none; }
      .nav-toggle { display: block; }
      .nav-links.open, .nav-auth.open {
        display: flex; flex-direction: column;
        position: absolute; top: 72px; left: 0; right: 0;
        background: #fff; padding: 20px 30px;
        box-shadow: var(--shadow);
        gap: 16px;
      }
      .hero {
        grid-template-columns: 1fr;
        padding: 120px 24px 60px;
      }
      .hero-text h1 { font-size: 2.2rem; }
      .hero-image { order: -1; }
      .features-grid { grid-template-columns: 1fr; }
      .courses-grid { grid-template-columns: 1fr; }
      .courses-header { flex-direction: column; align-items: flex-start; gap: 12px; }
      .cta h2 { font-size: 2rem; }
      .footer-grid { grid-template-columns: 1fr; }
    }