:root{
      --blue:#1366ff;
      --dark:#0b1b2b;
      --muted:#6b7280;
      --card:#f8fafc;
      --glass: rgba(255,255,255,0.06);
      --radius:14px;
    }
    *{box-sizing:border-box}
    html,body{height:100%;margin:0;font-family:Inter,system-ui,-apple-system,Segoe UI,Roboto,"Helvetica Neue",Arial;color:var(--dark);background:linear-gradient(180deg,#ffffff,#f3f6fb);-webkit-font-smoothing:antialiased}
    a{color:inherit;text-decoration:none}
    header{position:sticky;top:0;backdrop-filter: blur(6px);background:rgba(255,255,255,0.6);border-bottom:1px solid rgba(15,23,42,0.04);z-index:40}
    .container{max-width:1100px;margin:0 auto;padding:24px}

    /* Nav */
    .nav{display:flex;align-items:center;justify-content:space-between}
    .brand{display:flex;gap:12px;align-items:center}
    .logo{width:44px;height:44px;border-radius:10px;background:linear-gradient(135deg,var(--blue),#00b0ff);display:flex;align-items:center;justify-content:center;color:#fff;font-weight:700}
    nav ul{display:flex;gap:18px;align-items:center;margin:0;padding:0;list-style:none}
    .btn{background:var(--blue);color:#fff;padding:10px 16px;border-radius:10px;border:none;cursor:pointer;font-weight:600;font-family:system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;}
    .btn.secondary{background:transparent;color:var(--dark);border:1px solid rgba(15,23,42,0.06)}

    /* Hero */
    .hero{display:grid;grid-template-columns:1fr 420px;gap:32px;align-items:center;padding:64px 0}
    .hero h1{font-size:38px;margin:0 0 12px}
    .hero p{color:var(--muted);margin:0 0 20px}
    .hero .card{background:linear-gradient(180deg,#ffffff,#f8fbff);padding:22px;border-radius:18px;box-shadow:0 8px 30px rgba(13,38,76,0.06)}
    .features{display:flex;gap:12px;flex-wrap:wrap}
    .feature{background:var(--card);padding:8px 12px;border-radius:10px;font-size:13px}

    /* Courses grid */
    .courses-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
    .course{background:#fff;border-radius:12px;padding:18px;box-shadow:0 6px 18px rgba(12,25,48,0.04);border:1px solid rgba(11,20,34,0.03)}
    .course h3{margin:0 0 8px;font-size:18px}
    .meta{color:var(--muted);font-size:13px;margin-bottom:12px}

    /* Testimonials */
    .testimonials{display:flex;gap:14px}
    .tcard{background:linear-gradient(180deg,#fff,#f7fafc);padding:16px;border-radius:12px;flex:1}

    /* Responsive */
    @media(max-width:980px){
      .hero{grid-template-columns:1fr;}
      .courses-grid{grid-template-columns:repeat(2,1fr)}
    }
    @media(max-width:650px){
      .nav ul{display:none}
      .courses-grid{grid-template-columns:1fr}
      .container{padding:16px}
      .logo{width:40px;height:40px}
      .hero h1{font-size:28px}
    }

    /* Search and filters */
    .searchbar{display:flex;gap:8px;align-items:center;background:#fff;padding:10px;border-radius:12px;border:1px solid rgba(11,20,34,0.04)}
    input[type="search"],textarea,input[type="text"],input[type="email"]{width:100%;padding:10px;border-radius:10px;border:1px solid rgba(11,20,34,0.06);outline:none}
    label{font-size:14px;color:var(--muted)}

    /* Footer */
    footer{padding:36px 0;color:var(--muted);background-color:#ededed;}

    /* Modal */
    .modal-backdrop{position:fixed;inset:0;background:rgba(2,6,23,0.5);display:none;align-items:center;justify-content:center;z-index:60}
    .modal{background:#fff;padding:20px;border-radius:12px;max-width:700px;width:96%;box-shadow:0 18px 50px rgba(2,6,23,0.35)}
    .modal.active{display:block}

    /* small helpers */
    .row{display:flex;gap:12px;align-items:center}
    .gap{height:18px}
    .muted{color:var(--muted)}
    .chip{padding:6px 10px;border-radius:999px;background:#f1f5f9;font-size:13px}
    .course-actions{display:flex;gap:8px;justify-content:flex-end}

    /* course details page */
    .course-details{background:#fff;padding:20px;border-radius:12px;box-shadow:0 8px 30px rgba(12,25,48,0.04)}
    .syllabus{margin-top:12px}
    .syllabus li{margin:8px 0}

    /* small animations */
    .fade{transition:all .28s ease}
    .hover-lift{transition:transform .18s ease, box-shadow .18s ease}
    .hover-lift:hover{transform:translateY(-6px);box-shadow:0 18px 50px rgba(11,20,40,0.06)}