*{box-sizing:border-box}html,body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,Ubuntu,'Helvetica Neue',Arial}
.nav{display:flex;gap:12px;align-items:center;padding:10px 16px;border-bottom:1px solid #e5e7eb}
.nav .brand{font-weight:700}
.nav .spacer{flex:1}
.container{max-width:1100px;margin:0 auto;padding:24px 16px}
.hero{padding:60px 0}
.btn{display:inline-block;padding:8px 14px;border-radius:8px;border:1px solid #1f2937;background:#111827;color:#fff;text-decoration:none}
.btn:hover{filter:brightness(1.05)}
.search{display:flex;gap:8px;margin:12px 0}
.search input{flex:1;padding:8px;border:1px solid #d1d5db;border-radius:8px}
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:16px}
.card{display:block;border:1px solid #e5e7eb;border-radius:12px;overflow:hidden;text-decoration:none;color:inherit;background:#fff}
.card img{aspect-ratio:16/9;object-fit:cover;width:100%}
.card-body{padding:12px}
.muted{color:#6b7280;font-size:14px}
.pill{display:inline-block;padding:4px 10px;border-radius:999px;background:#d1fae5;color:#065f46}
.flash>div{padding:8px 12px;border-radius:8px;margin:8px 0}
.flash-success{background:#ecfdf5;color:#065f46}
.flash-error{background:#fef2f2;color:#991b1b}
.flash-info{background:#eff6ff;color:#1e40af}
.flash-warning{background:#fffbeb;color:#92400e}
.form{display:grid;gap:12px;max-width:520px}
.form input,.form textarea{width:100%;padding:10px;border:1px solid #d1d5db;border-radius:8px}
.course-hero{display:grid;grid-template-columns:1fr 1fr;gap:20px;align-items:start;margin-bottom:20px}
.course-hero img{width:100%;border-radius:12px;border:1px solid #e5e7eb}
.lessons{padding-left:18px}
.video iframe{width:100%;height:420px;border-radius:12px;border:1px solid #e5e7eb}
.quiz-item{padding:12px;border:1px solid #e5e7eb;border-radius:10px;margin:10px 0}
.opt{display:block;margin:6px 0}
@media (max-width: 800px){
  .course-hero{grid-template-columns:1fr}
}