*{box-sizing:border-box}
body{margin:0;font:16px/1.5 system-ui,sans-serif;background:#f6f6f8;color:#1b1b1f}
header{display:flex;justify-content:space-between;align-items:center;padding:12px 20px;background:#111;color:#fff}
header a,header span{color:#fff;text-decoration:none;margin-left:16px}
.logo{font-weight:700;margin:0}
main{max-width:960px;margin:24px auto;padding:0 16px}
.grade{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:16px}
.card{background:#fff;padding:16px;border-radius:8px;color:inherit;text-decoration:none;box-shadow:0 1px 3px #0002}
.form{display:grid;gap:12px;max-width:380px}
.form input{width:100%;padding:10px;border:1px solid #bbb;border-radius:6px;font:inherit}
button,.btn{padding:10px 16px;background:#111;color:#fff;border:0;border-radius:6px;font:inherit;cursor:pointer;text-decoration:none;display:inline-block}
.erro{background:#fde8e8;color:#9b1c1c;padding:10px;border-radius:6px}
.ok{background:#e6f6ea;color:#14532d;padding:10px;border-radius:6px}
.video{position:relative;aspect-ratio:16/9;background:#000}
.video iframe{position:absolute;inset:0;width:100%;height:100%;border:0}