:root{
  --bg:#090d14;
  --panel:#101827;
  --panel2:#121e31;
  --text:#f4f7fb;
  --muted:#b9c5d6;
  --red:#ff3454;
  --blue:#35a8ff;
  --gold:#ffd166;
  --green:#35e3a4;
  --line:rgba(255,255,255,.12);
  --shadow:0 22px 70px rgba(0,0,0,.35);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  font-family:Arial, Helvetica, sans-serif;
  color:var(--text);
  background:
    radial-gradient(circle at 12% 4%, rgba(255,52,84,.22), transparent 30%),
    radial-gradient(circle at 92% 10%, rgba(53,168,255,.22), transparent 30%),
    linear-gradient(180deg,#06080d 0%,#0a101b 52%,#070a11 100%);
  line-height:1.65;
}
a{color:#8ed4ff;text-decoration:none}
a:hover{text-decoration:underline}
.wrap{width:min(1100px,92vw);margin:0 auto;padding:24px 0 60px}
.topbar{display:flex;justify-content:space-between;align-items:center;gap:18px;padding:14px 0 22px;border-bottom:1px solid var(--line)}
.brand{font-weight:900;letter-spacing:.04em;color:#fff;text-transform:uppercase}
.brand span{color:var(--red)}
.navlinks{display:flex;flex-wrap:wrap;gap:10px}
.navlinks a,.play-button,.small-button{display:inline-flex;align-items:center;justify-content:center;border:1px solid rgba(255,255,255,.16);border-radius:999px;padding:10px 14px;background:rgba(255,255,255,.06);font-weight:800;color:#fff;box-shadow:0 10px 25px rgba(0,0,0,.18)}
.navlinks a:hover,.play-button:hover,.small-button:hover{text-decoration:none;background:rgba(255,255,255,.12)}
.hero{padding:54px 0 32px}
.eyebrow{color:var(--gold);font-weight:900;text-transform:uppercase;letter-spacing:.12em;font-size:.78rem;margin:0 0 8px}
h1{font-size:clamp(2.2rem,5vw,4.6rem);line-height:1.02;margin:0 0 16px;letter-spacing:-.05em;text-wrap:balance}
.subtitle{font-size:clamp(1.05rem,2.2vw,1.35rem);color:var(--muted);max-width:860px;margin:0}
.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:18px;margin:28px 0}
.card,.lesson-card{background:linear-gradient(180deg,rgba(255,255,255,.07),rgba(255,255,255,.035));border:1px solid var(--line);border-radius:24px;padding:24px;box-shadow:var(--shadow)}
.card h2,.lesson-card h2{margin-top:0;line-height:1.16;letter-spacing:-.02em}
.card p{color:var(--muted)}
.badge{display:inline-flex;margin-bottom:12px;padding:5px 10px;border-radius:999px;background:rgba(255,52,84,.16);color:#ffc7d0;font-size:.78rem;font-weight:900;text-transform:uppercase;letter-spacing:.08em}
.lesson-hero{padding:46px 0 20px}
.lesson-subtitle{font-size:1.18rem;color:var(--muted);max-width:900px}
.lesson-card{margin:18px 0}
.disclaimer{border-color:rgba(255,209,102,.35);background:rgba(255,209,102,.08)}
dl{display:grid;gap:14px}
dt{font-weight:900;color:#fff;font-size:1.02rem}
dd{margin:4px 0 0;color:var(--muted)}
ul,ol{padding-left:1.25rem}
li{margin:.35rem 0;color:var(--muted)}
strong{color:#fff}
.callout{border-left:5px solid var(--red);padding:14px 16px;background:rgba(255,52,84,.09);border-radius:14px;color:#ffdbe2}
.review-box{display:grid;gap:10px;padding:18px;border-radius:18px;background:rgba(53,168,255,.08);border:1px solid rgba(53,168,255,.2)}
.footer{padding:26px 0;color:var(--muted);border-top:1px solid var(--line);margin-top:30px;font-size:.95rem}
.quiz details{margin:12px 0;padding:12px 14px;border:1px solid var(--line);border-radius:14px;background:rgba(255,255,255,.04)}
.quiz summary{cursor:pointer;font-weight:900;color:#fff}
.table{width:100%;border-collapse:collapse;overflow:hidden;border-radius:14px}
.table th,.table td{border:1px solid var(--line);padding:10px 12px;text-align:left;vertical-align:top}.table th{background:rgba(255,255,255,.08);color:#fff}.table td{color:var(--muted)}
@media(max-width:640px){.topbar{align-items:flex-start;flex-direction:column}.navlinks a{padding:8px 12px}.lesson-card{padding:18px}h1{font-size:2.35rem}}