:root {
  --bg: #0b0f1a;
  --bg-soft: #111827;
  --card: #151d2e;
  --card-hover: #1a2438;
  --border: #253048;
  --text: #e8edf7;
  --muted: #93a0b8;
  --accent: #6366f1;
  --accent-2: #22d3ee;
  --green: #34d399;
  --red: #f87171;
  --amber: #fbbf24;
  --radius: 14px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

.container { max-width: 1100px; margin: 0 auto; padding: 0 24px; }
.hidden { display: none !important; }
.center { text-align: center; margin-top: 28px; }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(11, 15, 26, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.logo { font-size: 22px; font-weight: 800; color: var(--text); text-decoration: none; letter-spacing: -0.5px; }
.logo span { background: linear-gradient(90deg, var(--accent), var(--accent-2)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.nav-links { display: flex; align-items: center; gap: 22px; }
.nav-links a { color: var(--muted); text-decoration: none; font-size: 15px; font-weight: 500; }
.nav-links a:hover { color: var(--text); }

/* Buttons */
.btn {
  display: inline-block; padding: 12px 24px; border-radius: 10px; border: none; cursor: pointer;
  background: linear-gradient(90deg, var(--accent), #8b5cf6);
  color: #fff !important; font-weight: 600; font-size: 15px; text-decoration: none;
  transition: transform 0.15s, box-shadow 0.15s;
}
.btn:hover { transform: translateY(-1px); box-shadow: 0 8px 24px rgba(99, 102, 241, 0.35); }
.btn-sm { padding: 8px 16px; font-size: 14px; }
.btn-ghost { background: transparent; border: 1px solid var(--border); color: var(--text) !important; }
.btn-ghost:hover { box-shadow: none; border-color: var(--accent); }

/* Hero */
.hero { padding: 96px 0 72px; text-align: center; background: radial-gradient(ellipse 70% 50% at 50% -10%, rgba(99, 102, 241, 0.25), transparent); }
.eyebrow { color: var(--accent-2); font-weight: 600; font-size: 14px; text-transform: uppercase; letter-spacing: 1.5px; margin-bottom: 14px; }
.hero h1 { font-size: clamp(32px, 5.5vw, 56px); line-height: 1.12; font-weight: 800; letter-spacing: -1.5px; max-width: 780px; margin: 0 auto; }
.grad { background: linear-gradient(90deg, var(--accent), var(--accent-2)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.sub { color: var(--muted); font-size: 18px; max-width: 640px; margin: 20px auto 0; }
.hero-cta { margin-top: 32px; display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.stats { display: flex; gap: 56px; justify-content: center; margin-top: 64px; flex-wrap: wrap; }
.stat strong { display: block; font-size: 34px; font-weight: 800; background: linear-gradient(90deg, var(--accent), var(--accent-2)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.stat span { color: var(--muted); font-size: 14px; }

/* Sections */
.section { padding: 64px 0; }
.section h2 { font-size: 30px; font-weight: 800; letter-spacing: -0.5px; margin-bottom: 8px; }
.section-sub { color: var(--muted); margin-bottom: 24px; }
.section h2 + .grid, .section h2 + .plans { margin-top: 28px; }

/* Cards */
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 18px; }
.card {
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 24px; text-decoration: none; color: var(--text); display: block;
  transition: transform 0.15s, border-color 0.15s, background 0.15s;
}
.card:hover { transform: translateY(-3px); border-color: var(--accent); background: var(--card-hover); }
.card .icon { font-size: 30px; margin-bottom: 12px; }
.card h3 { font-size: 17px; font-weight: 700; margin-bottom: 6px; line-height: 1.35; }
.card p { color: var(--muted); font-size: 14px; }
.card .kicker { font-size: 12.5px; font-weight: 600; color: var(--accent-2); text-transform: uppercase; letter-spacing: 1px; margin-bottom: 8px; }
.card-foot { display: flex; gap: 8px; margin-top: 14px; flex-wrap: wrap; }

.chip {
  display: inline-block; font-size: 12px; font-weight: 600; padding: 3px 10px; border-radius: 999px;
  background: rgba(99, 102, 241, 0.15); color: #a5b4fc; border: 1px solid rgba(99, 102, 241, 0.3);
}
.chip.cyan { background: rgba(34, 211, 238, 0.12); color: #67e8f9; border-color: rgba(34, 211, 238, 0.3); }
.chip.green { background: rgba(52, 211, 153, 0.12); color: var(--green); border-color: rgba(52, 211, 153, 0.3); }
.chip.amber { background: rgba(251, 191, 36, 0.12); color: var(--amber); border-color: rgba(251, 191, 36, 0.3); }
.chip.red { background: rgba(248, 113, 113, 0.12); color: var(--red); border-color: rgba(248, 113, 113, 0.3); }

/* Pricing */
.plans { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 340px)); gap: 20px; justify-content: center; }
.plan { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 32px; position: relative; }
.plan.featured { border-color: var(--accent); box-shadow: 0 0 40px rgba(99, 102, 241, 0.2); }
.plan .badge { position: absolute; top: -12px; right: 20px; background: linear-gradient(90deg, var(--accent), var(--accent-2)); color: #fff; font-size: 12px; font-weight: 700; padding: 4px 12px; border-radius: 999px; }
.plan h3 { font-size: 19px; }
.plan .price { font-size: 40px; font-weight: 800; margin: 10px 0 2px; }
.plan .price small { font-size: 15px; color: var(--muted); font-weight: 500; }
.plan ul { list-style: none; margin: 20px 0 24px; }
.plan li { color: var(--muted); font-size: 14.5px; padding: 6px 0 6px 26px; position: relative; }
.plan li::before { content: "✓"; position: absolute; left: 0; color: var(--green); font-weight: 700; }
.plan .btn { width: 100%; text-align: center; }

/* Cert page */
.cert-head { padding: 64px 0 8px; background: radial-gradient(ellipse 70% 60% at 50% -20%, rgba(34, 211, 238, 0.15), transparent); }
.cert-head h1 { font-size: clamp(26px, 4vw, 40px); font-weight: 800; letter-spacing: -1px; }
.cert-head .sub { margin: 12px 0 0; max-width: 720px; }
.meta-row { display: flex; gap: 10px; margin-top: 18px; flex-wrap: wrap; }

/* Questions */
.qlist { display: flex; flex-direction: column; gap: 18px; max-width: 820px; margin: 0 auto; }
.qcard { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 26px; }
.qcard .qtop { display: flex; gap: 8px; align-items: center; margin-bottom: 14px; flex-wrap: wrap; }
.qcard .qnum { color: var(--muted); font-size: 13px; font-weight: 700; }
.qcard .qtext { font-size: 16.5px; font-weight: 600; line-height: 1.5; }
.options { display: flex; flex-direction: column; gap: 10px; margin-top: 18px; }
.opt {
  text-align: left; background: var(--bg-soft); border: 1px solid var(--border); color: var(--text);
  padding: 13px 16px; border-radius: 10px; cursor: pointer; font-size: 15px; line-height: 1.45;
  transition: border-color 0.12s, background 0.12s;
}
.opt:hover:not(:disabled) { border-color: var(--accent); }
.opt:disabled { cursor: default; opacity: 0.85; }
.opt.correct { border-color: var(--green); background: rgba(52, 211, 153, 0.1); }
.opt.wrong { border-color: var(--red); background: rgba(248, 113, 113, 0.08); }
.explain { margin-top: 16px; padding: 14px 16px; border-left: 3px solid var(--accent-2); background: rgba(34, 211, 238, 0.06); border-radius: 0 10px 10px 0; color: var(--muted); font-size: 14.5px; }
.explain strong { color: var(--accent-2); }

/* Locked question */
.qcard.locked { position: relative; overflow: hidden; }
.qcard.locked .qtext { filter: blur(0px); color: var(--muted); }
.lockbox {
  margin-top: 16px; padding: 20px; border: 1px dashed var(--border); border-radius: 10px;
  text-align: center; background: rgba(99, 102, 241, 0.05);
}
.lockbox p { color: var(--muted); font-size: 14.5px; margin-bottom: 14px; }
.lockbox .lock { font-size: 22px; display: block; margin-bottom: 6px; }

/* Footer */
.site-footer { border-top: 1px solid var(--border); padding: 32px 0; margin-top: 40px; }
.site-footer p { color: var(--muted); font-size: 13.5px; }

@media (max-width: 640px) {
  .nav-links { gap: 14px; }
  .nav-links a:not(.btn) { display: none; }
  .stats { gap: 32px; }
  .hero { padding: 64px 0 48px; }
}