:root {
  --bg: #0f172a;
  --panel: #111827;
  --panel-2: #1f2937;
  --text: #e5e7eb;
  --muted: #94a3b8;
  --accent: #22c55e;
  --accent-2: #38bdf8;
  --danger: #ef4444;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: linear-gradient(180deg, #0b1220 0%, #111827 100%);
  color: var(--text);
}
.container { width: min(1100px, calc(100% - 32px)); margin: 0 auto; }
.site-header { border-bottom: 1px solid #243145; background: rgba(10,15,25,.85); position: sticky; top: 0; backdrop-filter: blur(12px); }
.nav { display: flex; justify-content: space-between; align-items: center; padding: 16px 0; gap: 16px; }
.nav nav { display: flex; gap: 16px; flex-wrap: wrap; }
.nav a { color: var(--text); text-decoration: none; }
.brand { font-weight: 700; font-size: 1.2rem; }
main { padding: 28px 0 60px; }
.card { background: rgba(17,24,39,.88); border: 1px solid #243145; border-radius: 16px; padding: 20px; box-shadow: 0 12px 30px rgba(0,0,0,.18); }
.hero-grid, .grid-3 { display: grid; gap: 20px; }
.hero-grid { grid-template-columns: 2fr 1fr; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.hero-main h1 { font-size: 2.2rem; line-height: 1.15; }
.btn { display: inline-block; background: var(--accent); color: #052e16; padding: 12px 16px; border-radius: 10px; text-decoration: none; border: none; font-weight: 700; cursor: pointer; }
.btn-secondary { background: var(--accent-2); color: #082f49; }
.btn-disabled { opacity: .5; cursor: not-allowed; }
.form-card form { display: grid; gap: 12px; }
input, select, textarea { width: 100%; border-radius: 10px; border: 1px solid #314155; background: #0b1220; color: var(--text); padding: 12px; }
textarea { resize: vertical; min-height: 130px; }
.alert { padding: 12px 14px; border-radius: 10px; margin-bottom: 16px; }
.alert-error { background: rgba(239,68,68,.15); border: 1px solid rgba(239,68,68,.5); }
.alert-success { background: rgba(34,197,94,.15); border: 1px solid rgba(34,197,94,.5); }
.row { display: flex; align-items: center; }
.between { justify-content: space-between; }
.wrap { flex-wrap: wrap; }
.gap { gap: 12px; }
.top-space { margin-top: 24px; }
.top-space-small { margin-top: 12px; }
.narrow { max-width: 520px; margin: 0 auto; }
.stat { font-size: 2rem; font-weight: 700; margin: 0; }
.lesson-list { display: grid; gap: 16px; }
.lesson-card.locked { opacity: .65; }
.align-right { text-align: right; }
.target-text { font-size: 1.8rem; line-height: 1.6; letter-spacing: 2px; background: #0b1220; padding: 18px; border-radius: 12px; border: 1px dashed #334155; }
.score-box { background: #0b1220; border: 1px solid #243145; border-radius: 12px; padding: 12px 16px; min-width: 180px; }
.inline-score { display: flex; gap: 18px; margin: 14px 0; }
table { width: 100%; border-collapse: collapse; }
th, td { text-align: left; padding: 10px; border-bottom: 1px solid #243145; }
code { background: #0b1220; padding: 3px 6px; border-radius: 6px; }
@media (max-width: 820px) {
  .hero-grid, .grid-3 { grid-template-columns: 1fr; }
  .nav { flex-direction: column; align-items: flex-start; }
  .inline-score { flex-direction: column; gap: 8px; }
}