:root {
  --bg: #0b1120;
  --surface: #1e293b;
  --surface-2: #0f172a;
  --border: #334155;
  --text: #f8fafc;
  --muted: #94a3b8;
  --primary: #38bdf8;
  --primary-dark: #0284c7;
  --success: #22c55e;
  --warning: #f59e0b;
  --danger: #ef4444;
}

* { box-sizing: border-box; margin: 0; padding: 0; font-family: 'Segoe UI', system-ui, sans-serif; }
body { background: var(--bg); color: var(--text); min-height: 100vh; padding: 20px 14px; }
.container { max-width: 1100px; margin: 0 auto; }
.hidden { display: none !important; }

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 22px;
  margin-bottom: 18px;
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 14px 20px;
  margin-bottom: 18px;
}

h1 { font-size: 1.5rem; color: var(--primary); }
h2 { font-size: 1.2rem; margin-bottom: 12px; }
h3 { font-size: 1.05rem; margin-bottom: 8px; }
.muted { color: var(--muted); font-size: 0.9rem; }

.grid-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 12px;
  margin-bottom: 18px;
}
.stat-box {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px;
}
.stat-num { font-size: 1.8rem; font-weight: 800; color: var(--primary); }

.tabs { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 16px; }
.tab-btn {
  width: auto;
  padding: 9px 16px;
  background: var(--surface);
  color: var(--muted);
  border: 1px solid var(--border);
  border-radius: 10px;
  cursor: pointer;
  font-weight: 600;
}
.tab-btn.active { background: var(--primary); color: #0f172a; border-color: var(--primary); }

.form-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 12px; }
.form-group { margin-bottom: 12px; }
label { display: block; font-size: 0.85rem; color: var(--muted); margin-bottom: 5px; }
input, select, textarea {
  width: 100%;
  padding: 10px 12px;
  border-radius: 9px;
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--text);
  font-size: 0.95rem;
}

button {
  padding: 10px 16px;
  border: none;
  border-radius: 9px;
  background: var(--primary);
  color: #0f172a;
  font-weight: 700;
  cursor: pointer;
  transition: 0.15s;
}
button:hover { background: var(--primary-dark); color: #fff; }
button:disabled { opacity: 0.5; cursor: not-allowed; }
.btn-sm { padding: 6px 11px; font-size: 0.82rem; }
.btn-success { background: var(--success); color: #052e16; }
.btn-danger { background: var(--danger); color: #fff; }
.btn-secondary { background: var(--border); color: var(--text); }

.badge {
  display: inline-block;
  padding: 3px 9px;
  border-radius: 20px;
  font-size: 0.78rem;
  font-weight: 700;
}
.badge-green { background: rgba(34, 197, 94, 0.18); color: #4ade80; }
.badge-yellow { background: rgba(245, 158, 11, 0.18); color: #fbbf24; }
.badge-red { background: rgba(239, 68, 68, 0.18); color: #f87171; }
.badge-blue { background: rgba(56, 189, 248, 0.18); color: #38bdf8; }

table { width: 100%; border-collapse: collapse; font-size: 0.9rem; }
th, td { padding: 10px 8px; text-align: left; border-bottom: 1px solid var(--border); vertical-align: middle; }
th { color: var(--muted); font-weight: 600; }
.table-wrap { overflow-x: auto; }

.lesson-box {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px;
  margin-bottom: 14px;
}
.lesson-content { white-space: pre-wrap; line-height: 1.6; margin: 10px 0; color: #e2e8f0; }

.option-btn {
  width: 100%;
  text-align: left;
  background: var(--surface-2);
  color: var(--text);
  border: 1px solid var(--border);
  margin-bottom: 8px;
  padding: 12px 14px;
}
.option-btn.selected { border-color: var(--primary); background: rgba(56, 189, 248, 0.2); }

.alert { padding: 12px; border-radius: 10px; margin-bottom: 14px; font-size: 0.92rem; }
.alert-warn { background: rgba(245, 158, 11, 0.15); border: 1px solid var(--warning); color: #fcd34d; }
.alert-danger { background: rgba(239, 68, 68, 0.15); border: 1px solid var(--danger); color: #fca5a5; }