:root{
  --bg:#f4f6fb; --card:#ffffff; --ink:#1f2937; --muted:#6b7280;
  --brand:#2563eb; --brand-dark:#1d4ed8; --line:#e5e7eb;
  --ok:#16a34a; --ok-bg:#dcfce7; --err:#dc2626; --err-bg:#fee2e2;
  --warn:#d97706;
}
*{box-sizing:border-box}
body{
  margin:0;font-family:-apple-system,Segoe UI,Roboto,Helvetica,Arial,sans-serif;
  background:var(--bg);color:var(--ink);line-height:1.5;
}
a{color:var(--brand);text-decoration:none}
a:hover{text-decoration:underline}

/* Top bar */
.topbar{
  background:#111827;color:#fff;padding:14px 22px;display:flex;
  justify-content:space-between;align-items:center;
}
.topbar .brand{font-weight:700;font-size:18px;color:#fff}
.topbar nav a{color:#cbd5e1;margin-left:18px;font-size:14px}
.topbar nav a:hover{color:#fff}

.wrap{max-width:1000px;margin:26px auto;padding:0 18px}
.wrap-narrow{max-width:460px;margin:60px auto;padding:0 18px}

/* Cards */
.card{
  background:var(--card);border:1px solid var(--line);border-radius:12px;
  padding:24px;margin-bottom:20px;box-shadow:0 1px 2px rgba(0,0,0,.04);
}
.card h2{margin-top:0}

h1{font-size:24px;margin:0 0 18px}
.muted{color:var(--muted);font-size:14px}

/* Forms */
label{display:block;font-weight:600;font-size:14px;margin:14px 0 6px}
input[type=text],input[type=email],input[type=password],input[type=number],
select,textarea{
  width:100%;padding:10px 12px;border:1px solid var(--line);border-radius:8px;
  font-size:14px;font-family:inherit;background:#fff;
}
textarea{min-height:90px;resize:vertical}
input:focus,select:focus,textarea:focus{outline:2px solid var(--brand);border-color:var(--brand)}

.btn{
  display:inline-block;background:var(--brand);color:#fff;border:none;
  padding:11px 20px;border-radius:8px;font-size:14px;font-weight:600;
  cursor:pointer;text-decoration:none;
}
.btn:hover{background:var(--brand-dark);text-decoration:none}
.btn-secondary{background:#e5e7eb;color:#111827}
.btn-secondary:hover{background:#d1d5db}
.btn-danger{background:var(--err)}
.btn-sm{padding:6px 12px;font-size:13px}
.btn-block{display:block;width:100%;text-align:center}

/* Tables */
table{width:100%;border-collapse:collapse;font-size:14px}
th,td{padding:11px 12px;border-bottom:1px solid var(--line);text-align:left}
th{background:#f9fafb;font-size:12px;text-transform:uppercase;letter-spacing:.04em;color:var(--muted)}
tr:hover td{background:#fafbff}

/* Alerts */
.alert{padding:12px 16px;border-radius:8px;margin-bottom:16px;font-size:14px}
.alert-success{background:var(--ok-bg);color:#166534}
.alert-error{background:var(--err-bg);color:#991b1b}

/* Badges */
.badge{display:inline-block;padding:3px 10px;border-radius:999px;font-size:12px;font-weight:600}
.badge-ok{background:var(--ok-bg);color:#166534}
.badge-err{background:var(--err-bg);color:#991b1b}
.badge-warn{background:#fef3c7;color:#92400e}
.badge-info{background:#dbeafe;color:#1e40af}

/* Stat grid */
.stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:16px}
.stat{background:#fff;border:1px solid var(--line);border-radius:12px;padding:18px}
.stat .num{font-size:30px;font-weight:800;color:var(--brand)}
.stat .lbl{color:var(--muted);font-size:13px}

/* Exam */
.exam-header{
  position:sticky;top:0;z-index:10;background:#111827;color:#fff;
  padding:14px 22px;display:flex;justify-content:space-between;align-items:center;
}
.timer{font-size:20px;font-weight:800;font-variant-numeric:tabular-nums;
  background:#1f2937;padding:8px 16px;border-radius:8px}
.timer.danger{background:var(--err);animation:pulse 1s infinite}
@keyframes pulse{0%,100%{opacity:1}50%{opacity:.6}}
.q-block{background:#fff;border:1px solid var(--line);border-radius:12px;padding:22px;margin-bottom:18px}
.q-num{font-weight:700;color:var(--brand);font-size:13px;margin-bottom:6px}
.q-text{font-size:16px;font-weight:600;margin-bottom:14px;white-space:pre-wrap}
.opt{display:flex;align-items:flex-start;gap:10px;padding:10px 12px;border:1px solid var(--line);
  border-radius:8px;margin-bottom:8px;cursor:pointer}
.opt:hover{background:#f5f8ff}
.opt input{width:auto;margin-top:3px}
.q-marks{float:right;color:var(--muted);font-size:12px;font-weight:600}

.link-row{display:flex;gap:14px;margin-top:8px;font-size:14px}
.divider{border-top:1px solid var(--line);margin:22px 0}
.grid-2{display:grid;grid-template-columns:1fr 1fr;gap:16px}
@media(max-width:640px){.grid-2{grid-template-columns:1fr}}