:root {
  --bg: #f5f7fb;
  --card: #ffffff;
  --line: #d8dee9;
  --ink: #1d2733;
  --mut: #66707f;
  --brand: #173c74;
  --accent: #2f9e8f;
  --danger: #b03a48;
}

* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--ink); font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif; }

h1 { font-size: 22px; margin: 0 0 6px; }
h2 { font-size: 17px; margin: 0 0 6px; }
.muted { color: var(--mut); font-size: 13.5px; }
.empty { color: var(--mut); font-style: italic; }
.error { color: var(--danger); font-weight: 700; }
.notice { color: var(--accent); font-weight: 600; }

.topbar {
  display: flex; align-items: center; gap: 14px; flex-wrap: wrap;
  background: var(--brand); color: #fff; padding: 12px 16px;
}
.topbar .brand { display: flex; align-items: center; gap: 8px; }
.topbar .brand img { height: 26px; width: 26px; }
.topbar nav { display: flex; flex-wrap: wrap; gap: 6px; }
.topbar .nav {
  background: transparent; border: 1px solid rgba(255,255,255,.35); color: #fff;
  border-radius: 999px; padding: 7px 12px; font-size: 14px; cursor: pointer;
}
.topbar .nav.active { background: #fff; color: var(--brand); border-color: var(--brand); }
.topbar .user { margin-left: auto; display: flex; align-items: center; gap: 8px; color: #fff; font-size: 13px; }

.content { max-width: 880px; margin: 0 auto; padding: 18px 14px 34px; }

.card { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 18px; margin-bottom: 14px; }
.feature { border-left: 4px solid var(--accent); }
.eyebrow { color: var(--mut); font-size: 12px; text-transform: uppercase; letter-spacing: .05em; margin-bottom: 4px; }
.badge {
  display: inline-block; padding: 2px 9px; border-radius: 999px; font-size: 11.5px;
  background: #eef3ff; color: var(--brand);
}
.badge.ok { background: #e6f7e9; color: #1d5b31; }
.badge.bg { background: #ffecec; color: var(--danger); }

.row {
  display: flex; align-items: center; justify-content: space-between; gap: 10px;
  padding: 12px; border-bottom: 1px solid var(--line);
}
.row:last-child { border-bottom: 0; }
.row strong { display: block; }
.row small { display: block; color: var(--mut); font-size: 12.5px; }

.btn {
  min-height: 42px; padding: 9px 15px; border-radius: 9px; border: 1px solid var(--brand);
  background: var(--brand); color: #fff; font-size: 14px; font-weight: 600; cursor: pointer;
}
.btn.secondary { background: #fff; color: var(--brand); border-color: #b9c7dd; }
.btn.lime { background: #1d7f4f; color: #fff; border-color: #1d7f4f; }
.btn.danger { background: #fff; color: var(--danger); border-color: #e3b4ba; }
.btn:disabled { opacity: .55; }
.actions { display: flex; flex-wrap: wrap; gap: 8px; }

.form { display: flex; flex-direction: column; gap: 10px; }
.form label { display: flex; flex-direction: column; gap: 4px; font-size: 13.5px; font-weight: 600; }
.form input, .form select {
  border: 1px solid var(--line); border-radius: 8px; padding: 9px 10px; font-size: 15px; background: #fff;
}
.course-list { display: grid; gap: 10px; }
.options { display: grid; gap: 10px; }
.option {
  text-align: left; padding: 13px 14px; border-radius: 10px; font-size: 15.5px;
  border: 1px solid var(--line); background: #fff; cursor: pointer;
}
.option b { display: inline-block; min-width: 26px; background: var(--brand); color: #fff; border-radius: 6px; text-align: center; margin-right: 10px; padding: 2px 0; }
.option.selected { border-color: var(--accent); background: #ecf9f4; }
.quizbar { margin-bottom: 12px; }
.quiznav { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 12px; }
.feedback { border-radius: 10px; padding: 12px; margin-top: 12px; }
.feedback { background: #e6f7e9; border: 1px solid #a9d9ae; color: #1d5b31; }
.feedback.wrong { background: #ffecec; border: 1px solid #efb3b3; color: var(--danger); }

details.card summary { font-weight: 700; cursor: pointer; }
details.unit summary { font-weight: 600; cursor: pointer; margin: 8px 0; }

@media (max-width: 720px) {
  .topbar { flex-direction: column; align-items: flex-start; }
  .btn { width: 100%; }
  .actions, .quiznav { flex-direction: column; }
  .options .option { padding: 15px; }
}