:root {
  --bg: #f6f7f9;
  --surface: #ffffff;
  --border: #e2e5ea;
  --text: #1c2024;
  --muted: #5f6773;
  --accent: #2f6f4f;
  --accent-soft: #e6f1ea;
  --danger: #b3261e;
  --warn: #9a6700;
  --radius: 12px;
  --shadow: 0 1px 2px rgba(16, 24, 40, .06), 0 1px 3px rgba(16, 24, 40, .04);
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14161a; --surface: #1c1f24; --border: #2c313a; --text: #e8eaed;
    --muted: #9aa3af; --accent: #5fb488; --accent-soft: #1e2f27; --danger: #f2857d;
    --warn: #e0ac47; --shadow: none;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0; font-family: var(--font); background: var(--bg); color: var(--text);
  line-height: 1.55; -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
h1, h2, h3 { line-height: 1.25; font-weight: 650; letter-spacing: -.01em; }
h1 { font-size: 1.6rem; margin: 0 0 .2em; }
h2 { font-size: 1.2rem; }

.site-header {
  display: flex; align-items: center; gap: 1.5rem; padding: .9rem 1.5rem;
  background: var(--surface); border-bottom: 1px solid var(--border);
}
.site-header .brand { font-weight: 700; letter-spacing: -.02em; color: var(--text); }
.tagline { color: var(--muted); font-style: italic; margin: 0 0 1rem; }
.site-header nav { display: flex; align-items: center; gap: 1.1rem; flex-wrap: wrap; }
.site-header nav a { color: var(--muted); font-size: .92rem; }
.site-header .spacer { flex: 1; }
.site-header form { margin: 0; }

.container { max-width: 960px; margin: 0 auto; padding: 2rem 1.5rem 4rem; }
.container.wide { max-width: 1140px; }

.card {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 1.25rem 1.4rem; box-shadow: var(--shadow); margin-bottom: 1rem;
}
.grid { display: grid; gap: 1rem; }
.grid.cols-2 { grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); }
.grid.cols-3 { grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); }

.muted { color: var(--muted); }
.pill {
  display: inline-block; padding: .12rem .55rem; border-radius: 999px; font-size: .78rem;
  background: var(--accent-soft); color: var(--accent); font-weight: 600;
}
.pill-duplicate { background: rgba(179,38,30,.12); color: var(--danger); }
.pill-generic { background: rgba(154,103,0,.12); color: var(--warn); }
.stat { font-size: 2rem; font-weight: 700; letter-spacing: -.02em; }

.btn {
  display: inline-flex; align-items: center; gap: .4rem; padding: .55rem 1rem;
  border-radius: 9px; border: 1px solid var(--accent); background: var(--accent); color: #fff;
  font: inherit; font-weight: 600; font-size: .92rem; cursor: pointer;
}
.btn:hover { text-decoration: none; opacity: .93; }
.btn.ghost { background: transparent; color: var(--accent); }
.btn.subtle { background: var(--surface); color: var(--text); border-color: var(--border); }
.btn.danger { background: var(--danger); border-color: var(--danger); }
.btn.sm { padding: .35rem .7rem; font-size: .84rem; }
.btn.subtle.active { background: var(--accent-soft); color: var(--accent); border-color: var(--accent); }

label { display: block; font-size: .85rem; font-weight: 600; margin: .8rem 0 .25rem; }
input, select, textarea {
  width: 100%; padding: .5rem .65rem; border: 1px solid var(--border); border-radius: 8px;
  background: var(--bg); color: var(--text); font: inherit;
}
.inline-form { display: flex; gap: .6rem; flex-wrap: wrap; align-items: flex-end; }
.inline-form > div { flex: 1; min-width: 130px; }

table { width: 100%; border-collapse: collapse; }
th, td { text-align: left; padding: .55rem .6rem; border-bottom: 1px solid var(--border); font-size: .92rem; }
th { color: var(--muted); font-weight: 600; }

.breadcrumb { font-size: .85rem; color: var(--muted); margin-bottom: 1rem; }
.messages { list-style: none; padding: 0; }
.messages li { padding: .6rem .9rem; border-radius: 8px; background: var(--accent-soft); margin-bottom: .5rem; }
.messages li i { margin-right: .4rem; color: var(--accent); }

.choices { display: flex; flex-direction: column; gap: .55rem; margin: 1rem 0 .4rem; }
.choice {
  display: flex; align-items: flex-start; gap: .75rem;
  padding: .7rem .85rem; border: 1px solid var(--border); border-radius: 10px;
  background: var(--surface); cursor: pointer; transition: border-color .12s, background .12s;
}
.choice:hover { border-color: var(--accent); }
.choice-key {
  flex: none; width: 1.6rem; height: 1.6rem; border-radius: 50%;
  display: grid; place-items: center; font-size: .82rem; font-weight: 700;
  border: 1px solid var(--border); color: var(--muted); background: var(--bg);
}
.choice-body { display: flex; flex-direction: column; gap: .2rem; flex: 1; }
.choice-text { white-space: pre-wrap; }
.choice-note { font-size: .84rem; color: var(--muted); }
.choice-mark { flex: none; font-weight: 700; color: var(--accent); }
.choice-mark.wrong { color: var(--danger); }

.choice.selected { border-color: var(--accent); background: var(--accent-soft); }
.choice.selected .choice-key { border-color: var(--accent); background: var(--accent); color: #fff; }
.choice.correct { border-color: var(--accent); background: var(--accent-soft); }
.choice.correct .choice-key { border-color: var(--accent); background: var(--accent); color: #fff; }
.choice.wrong { border-color: var(--danger); background: rgba(179,38,30,.08); }
.choice.wrong .choice-key { border-color: var(--danger); background: var(--danger); color: #fff; }

.explain {
  margin-top: .7rem; padding: .7rem .85rem; border-radius: 9px;
  background: var(--accent-soft); font-size: .92rem;
}
.explain strong { color: var(--accent); margin-right: .3rem; }
.navigator { display: flex; flex-wrap: wrap; gap: .35rem; }
.navigator button {
  width: 2rem; height: 2rem; border-radius: 7px; border: 1px solid var(--border);
  background: var(--surface); color: var(--text); cursor: pointer; font-size: .8rem;
}
.navigator button.answered { background: var(--accent-soft); border-color: var(--accent); }
.navigator button.active { outline: 2px solid var(--accent); }

/* Generated objective study material (markdown-rendered). */
.study-material > :first-child { margin-top: 0; }
.study-material > :last-child { margin-bottom: 0; }
.study-material h2, .study-material h3, .study-material h4 {
  font-size: .95rem; margin: 1rem 0 .4rem; color: var(--accent);
}
.study-material ul, .study-material ol { margin: .4rem 0; padding-left: 1.25rem; }
.study-material li { margin: .25rem 0; }
.study-material p { margin: .5rem 0; }
.study-material table { margin: .6rem 0; font-size: .9rem; }
.study-material th, .study-material td {
  border: 1px solid var(--border); padding: .35rem .5rem; text-align: left;
}
.study-material th { background: var(--accent-soft); }
.study-material code {
  background: var(--accent-soft); padding: .1rem .3rem; border-radius: 4px; font-size: .88rem;
}

.q-nav { display: flex; align-items: center; gap: .5rem; flex-wrap: wrap; margin-top: 1rem; }
.q-nav .q-nav-pos { font-size: .85rem; margin: 0 .3rem; }
.q-nav .btn.disabled { opacity: .45; pointer-events: none; }

.bi { vertical-align: -.125em; margin-right: .4rem; }
.btn .bi { margin-right: 0; }
th a { white-space: nowrap; }
.truncate { max-width: 160px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
th a .bi { margin-right: 0; margin-left: .3rem; }
.choice-mark .bi { margin-right: 0; }
.stat .bi { font-size: 1.4rem; color: var(--accent); vertical-align: .06em; }
.choice-mark i.bi-check-circle-fill { color: var(--accent); }
.choice-mark.wrong i.bi-x-circle-fill { color: var(--danger); }

/* Title + primary-action row, shared by the course and statistics pages. */
.page-head {
  display: flex; justify-content: space-between; align-items: center;
  flex-wrap: wrap; gap: .8rem; margin-bottom: 1rem;
}
.page-head h1 { margin-bottom: 0; }

/* Statistics page: progress meters and chart frames. */
.progress {
  display: block; height: 6px; border-radius: 999px; background: var(--border);
  overflow: hidden; margin-top: .55rem;
}
.progress > span { display: block; height: 100%; background: var(--accent); border-radius: 999px; }

.stat-row { display: flex; align-items: baseline; gap: .5rem; flex-wrap: wrap; }
.stat-row .stat { line-height: 1.1; }
.stat-sub { font-size: .85rem; margin-top: .4rem; }

.grid.stat-grid { grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); }
.grid.chart-grid { grid-template-columns: repeat(auto-fit, minmax(400px, 1fr)); }
.chart-box { position: relative; height: 240px; margin-top: .4rem; }

.impersonating { display: flex; align-items: center; justify-content: center; gap: .75rem; padding: .4rem 1rem; background: var(--accent-soft); border-bottom: 2px solid var(--accent); }