/* ===== Comprehensive Exam Prep — shared styles ===== */
:root {
  --bg: #f7f8fb;
  --surface: #ffffff;
  --ink: #1c2333;
  --ink-soft: #4a5568;
  --ink-faint: #8a94a6;
  --accent: #3b5bdb;
  --accent-soft: #e7ecfd;
  --green: #2f9e44;
  --green-soft: #e6f7ea;
  --red: #e03131;
  --red-soft: #fdeaea;
  --amber: #e8890c;
  --amber-soft: #fdf3e2;
  --border: #e2e6ef;
  --code-bg: #f0f2f8;
  --shadow: 0 1px 3px rgba(20, 30, 60, .08), 0 8px 24px rgba(20, 30, 60, .06);
  --radius: 14px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.65;
  font-size: 16.5px;
}

/* ---------- top bar ---------- */
.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, .92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
  padding: 10px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
.topbar a { color: var(--accent); text-decoration: none; font-weight: 600; font-size: .92rem; }
.topbar a:hover { text-decoration: underline; }
.topbar .crumb { color: var(--ink-faint); font-size: .92rem; font-weight: 500; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

/* ---------- layout ---------- */
.wrap { max-width: 880px; margin: 0 auto; padding: 32px 20px 90px; }

.module-head { margin-bottom: 8px; }
.module-head .kicker {
  display: inline-block;
  font-size: .78rem;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--accent);
  background: var(--accent-soft);
  padding: 4px 12px;
  border-radius: 999px;
  margin-bottom: 12px;
}
h1 { font-size: 2rem; line-height: 1.2; margin: 0 0 10px; letter-spacing: -.02em; }
.lede { color: var(--ink-soft); font-size: 1.06rem; margin: 0 0 6px; }

h2 {
  font-size: 1.35rem;
  margin: 44px 0 12px;
  padding-top: 18px;
  border-top: 1px solid var(--border);
  letter-spacing: -.01em;
}
h2 .num { color: var(--accent); margin-right: 6px; }
h3 { font-size: 1.08rem; margin: 24px 0 8px; }
p { margin: 10px 0; }
ul, ol { margin: 10px 0; padding-left: 26px; }
li { margin: 5px 0; }
strong { color: var(--ink); }

a { color: var(--accent); }

code, .mono {
  font-family: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, monospace;
  font-size: .88em;
  background: var(--code-bg);
  padding: 2px 6px;
  border-radius: 6px;
}

/* ---------- audio recap ---------- */
.audio-card {
  display: flex;
  align-items: center;
  gap: 14px;
  background: linear-gradient(135deg, #eef1fd, #f3eefc);
  border: 1px solid #d5dcf5;
  border-radius: var(--radius);
  padding: 14px 18px;
  margin: 18px 0 6px;
  box-shadow: var(--shadow);
  flex-wrap: wrap;
}
.audio-card .audio-ico {
  flex-shrink: 0;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
}
.audio-card .audio-meta { flex: 1; min-width: 140px; }
.audio-card .audio-title { font-weight: 700; font-size: .95rem; }
.audio-card .audio-sub { color: var(--ink-soft); font-size: .8rem; }
.audio-card audio { flex: 2; min-width: 220px; width: 100%; height: 40px; }

/* ---------- callout boxes ---------- */
.box {
  border-radius: var(--radius);
  padding: 14px 18px;
  margin: 16px 0;
  border: 1px solid var(--border);
  background: var(--surface);
}
.box .box-title { font-weight: 700; font-size: .85rem; text-transform: uppercase; letter-spacing: .08em; margin-bottom: 6px; display: block; }
.box.idea { background: var(--accent-soft); border-color: #ccd8fa; }
.box.idea .box-title { color: var(--accent); }
.box.example { background: var(--green-soft); border-color: #c4e8cd; }
.box.example .box-title { color: var(--green); }
.box.warn { background: var(--amber-soft); border-color: #f3ddb4; }
.box.warn .box-title { color: var(--amber); }
.box.paper { background: #f3eefc; border-color: #ddd0f2; }
.box.paper .box-title { color: #7048b6; }
.box.exam { background: var(--red-soft); border-color: #f2c8c8; }
.box.exam .box-title { color: var(--red); }

/* ---------- math ---------- */
.math {
  font-family: "Times New Roman", "STIX Two Math", Georgia, serif;
  font-size: 1.12em;
  font-style: italic;
}
.eq {
  display: block;
  text-align: center;
  font-family: "Times New Roman", "STIX Two Math", Georgia, serif;
  font-size: 1.18em;
  margin: 16px auto;
  padding: 12px 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  overflow-x: auto;
}
.eq .lbl { float: right; color: var(--ink-faint); font-size: .8em; font-style: normal; font-family: inherit; }
sub, sup { font-size: .72em; }
.frac { display: inline-block; vertical-align: middle; text-align: center; margin: 0 3px; }
.frac > span { display: block; padding: 0 6px; }
.frac > span:first-child { border-bottom: 1.2px solid currentColor; }

/* ---------- tables ---------- */
table { border-collapse: collapse; width: 100%; margin: 16px 0; font-size: .93rem; background: var(--surface); border-radius: 10px; overflow: hidden; box-shadow: 0 0 0 1px var(--border); }
th { background: var(--code-bg); text-align: left; font-size: .82rem; text-transform: uppercase; letter-spacing: .05em; color: var(--ink-soft); }
th, td { padding: 9px 13px; border-bottom: 1px solid var(--border); }
tr:last-child td { border-bottom: none; }

/* ---------- diagrams (flow) ---------- */
.flow {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 18px 0;
  font-size: .9rem;
  font-weight: 600;
}
.flow .node {
  background: var(--surface);
  border: 1.5px solid var(--accent);
  color: var(--accent);
  border-radius: 10px;
  padding: 7px 13px;
  box-shadow: var(--shadow);
}
.flow .node.alt { border-color: var(--green); color: var(--green); }
.flow .node.warm { border-color: var(--amber); color: var(--amber); }
.flow .arr { color: var(--ink-faint); font-size: 1.1rem; }

/* ---------- quiz ---------- */
.quiz-section { margin-top: 56px; }
.quiz-banner {
  background: linear-gradient(135deg, #3b5bdb, #6a4fd0);
  color: #fff;
  border-radius: var(--radius);
  padding: 20px 24px;
  margin-bottom: 20px;
}
.quiz-banner h2 { border: none; margin: 0 0 4px; padding: 0; color: #fff; }
.quiz-banner p { margin: 0; opacity: .9; font-size: .95rem; }

.q-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 20px;
  margin: 14px 0;
  box-shadow: var(--shadow);
}
.q-card .q-num { font-size: .78rem; font-weight: 700; color: var(--accent); text-transform: uppercase; letter-spacing: .1em; }
.q-card .q-text { font-weight: 600; margin: 6px 0 12px; }
.q-opt {
  display: block;
  width: 100%;
  text-align: left;
  background: var(--bg);
  border: 1.5px solid var(--border);
  border-radius: 10px;
  padding: 10px 14px;
  margin: 7px 0;
  font: inherit;
  font-size: .95rem;
  color: var(--ink);
  cursor: pointer;
  transition: border-color .15s, background .15s;
}
.q-opt:hover:not(:disabled) { border-color: var(--accent); background: var(--accent-soft); }
.q-opt:disabled { cursor: default; }
.q-opt.correct { border-color: var(--green); background: var(--green-soft); font-weight: 600; }
.q-opt.wrong { border-color: var(--red); background: var(--red-soft); }
.q-expl {
  display: none;
  margin-top: 12px;
  padding: 12px 14px;
  border-radius: 10px;
  background: var(--code-bg);
  font-size: .92rem;
  border-left: 4px solid var(--accent);
}
.q-expl.show { display: block; }
.q-expl .tag { font-weight: 700; }
.q-expl .tag.ok { color: var(--green); }
.q-expl .tag.no { color: var(--red); }

.quiz-result {
  display: none;
  text-align: center;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px;
  margin-top: 20px;
  box-shadow: var(--shadow);
}
.quiz-result.show { display: block; }
.quiz-result .score { font-size: 2.4rem; font-weight: 800; letter-spacing: -.02em; }
.quiz-result .verdict { color: var(--ink-soft); margin-top: 4px; }
.quiz-result button {
  margin-top: 14px;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 10px;
  padding: 10px 20px;
  font: inherit;
  font-weight: 600;
  cursor: pointer;
}
.quiz-result button:hover { filter: brightness(1.08); }

/* ---------- pager ---------- */
.pager { display: flex; justify-content: space-between; gap: 12px; margin-top: 50px; }
.pager a {
  flex: 1;
  text-decoration: none;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 18px;
  color: var(--ink);
  box-shadow: var(--shadow);
  transition: transform .12s;
}
.pager a:hover { transform: translateY(-2px); }
.pager a .dir { font-size: .76rem; text-transform: uppercase; letter-spacing: .1em; color: var(--ink-faint); font-weight: 700; }
.pager a .name { font-weight: 700; color: var(--accent); }
.pager a.next { text-align: right; }
.pager .spacer { flex: 1; }

/* ---------- index (home) ---------- */
.hero {
  background: linear-gradient(135deg, #24336b, #3b5bdb 55%, #6a4fd0);
  color: #fff;
  border-radius: 20px;
  padding: 40px 36px;
  margin-bottom: 30px;
}
.hero h1 { color: #fff; font-size: 2.2rem; }
.hero p { color: rgba(255,255,255,.88); max-width: 640px; }
.hero .pillrow { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 16px; }
.hero .pill { background: rgba(255,255,255,.16); border-radius: 999px; padding: 5px 13px; font-size: .82rem; font-weight: 600; }

.path-note { color: var(--ink-soft); font-size: .95rem; margin: 0 0 22px; }

.mod-grid { display: grid; grid-template-columns: 1fr; gap: 14px; }
.mod-card {
  display: block;
  text-decoration: none;
  color: inherit;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 20px;
  box-shadow: var(--shadow);
  transition: transform .12s, border-color .12s;
  position: relative;
}
.mod-card:hover { transform: translateY(-2px); border-color: var(--accent); }
.mod-card .mod-top { display: flex; align-items: baseline; gap: 10px; }
.mod-card .mod-num {
  flex-shrink: 0;
  font-weight: 800;
  color: var(--accent);
  background: var(--accent-soft);
  border-radius: 8px;
  padding: 2px 10px;
  font-size: .85rem;
}
.mod-card .mod-title { font-weight: 700; font-size: 1.06rem; }
.mod-card .mod-desc { color: var(--ink-soft); font-size: .92rem; margin: 8px 0 0; }
.mod-card .mod-score {
  position: absolute;
  top: 16px;
  right: 18px;
  font-size: .8rem;
  font-weight: 700;
  border-radius: 999px;
  padding: 3px 10px;
  background: var(--code-bg);
  color: var(--ink-faint);
}
.mod-card .mod-score.pass { background: var(--green-soft); color: var(--green); }
.mod-card .mod-score.mid { background: var(--amber-soft); color: var(--amber); }

.phase-label {
  margin: 30px 0 12px;
  font-size: .8rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: .12em;
  color: var(--ink-faint);
}
.phase-label:first-of-type { margin-top: 0; }

footer { text-align: center; color: var(--ink-faint); font-size: .85rem; margin-top: 60px; }

@media (max-width: 640px) {
  h1 { font-size: 1.6rem; }
  .hero { padding: 28px 22px; }
  .wrap { padding: 22px 16px 70px; }
  .pager { flex-direction: column; }
}