:root {
  --blue: #0b4f9e;
  --blue-dark: #073a76;
  --blue-soft: #eaf2fc;
  --red: #c8102e;
  --gold: #c9a227;
  --green: #137a4a;
  --green-soft: #e8f6ee;
  --red-soft: #fdecef;
  --ink: #1d2733;
  --ink-soft: #55637a;
  --line: #e2e8f0;
  --bg: #f4f7fb;
  --card: #ffffff;
  --radius: 14px;
  --shadow: 0 4px 18px rgba(15, 45, 90, .08);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Source Han Sans SC", system-ui, -apple-system, "Segoe UI", sans-serif;
  font-size: 15.5px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

/* ---------------- 顶栏 ---------------- */
.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 22px;
  background: linear-gradient(105deg, var(--blue-dark), var(--blue) 55%, #1263bd);
  color: #fff;
  box-shadow: 0 2px 14px rgba(7, 40, 85, .25);
}

.brand { display: flex; align-items: center; gap: 12px; min-width: 0; }

.logo {
  width: 42px; height: 42px; flex: 0 0 42px;
  border-radius: 10px;
  background: rgba(255, 255, 255, .16);
  border: 1px solid rgba(255, 255, 255, .35);
  display: grid; place-items: center;
  font-size: 22px; font-weight: 700;
  letter-spacing: 1px;
}

.brand-text h1 { margin: 0; font-size: 17px; font-weight: 700; letter-spacing: .3px; }
.brand-text p { margin: 1px 0 0; font-size: 12px; opacity: .82; letter-spacing: .5px; }

.tabs { display: flex; gap: 8px; flex: 0 0 auto; }

.tab {
  border: 1px solid rgba(255, 255, 255, .35);
  background: rgba(255, 255, 255, .08);
  color: #fff;
  padding: 8px 16px;
  border-radius: 999px;
  font-size: 14px;
  cursor: pointer;
  transition: .18s;
  font-family: inherit;
}
.tab:hover { background: rgba(255, 255, 255, .2); }
.tab.is-active { background: #fff; color: var(--blue-dark); font-weight: 700; border-color: #fff; }

/* ---------------- 视图 ---------------- */
.view { display: none; }
.view.is-active { display: block; }

/* ---------------- 阅读页 ---------------- */
#view-read {
  display: none;
  grid-template-columns: 258px minmax(0, 1fr);
  gap: 20px;
  max-width: 1400px;
  margin: 0 auto;
  padding: 20px 22px 60px;
  align-items: start;
}
#view-read.is-active { display: grid; }

.sidebar {
  position: sticky;
  top: 82px;
  max-height: calc(100vh - 100px);
  overflow-y: auto;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 14px 12px;
  box-shadow: var(--shadow);
  scrollbar-width: thin;
}

.search-box { position: relative; margin-bottom: 6px; }
.search-box input {
  width: 100%;
  padding: 9px 30px 9px 12px;
  border: 1px solid var(--line);
  border-radius: 10px;
  font-size: 14px;
  font-family: inherit;
  background: #fbfdff;
  outline: none;
  transition: .18s;
}
.search-box input:focus { border-color: var(--blue); box-shadow: 0 0 0 3px rgba(11, 79, 158, .12); }
.clear-btn {
  position: absolute; right: 6px; top: 50%; transform: translateY(-50%);
  border: 0; background: transparent; color: var(--ink-soft);
  font-size: 18px; cursor: pointer; line-height: 1; padding: 2px 6px; border-radius: 6px;
}
.clear-btn:hover { background: #eef3fa; color: var(--ink); }

.nav-hint { font-size: 12px; color: var(--ink-soft); padding: 4px 4px 8px; border-bottom: 1px dashed var(--line); margin-bottom: 8px; }
.nav-hint b { color: var(--blue); }

.nav { list-style: none; margin: 0; padding: 0; }
.nav li { margin-bottom: 2px; }
.nav a {
  display: flex; align-items: center; gap: 8px;
  padding: 8px 10px;
  border-radius: 9px;
  color: var(--ink-soft);
  text-decoration: none;
  font-size: 14px;
  line-height: 1.4;
  transition: .15s;
  border-left: 3px solid transparent;
}
.nav a:hover { background: var(--blue-soft); color: var(--blue-dark); }
.nav a.is-active { background: var(--blue-soft); color: var(--blue-dark); font-weight: 700; border-left-color: var(--blue); }
.nav .n-icon { flex: 0 0 auto; }

.content-wrap { min-width: 0; }

.content-toolbar {
  display: flex; align-items: center; justify-content: space-between;
  gap: 12px; margin-bottom: 10px; min-height: 30px;
}
.search-result { font-size: 13px; color: var(--ink-soft); }
.search-result b { color: var(--red); }

.mini-btn {
  border: 1px solid var(--line); background: #fff; color: var(--ink-soft);
  font-size: 12.5px; padding: 5px 12px; border-radius: 999px; cursor: pointer;
  font-family: inherit; transition: .18s;
}
.mini-btn:hover { border-color: var(--blue); color: var(--blue); background: var(--blue-soft); }

.cat {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 20px 24px 8px;
  margin-bottom: 18px;
  scroll-margin-top: 84px;
}
.cat.is-hidden { display: none; }

.cat-title {
  display: flex; align-items: center; gap: 10px;
  margin: 0 0 6px;
  font-size: 19px;
  color: var(--blue-dark);
  padding-bottom: 10px;
  border-bottom: 2px solid var(--blue-soft);
}
.cat-icon { font-size: 20px; }

.item {
  padding: 16px 0 10px;
  border-bottom: 1px dashed var(--line);
  scroll-margin-top: 96px;
}
.item:last-child { border-bottom: 0; }
.item.is-hidden { display: none; }

.item-title {
  margin: 0 0 4px;
  font-size: 16.5px;
  color: #14355f;
  font-weight: 700;
  display: flex; flex-wrap: wrap; align-items: center; gap: 8px;
}

.tag {
  font-size: 11.5px;
  font-weight: 600;
  padding: 1px 8px;
  border-radius: 999px;
  background: var(--blue-soft);
  color: var(--blue);
  border: 1px solid #cfe0f5;
  line-height: 1.6;
}
.tag.hot { background: var(--red-soft); color: var(--red); border-color: #f6cdd5; }

.item p { margin: 7px 0; text-align: justify; }
.item p.strong-line { font-size: 17px; font-weight: 700; color: var(--red); letter-spacing: .5px; }
.item h4 { margin: 12px 0 4px; font-size: 15px; color: var(--blue); }

.item ol, .item ul { margin: 6px 0 6px; padding-left: 26px; }
.item li { margin: 4px 0; text-align: justify; }
.item ol { list-style: decimal; }
.item ul { list-style: "▪ "; }
.item ul.plain { list-style: none; padding-left: 8px; }
.item .sub { padding-left: 8px; }
.item .sub p { margin: 3px 0; color: var(--ink-soft); }

.item table {
  width: 100%;
  border-collapse: collapse;
  margin: 10px 0 14px;
  font-size: 14px;
  background: #fff;
  border-radius: 8px;
  overflow: hidden;
}
.item th, .item td {
  border: 1px solid var(--line);
  padding: 8px 12px;
  text-align: left;
}
.item th { background: var(--blue-soft); color: var(--blue-dark); font-weight: 700; }
.item tr:nth-child(even) td { background: #fafcff; }

mark { background: #fff2a8; color: inherit; padding: 0 2px; border-radius: 3px; }

.notes {
  background: #fffdf5;
  border: 1px solid #f0e3b8;
  border-radius: var(--radius);
  padding: 14px 18px;
  margin-bottom: 18px;
  font-size: 14px;
  color: #6b5a1e;
}
.notes summary { cursor: pointer; font-weight: 700; color: #8a6d10; }
.notes ul { margin: 10px 0 0; padding-left: 22px; }
.notes li { margin: 4px 0; }

.page-footer { text-align: center; color: var(--ink-soft); font-size: 13px; padding: 14px 0 4px; }

.back-top {
  position: fixed; right: 24px; bottom: 28px;
  width: 44px; height: 44px; border-radius: 50%;
  border: 0; background: var(--blue); color: #fff;
  font-size: 20px; cursor: pointer; box-shadow: 0 6px 18px rgba(11, 79, 158, .35);
  display: none; z-index: 40;
}
.back-top.is-show { display: block; }
.back-top:hover { background: var(--blue-dark); }

/* ---------------- 做题页 ---------------- */
#view-quiz { padding: 22px 22px 70px; }
.quiz-shell { max-width: 880px; margin: 0 auto; }

.quiz-panel { animation: fadeIn .25s ease; }
.quiz-panel.is-hidden { display: none; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }

.quiz-hero {
  background: linear-gradient(120deg, var(--blue-dark), var(--blue) 60%, #1a6fc4);
  color: #fff;
  border-radius: var(--radius);
  padding: 26px 28px;
  box-shadow: var(--shadow);
}
.quiz-hero h2 { margin: 0 0 6px; font-size: 22px; }
.quiz-hero p { margin: 0; font-size: 14px; opacity: .88; }

.hero-stats { display: flex; gap: 28px; margin-top: 18px; flex-wrap: wrap; }
.stat { display: flex; flex-direction: column; }
.stat b { font-size: 24px; line-height: 1.2; }
.stat span { font-size: 12.5px; opacity: .82; }

.quiz-config {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 14px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px;
  margin-top: 16px;
  box-shadow: var(--shadow);
}
.field { display: flex; flex-direction: column; gap: 6px; }
.field > span { font-size: 13px; color: var(--ink-soft); font-weight: 600; }
.field select {
  padding: 9px 12px;
  border: 1px solid var(--line);
  border-radius: 10px;
  font-size: 14px;
  font-family: inherit;
  background: #fbfdff;
  color: var(--ink);
  outline: none;
  cursor: pointer;
}
.field select:focus { border-color: var(--blue); box-shadow: 0 0 0 3px rgba(11, 79, 158, .12); }

.quiz-actions { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 18px; align-items: center; }
.quiz-actions.center { justify-content: center; }

.btn {
  border: 1px solid transparent;
  border-radius: 10px;
  padding: 10px 20px;
  font-size: 14.5px;
  font-family: inherit;
  cursor: pointer;
  transition: .18s;
  background: #fff;
}
.btn.big { padding: 13px 30px; font-size: 15.5px; font-weight: 600; }
.btn.primary { background: var(--blue); color: #fff; box-shadow: 0 4px 12px rgba(11, 79, 158, .28); }
.btn.primary:hover { background: var(--blue-dark); }
.btn.ghost { background: #fff; color: var(--blue); border-color: #bcd4ef; }
.btn.ghost:hover { background: var(--blue-soft); }
.btn.text { background: transparent; color: var(--ink-soft); border: 0; text-decoration: underline; padding: 10px 10px; }
.btn.text:hover { color: var(--red); }
.btn:disabled { opacity: .5; cursor: not-allowed; }
.btn.is-hidden { display: none; }

/* 答题头 */
.quiz-head {
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 12px 18px; margin-bottom: 14px; box-shadow: var(--shadow);
  flex-wrap: wrap;
}
.progress-info { display: flex; align-items: center; gap: 10px; font-size: 14px; color: var(--ink-soft); font-weight: 600; }
.progress-bar { width: 170px; height: 8px; background: #e9eff7; border-radius: 999px; overflow: hidden; }
.progress-bar i { display: block; height: 100%; width: 0; background: linear-gradient(90deg, var(--blue), #3f8ee0); transition: width .25s; }
.score-info { display: flex; align-items: center; gap: 14px; font-size: 14px; }
.score-info .ok { color: var(--green); }
.score-info .no { color: var(--red); }

.question-card {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 22px 24px 18px; box-shadow: var(--shadow);
}
.q-meta { display: flex; align-items: center; gap: 10px; margin-bottom: 10px; }
.badge {
  font-size: 12px; font-weight: 700; padding: 2px 10px; border-radius: 999px;
  background: var(--blue-soft); color: var(--blue); border: 1px solid #cfe0f5;
}
.q-cat { font-size: 12.5px; color: var(--ink-soft); }

.q-text { font-size: 17px; font-weight: 600; line-height: 1.7; margin-bottom: 16px; }

.options { display: flex; flex-direction: column; gap: 10px; }
.option {
  display: flex; align-items: flex-start; gap: 12px;
  padding: 12px 16px;
  border: 1.5px solid var(--line);
  border-radius: 11px;
  cursor: pointer;
  background: #fbfdff;
  transition: .15s;
  font-size: 15px;
}
.option:hover { border-color: #9dc2e8; background: var(--blue-soft); }
.option .key {
  flex: 0 0 24px; width: 24px; height: 24px; border-radius: 50%;
  background: #e9eff7; color: var(--ink-soft);
  display: grid; place-items: center; font-size: 13px; font-weight: 700;
  margin-top: 1px;
}
.option.is-picked { border-color: var(--blue); background: var(--blue-soft); }
.option.is-picked .key { background: var(--blue); color: #fff; }
.option.is-correct { border-color: var(--green); background: var(--green-soft); }
.option.is-correct .key { background: var(--green); color: #fff; }
.option.is-wrong { border-color: var(--red); background: var(--red-soft); }
.option.is-wrong .key { background: var(--red); color: #fff; }
.option.is-locked { cursor: default; }
.option.is-locked:hover { border-color: inherit; }
.option.is-locked.is-picked:hover { border-color: var(--blue); }
.option.is-locked.is-correct:hover { border-color: var(--green); }
.option.is-locked.is-wrong:hover { border-color: var(--red); }
.option.is-locked:not(.is-picked):not(.is-correct):not(.is-wrong):hover { border-color: var(--line); background: #fbfdff; }

.fill-area { margin-top: 4px; }
.fill-area.is-hidden { display: none; }
.fill-area input {
  width: 100%;
  padding: 13px 16px;
  font-size: 16px;
  font-family: inherit;
  border: 1.5px solid var(--line);
  border-radius: 11px;
  outline: none;
  background: #fbfdff;
}
.fill-area input:focus { border-color: var(--blue); box-shadow: 0 0 0 3px rgba(11, 79, 158, .12); }

.feedback { margin-top: 16px; border-radius: 11px; padding: 14px 18px; font-size: 14.5px; }
.feedback.is-hidden { display: none; }
.feedback.ok { background: var(--green-soft); border: 1px solid #b8e2cc; }
.feedback.no { background: var(--red-soft); border: 1px solid #f3c5ce; }
.feedback .fb-title { font-weight: 700; font-size: 15.5px; margin-bottom: 6px; }
.feedback.ok .fb-title { color: var(--green); }
.feedback.no .fb-title { color: var(--red); }
.feedback .fb-line { margin: 4px 0; color: #33465e; }
.feedback .fb-line b { color: var(--blue-dark); }

.q-actions { display: flex; justify-content: flex-end; gap: 12px; margin-top: 16px; }

/* 结果页 */
.result-hero {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 28px; text-align: center; box-shadow: var(--shadow);
}
.ring {
  width: 118px; height: 118px; margin: 0 auto 12px;
  border-radius: 50%;
  display: grid; place-items: center;
  background: conic-gradient(var(--blue) var(--p, 0%), #e9eff7 0);
  position: relative;
}
.ring::after {
  content: ""; position: absolute; inset: 9px; border-radius: 50%; background: #fff;
}
.ring b { position: relative; z-index: 1; font-size: 25px; color: var(--blue-dark); }
.result-hero h2 { margin: 6px 0 4px; font-size: 20px; color: var(--blue-dark); }
.result-hero p { margin: 0; color: var(--ink-soft); font-size: 14px; }
.result-hero .hero-stats { justify-content: center; color: var(--ink); }
.result-hero .stat b { color: var(--blue-dark); }
.result-hero .stat span { color: var(--ink-soft); opacity: 1; }

.result-list { margin-top: 16px; }
.res-item {
  background: var(--card); border: 1px solid var(--line); border-left: 4px solid var(--red);
  border-radius: 11px; padding: 14px 18px; margin-bottom: 10px; box-shadow: var(--shadow);
  font-size: 14.5px;
}
.res-item.ok { border-left-color: var(--green); }
.res-item .ri-q { font-weight: 600; margin-bottom: 6px; }
.res-item .ri-line { color: var(--ink-soft); font-size: 14px; margin: 3px 0; }
.res-item .ri-line b.no { color: var(--red); }
.res-item .ri-line b.ok { color: var(--green); }
.res-item .ri-exp { margin-top: 6px; padding-top: 6px; border-top: 1px dashed var(--line); color: #4a5b73; }

/* ---------------- 响应式 ---------------- */
@media (max-width: 900px) {
  #view-read.is-active { grid-template-columns: 1fr; }
  .sidebar { position: static; max-height: none; }
  .nav { display: flex; flex-wrap: wrap; gap: 6px; }
  .nav li { margin: 0; }
  .nav a { border-left: 0; border: 1px solid var(--line); padding: 6px 10px; font-size: 13px; }
  .nav a.is-active { border-color: var(--blue); }
  .topbar { flex-direction: column; align-items: stretch; gap: 10px; }
  .tabs { justify-content: center; }
  .brand { justify-content: center; text-align: center; }
  .brand-text h1 { font-size: 15px; }
  .cat { padding: 16px 16px 6px; }
  .q-text { font-size: 16px; }
  .progress-bar { width: 110px; }
}