:root {
  --bg: #f4f5f7;
  --surface: #ffffff;
  --surface-2: #fafbfc;
  --text: #1b1f24;
  --text-2: #4b5563;
  --muted: #8b93a1;
  --border: #e4e7ec;
  --border-strong: #ccd2db;
  --accent: #1f63d6;
  --accent-soft: #e9f0fd;
  --qp: #1f63d6;
  --qp-soft: #e9f0fd;
  --ms: #0f7a53;
  --ms-soft: #e6f4ee;
  --warn: #a15c00;
  --warn-soft: #fdf3e2;
  --radius: 10px;
  --radius-lg: 14px;
  --shadow: 0 1px 2px rgba(16, 24, 40, .06), 0 1px 3px rgba(16, 24, 40, .04);
  --font: system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }

/* 组件用了 display:flex/inline-flex，会盖掉 UA 的 [hidden]{display:none}，这里统一兜底 */
[hidden] { display: none !important; }

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 14px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
button { font-family: inherit; font-size: inherit; cursor: pointer; }
h1, h2, h3, h4 { margin: 0; font-weight: 600; }

/* ---------- 顶栏 ---------- */
.topbar {
  position: sticky;
  top: 0;
  z-index: 40;
  display: flex;
  align-items: center;
  gap: 18px;
  padding: 10px 18px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}

.brand { display: flex; align-items: center; gap: 10px; flex: none; }

.brand-mark {
  width: 32px; height: 32px;
  display: grid; place-items: center;
  background: var(--accent);
  color: #fff;
  border-radius: 9px;
  font-weight: 600;
  font-size: 13px;
  letter-spacing: .5px;
}

.brand-text { display: flex; flex-direction: column; line-height: 1.25; }
.brand-text strong { font-size: 14px; font-weight: 600; }
.brand-text em { font-style: normal; font-size: 11px; color: var(--muted); }

.searchbox { display: flex; flex: 1; max-width: 520px; gap: 6px; }

.searchbox input {
  flex: 1;
  padding: 8px 12px;
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  background: var(--surface-2);
  font-family: inherit;
  font-size: 13px;
  color: var(--text);
}
.searchbox input:focus { outline: 2px solid var(--accent-soft); border-color: var(--accent); }

.searchbox button {
  padding: 8px 16px;
  border: none;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  font-weight: 500;
}
.searchbox button:hover { background: #17509f; }

.topnav { display: flex; gap: 4px; margin-left: auto; flex: none; }
.topnav a {
  padding: 7px 12px;
  border-radius: 8px;
  font-size: 13px;
  color: var(--text-2);
}
.topnav a:hover { background: var(--surface-2); color: var(--text); }
.topnav a.active { background: var(--accent-soft); color: var(--accent); font-weight: 500; }

/* ---------- 布局 ---------- */
.shell { display: flex; height: calc(100vh - 53px); }

.sidebar {
  width: 268px;
  flex: none;
  display: flex;
  flex-direction: column;
  background: var(--surface);
  border-right: 1px solid var(--border);
}

.side-head {
  padding: 12px 14px 10px;
  border-bottom: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 12px;
  font-weight: 500;
  color: var(--text-2);
}
.side-head input {
  padding: 6px 10px;
  border: 1px solid var(--border);
  border-radius: 7px;
  font-family: inherit;
  font-size: 12px;
  background: var(--surface-2);
}
.side-head input:focus { outline: 2px solid var(--accent-soft); border-color: var(--accent); }

.tree { flex: 1; overflow-y: auto; padding: 8px 8px 40px; }

.tree-group > summary {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 8px;
  border-radius: 7px;
  font-weight: 600;
  font-size: 13px;
  cursor: pointer;
  list-style: none;
}
.tree-group > summary::-webkit-details-marker { display: none; }
.tree-group > summary::before {
  content: "";
  width: 0; height: 0;
  border-left: 5px solid var(--muted);
  border-top: 4px solid transparent;
  border-bottom: 4px solid transparent;
  transition: transform .15s;
}
.tree-group[open] > summary::before { transform: rotate(90deg); }
.tree-group > summary:hover { background: var(--surface-2); }

.tree-l2 > summary {
  display: flex; align-items: center; gap: 6px;
  padding: 4px 8px 4px 16px;
  border-radius: 6px;
  font-size: 12.5px;
  color: var(--text-2);
  cursor: pointer;
  list-style: none;
}
.tree-l2 > summary::-webkit-details-marker { display: none; }
.tree-l2 > summary::before {
  content: "";
  width: 0; height: 0;
  border-left: 4px solid var(--muted);
  border-top: 3px solid transparent;
  border-bottom: 3px solid transparent;
}
.tree-l2[open] > summary::before { transform: rotate(90deg); }
.tree-l2 > summary:hover { background: var(--surface-2); }

.tree-l3 { padding: 2px 0 2px 26px; display: flex; flex-wrap: wrap; gap: 4px; }

.pill {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 3px 8px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--surface-2);
  font-size: 12px;
  color: var(--text-2);
  white-space: nowrap;
}
.pill:hover { border-color: var(--accent); color: var(--accent); background: var(--accent-soft); }
.pill.current { background: var(--accent); border-color: var(--accent); color: #fff; font-weight: 500; }
.pill .dot { width: 6px; height: 6px; border-radius: 50%; background: var(--qp); }
.pill.spec .dot { background: var(--ms); }

.tree-count { color: var(--muted); font-weight: 400; font-size: 11px; }

.main { flex: 1; overflow-y: auto; scroll-behavior: smooth; }

/* ---------- 通用块 ---------- */
.wrap { max-width: 1180px; margin: 0 auto; padding: 22px 24px 60px; }
.wrap.wide { max-width: none; padding: 0; }

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
}

.page-title { font-size: 20px; margin-bottom: 4px; }
.page-sub { color: var(--muted); font-size: 13px; margin-bottom: 20px; }

.stat-row { display: flex; flex-wrap: wrap; gap: 10px; margin: 18px 0 26px; }
.stat {
  flex: 1 1 140px;
  padding: 12px 14px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.stat b { display: block; font-size: 20px; font-weight: 600; line-height: 1.3; }
.stat span { color: var(--muted); font-size: 12px; }

.section-title {
  display: flex; align-items: baseline; gap: 10px;
  margin: 26px 0 12px;
  font-size: 15px;
  font-weight: 600;
}
.section-title em { font-style: normal; font-size: 12px; color: var(--muted); font-weight: 400; }

.year-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 12px; }

.paper-card {
  display: block;
  padding: 14px 15px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: border-color .15s, transform .15s;
}
.paper-card:hover { border-color: var(--accent); transform: translateY(-1px); }
.paper-card h4 { font-size: 13.5px; margin-bottom: 3px; }
.paper-card .meta { color: var(--muted); font-size: 12px; display: flex; gap: 8px; flex-wrap: wrap; }
.paper-card .tags { margin-top: 8px; display: flex; gap: 5px; flex-wrap: wrap; }

.tag {
  padding: 1px 7px;
  border-radius: 5px;
  font-size: 11px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--text-2);
}
.tag.qp { background: var(--qp-soft); border-color: #c7dcf8; color: var(--qp); }
.tag.ms { background: var(--ms-soft); border-color: #bfe4d4; color: var(--ms); }
.tag.spec { background: var(--warn-soft); border-color: #f0dcb8; color: var(--warn); }

/* ---------- 阅读器 ---------- */
.reader { display: flex; flex-direction: column; height: 100%; }

.reader-bar {
  position: sticky; top: 0; z-index: 30;
  display: flex; align-items: center; gap: 12px; flex-wrap: wrap;
  padding: 9px 16px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}
.reader-bar .rb-title { font-weight: 600; font-size: 14px; }
.reader-bar .rb-meta { color: var(--muted); font-size: 12px; }
.reader-bar .spacer { flex: 1; }

.seg { display: inline-flex; border: 1px solid var(--border-strong); border-radius: 8px; overflow: hidden; }
.seg button {
  padding: 6px 13px;
  border: none;
  background: var(--surface);
  color: var(--text-2);
  font-size: 12.5px;
}
.seg button + button { border-left: 1px solid var(--border); }
.seg button:hover { background: var(--surface-2); }
.seg button.on { background: var(--accent); color: #fff; font-weight: 500; }
.seg button.on.ms-on { background: var(--ms); }
.seg button.on.qp-on { background: var(--qp); }

.icon-btn {
  padding: 6px 10px;
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  background: var(--surface);
  color: var(--text-2);
  font-size: 12.5px;
}
.icon-btn:hover { border-color: var(--accent); color: var(--accent); }
.icon-btn.on { background: var(--accent-soft); border-color: var(--accent); color: var(--accent); font-weight: 500; }

.qnav {
  display: flex; align-items: center; gap: 6px; flex-wrap: wrap;
  padding: 8px 16px;
  background: var(--surface-2);
  border-bottom: 1px solid var(--border);
  font-size: 12px;
  color: var(--muted);
}
.qnav .qbtn {
  min-width: 28px;
  padding: 2px 7px;
  border: 1px solid var(--border-strong);
  border-radius: 6px;
  background: var(--surface);
  color: var(--text-2);
  font-size: 12px;
}
.qnav .qbtn:hover { border-color: var(--qp); color: var(--qp); background: var(--qp-soft); }
.qnav .qbtn.active {
  background: var(--qp);
  border-color: var(--qp);
  color: #fff;
  font-weight: 600;
}

.panes { flex: 1; display: flex; min-height: 0; gap: 1px; background: var(--border); }
.pane { flex: 1; overflow-y: auto; background: var(--bg); padding: 18px 0 60px; min-width: 0; }
.pane-head {
  position: sticky; top: 0; z-index: 5;
  margin: 0 auto 14px;
  width: max-content;
  padding: 4px 14px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 500;
  background: rgba(255, 255, 255, .92);
  border: 1px solid var(--border);
  backdrop-filter: blur(6px);
}
.pane-head.qp { color: var(--qp); }
.pane-head.ms { color: var(--ms); }
.pane-now { margin-left: 6px; color: var(--text-2); font-weight: 400; }

.pages { display: flex; flex-direction: column; align-items: center; gap: 18px; padding: 0 18px; }
/* 适应宽度时铺满栏宽；切换到 100%/150%/200% 时由内联 width 覆盖并放开 max-width */
.pages img {
  display: block;
  width: 100%;
  height: auto;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 6px;
}

.page-fig { position: relative; margin: 0; max-width: 100%; width: 100%; }
.page-fig figcaption {
  text-align: center;
  font-size: 11px;
  color: var(--muted);
  padding-top: 5px;
}
.skeleton {
  background: repeating-linear-gradient(45deg, #eef0f3, #eef0f3 12px, #e7eaee 12px, #e7eaee 24px);
  border: 1px solid var(--border);
  border-radius: 6px;
}

.qmark {
  position: absolute;
  left: 0; right: 0;
  height: 0;
  pointer-events: none;
}
.qmark::before {
  content: attr(data-label);
  position: absolute;
  left: -30px; top: -9px;
  width: 24px; height: 18px;
  display: grid; place-items: center;
  background: var(--qp);
  color: #fff;
  border-radius: 4px;
  font-size: 11px;
  font-weight: 600;
}
.qmark.hit::after {
  content: "";
  position: absolute;
  left: 0; right: 0; top: 0;
  height: 3px;
  background: #ffb703;
  border-radius: 2px;
  animation: flash 1.2s ease-out 2;
}
@keyframes flash { from { opacity: 1; } to { opacity: .15; } }

/* ---------- 说明页的字段表 ---------- */
.kv-table { width: 100%; border-collapse: collapse; background: var(--surface); font-size: 13px; }
.kv-table th, .kv-table td {
  border: 1px solid var(--border);
  padding: 8px 10px;
  vertical-align: top;
  text-align: left;
}
.kv-table thead th {
  background: var(--ms-soft);
  color: var(--ms);
  font-weight: 600;
  font-size: 12px;
}

.notice {
  padding: 10px 14px;
  border-radius: var(--radius);
  background: var(--warn-soft);
  border: 1px solid #f0dcb8;
  color: var(--warn);
  font-size: 12.5px;
  margin-bottom: 14px;
}
.notice.info { background: var(--accent-soft); border-color: #c7dcf8; color: var(--accent); }

/* ---------- 搜索 / 收藏 ---------- */
.result {
  display: block;
  padding: 13px 15px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  margin-bottom: 10px;
}
.result:hover { border-color: var(--accent); }
.result h4 { font-size: 13.5px; margin-bottom: 4px; display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
.result .snippet { color: var(--text-2); font-size: 12.5px; }
.result .snippet mark { background: #fff2a8; color: inherit; padding: 0 2px; border-radius: 3px; }
.result .where { color: var(--muted); font-size: 11.5px; margin-top: 5px; }

.empty { text-align: center; color: var(--muted); padding: 60px 20px; font-size: 13px; }

/* ---------- 灯箱 ---------- */
.lightbox {
  position: fixed; inset: 0; z-index: 100;
  background: rgba(16, 20, 26, .88);
  display: flex; align-items: center; justify-content: center;
  padding: 24px;
}
.lightbox img { max-width: 100%; max-height: 100%; border-radius: 6px; }
.lb-close {
  position: absolute; top: 14px; right: 18px;
  width: 36px; height: 36px;
  border-radius: 50%;
  border: none;
  background: rgba(255, 255, 255, .16);
  color: #fff;
  font-size: 22px;
  line-height: 1;
}

/* ---------- 逐题索引页 ---------- */
/* 首页入口卡 */
.ix-entry {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  background: var(--surface);
  border: 1px solid var(--border-strong);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius-lg);
  padding: 15px 18px;
  margin: 0 0 26px;
  text-decoration: none;
  color: inherit;
  box-shadow: var(--shadow);
}
.ix-entry:hover { border-color: var(--accent); }
.ix-entry-txt { flex: 1 1 320px; }
.ix-entry-txt b { display: block; font-size: 14.5px; margin-bottom: 3px; }
.ix-entry-txt span { color: var(--text-2); font-size: 12.5px; line-height: 1.5; }
.ix-entry-go {
  flex: none;
  padding: 7px 14px;
  border-radius: 8px;
  background: var(--accent-soft);
  color: var(--accent);
  font-weight: 600;
  font-size: 13px;
  white-space: nowrap;
}

/* 主题按钮组 */
.ix-topics { display: flex; flex-wrap: wrap; gap: 6px; margin: 20px 0 14px; }
.ix-tbtn {
  font-family: inherit;
  font-size: 12.5px;
  padding: 4px 11px;
  border-radius: 999px;
  border: 1px solid var(--border-strong);
  background: var(--surface);
  color: var(--text-2);
  cursor: pointer;
}
.ix-tbtn b { font-weight: 600; color: var(--muted); margin-left: 3px; }
.ix-tbtn:hover { border-color: var(--accent); color: var(--accent); }
.ix-tbtn.on { background: var(--accent); border-color: var(--accent); color: #fff; font-weight: 500; }
.ix-tbtn.on b { color: rgba(255, 255, 255, .8); }

/* 筛选条 */
.ix-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 7px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 10px 13px;
  margin-bottom: 12px;
}
.ix-bar label { font-size: 12px; color: var(--muted); }
.ix-spacer { flex: 1 1 20px; }
.ix-select, #ixKw {
  font-family: inherit;
  font-size: 12.5px;
  border: 1px solid var(--border-strong);
  background: var(--surface);
  color: var(--text);
  border-radius: 8px;
  padding: 5px 9px;
  max-width: 190px;
}
#ixKw { min-width: 190px; flex: 0 1 220px; }

.ix-count { color: var(--text-2); font-size: 12.5px; margin: 0 2px 8px; }

/* 表格 */
.ix-tablewrap {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: auto;
}
.ix-table { width: 100%; border-collapse: collapse; font-size: 13px; }
.ix-table th, .ix-table td {
  border-bottom: 1px solid var(--border);
  padding: 8px 10px;
  text-align: left;
  vertical-align: top;
}
.ix-table thead th {
  position: sticky;
  top: 0;
  z-index: 2;
  background: var(--surface-2);
  color: var(--text-2);
  font-size: 11.5px;
  font-weight: 600;
  white-space: nowrap;
}
.ix-table tbody tr:last-child td { border-bottom: none; }
.ix-table tbody tr:hover { background: var(--surface-2); }
.ix-table td.ix-paper { white-space: nowrap; }
.ix-table td.ix-paper b { display: block; font-weight: 600; }
.ix-table td.ix-paper span { color: var(--muted); font-size: 11.5px; }
.ix-table td.ix-q { font-weight: 600; white-space: nowrap; }
.ix-table td.ix-num { font-variant-numeric: tabular-nums; color: var(--text-2); white-space: nowrap; }
.ix-table td.ix-topic { font-weight: 500; }
.ix-table td.ix-ev {
  color: var(--muted);
  font-size: 11.5px;
  font-family: var(--mono);
  word-break: break-word;
}
.ix-table td.ix-go { white-space: nowrap; }
.ix-table td.ix-go a {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 7px;
  background: var(--accent-soft);
  color: var(--accent);
  font-weight: 600;
  font-size: 12px;
  text-decoration: none;
}
.ix-table td.ix-go a:hover { background: #dbe8fc; }

.ix-pill {
  display: inline-block;
  padding: 1px 8px;
  border-radius: 999px;
  font-size: 11.5px;
  font-weight: 600;
  white-space: nowrap;
}
.lv-foundation { background: #e8f5ee; color: #1a7f52; }
.lv-moderate { background: var(--accent-soft); color: var(--accent); }
.lv-advanced { background: var(--warn-soft); color: var(--warn); }
.lv-challenging { background: #fdeaea; color: #b3341f; }
.cf-high { background: #e8f5ee; color: #1a7f52; }
.cf-medium { background: #eef0f3; color: #5b6373; }
.cf-low { background: #fdeaea; color: #b3341f; }

/* 分页 */
.ix-pager { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; margin: 14px 0 0; }
.ix-pageinfo { color: var(--text-2); font-size: 12.5px; font-variant-numeric: tabular-nums; padding: 0 4px; }
.icon-btn[disabled] { opacity: .45; cursor: default; }
.icon-btn[disabled]:hover { border-color: var(--border-strong); color: var(--text-2); }

.ix-note { color: var(--muted); font-size: 12.5px; margin: 20px 0 0; line-height: 1.7; }

/* ---------- 移动端 ---------- */
.menu-btn {
  display: none;
  padding: 7px 11px;
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  background: var(--surface);
  color: var(--text-2);
  font-size: 12.5px;
}

@media (max-width: 900px) {
  .menu-btn { display: inline-block; }
  .sidebar { position: fixed; left: 0; top: 53px; bottom: 0; z-index: 50; transform: translateX(-100%); transition: transform .2s; }
  .sidebar.open { transform: none; box-shadow: 0 8px 30px rgba(0, 0, 0, .16); }
  .brand-text em { display: none; }
  .panes { flex-direction: column; }
  .pane { flex: 1 1 auto; }
  .searchbox { max-width: none; }
  .topnav a { padding: 7px 8px; }
  /* 索引页窄屏：隐藏「匹配依据」列，筛选条占满一行 */
  .ix-table td.ix-ev { display: none; }
  .ix-table thead th:nth-child(8) { display: none; }
  .ix-table { font-size: 12.5px; }
  #ixKw { flex: 1 1 100%; max-width: none; }
  .ix-select { max-width: none; }
}