:root {
  --bg: #fbfbf9; --panel: #ffffff; --ink: #1d2733; --muted: #5c6773; --line: #e3e6ea;
  --blue: #2f6fb3; --blue-soft: #e7f0fa; --orange: #d9692b; --orange-soft: #fbece3;
  --green: #3f8f4a; --green-soft: #e6f3e7; --red: #c0392b; --red-soft: #fbe4e1; --yellow-soft: #fff4c7;
  --radius: 10px; --shadow: 0 1px 3px rgba(20, 30, 40, .08);
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, "Songti SC", "Noto Serif CJK SC", serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--bg); color: var(--ink); font: 16px/1.6 var(--sans); }
a { color: var(--blue); text-decoration: none; }
a:hover { text-decoration: underline; }
button, select, input, textarea { font: inherit; color: inherit; }

.topbar { position: sticky; top: 0; z-index: 10; display: flex; align-items: center; gap: 24px;
  padding: 0 24px; height: 56px; background: rgba(255,255,255,.92); backdrop-filter: blur(6px);
  border-bottom: 1px solid var(--line); }
.brand { font-weight: 700; font-size: 18px; color: var(--ink); letter-spacing: .2px; }
.topbar nav { display: flex; gap: 4px; flex: 1; overflow-x: auto; }
.topbar nav a { padding: 6px 12px; border-radius: 8px; color: var(--muted); white-space: nowrap; }
.topbar nav a:hover { background: #f0f2f4; text-decoration: none; }
.topbar nav a.active { color: var(--blue); background: var(--blue-soft); font-weight: 600; }
.contact { color: var(--muted); font-size: 15px; white-space: nowrap; }
.contact:hover { color: var(--blue); text-decoration: none; }
.lang { border: 1px solid var(--line); background: #fff; border-radius: 8px; padding: 4px 12px; cursor: pointer; }

main { max-width: 1480px; margin: 0 auto; padding: 24px 24px 64px; }
main.tight { padding-top: 12px; }
.narrow { max-width: 900px; margin: 0 auto; }
h1 { font: 700 34px/1.25 var(--serif); margin: 12px 0 20px; text-align: center; }
h2 { font: 700 24px/1.3 var(--serif); margin: 40px 0 14px; }
h3 { font-size: 17px; margin: 18px 0 8px; }
.muted { color: var(--muted); }
.small { font-size: 14px; }
.center { text-align: center; }
.authors { text-align: center; font-size: 18px; margin: 4px 0 0; }
.affil { text-align: center; color: var(--muted); margin: 2px 0 18px; }
.buttons { display: flex; justify-content: center; gap: 10px; flex-wrap: wrap; margin: 18px 0; }
.btn { display: inline-flex; align-items: center; gap: 6px; border: 1px solid var(--ink); background: var(--ink);
  color: #fff; border-radius: 999px; padding: 7px 18px; cursor: pointer; font-weight: 600; font-size: 15px; }
.btn:hover { text-decoration: none; opacity: .9; }
.btn.ghost { background: #fff; color: var(--ink); }
.btn.blue { background: var(--blue); border-color: var(--blue); }
.btn.red { background: #fff; color: var(--red); border-color: var(--red); }
.btn:disabled { opacity: .45; cursor: default; }
.tldr { background: var(--blue-soft); border-radius: var(--radius); padding: 14px 18px; font-size: 17px; }
figure { margin: 0; }
figure img { width: 100%; border: 1px solid var(--line); border-radius: var(--radius); background: #fff; }
figcaption { color: var(--muted); font-size: 14px; margin-top: 8px; }
.abstract { text-align: justify; }
pre.bib { background: #f3f4f6; border-radius: var(--radius); padding: 14px; overflow-x: auto; font-size: 13px; position: relative; }

.charts { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; }
.chart { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 12px; }
.chart h4 { margin: 0 0 4px; font-size: 14px; }
.legend { display: flex; gap: 14px; font-size: 13px; color: var(--muted); justify-content: center; margin-top: 6px; }
.legend i { display: inline-block; width: 12px; height: 3px; margin-right: 5px; vertical-align: middle; }

.card { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); padding: 18px; }
.grid2 { display: grid; grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr); gap: 18px; }
.field { margin: 12px 0; }
.field label { display: block; font-weight: 600; font-size: 14px; margin-bottom: 4px; }
textarea, input[type=text], input[type=password], select { width: 100%; border: 1px solid #cfd5db; border-radius: 8px; padding: 8px 10px; background: #fff; }
textarea { min-height: 110px; resize: vertical; }
.chips { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 6px; }
.chip { border: 1px solid var(--line); background: #fff; border-radius: 999px; padding: 3px 10px; font-size: 13px; cursor: pointer; color: var(--muted); max-width: 100%; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.chip:hover { border-color: var(--blue); color: var(--blue); }
.seg { display: inline-flex; border: 1px solid #cfd5db; border-radius: 8px; overflow: hidden; }
.seg button { border: 0; background: #fff; padding: 6px 14px; cursor: pointer; border-right: 1px solid #cfd5db; }
.seg button:last-child { border-right: 0; }
.seg button.on { background: var(--blue); color: #fff; }
.row { display: flex; gap: 12px; flex-wrap: wrap; align-items: flex-end; }
.row > * { flex: 1; min-width: 160px; }
.note { font-size: 13px; color: var(--muted); margin-top: 6px; }
.status { margin: 14px 0; padding: 10px 14px; border-radius: 8px; background: #f3f4f6; }
.status.err { background: var(--red-soft); color: var(--red); }
.status.ok { background: var(--green-soft); color: var(--green); }

.live { display: grid; grid-template-columns: 220px minmax(0, 1fr) 340px; gap: 16px; margin-top: 18px; align-items: start; }
.live.story { grid-template-columns: 200px minmax(0, 1fr) 400px; }
.reader { max-width: none; }
.stack { display: flex; flex-direction: column; gap: 12px; }
.kv h4 { margin: 0 0 6px; font-size: 14px; }
.kv > div { display: flex; justify-content: space-between; gap: 8px; font-size: 13.5px; padding: 3px 0; border-bottom: 1px dashed var(--line); }
.kv > div:last-child { border-bottom: 0; }
.kv > div span { color: var(--muted); }
.stack .collapse { max-height: 26vh; }
.stack .collapse.state-box { max-height: 58vh; }
.back { margin: 0 0 10px; }
.caret { display: inline-block; width: 2px; height: 1em; background: var(--blue); vertical-align: -2px; animation: blink 1s step-end infinite; }
@keyframes blink { 50% { opacity: 0; } }
.side { position: sticky; top: 72px; max-height: calc(100vh - 90px); overflow: auto; }
.outline-list { list-style: none; padding: 0; margin: 0; }
.outline-list li { padding: 6px 8px; border-radius: 6px; font-size: 14px; cursor: pointer; color: var(--muted); }
.outline-list li.done { color: var(--ink); }
.outline-list li.cur { background: var(--blue-soft); color: var(--blue); font-weight: 600; }
.outline-list li.sel { outline: 2px solid var(--blue); }
.outline-list li .w { float: right; font-size: 12px; color: var(--muted); }
.outline-list li.check::after { content: " ●"; color: var(--orange); font-size: 10px; }

.reader { font: 18px/1.85 var(--serif); }
.reader h3 { font: 700 22px/1.3 var(--serif); margin: 4px 0 14px; }
.reader p { margin: 0 0 1em; }
.reader .placeholder { color: var(--muted); font: 15px/1.6 var(--sans); }
mark { background: none; color: inherit; transition: background .3s; }
mark.err.on { background: var(--red-soft); box-shadow: 0 2px 0 var(--red); }
mark.pair.on { background: var(--yellow-soft); box-shadow: 0 2px 0 #d4a800; }
.errs .e.sel { border-color: var(--red); background: var(--red-soft); }

.state h4 { margin: 12px 0 6px; font-size: 14px; display: flex; justify-content: space-between; }
.state h4 .n { color: var(--muted); font-weight: 400; }
.entry { border-left: 3px solid var(--line); padding: 4px 8px; margin: 0 0 6px; font-size: 13.5px; line-height: 1.5; background: #fafbfc; border-radius: 0 6px 6px 0; }
.entry b { font-weight: 600; }
.entry .k { color: var(--muted); font-size: 12px; font-family: ui-monospace, Menlo, monospace; }
.entry.new { border-left-color: var(--green); background: var(--green-soft); }
.entry.changed { border-left-color: var(--blue); background: var(--blue-soft); }
.entry.resolved { border-left-color: var(--orange); background: var(--orange-soft); text-decoration: line-through; color: var(--muted); }
.tag { display: inline-block; font-size: 11px; padding: 0 6px; border-radius: 999px; margin-left: 4px; vertical-align: 1px; }
.tag.new { background: var(--green); color: #fff; }
.tag.changed { background: var(--blue); color: #fff; }
.tools { font-size: 13px; }
.tools .t { display: flex; gap: 6px; padding: 3px 0; border-bottom: 1px dashed var(--line); }
.tools .t .nm { font-weight: 600; min-width: 64px; }
.tools .t.bad .nm { color: var(--red); }
.tools .t.update .nm { color: var(--green); }
.tools .t.read .nm, .tools .t.search .nm { color: var(--blue); }
.collapse { max-height: 38vh; overflow: auto; }
details summary { cursor: pointer; font-weight: 600; font-size: 14px; }

.filters { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 10px; margin: 16px 0; }
.list { display: grid; gap: 8px; }
.item { display: grid; grid-template-columns: 1fr auto; gap: 8px; padding: 12px 14px; cursor: pointer; }
.item:hover { border-color: var(--blue); }
.item .p { font-size: 14.5px; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.item .meta { font-size: 12.5px; color: var(--muted); }
.badge { display: inline-block; font-size: 12px; padding: 1px 8px; border-radius: 999px; background: #eef0f3; color: var(--muted); margin-right: 4px; }
.badge.nstagent { background: var(--blue-soft); color: var(--blue); }
.badge.rollsum { background: var(--orange-soft); color: var(--orange); }
.badge.case { background: var(--yellow-soft); color: #8a6d00; }
.scorebox { display: flex; gap: 16px; font-size: 13px; }
.scorebox div b { display: block; font-size: 18px; }
.errs .e { font-size: 13.5px; padding: 8px 10px; border-radius: 8px; background: #fafbfc; border: 1px solid var(--line); margin-bottom: 8px; cursor: pointer; }
.errs .e:hover { border-color: var(--red); }
.errs .e .h { font-weight: 600; font-size: 12.5px; color: var(--red); margin-bottom: 2px; }
.errs .e q { display: block; margin: 2px 0; }
.chnav { display: flex; justify-content: space-between; margin-top: 18px; }

.cases { display: grid; gap: 18px; }
.case h3 { margin-top: 0; font: 700 19px/1.35 var(--serif); }
.vs { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-top: 12px; }
.vs .side-card { border: 1px solid var(--line); border-radius: 8px; padding: 10px 12px; }
.vs .big { font-size: 28px; font-weight: 700; }
.vs .nst { border-top: 4px solid var(--blue); }
.vs .roll { border-top: 4px solid var(--orange); }

.foot { text-align: center; color: var(--muted); font-size: 13px; padding: 24px; border-top: 1px solid var(--line); }
.spinner { display: inline-block; width: 14px; height: 14px; border: 2px solid #cdd3da; border-top-color: var(--blue); border-radius: 50%; animation: spin 1s linear infinite; vertical-align: -2px; margin-right: 6px; }
@keyframes spin { to { transform: rotate(360deg); } }

@media (max-width: 980px) {
  .live { grid-template-columns: 1fr; }
  .side { position: static; max-height: none; }
  .grid2 { grid-template-columns: 1fr; }
  .filters { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 560px) {
  main { padding: 20px 16px 48px; }
  h1 { font-size: 26px; }
  .topbar { gap: 10px; padding: 0 12px; }
  .vs { grid-template-columns: 1fr; }
  .charts { grid-template-columns: 1fr; }
}

.synopsis { font: 15px/1.7 var(--sans); color: var(--muted); background: #f6f7f9; border-radius: 8px; padding: 10px 14px; }
.synopsis .label { font-size: 12.5px; font-weight: 600; color: var(--ink); margin-bottom: 2px; }

/* Method name as in the paper: \textsc{NstAgent} in Times. */
.nst { font-family: "Times New Roman", Times, "Nimbus Roman", "TeX Gyre Termes", serif; font-variant: small-caps; font-weight: inherit; letter-spacing: .01em; }
.brand .nst { font-weight: 700; font-size: 21px; }

/* ---------------------------------------------------------------- length picker */
.lenrow { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }
.customlen { width: 130px !important; transition: opacity .2s, transform .2s; }
.hidden { display: none; }

/* ---------------------------------------------------------------- motion */
@keyframes rise { from { opacity: 0; transform: translateY(.35em); filter: blur(4px); } to { opacity: 1; transform: none; filter: none; } }
@keyframes fadeIn { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }
@keyframes draw { from { stroke-dashoffset: 400; } to { stroke-dashoffset: 0; } }
@keyframes pop { from { opacity: 0; transform: scale(.4); } to { opacity: 1; transform: none; } }
@keyframes glow { 0% { box-shadow: 0 0 0 0 rgba(63, 143, 74, .35); } 100% { box-shadow: 0 0 0 8px rgba(63, 143, 74, 0); } }

/* headings appear character by character */
.rv { display: inline-block; white-space: pre; opacity: 0; animation: rise .55s cubic-bezier(.2, .7, .2, 1) forwards; }

/* page content slides in once per page */
main.enter > * { animation: fadeIn .45s ease both; }
main.enter > *:nth-child(2) { animation-delay: .05s; }
main.enter .narrow > *:not(h1):not(h2) { animation: fadeIn .5s ease both; }
main.enter .narrow > *:nth-child(2) { animation-delay: .15s; }
main.enter .narrow > *:nth-child(3) { animation-delay: .22s; }
main.enter .narrow > *:nth-child(4) { animation-delay: .29s; }
main.enter .narrow > *:nth-child(n+5) { animation-delay: .36s; }
main.enter .list > .item { animation: fadeIn .4s ease both; }
main.enter .list > .item:nth-child(2) { animation-delay: .04s; }
main.enter .list > .item:nth-child(3) { animation-delay: .08s; }
main.enter .list > .item:nth-child(4) { animation-delay: .12s; }
main.enter .list > .item:nth-child(n+5) { animation-delay: .16s; }
main.enter .cases > .case:nth-child(2) { animation-delay: .1s; }
main.enter .cases > .case:nth-child(3) { animation-delay: .2s; }

/* result charts draw their lines */
.chart polyline { stroke-dasharray: 400; stroke-dashoffset: 400; animation: draw 1.4s .3s ease-out forwards; }
.chart circle { opacity: 0; animation: pop .35s ease-out forwards; animation-delay: 1.2s; transform-box: fill-box; transform-origin: center; }

/* buttons and cards respond to the pointer */
.btn, .chip, .item, .seg button { transition: transform .15s ease, box-shadow .15s ease, background .15s, color .15s, border-color .15s; }
.btn:hover:not(:disabled) { transform: translateY(-1px); box-shadow: 0 4px 12px rgba(20, 30, 40, .12); }
.item:hover { transform: translateY(-1px); box-shadow: 0 6px 16px rgba(20, 30, 40, .08); }
.errs .e { transition: border-color .2s, background .2s; }

/* story text fades in when the chapter changes; streamed paragraphs fade in too */
.live.story .reader > p, .live.story .reader > h3 { animation: fadeIn .35s ease both; }

/* newly added state entries glow once */
.live.story .entry.new { animation: glow 1.2s ease-out 1; }
.live.story .tag { animation: pop .3s ease-out both; }


@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
  .rv, .chart polyline, .chart circle { opacity: 1; stroke-dashoffset: 0; }
}

/* ---------------------------------------------------------------- chat about the paper */
.chat { position: fixed; right: 24px; bottom: 24px; z-index: 50; display: none; font: 14.5px/1.6 var(--sans); }
.chat.shown { display: block; }
.chat-fab { width: 58px; height: 58px; border-radius: 50%; border: 0; cursor: pointer; color: #fff;
  background: linear-gradient(135deg, #3b82c9, #2f6fb3 55%, #245a94); box-shadow: 0 8px 22px rgba(47, 111, 179, .38);
  display: grid; place-items: center; transition: transform .2s ease, box-shadow .2s ease; animation: pop .4s ease-out both; }
.chat-fab:hover { transform: translateY(-2px) scale(1.04); box-shadow: 0 12px 28px rgba(47, 111, 179, .45); }
.chat-fab::after { content: ""; position: absolute; inset: 0; border-radius: 50%; box-shadow: 0 0 0 0 rgba(47, 111, 179, .45); }
.chat.tip .chat-fab::after { animation: ring 1.6s ease-out 2; }
@keyframes ring { to { box-shadow: 0 0 0 14px rgba(47, 111, 179, 0); } }
.chat-tip { position: absolute; right: 70px; bottom: 11px; white-space: nowrap; background: #fff; color: var(--blue);
  border: 1px solid #cfe0f3; border-radius: 12px; padding: 7px 12px; box-shadow: 0 6px 18px rgba(20, 30, 40, .12);
  opacity: 0; transform: translateX(8px) scale(.96); pointer-events: none; transition: opacity .3s ease, transform .3s ease; }
.chat-tip::after { content: ""; position: absolute; right: -6px; top: 50%; width: 10px; height: 10px; background: #fff;
  border-right: 1px solid #cfe0f3; border-top: 1px solid #cfe0f3; transform: translateY(-50%) rotate(45deg); }
.chat.tip:not(.open) .chat-tip { opacity: 1; transform: none; }
.chat-panel { position: absolute; right: 0; bottom: 0; width: 380px; height: min(580px, calc(100vh - 110px));
  background: #fff; border-radius: 16px; box-shadow: 0 18px 48px rgba(20, 30, 40, .22); display: flex; flex-direction: column;
  overflow: hidden; opacity: 0; transform: translateY(16px) scale(.96); transform-origin: bottom right; pointer-events: none;
  transition: opacity .25s ease, transform .25s ease; }
.chat.open .chat-panel { opacity: 1; transform: none; pointer-events: auto; }
.chat.open .chat-fab { opacity: 0; pointer-events: none; transform: scale(.6); }
.chat-panel header { display: flex; justify-content: space-between; align-items: center; padding: 14px 16px; color: #fff;
  background: linear-gradient(135deg, #3b82c9, #2f6fb3 60%, #245a94); }
.chat-title { font-size: 15.5px; }
.chat-sub { font-size: 12.5px; opacity: .85; }
.chat-x { background: rgba(255, 255, 255, .15); border: 0; color: #fff; width: 30px; height: 30px; border-radius: 50%; font-size: 20px; line-height: 1; cursor: pointer; }
.chat-x:hover { background: rgba(255, 255, 255, .28); }
.chat-body { flex: 1; overflow-y: auto; padding: 14px; background: #f5f8fc; display: flex; flex-direction: column; gap: 10px; }
.msg { display: flex; animation: fadeIn .25s ease both; }
.msg.me { justify-content: flex-end; }
.bubble { max-width: 85%; padding: 9px 12px; border-radius: 14px; background: #fff; border: 1px solid #e3eaf3; word-wrap: break-word; }
.msg.me .bubble { background: var(--blue); color: #fff; border-color: var(--blue); border-bottom-right-radius: 4px; }
.msg.bot .bubble { border-bottom-left-radius: 4px; }
.msg.err .bubble { color: var(--red); background: var(--red-soft); border-color: #f3c7c1; }
.bubble p { margin: 0 0 .5em; } .bubble p:last-child { margin-bottom: 0; }
.bubble ul, .bubble ol { margin: .2em 0 .5em; padding-left: 1.3em; }
.bubble code { background: #eef3fa; border-radius: 4px; padding: 0 4px; font-size: 13px; }
.msg.me .bubble a { color: #fff; }
.chat-sugs { display: flex; flex-wrap: wrap; gap: 6px; }
.chat-sugs .chip { color: var(--blue); border-color: #cfe0f3; background: #fff; white-space: normal; text-align: left; }
.typing { display: flex; gap: 4px; align-items: center; padding: 12px 14px; }
.typing i { width: 7px; height: 7px; border-radius: 50%; background: #8fb3da; animation: bounce 1s infinite ease-in-out; }
.typing i:nth-child(2) { animation-delay: .15s; } .typing i:nth-child(3) { animation-delay: .3s; }
@keyframes bounce { 0%, 80%, 100% { transform: translateY(0); opacity: .5; } 40% { transform: translateY(-5px); opacity: 1; } }
.chat-form { display: flex; gap: 8px; padding: 10px; border-top: 1px solid #e3eaf3; background: #fff; align-items: flex-end; }
.chat-form textarea { flex: 1; min-height: 38px; max-height: 120px; resize: none; border-radius: 10px; padding: 8px 10px; }
.chat-form textarea:focus { outline: none; border-color: var(--blue); box-shadow: 0 0 0 3px var(--blue-soft); }
.chat-send { width: 38px; height: 38px; border: 0; border-radius: 10px; background: var(--blue); color: #fff; cursor: pointer; display: grid; place-items: center; }
.chat-send:hover { background: #245a94; }
@media (max-width: 560px) {
  .chat { right: 14px; bottom: 14px; }
  .chat-panel { width: calc(100vw - 28px); height: calc(100vh - 90px); }
  .chat-tip { display: none; }
}
.bubble .tbl { overflow-x: auto; margin: .3em 0 .6em; }
.bubble table { border-collapse: collapse; font-size: 13px; }
.bubble th, .bubble td { border: 1px solid #dbe4ef; padding: 3px 7px; text-align: left; white-space: nowrap; }
.bubble th { background: #eef3fa; }