/* LimiX Studio — deep immersive dark theme (DeepSeek-inspired) */
:root {
  --bg: #070b16;
  --bg2: #0a1020;
  --panel: rgba(255, 255, 255, .035);
  --panel2: rgba(255, 255, 255, .055);
  --line: rgba(255, 255, 255, .09);
  --line2: rgba(255, 255, 255, .14);
  --ink: #e9edf6;
  --ink2: #aab2c5;
  --mut: #6b7387;
  --blue: #6e8fe8;
  --blue-d: #4a6fd4;
  --blue-glow: rgba(110, 143, 232, .35);
  --ok: #2dd4a7;
  --warn: #f0b35c;
  --err: #ef6a6a;
  --ctx: rgba(110, 143, 232, .55);
  --qry: rgba(45, 212, 167, .55);
  --r: 16px;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Segoe UI", "Microsoft YaHei", sans-serif;
  background: var(--bg); color: var(--ink); line-height: 1.65;
  -webkit-font-smoothing: antialiased; overflow-x: hidden;
}
.hidden { display: none !important; }
a { color: var(--blue); text-decoration: none; }
::selection { background: rgba(110, 143, 232, .3); }

/* ---------- animated causal-network background ---------- */
#bg {
  position: fixed; inset: 0; z-index: 0; pointer-events: none;
  transition: opacity .8s ease; opacity: 1;
}
body.working #bg { opacity: .38; }
main, .nav, .ft { position: relative; z-index: 1; }

/* ---------- nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 40;
  background: rgba(7, 11, 22, .72); backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--line);
}
.nav-in { max-width: 1240px; margin: 0 auto; padding: 0 24px; height: 54px; display: flex; align-items: center; justify-content: space-between; }
.brand { display: flex; align-items: center; gap: 8px; color: var(--ink); font-weight: 800; font-size: 17px; }
.brand em { font-style: normal; font-weight: 500; color: var(--mut); }
.bm { width: 22px; height: 22px; color: var(--blue); }
img.bm { object-fit: contain; filter: brightness(1.55) saturate(1.1); } /* official mark lifted for dark bg */

/* ---------- inference progress ---------- */
.prog { margin-top: 14px; border: 1px solid var(--line); border-radius: 11px; padding: 12px 14px; background: var(--panel); }
.prog-stage { font-size: 12.5px; font-weight: 600; color: var(--ink2); margin-bottom: 8px; }
.prog-bar { height: 6px; border-radius: 99px; background: rgba(255, 255, 255, .07); overflow: hidden; }
#prog-fill {
  height: 100%; width: 0%; border-radius: 99px;
  background: linear-gradient(90deg, var(--blue-d), var(--blue) 60%, #3ec6b8);
  box-shadow: 0 0 12px rgba(110, 143, 232, .6);
  transition: width .18s ease-out;
}
.prog-meta { display: flex; justify-content: space-between; margin-top: 7px; font-size: 11px; color: var(--mut); font-variant-numeric: tabular-nums; }
.nav-r { display: flex; align-items: center; gap: 18px; }
.nav-r a { color: var(--ink2); font-size: 13.5px; font-weight: 600; }
.nav-r a:hover { color: var(--blue); }
.st { display: inline-flex; align-items: center; gap: 6px; font-size: 12.5px; color: var(--mut); }
.st b { white-space: nowrap; }
.st i { width: 8px; height: 8px; border-radius: 50%; background: var(--warn); animation: pl 1.2s infinite; box-shadow: 0 0 8px currentColor; }
.st.ready i { background: var(--ok); animation: none; }
.st.error i { background: var(--err); animation: none; }
@keyframes pl { 50% { opacity: .3; } }

/* ---------- landing scroll morph ---------- */
#landing { height: 150vh; position: relative; z-index: 1; }
.lv-sticky { position: sticky; top: 0; height: 100vh; height: 100svh; overflow: hidden; }
.hero { position: absolute; inset: 0; display: flex; align-items: center; justify-content: center; padding: 0 24px; will-change: opacity, transform; }
.finale {
  position: absolute; inset: 0; display: flex; flex-direction: column;
  align-items: center; justify-content: flex-end; padding: 0 24px 7vh;
  opacity: 0; pointer-events: none; will-change: opacity, transform;
  text-align: center;
}
.fin-tag {
  font-size: clamp(18px, 2.6vw, 26px); font-weight: 700; letter-spacing: 1px;
  color: var(--ink); text-shadow: 0 0 40px rgba(110, 143, 232, .35);
}
.cta2 {
  margin-top: 18px; padding: 12px 34px; border: 1.5px solid rgba(110, 143, 232, .5);
  border-radius: 14px; cursor: pointer; font-size: 15px; font-weight: 700; color: #fff;
  background: linear-gradient(135deg, var(--blue-d), #5a82e8);
  box-shadow: 0 8px 30px rgba(74, 111, 212, .4); transition: all .2s;
}
.cta2:hover { transform: translateY(-2px); box-shadow: 0 12px 38px rgba(74, 111, 212, .55); }
.scroll-cue { margin-top: 44px; display: flex; flex-direction: column; align-items: center; gap: 8px; color: var(--mut); font-size: 12px; letter-spacing: 2px; }
.scroll-cue i { width: 1px; height: 34px; background: linear-gradient(180deg, var(--blue), transparent); display: block; animation: cue 1.8s ease-in-out infinite; }
@keyframes cue { 0% { transform: scaleY(.2); transform-origin: top; opacity: 0; } 45% { transform: scaleY(1); opacity: 1; } 100% { transform: scaleY(1); opacity: 0; } }
.finale .edu { margin-top: 5vh; width: min(860px, 100%); }
.finale .edu-card { backdrop-filter: none; } /* avoid compositing jank during scroll morph */

/* history item delete button */
.he-del {
  border: none; background: none; color: var(--mut); cursor: pointer;
  font-size: 12px; padding: 2px 5px; flex-shrink: 0; opacity: 0; transition: opacity .13s;
}
.he:hover .he-del { opacity: 1; }
.he-del:hover { color: var(--err); }

/* ---------- hero ---------- */
.hero-in { text-align: center; max-width: 860px; }
.kicker {
  display: inline-block; font-size: 12.5px; letter-spacing: 2.5px; font-weight: 600;
  color: var(--blue); border: 1px solid rgba(110, 143, 232, .35); border-radius: 99px;
  padding: 6px 18px; background: rgba(110, 143, 232, .07);
  text-shadow: 0 0 18px var(--blue-glow);
  max-width: 100%; text-align: center;
}
.hero h1 {
  margin-top: 26px; font-size: clamp(38px, 6.4vw, 66px); font-weight: 800;
  letter-spacing: 1px; line-height: 1.25;
  text-shadow: 0 0 60px rgba(110, 143, 232, .25);
}
.grad {
  background: linear-gradient(115deg, #9db8ff 0%, #6e8fe8 45%, #3ec6b8 100%);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.sub { margin-top: 20px; color: var(--ink2); font-size: 16.5px; line-height: 2; }
.cta-row { margin-top: 36px; display: flex; justify-content: center; }
.drop {
  position: relative; overflow: hidden;
  display: flex; flex-direction: column; align-items: center; gap: 4px;
  padding: 26px 54px; cursor: pointer; border-radius: 20px;
  min-width: min(420px, 100%);               /* zh/en keep the same box size */
  border: 1.5px solid rgba(110, 143, 232, .4);
  background: linear-gradient(180deg, rgba(110, 143, 232, .13), rgba(110, 143, 232, .04));
  box-shadow: 0 0 44px rgba(110, 143, 232, .14), inset 0 0 30px rgba(110, 143, 232, .05);
  transition: all .2s;
  animation: dropBreath 3.8s ease-in-out infinite;
}
.drop:hover, .drop.ov {
  border-color: var(--blue); transform: translateY(-2px);
  box-shadow: 0 0 60px rgba(110, 143, 232, .3), inset 0 0 34px rgba(110, 143, 232, .1);
}
.drop:focus-visible { outline: 2px solid var(--blue); outline-offset: 3px; border-color: var(--blue); }
/* travelling sheen — signals "this is the entry point" without screaming */
.drop::after {
  content: ""; position: absolute; inset: 0; border-radius: inherit; pointer-events: none;
  background: linear-gradient(112deg, transparent 34%, rgba(170, 196, 255, .16) 50%, transparent 66%);
  transform: translateX(-130%);
  animation: dropSheen 5.4s ease-in-out infinite;
}
@keyframes dropBreath {
  0%, 100% {
    border-color: rgba(110, 143, 232, .38);
    box-shadow: 0 0 44px rgba(110, 143, 232, .14), inset 0 0 30px rgba(110, 143, 232, .05);
  }
  50% {
    border-color: rgba(140, 170, 240, .78);
    box-shadow: 0 0 64px rgba(110, 143, 232, .34), inset 0 0 38px rgba(110, 143, 232, .11);
  }
}
@keyframes dropSheen {
  0%, 52% { transform: translateX(-130%); }
  88%, 100% { transform: translateX(130%); }
}
/* stronger pulse when the finale CTA sends the user back up here */
.drop.attn { animation: dropAttn 1.15s ease-in-out 2; }
@keyframes dropAttn {
  50% {
    border-color: #9db8ff;
    box-shadow: 0 0 78px rgba(110, 143, 232, .55), inset 0 0 46px rgba(110, 143, 232, .2);
  }
}
@media (prefers-reduced-motion: reduce) {
  .drop, .drop::after, .drop.attn { animation: none; }
}
.drop svg { width: 26px; height: 26px; color: var(--blue); }
.drop span { font-size: 16px; font-weight: 700; margin-top: 6px; }
.drop small { font-size: 12px; color: var(--mut); }
.ex-row { margin-top: 24px; font-size: 13px; color: var(--mut); display: flex; gap: 8px; justify-content: center; flex-wrap: wrap; align-items: center; }
.ex {
  border: 1px solid var(--line2); background: var(--panel); border-radius: 99px;
  padding: 6px 15px; font-size: 13px; font-weight: 600; color: var(--ink2); cursor: pointer; transition: all .15s;
}
.ex:hover { border-color: var(--blue); color: var(--blue); background: rgba(110, 143, 232, .1); }

/* ---------- education cards ---------- */
.edu { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin-top: 58px; text-align: left; }
.edu-card {
  border: 1px solid var(--line); border-radius: var(--r); padding: 20px 22px;
  background: var(--panel); backdrop-filter: blur(8px); transition: all .2s;
}
.edu-card:hover { border-color: rgba(110, 143, 232, .4); background: var(--panel2); transform: translateY(-3px); }
.ei { font-size: 22px; }
.edu-card h3 { font-size: 15px; font-weight: 700; margin: 8px 0 6px; }
.edu-card p { font-size: 13px; color: var(--mut); line-height: 1.75; }

/* ---------- workbench ---------- */
.work { max-width: 1240px; margin: 0 auto; padding: 26px 24px 80px; }
.work-grid { display: grid; grid-template-columns: 372px 1fr; gap: 22px; align-items: start; }
@media (max-width: 980px) { .work-grid { grid-template-columns: 1fr; } }

.panel {
  border: 1px solid var(--line); border-radius: var(--r);
  background: rgba(10, 16, 32, .82); backdrop-filter: blur(14px);
  padding: 20px; position: sticky; top: 76px;
}
.p-title { font-size: 12px; font-weight: 700; letter-spacing: 1.5px; color: var(--mut); margin-bottom: 10px; }
.p-title.mt { margin-top: 22px; }

/* chips */
.chip {
  display: flex; align-items: center; gap: 9px; padding: 9px 12px;
  border: 1px solid var(--line); border-radius: 11px; background: var(--panel); font-size: 13px;
}
.chip + .chip { margin-top: 8px; }
.ci { font-size: 11px; font-weight: 700; color: var(--blue); background: rgba(110, 143, 232, .13); padding: 2px 9px; border-radius: 99px; flex-shrink: 0; }
.ci.q { color: var(--ok); background: rgba(45, 212, 167, .12); }
.cn { font-weight: 600; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.cm { color: var(--mut); font-size: 11.5px; margin-left: auto; white-space: nowrap; }
.cx { border: none; background: none; color: var(--mut); cursor: pointer; font-size: 13px; padding: 2px 4px; flex-shrink: 0; }
.cx:hover { color: var(--err); }
.linklike {
  border: 1px dashed rgba(110, 143, 232, .4); background: none; color: var(--blue);
  font-size: 12.5px; font-weight: 600; border-radius: 10px; padding: 8px 12px;
  cursor: pointer; width: 100%; margin-top: 8px; transition: background .15s;
}
.linklike:hover { background: rgba(110, 143, 232, .1); }
.note { margin-top: 10px; font-size: 12px; color: var(--mut); background: var(--panel); border: 1px solid var(--line); border-radius: 10px; padding: 8px 11px; line-height: 1.7; }
.note b { color: var(--ink2); }

/* preview */
.pv { margin-top: 12px; }
.pv summary { font-size: 13px; font-weight: 600; cursor: pointer; user-select: none; color: var(--ink2); }
.lg { font-size: 11px; font-weight: 500; color: var(--mut); margin-left: 8px; }
.lg i { display: inline-block; width: 9px; height: 9px; border-radius: 3px; margin: 0 4px 0 10px; vertical-align: -1px; }
.lg i.a { background: var(--ctx); margin-left: 8px; }
.lg i.b { background: var(--qry); }
.ts { overflow: auto; border: 1px solid var(--line); border-radius: 10px; max-height: 240px; margin-top: 8px; }
.ts.tall { max-height: 380px; }
table { border-collapse: collapse; width: 100%; font-size: 12px; white-space: nowrap; }
thead th {
  position: sticky; top: 0; background: #10182e; color: var(--mut); font-weight: 600;
  text-align: left; padding: 7px 10px; border-bottom: 1px solid var(--line); z-index: 1;
}
tbody td { padding: 5px 10px; border-bottom: 1px solid rgba(255, 255, 255, .04); color: var(--ink2); font-variant-numeric: tabular-nums; }
tbody tr.rctx td:first-child { box-shadow: inset 3px 0 0 var(--ctx); }
tbody tr.rqry td:first-child { box-shadow: inset 3px 0 0 var(--qry); }
td.imp { background: rgba(45, 212, 167, .13); color: var(--ok); font-weight: 600; }

/* sliders / controls */
.split { margin-top: 14px; }
.split label { display: flex; justify-content: space-between; font-size: 12.5px; font-weight: 600; color: var(--ink2); }
.split output { color: var(--blue); font-weight: 700; }
input[type=range] { width: 100%; margin-top: 6px; accent-color: var(--blue); }
.sm { font-size: 11.5px; color: var(--mut); margin-top: 4px; line-height: 1.6; }

.tsel { display: grid; grid-template-columns: repeat(3, 1fr); gap: 7px; }
.tb {
  border: 1.5px solid var(--line); background: var(--panel); border-radius: 11px;
  padding: 10px 4px; cursor: pointer; font-size: 13px; font-weight: 700; color: var(--ink2); transition: all .13s;
}
.tb:hover { border-color: rgba(110, 143, 232, .5); }
.tb.active { border-color: var(--blue); background: rgba(110, 143, 232, .14); color: var(--blue); box-shadow: 0 0 18px rgba(110, 143, 232, .12); }
.tdesc { font-size: 11.5px; color: var(--mut); margin-top: 8px; }
.badge { display: inline-block; font-size: 11.5px; font-weight: 700; color: var(--ok); background: rgba(45, 212, 167, .1); border: 1px solid rgba(45, 212, 167, .35); padding: 2px 10px; border-radius: 99px; margin-top: 8px; }
/* advisory: the user's task choice cannot run on the chosen target column */
.twarn {
  margin-top: 8px; display: flex; flex-wrap: wrap; align-items: center; gap: 8px;
  font-size: 11.5px; line-height: 1.5; color: var(--warn);
  background: rgba(240, 179, 92, .09); border: 1px solid rgba(240, 179, 92, .32);
  border-radius: 10px; padding: 7px 10px;
}
.twarn-fix {
  flex-shrink: 0; border: 1px solid rgba(240, 179, 92, .5); background: rgba(240, 179, 92, .12);
  color: var(--warn); border-radius: 8px; padding: 2px 9px; font-size: 11px; font-weight: 700;
  cursor: pointer; transition: all .15s;
}
.twarn-fix:hover { background: rgba(240, 179, 92, .22); }
/* result card produced with settings other than the current panel state */
.rc-stale {
  font-size: 10.5px; font-weight: 700; color: var(--warn); white-space: nowrap;
  border: 1px solid rgba(240, 179, 92, .42); background: rgba(240, 179, 92, .1);
  border-radius: 99px; padding: 1px 8px; margin-left: 6px; flex-shrink: 0;
}

.frow { display: grid; grid-template-columns: 52px 1fr; gap: 8px; align-items: center; margin-top: 14px; }
.frow label { font-size: 12.5px; font-weight: 600; color: var(--ink2); }
.sel { padding: 8px 11px; font-size: 13px; border: 1.5px solid var(--line); border-radius: 10px; background: var(--bg2); color: var(--ink); outline: none; }
/* imputation has no target column: show why instead of an empty selector */
.tnote {
  margin-top: 10px; font-size: 11.5px; line-height: 1.55; color: var(--mut);
  border: 1px dashed var(--line2); border-radius: 10px; padding: 7px 10px;
}
.sel:focus { border-color: var(--blue); }

.run {
  width: 100%; margin-top: 18px; padding: 12px; border: none; border-radius: 12px;
  background: linear-gradient(135deg, var(--blue-d), #5a82e8); color: #fff;
  font-size: 15px; font-weight: 700; cursor: pointer;
  box-shadow: 0 6px 24px rgba(74, 111, 212, .35); transition: all .15s;
}
.run:hover:not(:disabled) { transform: translateY(-1px); box-shadow: 0 10px 30px rgba(74, 111, 212, .5); }
.run:disabled { opacity: .4; cursor: not-allowed; box-shadow: none; }
.rh { font-size: 11px; color: var(--mut); margin-top: 9px; text-align: center; }

/* ---------- run history ---------- */
.h-empty {
  border: 1px dashed var(--line2); border-radius: var(--r); padding: 60px 30px;
  text-align: center; color: var(--ink2);
}
.he-icon { font-size: 26px; color: var(--blue); text-shadow: 0 0 24px var(--blue-glow); margin-bottom: 12px; }
.he-sub { font-size: 13px; color: var(--mut); margin-top: 6px; }

.run-card {
  border: 1px solid var(--line); border-radius: var(--r);
  background: rgba(10, 16, 32, .82); backdrop-filter: blur(14px);
  margin-bottom: 18px; overflow: hidden;
  animation: rise .45s ease both;
}
@keyframes rise { from { opacity: 0; transform: translateY(14px); } }
.rc-head { display: flex; align-items: center; gap: 10px; padding: 13px 18px; border-bottom: 1px solid var(--line); cursor: pointer; user-select: none; }
.rc-head:hover { background: var(--panel); }
.rc-no {
  font-size: 11px; font-weight: 800; color: var(--blue); background: rgba(110, 143, 232, .13);
  border-radius: 8px; padding: 3px 9px; flex-shrink: 0;
}
.rc-title { font-size: 14px; font-weight: 700; }
.rc-meta { font-size: 11.5px; color: var(--mut); margin-left: auto; white-space: nowrap; }
.rc-fold { color: var(--mut); font-size: 12px; transition: transform .2s; flex-shrink: 0; }
.run-card.closed .rc-fold { transform: rotate(-90deg); }
.rc-body { padding: 16px 18px; }
.run-card.closed .rc-body { display: none; }

.mrow { display: grid; grid-template-columns: repeat(auto-fit, minmax(118px, 1fr)); gap: 9px; }
.mc { background: var(--panel); border: 1px solid var(--line); border-radius: 11px; padding: 10px 13px; }
.mc .l { font-size: 11px; color: var(--mut); font-weight: 600; }
.mc .v { font-size: 21px; font-weight: 800; color: var(--ink); margin-top: 1px; font-variant-numeric: tabular-nums; }
.mc .v.hl { color: var(--blue); text-shadow: 0 0 18px var(--blue-glow); }

.cgrid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 10px; margin-top: 10px; }
.cb { border: 1px solid var(--line); border-radius: 11px; padding: 12px 13px; background: var(--panel); }
.cb h4 { font-size: 12.5px; font-weight: 700; color: var(--ink2); margin-bottom: 6px; }
.cb svg { width: 100%; height: auto; display: block; }
.cb p { font-size: 12px; color: var(--mut); }
.cb { max-height: 380px; overflow: auto; }
.cb-cell { display: flex; flex-direction: column; min-width: 0; }
.cn-note { font-size: 11px; color: var(--mut); margin-top: 5px; line-height: 1.5; }

/* ---------- collapsible result tables ---------- */
.tbl {
  margin-top: 14px; border: 1px solid var(--line); border-radius: 11px;
  background: var(--panel); overflow: hidden;
}
.tbl > summary {
  display: flex; align-items: center; gap: 8px;
  padding: 10px 14px; cursor: pointer; user-select: none;
  font-size: 13px; font-weight: 700; color: var(--ink2);
  list-style: none;
}
.tbl > summary::-webkit-details-marker { display: none; }
.tbl > summary:hover { background: var(--panel2); }
.tbl-arrow {
  flex-shrink: 0; width: 0; height: 0;
  border-left: 5px solid var(--mut); border-top: 4px solid transparent; border-bottom: 4px solid transparent;
  transition: transform .18s ease;
}
.tbl[open] > summary .tbl-arrow { transform: rotate(90deg); }
.tbl-meta { margin-left: auto; font-size: 11.5px; font-weight: 500; color: var(--mut); font-variant-numeric: tabular-nums; }
.tbl-head {
  display: flex; align-items: center; gap: 8px; padding: 10px 14px;
  font-size: 13px; font-weight: 700; color: var(--ink2);
}
.tbl .ph { padding: 0 14px; margin: 6px 0 8px; }
.tbl .ts { max-height: 320px; margin: 0 14px 14px; }
.tbl.open .ts { max-height: 260px; }
td.rown, th.rown { color: var(--mut); font-weight: 600; text-align: right; width: 1%; white-space: nowrap; }

/* ---------- column picker (bounded-width matrix inspection) ---------- */
.colpick { padding: 4px 14px 10px; }
.cp-hint { font-size: 11.5px; color: var(--mut); margin-bottom: 8px; }
.cp-chips { display: flex; flex-wrap: wrap; gap: 6px; max-height: 116px; overflow: auto; }
.cp-chip {
  max-width: 160px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
  border: 1px solid var(--line2); background: transparent; color: var(--ink2);
  border-radius: 99px; padding: 4px 11px; font-size: 12px; font-weight: 600; cursor: pointer;
  transition: all .13s;
}
.cp-chip:hover { border-color: var(--blue); color: var(--blue); }
.cp-chip.on { background: rgba(110, 143, 232, .16); border-color: var(--blue); color: var(--blue); }

/* layout safety: no child may ever widen the card or the page */
.run-card, .rc-body, .tbl, .cb-cell, .cgrid > * { min-width: 0; max-width: 100%; }
.ts { width: 100%; }
.ts table { width: max-content; min-width: 100%; }

.hint {
  display: flex; gap: 9px; align-items: flex-start; margin-top: 12px;
  font-size: 12.5px; color: var(--ink2);
  border: 1px solid rgba(110, 143, 232, .28); border-radius: 11px;
  background: rgba(110, 143, 232, .07); padding: 10px 13px; line-height: 1.7;
}
.hint .hi { color: var(--blue); flex-shrink: 0; }

.ph { display: flex; justify-content: space-between; align-items: center; margin: 14px 0 8px; }
.ph h3 { font-size: 13px; font-weight: 700; color: var(--ink2); }
.lk { border: 1px solid var(--line2); background: none; border-radius: 8px; padding: 4px 12px; font-size: 12px; font-weight: 600; color: var(--blue); cursor: pointer; }
.lk:hover { background: rgba(110, 143, 232, .12); }

/* ---------- footer / toast ---------- */
.ft { border-top: 1px solid var(--line); padding: 22px; text-align: center; font-size: 12.5px; color: var(--mut); background: rgba(7, 11, 22, .6); }
.toast {
  position: fixed; left: 50%; bottom: 30px; transform: translateX(-50%); z-index: 90; max-width: 82vw;
  background: #1a2440; border: 1px solid var(--line2); color: var(--ink);
  font-size: 13.5px; padding: 11px 18px; border-radius: 12px; box-shadow: 0 10px 30px rgba(0, 0, 0, .5);
}
.toast.error { background: #3a1620; border-color: rgba(239, 106, 106, .4); }

/* ---------- lang toggle (DeepSeek-style) ---------- */
.lang-btn {
  display: inline-flex; align-items: center; gap: 6px;
  border: 1px solid var(--line2); background: var(--panel); color: var(--ink2);
  border-radius: 99px; padding: 5px 13px; font-size: 12.5px; font-weight: 700;
  cursor: pointer; transition: all .15s;
  min-width: 74px; justify-content: center;   /* "EN" / "中文" — nav never shifts */
}
.lang-btn:hover { border-color: var(--blue); color: var(--blue); }
.lg-ic { width: 15px; height: 15px; }

/* ---------- history panel ---------- */
.hist-wrap { border-top: 1px solid var(--line); margin-top: 20px; padding-top: 4px; }
.hist-note { display: flex; align-items: center; gap: 8px; margin-top: 8px; font-size: 11px; color: var(--mut); line-height: 1.5; }
.hist-restore {
  flex-shrink: 0; border: 1px solid var(--line2); background: var(--panel); color: var(--ink2);
  border-radius: 8px; padding: 2px 9px; font-size: 11px; font-weight: 600; cursor: pointer; transition: all .15s;
}
.hist-restore:hover { border-color: var(--blue); color: var(--blue); }
.hist-count { font-size: 11px; color: var(--mut); font-weight: 500; margin-left: 4px; }
.hist-clear {
  float: right; border: none; background: none; color: var(--mut);
  font-size: 11px; cursor: pointer; padding: 1px 4px;
}
.hist-clear:hover { color: var(--err); }
.he {
  display: flex; gap: 9px; align-items: center; padding: 8px 10px; margin-top: 6px;
  border: 1px solid var(--line); border-radius: 10px; background: var(--panel);
  cursor: pointer; transition: all .13s;
}
.he:hover { border-color: rgba(110, 143, 232, .45); background: var(--panel2); }
.he-no {
  font-size: 10.5px; font-weight: 800; color: var(--blue);
  background: rgba(110, 143, 232, .13); border-radius: 7px; padding: 2px 7px; flex-shrink: 0;
}
.he-info { min-width: 0; }
.he-info b { display: block; font-size: 12.5px; font-weight: 600; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.he-info small { display: block; font-size: 11px; color: var(--mut); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.he-kv { margin-left: auto; font-size: 11px; font-weight: 700; color: var(--ok); flex-shrink: 0; }

/* ---------- recent (hero) ---------- */
.recent { margin-top: 26px; }
.recent-t { font-size: 12px; font-weight: 700; letter-spacing: 1.5px; color: var(--mut); margin-bottom: 10px; }
#recent-list { display: flex; gap: 8px; justify-content: center; flex-wrap: wrap; }
.rc-chip {
  display: inline-flex; align-items: center; gap: 7px;
  border: 1px solid var(--line2); background: var(--panel); border-radius: 99px;
  padding: 6px 14px; font-size: 12.5px; color: var(--ink2); cursor: pointer; transition: all .15s;
}
.rc-chip:hover { border-color: var(--blue); color: var(--blue); background: rgba(110, 143, 232, .1); }
.rc-chip b { color: var(--blue); font-weight: 700; }

@media (max-width: 640px) {
  .hero { padding: 0 18px; }
  .hero h1 { font-size: clamp(32px, 9vw, 44px); }
  .sub { font-size: 14.5px; }
  .kicker { font-size: 11px; letter-spacing: 1.6px; padding: 5px 14px; }
  .cta-row { margin-top: 26px; }
  .drop { padding: 20px 24px; min-width: 100%; }
  .drop span { font-size: 15px; }
  .drop small { font-size: 11.5px; }
  .ex-row { margin-top: 18px; }
  .scroll-cue { margin-top: 26px; }

  /* finale: bounded height so the wordmark never floats over the copy */
  .finale { padding: 0 18px 4.5vh; }
  .fin-tag { font-size: 17px; letter-spacing: .5px; }
  .cta2 { margin-top: 12px; padding: 10px 24px; font-size: 14px; }
  .finale .edu {
    margin-top: 3vh; display: flex; gap: 10px; overflow-x: auto;
    scroll-snap-type: x mandatory; padding-bottom: 8px; scrollbar-width: none;
  }
  .finale .edu::-webkit-scrollbar { display: none; }
  .finale .edu-card { min-width: 80%; scroll-snap-align: center; padding: 14px 16px; }
  .finale .edu-card p { font-size: 12.5px; }

  .edu { grid-template-columns: 1fr; margin-top: 40px; }
  .panel { position: static; }
  .cm { display: none; }
}

/* landscape phones / very short viewports: drop the cards entirely */
@media (max-height: 560px) and (max-width: 900px) {
  .finale .edu { display: none; }
  .fin-tag { font-size: 15px; }
}