:root{
  --nn-blue:#3157d5;--nn-blue-2:#2448b8;--nn-ink:#172033;--nn-muted:#667085;
  --nn-line:#d8dfec;--nn-paper:#fffef8;--nn-green:#067647;--nn-red:#b42318;
  --nn-cell:44px;--nn-grid:rgba(70,116,180,.22);--nn-orange:#b54708;
}
*{box-sizing:border-box}
button,input{font:inherit}
button{cursor:pointer}
.nn{
  --nn-shell-height:650px;
  width:100%;
  margin:0;
  padding:12px 12px 12px 58px;
  position:relative;
  display:flex;
  flex-direction:column;
  height:var(--nn-shell-height);
  min-height:var(--nn-shell-height);
  max-height:var(--nn-shell-height);
  overflow:hidden;
  background:#fff;
  color:var(--nn-ink);
  font-family:ui-rounded,"SF Pro Rounded",Inter,system-ui,sans-serif;
  container-type:inline-size;
}
.nn h2{margin:0 0 10px;font-size:clamp(23px,3vw,32px);line-height:1.15}
.nn-progress{position:absolute;left:16px;top:72px;bottom:18px;width:34px;display:flex;flex-direction:column;align-items:center;gap:10px;z-index:4}
.nn-progress::before{content:"";position:absolute;top:15px;bottom:15px;left:50%;width:2px;transform:translateX(-50%);background:#e4e7ec;z-index:-1}
.nn-stage-pill{width:31px;height:31px;min-height:31px;border-radius:50%;border:2px solid #d7deea;background:#fff;color:var(--nn-muted);font-weight:850;font-size:12px;display:grid;place-items:center;box-shadow:0 0 0 4px #fff;padding:0}
.nn-stage-pill[data-state=current]{background:var(--nn-blue);border-color:var(--nn-blue);color:#fff;box-shadow:0 0 0 4px #edf2ff;transform:scale(1.08)}
.nn-stage-pill[data-state=done]{background:#12b76a;border-color:#12b76a;color:#fff}
.nn-stage-pill[data-state=todo]{opacity:.52}
.nn-toolbar{
  display:flex;
  flex:0 0 auto;
  flex-wrap:wrap;
  align-items:center;
  gap:8px;
  margin:0 0 8px;
}
.nn-icon{
  flex:0 0 44px;width:44px;min-height:44px;padding:0;
  border:1px solid #d8dfec;border-radius:12px;background:#fff;color:#243451;
  display:grid;place-items:center;font-size:20px;
}
.nn-icon:hover:not(:disabled){border-color:var(--nn-blue);background:#f5f7ff}
.nn-icon[aria-pressed="true"]{background:#eef6f2;border-color:#d8e9df}
.nn-repeat{padding:0 8px;white-space:nowrap;font-size:12px;min-height:44px;border:1px solid #d8dfec;border-radius:12px;background:#fff;color:#243451;font-weight:750}
.nn-skip{margin-left:auto;white-space:nowrap;font-size:12px;padding:0 10px;min-height:44px;border:1px solid #d8dfec;border-radius:12px;background:#fff;color:#475467}
.nn-primary{
  min-height:42px;
  padding:8px 14px;
  border:1px solid var(--nn-blue);
  border-radius:12px;
  background:var(--nn-blue);
  color:#fff;
  font-weight:800;
}
.nn-primary:hover:not(:disabled){background:var(--nn-blue-2);border-color:var(--nn-blue-2)}
.nn-tool{
  display:inline-flex;
  align-items:center;
  gap:8px;
  min-height:42px;
  padding:6px 12px 6px 6px;
  border:0;
  border-radius:13px;
  background:#fff;
  color:#1d2939;
  box-shadow:0 1px 2px rgba(16,24,40,.06),0 0 0 1px rgba(16,24,40,.04);
  font-size:13px;
  font-weight:750;
}
.nn-tool:hover:not(:disabled){background:#f8fafc;box-shadow:0 4px 10px rgba(16,24,40,.08),0 0 0 1px rgba(49,87,213,.16)}
.nn-tool-icon{display:grid;width:30px;height:30px;flex:0 0 auto;place-items:center;border-radius:10px;background:#eef2ff;color:#3538cd}
.nn-tool[aria-pressed="true"] .nn-tool-icon{background:#d1fadf;color:var(--nn-green)}
.nn-tool-ghost{padding:6px 12px;background:transparent;box-shadow:none;color:#475467;font-weight:650}
.nn-admin-scrub{
  display:inline-flex;
  align-items:center;
  gap:8px;
  margin-left:auto;
  padding:4px 8px;
  border:1px dashed #9db4f3;
  border-radius:12px;
  background:#f5f8ff;
}
.nn-admin-scrub button{
  min-width:42px;
  min-height:36px;
  border:1px solid #d8dfec;
  border-radius:10px;
  background:#fff;
  font-weight:900;
}
.nn-admin-slide{min-width:4.5em;text-align:center;font-size:12px;font-weight:800;color:#2448b8;font-variant-numeric:tabular-nums}
.nn-phase{min-height:20px;margin:0 0 10px;color:var(--nn-muted);font-size:13px;font-weight:800}
.nn-paper{position:relative;flex:1 1 auto;min-height:0;border:1px solid #d8e2f1;border-radius:18px;padding:18px;background-color:var(--nn-paper);background-image:linear-gradient(var(--nn-grid) 1px,transparent 1px),linear-gradient(90deg,var(--nn-grid) 1px,transparent 1px);background-size:var(--nn-cell) var(--nn-cell);overflow:hidden;box-shadow:inset 0 0 0 1px rgba(70,116,180,.05)}
.nn-scene{min-height:340px;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:16px;text-align:center;position:relative;overflow:hidden}
.nn-card{width:min(760px,96%);background:rgba(255,255,255,.93);border:1px solid #e4e7ec;border-radius:18px;padding:22px;box-shadow:0 8px 28px rgba(16,24,40,.06)}
.nn-big-example{font-size:clamp(38px,7vw,72px);font-weight:900;letter-spacing:.01em;font-variant-numeric:tabular-nums;margin:5px 0 14px}
.nn-big-example .nn-minus-sign{display:inline-block;color:var(--nn-red);transform-origin:center}
.nn-big-example[data-pulse=true] .nn-minus-sign{animation:nnPulse .72s ease-in-out 2}
.nn-explain{font-size:clamp(18px,2.3vw,25px);line-height:1.45;font-weight:700;margin:0 auto;max-width:820px}
.nn-explain strong{color:#183a9c}
.nn-expression{min-height:64px;width:min(100%,920px);max-width:100%;display:flex;align-items:center;justify-content:center;flex-wrap:nowrap;white-space:nowrap;overflow:hidden;padding:10px 22px;border-radius:16px;background:#fff;border:1px solid #dbe4ff;font-size:clamp(22px,5.2vw,52px);font-weight:900;font-variant-numeric:tabular-nums;box-shadow:0 8px 24px rgba(49,87,213,.06)}
.nn-expression .nn-answer{color:var(--nn-blue);display:inline-block;flex:0 0 auto;white-space:nowrap}
.nn-expression .nn-answer[data-pop=true]{animation:nnAnswerPop .6s cubic-bezier(.2,.8,.2,1)}
.nn-hint{display:none!important}
.nn-actions{display:flex;flex-wrap:wrap;gap:8px;margin-top:10px;align-items:center}
.nn-primary,.nn-secondary,.nn-choice{min-height:44px;border-radius:12px;padding:9px 14px;font-weight:800;border:1px solid #d8dfec;background:#fff;color:#243451}
.nn-primary{background:var(--nn-blue);border-color:var(--nn-blue);color:#fff}
.nn-primary:hover{background:var(--nn-blue-2)}
.nn-secondary:hover,.nn-choice:hover{border-color:#9db4f3;background:#f5f7ff}
.nn-streak{margin-left:auto;font-size:13px;font-weight:850;color:#475467;background:#f2f4f7;border-radius:999px;padding:7px 12px}
.nn-input-wrap{display:flex;gap:8px;justify-content:center;align-items:center;flex-wrap:nowrap;width:100%;max-width:100%}
.nn-answer-input{width:min(132px,36vw);flex:0 0 auto;height:54px;text-align:center;border:2px solid #9db4f3;border-radius:13px;background:#fff;font-size:28px;font-weight:900;color:var(--nn-ink);outline:none}
.nn-answer-input:focus{box-shadow:0 0 0 4px #edf2ff;border-color:var(--nn-blue)}
.nn-rule{width:min(780px,96%);background:#fff;border:1px solid #dbe4ff;border-radius:18px;padding:16px 20px;text-align:left;box-shadow:0 8px 26px rgba(49,87,213,.06)}
.nn-rule-title{font-size:16px;color:#2448b8;font-weight:900;margin-bottom:7px}
.nn-rule-main{font-size:clamp(19px,2.3vw,27px);font-weight:850;line-height:1.35}
.nn-rule-sub{margin-top:8px;color:#475467;line-height:1.4}
.nn-math-steps{display:flex;flex-wrap:nowrap;justify-content:center;align-items:center;gap:8px;width:min(100%,920px);max-width:100%;overflow:hidden;font-size:clamp(16px,3.6vw,42px);font-weight:900;white-space:nowrap}
.nn-step-chip{padding:8px 13px;border-radius:14px;background:#fff;border:1px solid #dbe4ff;transition:.25s transform,.25s box-shadow,.25s background;flex:0 1 auto;min-width:0;white-space:nowrap}
.nn-step-chip[data-active=true]{transform:scale(1.06);background:#edf2ff;box-shadow:0 0 0 4px rgba(49,87,213,.12)}
.nn-arrow{font-size:28px;color:#667085}
.nn-complete{width:min(720px,96%);padding:26px;border-radius:20px;background:#ecfdf3;border:1px solid #abefc6}
.nn-complete h3{font-size:28px;margin:0 0 8px;color:#05603a}
.nn-hidden{display:none!important}

/* number line */
.nn-axis-wrap{width:min(920px,100%);padding:22px 18px 34px;background:rgba(255,255,255,.94);border:1px solid #e4e7ec;border-radius:18px;box-shadow:0 8px 28px rgba(16,24,40,.06);overflow:visible;position:relative}
.nn-axis-context{min-height:34px;font-size:20px;font-weight:850;color:#2448b8;margin-bottom:4px}
.nn-axis{height:138px;position:relative;margin:8px 24px 0}
.nn-axis-line{position:absolute;left:0;right:0;top:57px;height:4px;background:#344054;border-radius:4px}
.nn-axis-line::before,.nn-axis-line::after{content:"";position:absolute;top:50%;width:12px;height:12px;border-top:4px solid #344054;border-right:4px solid #344054}
.nn-axis-line::before{left:-1px;transform:translateY(-50%) rotate(-135deg)}
.nn-axis-line::after{right:-1px;transform:translateY(-50%) rotate(45deg)}
.nn-ticks{position:absolute;inset:0;display:grid;grid-template-columns:repeat(21,1fr)}
.nn-tick{position:relative;height:118px;border:0;background:transparent;padding:0;min-width:0;color:var(--nn-ink)}
.nn-tick::before{content:"";position:absolute;left:50%;top:44px;width:3px;height:28px;background:#344054;transform:translateX(-50%);border-radius:2px;transition:.2s}
.nn-tick[data-zero=true]::before{height:38px;top:39px;background:var(--nn-blue)}
.nn-tick-label{position:absolute;left:50%;top:83px;transform:translateX(-50%);min-width:30px;padding:2px 4px;border-radius:7px;font-size:17px;font-weight:900;opacity:0;transition:.25s;white-space:nowrap}
.nn-tick[data-show=true] .nn-tick-label{opacity:1}
.nn-tick[data-highlight=true]::before{background:var(--nn-blue);height:42px;top:37px;box-shadow:0 0 0 6px rgba(49,87,213,.12)}
.nn-tick[data-highlight=true] .nn-tick-label{opacity:1;color:#fff;background:var(--nn-blue);transform:translateX(-50%) scale(1.12)}
.nn-tick[data-clickable=true]:hover::before{background:#3157d5;box-shadow:0 0 0 6px rgba(49,87,213,.1)}
.nn-marker{position:absolute;top:17px;left:50%;width:30px;height:30px;border-radius:50%;background:#f04438;color:#fff;display:grid;place-items:center;font-size:11px;font-weight:900;transform:translateX(-50%);box-shadow:0 5px 14px rgba(240,68,56,.25);opacity:0;transition:left .65s cubic-bezier(.2,.8,.2,1),opacity .2s,transform .25s;z-index:5}
.nn-marker[data-show=true]{opacity:1}
.nn-marker[data-pulse=true]{animation:nnMarkerPulse .6s ease-in-out 2}
.nn-edge-result{position:absolute;left:-10px;top:7px;padding:8px 12px;border-radius:12px;background:#fff0ed;color:#b42318;border:1px solid #f1a29b;font-size:18px;font-weight:900;opacity:0;transform:translateX(10px);transition:.4s}
.nn-edge-result[data-show=true]{opacity:1;transform:translateX(-18px)}
.nn-axis-note{margin-top:0;color:#667085;font-size:13px;font-weight:700}

@keyframes nnPulse{0%,100%{transform:scale(1)}50%{transform:scale(1.18);color:#f04438}}
@keyframes nnAnswerPop{0%{transform:translateY(-8px) scale(.85);opacity:0}65%{transform:translateY(2px) scale(1.06)}100%{transform:none;opacity:1}}
@keyframes nnMarkerPulse{0%,100%{transform:translateX(-50%) scale(1)}50%{transform:translateX(-50%) scale(1.28)}}
@media(max-width:720px){
 .nn{padding:10px 8px 10px 46px}
 .nn .ng-progress{left:7px;top:58px;bottom:10px;width:30px;gap:8px}
 .nn-paper{padding:8px;min-height:0}
 .nn-card{padding:14px}
 .nn-axis-wrap{padding:12px 4px 24px;width:100%}
 .nn-axis{margin-left:8px;margin-right:8px}
 .nn-tick-label{font-size:12px;min-width:20px}
 .nn-expression{font-size:clamp(20px,6.2vw,32px);padding:8px 12px;min-height:52px}
 .nn-math-steps{gap:6px;font-size:clamp(14px,4.2vw,22px)}
 .nn-step-chip{padding:6px 8px}
 .nn-arrow{font-size:18px;flex:0 0 auto}
 .nn-toolbar{gap:6px;flex-wrap:nowrap;overflow-x:auto;scrollbar-width:none}
 .nn-toolbar::-webkit-scrollbar{display:none}
 .nn-tool{font-size:12px;flex:0 0 auto}
 .nn-primary{flex:0 0 auto;white-space:nowrap}
 .nn-tool-ghost{white-space:nowrap}
 .nn-streak{margin-left:0;flex:0 0 auto}
 .nn-phase{white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
 .nn-axis-context{font-size:16px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
 .nn-input-wrap .nn-primary{padding:9px 12px;white-space:nowrap}
}
@media(prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}}

.nn h2{margin:0 0 8px;font-size:clamp(20px,2.4vw,28px);line-height:1.15;font-weight:850}
.nn .ng-progress button{
  flex:0 0 30px;width:30px;height:30px;min-height:30px;max-height:30px;
  padding:0;border-radius:50%;font-size:11px;font-weight:800;line-height:1;
}
.nn .ng-progress button[data-state=todo]{opacity:.55}
.nn[data-admin="1"] .ng-progress button[data-state=todo]{opacity:1}
.nn-work{flex:1 1 auto;min-height:0;overflow:auto;overscroll-behavior:contain;scrollbar-width:thin}