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solid var(--line);border-radius:11px;max-width:100%}.data-preview table{border-collapse:collapse;font-size:12.5px;width:100%;white-space:nowrap}.data-preview th{background:#f6f6fc;color:#667089;text-align:left}.data-preview th,.data-preview td{padding:8px 11px;border-bottom:1px solid #eceef5}.data-preview tr:last-child td{border-bottom:0}.task{border-top:1px solid #edf0f6;padding:15px 0}.task:last-child{padding-bottom:0}.task strong{font-size:15px}.task p{font-size:13.5px;color:#949bad;line-height:1.9;margin:4px 0}.task-answer{padding:12px;background:#f6f5ff;border-radius:10px;color:#5b5d9b;font-size:13.5px;line-height:1.9;margin-top:9px}.task details summary{cursor:pointer;color:#6a65db;font-size:13.5px;font-weight:750;margin-top:8px}.glossary-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:11px}.glossary-item{padding:18px 20px}.glossary-item strong{font-size:15.5px;display:block}.glossary-item em{font-style:normal;font-size:13.5px;color:var(--accent);margin-left:5px}.glossary-item p{font-size:13.5px;color:#8e97a7;margin:6px 0 0;line-height:1.85}.tool-switch{display:flex;gap:7px;margin-bottom:19px;flex-wrap:wrap}.settings-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:17px}.setting{padding:25px}.setting h3{font-size:19px;margin-bottom:9px}.setting p{font-size:15px;color:#99a1b0;line-height:1.9}.setting .btn{margin-top:10px}.file-input{display:none}.notes-list{display:flex;flex-direction:column;gap:9px}.note-row{padding:13px 16px;border:1px solid #ebedf6;border-radius:10px;cursor:pointer;display:flex;gap:10px;justify-content:space-between;align-items:center}.note-row:hover{border-color:#bbb5fa}.note-row b{font-size:15px}.note-row small{color:#9fa8b6}.separator{height:1px;background:var(--line);margin:17px 0}.source-list a{display:block;padding:13px 15px;border:1px solid var(--line);border-radius:9px;margin-top:8px}.source-list a:hover{border-color:#b5adf2}.source-list strong{font-size:15px;color:#6560d1}.source-list p{font-size:12.5px;color:#9ba4b4;margin:3px 0 0}.section-inset{padding:23px}.feature-list{display:grid;grid-template-columns:repeat(3,1fr);gap:13px}.feature{padding:17px}.feature b{display:block;font-size:15.5px;margin-bottom:7px}.feature p{font-size:13.5px;color:#929cae;margin:0;line-height:1.85}.lesson-switches{display:flex;justify-content:space-between;gap:15px;margin-top:16px}.lesson-switches .btn{max-width:50%}#toast{position:fixed;bottom:27px;right:27px;background:#26304e;color:#fff;border-radius:11px;padding:11px 16px;font-size:15px;box-shadow:0 12px 35px #111a3c40;z-index:100;opacity:0;transform:translateY(12px);pointer-events:none;transition:.2s}#toast.show{opacity:1;transform:none}.shade{display:none}::selection{background:#ddd8ff;color:#292253}
@media(max-width:1240px){.course-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.hero-art{width:195px}.glass-card.art-one{width:190px}.metrics{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:950px){.sidebar{width:215px}.workspace{margin-left:215px;width:calc(100% - 215px)}main{padding:27px 27px 65px}.topbar{padding:0 27px}.footer{padding:18px 27px}.hero{padding:28px}.hero h1{font-size:32px}.hero-art{display:none}.split,.method-grid{grid-template-columns:1fr}.lesson-layout{grid-template-columns:1fr}.lesson-side{position:static}.bottom-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:740px){.sidebar{width:260px;transform:translateX(-105%);transition:transform .22s;box-shadow:0 12px 60px #13152b20}.sidebar.open{transform:none}.shade{display:none}.shade.open{display:block;position:fixed;inset:0;background:#17182d72;z-index:25}.workspace{margin:0;width:100%}.mobile-toggle{display:block}.topbar{padding:0 19px;height:60px}.top-right .top-mode,.top-divider{display:none}.top-left{gap:10px}main{padding:22px 16px 55px}.footer{padding:16px 16px 23px;flex-direction:column;gap:2px}.hero{padding:30px 25px;min-height:240px}.hero h1{font-size:30px}.metrics{gap:10px;margin:14px 0 22px}.metric{padding:17px}.metric strong{font-size:27px}.bottom-grid,.course-grid,.lab-grid,.glossary-grid,.settings-grid,.feature-list{grid-template-columns:1fr}.toolbar{align-items:stretch}.searchbox{width:100%}.filter-tabs{gap:5px}.tab{padding:7px 9px}.page-head{align-items:flex-start;flex-direction:column}.page-head h1{font-size:30px}.lesson-hero{padding:24px}.lesson-hero h1{font-size:27px}.lesson-block{padding:20px}.lesson-side .card{padding:20px}.method-form,.method-result{padding:20px}}


/* StatLab V1.1 — comfortable reading, accessible controls, dual theme */
:root {
  color-scheme: light;
  --text-secondary:#606d84;
  --text-tertiary:#7a879d;
  --panel-tint:#f5f3ff;
  --table-line:#e8ecf4;
  --nav-hover:#f3f0ff;
  --nav-active:#eeeaff;
  --focus-ring:rgba(100,92,244,.35);
}
body {font-size:16px; line-height:1.75; -webkit-font-smoothing:antialiased;}
button,input,select,textarea {line-height:1.5;}
button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible {
  outline:3px solid var(--focus-ring); outline-offset:2px;
}
.sidebar{width:268px;padding-top:29px;}
.workspace{margin-left:268px;width:calc(100% - 268px);}
.identity{padding-bottom:39px;}
.side-nav a{padding:12px 13px;}
.topbar{min-height:77px;height:auto;padding-top:10px;padding-bottom:10px;}
.top-left{min-width:0;}
.crumb-here{max-width:360px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;}
.top-right{gap:12px;flex-shrink:0;}
.nav-ico{font-size:21px;}
main{padding-top:40px;}
.page-sub{line-height:1.8;}
.hero p{font-size:16px;}
.btn{min-height:42px;font-size:14px;padding:10px 17px;}
.btn.sm{min-height:37px;font-size:13px;padding:8px 13px;}
.metric .metric-top{font-size:14px;}
.metric small{font-size:13px;}
.phase-description strong{font-size:15px;}
.phase-description span,.phase-count{font-size:13px;}
.course-card{min-height:224px;}
.course-card p{font-size:14.5px;line-height:1.8;}
.course-end{font-size:13px;}
.lesson-layout{grid-template-columns:minmax(0,1fr) 252px;gap:19px;}
.lesson-wrap{max-width:1120px;}
.lesson-block{padding:27px 30px;}
.lesson-block h2{font-size:21px;}
.context-block,.steps li,.bullets,.warning{font-size:16px;}
.steps li{padding-bottom:18px;padding-left:42px;}
.steps li:before{width:27px;height:27px;font-size:13px;}
.quiz-option{font-size:15px;padding:13px 15px;}
.quiz-feedback{font-size:15px;}
.lesson-side h3{font-size:16px;}
.lesson-side .btn{font-size:14px;}
.small-muted,.form-tip{font-size:14px;}
.codebox{font-size:13.5px;line-height:1.85;}
.field label{font-size:15px;}
.result-description,.method-extras p{font-size:15px;}
.dataset p,.task p,.glossary-item p,.setting p,.feature p{font-size:14.5px;}
.data-preview table{font-size:13.5px;line-height:1.5;}
.data-preview th,.data-preview td{padding:11px 13px;}
.searchbox input,.input,.select,.textarea{font-size:15px;}
.textarea{line-height:1.85;}
.pill{font-size:12px;padding:5px 9px;}
.status-pill{font-size:12px;}
.top-mode{font-size:13px;}
.crumb-base{font-size:12px;}
.crumb-here{font-size:13px;}
/* All visitors can toggle theme from the fixed header on desktop and mobile. */
.theme-toggle{display:inline-flex;align-items:center;justify-content:center;gap:9px;
  border:1px solid var(--line);border-radius:12px;padding:9px 13px;min-height:40px;
  background:var(--card);color:var(--ink);font-weight:750;font-size:13.5px;
  box-shadow:var(--shadow);white-space:nowrap;transition:background .2s,border-color .2s,color .2s;
}
.theme-toggle:hover{border-color:var(--accent);background:var(--soft);}
.theme-icon{font-size:18px;line-height:1;width:20px;display:inline-grid;place-items:center;}
.theme-toggle .theme-text{display:inline-block;}
/* Keep text readable on narrow screens without forcing horizontal scrolling. */
@media(max-width:1240px){
  .sidebar{width:238px;}.workspace{margin-left:238px;width:calc(100% - 238px);}
  .topbar{padding-left:25px;padding-right:25px;}
  main{padding-left:26px;padding-right:26px;}
}
@media(max-width:1060px){
  .offline-badge,.mini-avatar{display:none;}
  .crumb-here{max-width:220px;}
}
@media(max-width:950px){
  .sidebar{width:226px;}.workspace{margin-left:226px;width:calc(100% - 226px);}
  .lesson-layout{grid-template-columns:1fr;}
  .topbar{padding-left:23px;padding-right:23px;}
  .hero h1{font-size:33px;}
}
@media(max-width:740px){
  .sidebar{width:min(290px,85vw);}
  .workspace{margin:0;width:100%;}
  .topbar{padding:10px 15px;min-height:64px;}
  .top-right{gap:6px;}
  .crumb-base{display:none;}.crumb-sep{display:none;}
  .crumb-here{max-width:145px;font-size:13px;}
  .theme-toggle{padding:8px 10px;min-height:38px;gap:4px;}
  .theme-toggle .theme-text{font-size:12px;}
  main{padding:22px 15px 55px;}
  .hero{padding:27px 23px;}
  .hero h1{font-size:29px;}
  .hero p{font-size:15px;}
  .lesson-block{padding:22px 20px;}
  .course-card p{font-size:14px;}
  .context-block,.steps li,.bullets,.warning{font-size:15.5px;}
  .data-preview table{font-size:13px;}
}
@media(max-width:360px){
  .crumb-here{max-width:105px;}
  .theme-toggle .theme-text{display:none;}
  .theme-toggle{width:39px;padding:7px;}
}

/* Night theme: tuned for reading statistics long-term, not just inverted colors. */
html[data-theme="dark"]{
  color-scheme:dark;
  --ink:#edf1fc;
  --muted:#b0bed5;
  --thin:#8697b3;
  --accent:#aca2ff;
  --accent-dark:#887ef5;
  --bg:#0d1321;
  --white:#202b43;
  --line:#2b3850;
  --card:#192339;
  --side:#121b2e;
  --soft:#282746;
  --shadow:0 12px 35px rgba(0,0,0,.17);
  --text-secondary:#bcc8dd;
  --text-tertiary:#a0afca;
  --panel-tint:#242942;
  --table-line:#2b3850;
  --nav-hover:#212b42;
  --nav-active:#302d56;
  --focus-ring:rgba(172,162,255,.55);
}
html[data-theme="dark"] body{background:var(--bg);color:var(--ink);}
html[data-theme="dark"] .sidebar{background:var(--side);border-right-color:var(--line);}
html[data-theme="dark"] .topbar{background:rgba(18,27,46,.9);border-bottom-color:var(--line);}
html[data-theme="dark"] .card{background:var(--card);border-color:var(--line);}
html[data-theme="dark"] .side-nav a{color:#bac6dd;}
html[data-theme="dark"] .side-nav a:hover{background:var(--nav-hover);color:#e1dcff;}
html[data-theme="dark"] .side-nav a.active{background:var(--nav-active);color:#d1caff;}
html[data-theme="dark"] .nav-pill{background:#42386e;color:#d9d2ff;}
html[data-theme="dark"] .side-label,html[data-theme="dark"] .sidebar-bottom span,
html[data-theme="dark"] .crumb-base,html[data-theme="dark"] .crumb-sep{color:#96a5be;}
html[data-theme="dark"] .identity small{color:#a5b3ca;}
html[data-theme="dark"] .sidebar-bottom p,html[data-theme="dark"] .top-mode,
html[data-theme="dark"] .crumb-here,html[data-theme="dark"] .icon-button{color:#c0cbe0;}
html[data-theme="dark"] .slogan-mark{color:#8e7ef0;}
html[data-theme="dark"] .mode-container{background:#0e1728;border-color:var(--line);}
html[data-theme="dark"] .mode-choice{color:#bbc6df;}
html[data-theme="dark"] .mode-choice.active{background:#343250;color:#d7ceff;box-shadow:none;}
html[data-theme="dark"] .offline-badge{background:#1a3c37;color:#9ce8c3;}
html[data-theme="dark"] .top-divider{background:var(--line);}
html[data-theme="dark"] .mini-avatar{background:#38325a;color:#d7ceff;}
html[data-theme="dark"] .footer{color:#9ba9c3;}
html[data-theme="dark"] .kicker{color:#b5adff;}
html[data-theme="dark"] .btn:not(.secondary):not(.ghost):not(.danger){background:#7770e8;color:#fff;}
html[data-theme="dark"] .btn:not(.secondary):not(.ghost):not(.danger):hover{background:#8e85ff;}
html[data-theme="dark"] .btn.secondary{background:#252f49;border-color:#435072;color:#dad5ff;}
html[data-theme="dark"] .btn.secondary:hover{background:#303455;}
html[data-theme="dark"] .btn.ghost{color:#c9c1ff;border-color:#534c7b;}
html[data-theme="dark"] .btn.ghost:hover{background:#302c51;}
html[data-theme="dark"] .btn.danger{background:#49293d;color:#ffc0cb;}
html[data-theme="dark"] .btn.danger:hover{background:#633047;}
html[data-theme="dark"] .hero{background:linear-gradient(115deg,#24264e 0%,#1d345b 64%,#2c2a55 100%);}
html[data-theme="dark"] .hero .btn{background:#fff;color:#4e47d3;}
html[data-theme="dark"] .hero .btn:hover{background:#eeebff;}
html[data-theme="dark"] .metric .metric-top,html[data-theme="dark"] .metric small,
html[data-theme="dark"] .phase-description span,html[data-theme="dark"] .phase-count,
html[data-theme="dark"] .course-no,html[data-theme="dark"] .course-card p,
html[data-theme="dark"] .course-end,html[data-theme="dark"] .dataset p,
html[data-theme="dark"] .task p,html[data-theme="dark"] .glossary-item p,
html[data-theme="dark"] .setting p,html[data-theme="dark"] .feature p,
html[data-theme="dark"] .source-list p,html[data-theme="dark"] .small-muted,
html[data-theme="dark"] .form-tip,html[data-theme="dark"] .result-heading,
html[data-theme="dark"] .result-description,html[data-theme="dark"] .method-extras strong,
html[data-theme="dark"] .method-extras p,html[data-theme="dark"] .field label,
html[data-theme="dark"] .action-card p,html[data-theme="dark"] .note-card p,
html[data-theme="dark"] .eyebrow,html[data-theme="dark"] .empty,
html[data-theme="dark"] .note-row small,html[data-theme="dark"] .back-button{
  color:var(--text-secondary);
}
html[data-theme="dark"] .metric-top .tile-icon,html[data-theme="dark"] .action-icon,
html[data-theme="dark"] .phase-num,html[data-theme="dark"] .dataset-icon,
html[data-theme="dark"] .steps li:before,
html[data-theme="dark"] .lesson-block h2 .circle-index{
  background:#343153;color:#c6beff;
}
html[data-theme="dark"] .progress-track{background:#303a52;}
html[data-theme="dark"] .phase-row,html[data-theme="dark"] .course-end,
html[data-theme="dark"] .method-extras,html[data-theme="dark"] .task{
  border-color:var(--line);
}
html[data-theme="dark"] .note-card{background:linear-gradient(145deg,#242e3b,#1b263d);}
html[data-theme="dark"] .note-mark{background:#55482c;}
html[data-theme="dark"] .pill{background:#37325b;color:#d9d2ff;}
html[data-theme="dark"] .pill.green{background:#1f483e;color:#a9efcd;}
html[data-theme="dark"] .pill.yellow{background:#4d3b2d;color:#f0c886;}
html[data-theme="dark"] .pill.gray,html[data-theme="dark"] .status-pill{
  background:#2f3a50;color:#cad4e6;
}
html[data-theme="dark"] .searchbox,html[data-theme="dark"] .input,
html[data-theme="dark"] .select,html[data-theme="dark"] .textarea,
html[data-theme="dark"] .tab{background:#131d32;border-color:#39475f;color:#e7edf9;}
html[data-theme="dark"] .searchbox input{color:#e7edf9;}
html[data-theme="dark"] input::placeholder,html[data-theme="dark"] textarea::placeholder{color:#99a9c1;opacity:1;}
html[data-theme="dark"] .tab.active{background:#7770e8;color:white;border-color:#7770e8;}
html[data-theme="dark"] .course-card:hover,html[data-theme="dark"] .action-card:hover,
html[data-theme="dark"] .note-row:hover,html[data-theme="dark"] .source-list a:hover{border-color:#8e82f9;}
html[data-theme="dark"] .context-block{background:#252b46;border-color:#444370;color:#dce3f6;}
html[data-theme="dark"] .steps li,html[data-theme="dark"] .bullets{color:#d8e0f1;}
html[data-theme="dark"] .warning{background:#4b3c29;border-color:#6b5330;color:#ffe1a6;}
html[data-theme="dark"] .quiz-option{background:#192741;color:#d8e3f8;border-color:#344666;}
html[data-theme="dark"] .quiz-option b{background:#303d56;color:#d4e0f5;}
html[data-theme="dark"] .quiz-option.picked{background:#343156;border-color:#a79bff;}
html[data-theme="dark"] .quiz-option.correct{background:#1b4a40;border-color:#4fb990;}
html[data-theme="dark"] .quiz-feedback{background:#2b3152;color:#dcd9ff;}
html[data-theme="dark"] .codebox{background:#10192e;color:#d1defe;border:1px solid #344363;}
html[data-theme="dark"] .data-preview{border-color:var(--line);}
html[data-theme="dark"] .data-preview th{background:#293653;color:#e1e8fa;}
html[data-theme="dark"] .data-preview td,html[data-theme="dark"] .data-preview th{border-bottom-color:#37445e;}
html[data-theme="dark"] .task-answer{background:#302d52;color:#e5ddff;}
html[data-theme="dark"] .task details summary,html[data-theme="dark"] .source-list strong{color:#c3b9ff;}
html[data-theme="dark"] .note-row,html[data-theme="dark"] .source-list a{border-color:var(--line);}
html[data-theme="dark"] .separator{background:var(--line);}
html[data-theme="dark"] #toast{background:#d9d5ff;color:#17182d;}
html[data-theme="dark"] ::selection{background:#736bd7;color:#fff;}
@media(prefers-reduced-motion:reduce){
  *,*::before,*::after{scroll-behavior:auto!important;transition-duration:0.01ms!important;animation-duration:0.01ms!important;}
}

/* V1.1 mobile dataset fix: wide variable tables scroll inside their own panel. */
.lab-grid,.dataset{min-width:0;}
.data-preview{display:block;max-width:100%;min-width:0;overflow-x:auto;overscroll-behavior-x:contain;}
@media(max-width:740px){
  .lab-grid{grid-template-columns:minmax(0,1fr);}
  .dataset{width:100%;}
}

/* Contact and feedback entry */
.sidebar-contact{width:100%;display:flex;align-items:center;gap:10px;border:1px solid #e5e3fb;background:#f7f6ff;color:#505878;border-radius:12px;padding:11px 12px;margin:0 0 25px;text-align:left;transition:.18s;box-shadow:0 7px 20px rgba(73,66,163,.06)}.sidebar-contact span{letter-spacing:normal}
.sidebar-contact:hover{border-color:#bdb7fc;background:#efedff;transform:translateY(-1px)}
.contact-entry-icon{width:33px;height:33px;border-radius:9px;display:grid;place-items:center;background:#e8e5ff;color:#5f57dd;font-size:16px;flex-shrink:0}
.contact-entry-copy{min-width:0;flex:1}.contact-entry-copy strong{display:block;color:var(--ink);font-size:14px;line-height:1.35}.contact-entry-copy small{display:block;color:#929caf;font-size:11.5px;line-height:1.45;margin-top:2px}.contact-entry-arrow{color:#8c94a8;font-size:22px;line-height:1}
body.modal-open{overflow:hidden}.contact-layer[hidden]{display:none}.contact-layer{position:fixed;inset:0;z-index:120;display:grid;place-items:center;padding:22px}.contact-backdrop{position:absolute;inset:0;border:0;background:rgba(20,23,45,.55);backdrop-filter:blur(4px)}
.contact-card{position:relative;width:min(500px,100%);background:var(--card);border:1px solid var(--line);border-radius:20px;box-shadow:0 24px 80px rgba(16,20,48,.25);padding:27px;color:var(--ink)}
.contact-card-head{display:flex;align-items:flex-start;justify-content:space-between;gap:18px}.contact-card-head h2{margin:4px 0 0;font-size:24px}.contact-close{width:38px;height:38px;border-radius:10px;border:1px solid var(--line);background:var(--white);color:var(--muted);font-size:25px;line-height:1;display:grid;place-items:center}.contact-close:hover{background:var(--soft);color:var(--ink)}
.contact-intro{color:var(--muted);font-size:14.5px;line-height:1.8;margin:14px 0 19px}.contact-item{border:1px solid var(--line);background:var(--white);border-radius:13px;padding:14px;margin-top:11px}.contact-item-label{font-size:12px;color:var(--text-tertiary);font-weight:800;letter-spacing:.5px;margin-bottom:7px}.contact-item-actions{display:flex;align-items:center;gap:8px}.contact-copy{min-width:0;flex:1;display:flex;align-items:center;justify-content:space-between;gap:12px;border:0;background:transparent;color:var(--ink);padding:4px 2px;text-align:left}.contact-copy span{font-size:14.5px;overflow-wrap:anywhere}.contact-copy b{color:var(--accent);font-size:12px;white-space:nowrap}.contact-copy:hover span{color:var(--accent)}.contact-mail{font-size:12px;font-weight:800;color:var(--accent);white-space:nowrap;padding:6px 8px;border-left:1px solid var(--line)}.contact-note{font-size:12px;color:var(--text-tertiary);line-height:1.7;margin:15px 2px 0}
html[data-theme="dark"] .sidebar-contact{background:#1b2740;border-color:#34415c;color:#c6d0e2;box-shadow:none}html[data-theme="dark"] .sidebar-contact:hover{background:#252d4b;border-color:#766ced}html[data-theme="dark"] .contact-entry-icon{background:#353058;color:#cec7ff}html[data-theme="dark"] .contact-entry-copy small{color:#a3b0c8}html[data-theme="dark"] .contact-backdrop{background:rgba(3,7,17,.7)}html[data-theme="dark"] .contact-item{background:#131d32}html[data-theme="dark"] .contact-close{background:#131d32}
@media(max-width:740px){.sidebar-contact{margin-bottom:22px}.contact-layer{place-items:end center;padding:12px}.contact-card{width:100%;max-height:calc(100vh - 24px);overflow:auto;border-radius:18px;padding:23px 19px}.contact-item-actions{align-items:stretch}.contact-copy span{font-size:14px}.contact-mail{display:flex;align-items:center}}