@font-face{font-family:MathSerif;src:url(/assets/KaTeX_Main-Regular-B22Nviop.woff2) format("woff2");font-display:swap}:root{--text-caption:14px;--text-small:15px;--text-ui:16px;--text-body:17px;--text-lead:18px;font-family:Inter,-apple-system,BlinkMacSystemFont,Segoe UI,Apple SD Gothic Neo,Noto Sans KR,sans-serif;color:#202723;background:#f8f9f5;font-synthesis:none;--paper:#f8f9f5;--ink:#202723;--muted:#59645d;--line:#dee3dc;--blue:#294fc4;--serif:MathSerif,Georgia,serif}*{box-sizing:border-box}body{margin:0;font-size:var(--text-body);line-height:1.6}button,input,select,textarea{font:inherit}button,a,input{-webkit-tap-highlight-color:transparent}button,a{touch-action:manipulation}button{cursor:pointer}a{color:inherit;text-decoration:none}button{color:inherit}button:disabled{cursor:default;opacity:.45}svg{display:block}button svg,a svg{width:20px;height:20px;flex:none}a:focus-visible,button:focus-visible,input:focus-visible,summary:focus-visible{outline:2px solid var(--blue);outline-offset:5px}input[type=range]{accent-color:var(--blue);cursor:pointer}input[type=checkbox]{accent-color:var(--blue)}[hidden]{display:none!important}h1,h2,h3,p{margin:0}h1,h2,h3{font-weight:550;word-break:keep-all}p{line-height:1.7;word-break:keep-all}h1{letter-spacing:-.065em}button{border:0;background:none}.skip-link{position:fixed;left:20px;top:-80px;z-index:100;background:var(--blue);padding:12px 20px;color:#fff}.skip-link:focus{top:12px}.site-header{height:100px;border-bottom:1px solid var(--line);display:flex;align-items:center;gap:48px;padding:0 5.5vw;max-width:1800px;margin:auto}.brand{display:flex;align-items:center;gap:11px;font-size:24px;font-weight:650;letter-spacing:-1px;white-space:nowrap}.brand-mark{background:var(--blue);color:#fff;font-family:var(--serif);font-size:38px;border-radius:50%;width:40px;height:40px;display:grid;place-content:center;line-height:1;padding-bottom:5px}.brand-by{display:block;font-size:var(--text-caption);letter-spacing:1.4px;text-transform:uppercase;font-weight:450;color:var(--muted);margin-top:4px}.site-header nav{display:flex;align-items:center;gap:36px;margin:auto;font-size:var(--text-lead)}.site-header nav a{padding:12px 0;position:relative;color:#5e6761}.site-header nav a:hover,.site-header nav a[aria-current]{color:var(--blue)}.site-header nav a[aria-current]:after{content:"";position:absolute;height:2px;bottom:2px;background:var(--blue);left:0;right:0}.header-start{display:flex;align-items:center;gap:16px;font-size:var(--text-body);border-bottom:1px solid #a3aba3;padding:8px 0}.header-start svg{width:18px}main{min-height:65vh;outline:none}main>section,main>.math-workspace,main>.workspace-bottom,main>.lesson-steps,main>.source-details{max-width:1280px;margin-left:auto;margin-right:auto}.eyebrow{text-transform:uppercase;font-size:var(--text-small);font-weight:550;letter-spacing:1.5px;color:#68786c;display:flex;align-items:center;gap:12px}.small-rule{height:1px;width:24px;background:#809b85}.home-hero{display:grid;grid-template-columns:1fr 1.04fr;gap:60px;align-items:center;min-height:600px;padding:54px 0 62px}.hero-copy h1{font-size:clamp(38px,4.1vw,61px);line-height:1.36;margin:26px 0 25px}.hero-description{font-size:16px;color:#6c756e;line-height:1.9}.hero-actions{display:flex;align-items:center;gap:24px;margin-top:35px}.button{display:inline-flex;align-items:center;justify-content:center;gap:20px;border:1px solid var(--line);padding:14px 20px;min-height:46px;font-size:var(--text-body);font-weight:550;white-space:nowrap}.button.primary{background:var(--blue);border-color:var(--blue);color:#fff}.button:hover{filter:brightness(.96)}.button svg,.text-link svg{transition:transform .18s ease}.button:hover svg,.text-link:hover svg{transform:translate(3px)}.text-link{display:inline-flex;gap:10px;align-items:center;font-size:var(--text-body);white-space:nowrap}.hero-note{display:block;font-size:var(--text-small);color:#8a928d;margin-top:22px}.hero-visual{min-width:0;padding:20px 0 0;position:relative}.visual-heading{display:flex;justify-content:space-between;font-size:var(--text-caption);letter-spacing:.8px;color:#7c857e;padding:0 14px 0 24px}.visual-heading span:first-child{color:#465b4e}.function-preview{width:100%;height:auto}.preview-grid{stroke:#e5e9e2;fill:none;stroke-width:.7}.preview-axis{stroke:#85968b;fill:none;stroke-width:1}.preview-reference{stroke:#c4cfca;fill:none;stroke-width:1.5;stroke-dasharray:4 5}.preview-curve{stroke:var(--blue);fill:none;stroke-width:2.5;stroke-linecap:round}.preview-labels{font:12px var(--serif);fill:#7e8b82}.curve-label{font:italic 24px var(--serif);fill:var(--blue)}.hero-slider{display:flex;align-items:center;gap:18px;margin:1px 30px 0;font-size:var(--text-small);color:#748177}.hero-slider label{display:flex;align-items:center;gap:12px;white-space:nowrap}.hero-slider output{font-variant-numeric:tabular-nums;min-width:23px;color:#35473c}.hero-slider input{min-width:50px;flex:1}.math-letter{font:italic 24px var(--serif);color:var(--ink)}.concept-section{padding:50px 0 48px;border-top:1px solid var(--line)}.section-heading{display:flex;align-items:end;justify-content:space-between;gap:24px;margin-bottom:30px}.section-heading h2{font-size:29px;letter-spacing:-1.2px;margin-top:13px}.section-heading>.text-link{color:var(--muted)}.concept-row{display:grid;grid-template-columns:45px minmax(210px,1fr) minmax(150px,.7fr) 145px;align-items:center;gap:20px;padding:27px 4px;border-bottom:1px solid var(--line);transition:background .2s,padding .2s}.concept-row:hover{background:#eff2ea;padding-left:14px;padding-right:14px}.concept-number{font:13px var(--serif);color:#8b968d;align-self:start;padding-top:5px}.concept-name .eyebrow{font-size:var(--text-caption);letter-spacing:.7px}.concept-name h3{font-size:20px;letter-spacing:-.65px;margin:8px 0}.concept-name p{font-size:var(--text-ui);color:#7b827c}.row-formula{font:italic 22px var(--serif);color:#697e6d;white-space:nowrap;text-align:center}.row-action{display:flex;align-items:center;justify-content:end;gap:10px;font-size:var(--text-ui);color:#636f65}.row-action svg{width:17px}.learning-way{display:grid;grid-template-columns:1fr 1.1fr;padding:64px 0 85px;gap:90px}.learning-way h2{font-size:34px;line-height:1.5;letter-spacing:-1.8px;margin-top:20px}.learning-way ol{list-style:none;padding:0;margin:0;display:grid;gap:25px}.learning-way li{display:flex;align-items:start;gap:30px}.learning-way li>span{font:13px var(--serif);color:#8b998d;padding-top:4px}.learning-way h3{font-size:16px;margin-bottom:8px}.learning-way p{font-size:var(--text-body);color:var(--muted)}.site-footer{border-top:1px solid var(--line);margin:0 auto;max-width:1800px;padding:35px 5.5vw;display:flex;align-items:center;gap:40px;font-size:var(--text-small);color:#7d877e}.footer-brand{font-size:16px;letter-spacing:-.4px;color:#48574c}.footer-brand span{font-size:var(--text-caption);letter-spacing:0;margin-left:8px}.site-footer>span{margin-left:auto}.page-intro{padding:65px 0 44px}.page-intro h1{font-size:46px;margin:20px 0}.page-intro p:not(.eyebrow){font-size:15px;color:var(--muted)}.catalog{padding-bottom:90px;min-height:55vh}.catalog-tools{display:flex;justify-content:space-between;align-items:center;padding:18px 0;border-top:1px solid var(--line);border-bottom:1px solid var(--line);font-size:var(--text-ui);color:var(--muted)}.search-box{display:flex;align-items:center;gap:14px}.search-box svg{width:16px;height:16px;transform:rotate(-45deg)}.search-box input{background:transparent;border:0;padding:10px 0;font-size:var(--text-body);width:230px;outline-offset:2px}.quiet-note{display:flex;gap:20px;margin-top:40px;padding:20px 0;font-size:var(--text-body);color:var(--muted)}.quiet-note strong{font-weight:500;color:#3f5444}#search-empty{padding:60px 0;text-align:center}.notebook-page{padding-bottom:70px}.notebook-page>.section-heading{font-size:var(--text-body);color:var(--muted)}.empty-notes{border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:75px 24px;text-align:center}.empty-equation{font:italic 42px var(--serif);color:#b1bda9;display:block;margin-bottom:25px}.empty-notes h2{font-size:23px}.empty-notes p{font-size:var(--text-body);color:var(--muted);margin:14px 0 22px}.empty-notes a{color:var(--blue)}.storage-footnote{margin-top:22px;font-size:var(--text-ui);color:var(--muted)}.note-row{display:flex;align-items:center;border-top:1px solid var(--line);gap:24px}.note-row>a{display:flex;align-items:center;gap:24px;flex:1;padding:26px 0;min-width:0}.note-row h2{font-size:18px;overflow-wrap:anywhere}.note-row p{font-size:var(--text-ui);color:var(--muted);margin-top:8px}.note-row a>svg{margin-left:auto}.note-symbol{font:italic 35px var(--serif);color:var(--blue);width:45px}.subtle-button{font-size:var(--text-small);color:var(--muted);padding:8px}.loading-state{padding:120px 8vw;color:var(--muted);font-size:var(--text-lead)}#main{animation:arrive .3s ease}.hero-visual{animation:arrive .65s ease}.concept-row svg{transition:transform .18s}.concept-row:hover svg{transform:translate(4px)}@keyframes arrive{0%{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}@media (min-width:1550px){.home-hero{min-height:680px}}@media (max-width:1430px){main>section,main>.math-workspace,main>.workspace-bottom,main>.lesson-steps,main>.source-details{margin-left:5.5vw;margin-right:5.5vw}.hero-actions{gap:18px}.hero-actions .text-link{font-size:var(--text-ui)}.home-hero{gap:40px}.hero-slider>span{font-size:var(--text-caption)}}@media (max-width:1000px){.site-header{gap:24px;height:86px}.site-header nav{gap:22px;margin-left:auto;margin-right:0}.header-start{display:none}.home-hero{gap:20px;min-height:530px}.hero-copy h1{font-size:42px}.hero-actions{align-items:start;flex-direction:column;gap:18px}.hero-slider{margin:0 8px;gap:10px}.hero-slider>span{display:none}.hero-description{font-size:var(--text-lead)}.concept-row{grid-template-columns:30px 1fr 180px;gap:15px}.row-action{grid-column:2/4;justify-content:start;margin-top:0}.row-formula{font-size:20px}.learning-way{gap:45px}.site-footer{gap:20px;flex-wrap:wrap}.site-footer>span{margin-left:0}}@media (max-width:650px){.site-header{height:78px;padding:0 6vw;gap:12px;flex-wrap:wrap;align-content:center}.brand{font-size:18px;gap:8px}.brand-mark{height:31px;width:31px;font-size:30px}.brand-by{font-size:var(--text-caption);letter-spacing:1px;margin-top:2px}.site-header nav{gap:16px;font-size:var(--text-small)}.site-header nav a{padding:8px 0}.home-hero{grid-template-columns:1fr;padding:38px 0 32px;gap:24px}.hero-copy h1{font-size:41px;margin:20px 0}.eyebrow{font-size:var(--text-caption);letter-spacing:1px}.hero-description{font-size:var(--text-lead)}.hero-actions{flex-direction:row;align-items:center;gap:16px;margin-top:25px}.button{font-size:var(--text-small);padding:12px 14px;gap:12px}.hero-actions .text-link{font-size:var(--text-caption);gap:4px}.hero-actions .text-link svg{width:15px}.hero-note{font-size:var(--text-caption);margin-top:15px}.hero-visual{padding-top:8px}.visual-heading{padding:0 12px;font-size:var(--text-caption)}.hero-slider{margin:0 20px}.hero-slider>span{display:block;font-size:var(--text-caption)}.concept-section{padding:34px 0}.section-heading{align-items:center;gap:12px;margin-bottom:18px}.section-heading h2{font-size:24px}.section-heading .text-link{font-size:var(--text-caption);gap:4px}.concept-row{grid-template-columns:22px 1fr;gap:12px;padding:23px 0}.concept-number{font-size:var(--text-small)}.concept-name h3{font-size:18px}.concept-name p{font-size:var(--text-ui)}.row-formula{grid-column:2;text-align:left;font-size:22px;margin:4px 0;color:var(--blue)}.row-action{grid-column:2;font-size:var(--text-small)}.concept-row:hover{padding-left:0;padding-right:0}.learning-way{grid-template-columns:1fr;gap:34px;padding:36px 0 50px}.learning-way h2{font-size:29px;margin-top:14px}.learning-way li{gap:20px}.site-footer{padding:26px 6vw;display:grid;gap:10px;font-size:var(--text-caption)}.page-intro{padding:36px 0 28px}.page-intro h1{font-size:34px;line-height:1.4;margin:15px 0}.page-intro p:not(.eyebrow){font-size:var(--text-body)}.catalog-tools{align-items:start;gap:14px;flex-direction:column}.search-box,.search-box input{width:100%}.quiet-note{flex-direction:column;gap:8px;font-size:var(--text-ui)}.empty-notes{padding:55px 12px}.empty-notes h2{font-size:20px}.note-row{gap:10px}.note-row>a{gap:15px}.note-row h2{font-size:16px}.note-symbol{width:26px}.storage-footnote{font-size:var(--text-small)}}@media (prefers-reduced-motion:reduce){*,*:before,*:after{animation:none!important;transition:none!important;scroll-behavior:auto!important}}.skip-link:not(:focus){clip-path:inset(50%);width:1px;height:1px;overflow:hidden;white-space:nowrap;padding:0}@media (max-width:650px){.site-header{height:auto;min-height:92px;padding-top:14px;padding-bottom:10px;gap:10px 20px}.site-header nav{width:100%;margin:0;justify-content:space-between;gap:12px;font-size:var(--text-ui)}.site-header nav a{padding:6px 0}}.site-header{height:auto;min-height:90px;padding-block:14px}.site-header nav{flex-wrap:wrap}.hero-actions,.workspace-top-actions{flex-wrap:wrap}.text-link{white-space:normal}.site-footer{line-height:1.7}@media (max-width:650px){.site-header{min-height:112px}.hero-actions,.section-heading{flex-wrap:wrap}}.gallery-heading{display:flex;justify-content:space-between;align-items:center;gap:24px;padding:44px 0 32px}.gallery-heading h1{font-size:36px;margin:14px 0}.gallery-heading p:not(.eyebrow){font-size:var(--text-lead);color:var(--muted)}.graph-gallery{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:36px 28px;padding-bottom:40px}.graph-example{min-width:0;display:block}.graph-example>svg{width:100%;height:auto;background:#eef2ed;transition:background .18s}.graph-example:hover>svg{background:#e5ece4}.thumbnail-axis{stroke:#cfd8d0;stroke-width:.7;fill:none}.thumbnail-curves{fill:none;stroke-width:1.6;stroke-linejoin:round}.graph-example>div{padding:16px 0}.example-category{font-size:var(--text-caption);color:var(--muted)}.graph-example h2{font-size:20px;margin:7px 0;letter-spacing:-.6px}.graph-example p{font-size:var(--text-ui);color:var(--muted)}.example-open{display:flex;align-items:center;gap:12px;font-size:var(--text-ui);color:var(--blue);margin-top:15px}.example-open svg{width:16px}.gallery-learning{border-top:1px solid var(--line);padding:25px 0 45px;display:flex;gap:25px;font-size:var(--text-body);color:var(--muted)}.studio-examples{padding:28px 0 35px}.example-strip{display:grid;grid-template-columns:repeat(6,minmax(0,1fr));gap:18px}.example-strip .graph-example h2{font-size:var(--text-body)}.example-strip .graph-example>div{padding:8px 0}.example-strip .example-category{font-size:var(--text-caption)}.example-save-hint{font-size:var(--text-small);color:var(--muted);margin-top:12px}.graph-studio{--studio-gap:28px}.graph-studio .workspace-heading{padding:20px 0;gap:16px}.graph-studio .workspace-heading h1{font-size:23px;margin-top:7px;letter-spacing:-.8px}.graph-studio .math-workspace{grid-template-columns:minmax(330px,.7fr) minmax(0,1.3fr);min-height:0}.graph-studio .formula-panel{padding:18px var(--studio-gap) 20px 0}.graph-studio .graph-panel{padding:18px 0 20px var(--studio-gap)}.graph-studio .note-title-label{margin-bottom:12px}.graph-studio .note-title-label input{font-size:19px;padding:8px 0}.graph-studio .panel-heading{margin-bottom:12px}.graph-studio .expression-line{min-height:66px;padding:10px 0}.graph-studio .math-hint{margin:12px 0 22px}.graph-studio .parameter{margin:15px 0}.graph-studio .parameters{margin-top:6px}.graph-studio .parameter-heading{margin-bottom:12px}.graph-studio .domain{margin-top:20px;padding-top:18px;gap:10px}.graph-studio .graph-caption{margin-top:4px;padding-top:14px}.graph-studio .workspace-bottom{padding:18px 0}.graph-studio .source-details{padding-bottom:12px}.graph-studio .graph-bottom{padding:10px 7px}.graph-studio .graph-panel{align-self:start;position:sticky;top:16px}.site-header{height:78px}.graph-studio+.site-footer{margin-top:0}@media (min-width:1431px){.graph-studio>section,.graph-studio>.math-workspace,.graph-studio>.workspace-bottom,.graph-studio>.source-details{max-width:1440px;margin-left:4vw;margin-right:4vw}}@media (max-width:1050px){.graph-studio .math-workspace{grid-template-columns:minmax(300px,.85fr) minmax(0,1.15fr)}.graph-studio{--studio-gap:18px}.example-strip{grid-template-columns:repeat(3,minmax(0,1fr))}.graph-gallery{gap:25px 18px}}@media (max-width:800px){.graph-studio .math-workspace{display:flex;flex-direction:column}.graph-studio .graph-panel{order:-1;width:100%;position:static;padding:12px 0;border-top:0;border-bottom:1px solid var(--line)}.graph-studio .formula-panel{padding:18px 0;width:100%;border:0}.graph-studio #learning-graph{max-height:46svh;min-height:0;width:auto;max-width:100%;margin:auto}.graph-studio .graph-caption{display:none}.graph-studio .workspace-top-actions{flex-direction:row;flex-wrap:wrap;justify-content:end;max-width:210px}.graph-studio #save-status{order:3;max-width:100%;width:100%;text-align:right}.graph-studio .workspace-top-actions>.text-link{font-size:var(--text-small)}.gallery-heading h1{font-size:29px}.graph-gallery{grid-template-columns:repeat(2,minmax(0,1fr))}.graph-studio .workspace-heading h1{font-size:22px}}@media (max-width:500px){.gallery-heading{padding:30px 0 22px;align-items:start}.gallery-heading h1{font-size:27px;line-height:1.4}.gallery-heading p:not(.eyebrow){font-size:var(--text-ui)}.graph-gallery{gap:20px 14px}.graph-example h2{font-size:16px}.graph-example p{font-size:var(--text-small)}.gallery-learning{flex-direction:column;gap:12px}.example-strip{grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}.studio-examples .section-heading{align-items:start}.graph-studio .workspace-top-actions{max-width:180px;gap:8px}.graph-studio .workspace-heading{gap:8px}.site-header nav{gap:14px}.graph-studio .graph-bottom{gap:10px}}.graph-studio .expression-line:has(.me-matrix){display:grid;grid-template-columns:minmax(0,1fr);gap:8px}.graph-studio .expression-line:has(.me-matrix) .expression-label{font-size:20px}.graph-studio .expression-line:has(.me-matrix) .remove-formula{position:absolute;right:0;top:10px}.graph-studio .expression-line:has(.me-matrix) .math-expression{width:100%;padding-left:10px}