@import url('https://fonts.googleapis.com/css2?family=Nanum+Gothic:wght@400;700;800&display=swap');
.intro .wrap{position:relative}.blog-mascot{position:absolute;right:22px;bottom:0;display:flex;flex-direction:column;align-items:center;gap:5px}.blog-mascot img{width:94px;height:94px;border-radius:50%;object-fit:cover}.blog-mascot span{font-size:10px;color:#65776c}@media(max-width:760px){.blog-mascot{right:0;bottom:0}.blog-mascot img{width:62px;height:62px}.blog-mascot span{display:none}}@media(max-width:360px){.blog-mascot{bottom:4px}.blog-mascot img{width:48px;height:48px}}
:root{--ink:#233934;--muted:#61706b;--green:#205a50;--line:#dce5df;--paper:#fafcfb;--mint:#edf5f0}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:95px}body{margin:0;background:var(--paper);color:var(--ink);font-family:'Nanum Gothic','Malgun Gothic',sans-serif;font-size:15px;line-height:1.8;letter-spacing:0}a{color:inherit;text-decoration:none}button{font:inherit;cursor:pointer}a,button,summary{-webkit-tap-highlight-color:transparent}button,a,summary{touch-action:manipulation}:focus-visible{outline:3px solid #c57c43;outline-offset:5px}h1,h2,h3,p{margin:0}h1{font-size:46px;line-height:1.3;font-weight:800;margin:12px 0 18px}h2{font-size:29px;line-height:1.45;margin:5px 0 12px;font-weight:800}h3{font-size:19px;line-height:1.5}p{color:var(--muted)}.wrap{width:min(1120px,calc(100% - 64px));margin:auto}.eyebrow{font-size:11px;font-weight:800;color:var(--green)}header{position:sticky;top:0;z-index:20;background:rgba(250,252,251,.97);border-bottom:1px solid var(--line)}.header-inner{display:flex;align-items:center;justify-content:space-between;min-height:84px;gap:20px}.brand{font-size:23px;font-weight:800;white-space:nowrap}.brand span{display:block;font-size:9px;color:var(--muted);line-height:1.3}nav{display:flex;gap:26px;align-items:center}nav a{font-size:13px;font-weight:700;display:flex;align-items:center;gap:3px}nav a:hover,.text-link:hover{color:#a55445}svg{width:18px;height:18px;flex-shrink:0}.icon-button{width:44px;height:44px;align-items:center;justify-content:center;background:none;border:1px solid var(--line);border-radius:4px}#menu{display:none}.intro{padding:49px 0 43px;border-bottom:1px solid var(--line);background:#f6f9f7 url('assets/math-banner.png') no-repeat right center;background-size:auto 180px}.intro .wrap{background:linear-gradient(90deg,#f6f9f7 0%,#f6f9f7 48%,transparent 76%)}.lead{font-size:24px;line-height:1.65;color:var(--ink);font-weight:700}.intro-copy{margin-top:16px;font-size:14px}.actions{display:flex;gap:24px;align-items:center;flex-wrap:wrap;margin-top:25px}.button{min-height:46px;display:inline-flex;align-items:center;justify-content:center;gap:12px;padding:11px 19px;border-radius:4px;font-size:13px;font-weight:700}.primary{background:var(--green);color:#fff}.primary:hover{background:#123d35}.text-link{display:inline-flex;align-items:center;gap:8px;font-size:13px;font-weight:700}.section{padding:68px 0;border-bottom:1px solid var(--line)}.section-head{display:flex;justify-content:space-between;align-items:flex-end;gap:24px;margin-bottom:27px}.section-head p:not(.eyebrow){font-size:14px}.filters{display:flex;gap:8px;margin-bottom:24px;flex-wrap:wrap}.filters button{border:1px solid var(--line);background:transparent;color:var(--muted);padding:8px 17px;border-radius:4px;font-size:13px;min-height:42px}.filters .active{background:var(--ink);border-color:var(--ink);color:white}.resource-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:24px;min-height:320px}.resource-card{border:1px solid var(--line);border-radius:6px;overflow:hidden;background:#fff;padding:0 24px 24px;display:flex;align-items:flex-start;flex-direction:column}.resource-art{height:85px;margin:0 -24px 20px;width:calc(100% + 48px);display:flex;align-items:center;justify-content:center}.resource-art svg{height:32px;width:32px;stroke-width:1.3}.mint{background:#e9f2ec;color:#32695b}.blue{background:#eaf0f7;color:#476b8f}.rose{background:#f7edec;color:#a26760}.resource-meta{font-size:11px;font-weight:700;margin-bottom:7px}.resource-card h3{margin-bottom:10px}.resource-card>p:not(.resource-meta){font-size:13px;line-height:1.8;margin-bottom:20px}.resource-card a{margin-top:auto}.small-note{font-size:12px;color:var(--muted)}.section>.wrap>.small-note{margin-top:20px}.tint{background:#f0f5f2}.app-layout{display:grid;grid-template-columns:1.35fr 1fr;gap:48px;align-items:center}.app-preview{display:block;border:1px solid #d1ded7;border-radius:6px;overflow:hidden;background:white}.app-preview img{display:block;width:100%;height:auto;aspect-ratio:1.6;object-fit:cover;object-position:top}.tag{display:inline-block;font-size:11px;font-weight:700;padding:3px 9px;border:1px solid #cbd6cf;border-radius:3px;white-space:nowrap}.green{color:var(--green);background:#e0ece3}.app-details h3{margin:14px 0 12px;font-size:22px}.app-details>p{font-size:14px}.app-details .small-note{font-size:11px;margin-top:12px}.simple-list{list-style:none;padding:0;margin:20px 0;font-size:13px}.simple-list li{padding:6px 0}.simple-list span{font-size:11px;color:#688275;margin-right:10px}.paper-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:32px;margin-top:35px}.paper-grid article{padding:0 24px 0 0;border-right:1px solid var(--line)}.paper-grid article:last-child{border:0}.paper-grid svg{width:28px;height:28px;color:var(--green);margin-bottom:15px}.paper-grid h3{margin-bottom:10px}.paper-grid p{font-size:14px}.paper-grid small{display:block;font-size:11px;color:#777e74;margin-top:16px}.lesson-band{background:#f1f4f8}.lesson-band h2{font-size:33px}.lesson-intro{max-width:700px;font-size:15px}.facts{display:grid;grid-template-columns:repeat(3,1fr);margin:30px 0;border-top:1px solid #d4dde0;border-bottom:1px solid #d4dde0;padding:22px 0}.facts strong{display:block;font-size:25px}.facts span{font-size:12px;color:var(--muted)}.lesson-points{display:grid;grid-template-columns:repeat(3,1fr);gap:35px;margin-bottom:28px}.lesson-points h3{font-size:16px;margin-bottom:8px}.lesson-points p{font-size:13px}details{border-top:1px solid #d4dde0;border-bottom:1px solid #d4dde0;padding:15px 0}summary{font-weight:700;cursor:pointer;font-size:14px}details p{font-size:13px;margin-top:12px}.teacher-layout{display:grid;grid-template-columns:1fr 1.7fr;gap:60px}.teacher-layout .text-link{margin-top:18px}.teacher-copy p{margin-top:16px;font-size:14px}.contact-band{background:#edf3ef}.contact-layout{display:flex;justify-content:space-between;gap:35px;align-items:center}.contact-layout p{font-size:14px}.contact-layout .small-note{font-size:12px;margin-top:15px}.contact-actions{display:flex;align-items:flex-start;flex-direction:column;gap:12px;min-width:220px}footer{padding:30px 0;background:#fff}.footer-inner{display:flex;justify-content:space-between;gap:25px;font-size:12px}.footer-inner p{font-size:11px;margin-top:5px}.skip{position:fixed;left:12px;top:-100px;padding:10px;background:white;z-index:100}.skip:focus{top:10px}@media(min-width:1600px){.intro{background-position:calc(50% + 380px) center}}@media(max-width:950px){nav{gap:14px}nav a{font-size:12px}.app-layout{gap:25px}.wrap{width:calc(100% - 40px)}.resource-card{padding-left:18px;padding-right:18px}.resource-art{margin-left:-18px;margin-right:-18px;width:calc(100% + 36px)}}@media(max-width:760px){html{scroll-padding-top:85px}.header-inner{min-height:72px}.brand{font-size:21px}#menu{display:flex}nav{display:none;position:absolute;top:72px;left:0;right:0;background:var(--paper);border-bottom:1px solid var(--line);padding:15px 24px;box-shadow:0 8px 12px #2339340a}nav.open{display:flex;flex-direction:column;align-items:stretch;gap:0}nav a{font-size:14px;padding:11px 0}.intro{padding:34px 0;background-image:none}.intro .wrap{background:none}h1{font-size:38px;margin:8px 0 15px}.lead{font-size:20px}.intro-copy{font-size:13px}.actions{gap:18px}.section{padding:44px 0}h2{font-size:25px}.section-head{display:block}.section-head>.text-link,.section-head>.tag{margin-top:17px}.resource-grid{grid-template-columns:1fr;min-height:0;gap:18px}.resource-art{height:66px}.resource-card{padding-bottom:20px}.resource-card h3{font-size:19px}.resource-card>p:not(.resource-meta){margin-bottom:14px}.app-layout{grid-template-columns:1fr}.app-details h3{font-size:21px}.paper-grid{grid-template-columns:1fr;gap:24px}.paper-grid article{border-right:0;border-bottom:1px solid var(--line);padding-bottom:24px}.paper-grid svg{margin-bottom:8px}.lesson-band h2{font-size:29px}.facts{gap:10px}.facts strong{font-size:20px}.facts span{font-size:11px}.lesson-points{grid-template-columns:1fr;gap:20px}.teacher-layout{grid-template-columns:1fr;gap:25px}.contact-layout{display:block}.contact-actions{margin-top:24px}.footer-inner{flex-direction:column}.intro .actions{align-items:flex-start;flex-direction:column;gap:15px}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}