:root{--ink:#17233d;--muted:#657089;--navy:#213e77;--blue:#4268aa;--pale:#f4f7fc;--line:#dce4f0;--white:#fff;--accent:#e8efff;--green:#e9f7ef;--orange:#fff4e4;--shadow:0 8px 28px rgba(25,48,90,.08)}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:#f6f8fc;color:var(--ink);font-family:Inter,"Noto Sans KR",system-ui,-apple-system,sans-serif;line-height:1.65}button,input{font:inherit}button{color:inherit}.site-header{position:sticky;top:0;z-index:10;display:flex;align-items:center;justify-content:space-between;gap:18px;padding:14px clamp(16px,4vw,52px);background:rgba(255,255,255,.96);border-bottom:1px solid var(--line);backdrop-filter:blur(10px)}.brand{border:0;background:none;padding:4px 0;font-weight:850;letter-spacing:.03em;color:var(--navy);cursor:pointer}.search-wrap{width:min(430px,52vw)}#search{width:100%;border:1px solid var(--line);border-radius:999px;background:#f8faff;padding:10px 15px;color:var(--ink)}#search:focus{outline:3px solid #dce7fb;border-color:#91a9d5}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}#app{max-width:1180px;margin:0 auto;padding:30px clamp(16px,4vw,48px) 72px}.loading,.error{padding:34px;border-radius:16px;background:#fff;border:1px solid var(--line)}.hero{padding:34px clamp(22px,5vw,52px);border-radius:22px;color:#fff;background:linear-gradient(125deg,#1f376c,#3d69ab);box-shadow:var(--shadow)}.hero small{color:#dfe9ff}.hero h1{max-width:780px;margin:8px 0 10px;font-size:clamp(29px,5vw,48px);line-height:1.2}.hero p{max-width:750px;margin:0;color:#edf3ff}.area{margin-top:34px}.area-head{display:flex;align-items:end;justify-content:space-between;gap:16px;margin-bottom:13px}.area h2{margin:0;font-size:clamp(23px,3vw,31px)}.area-count{color:var(--muted);font-size:14px}.topic{margin-top:18px}.topic h3{margin:0 0 10px;font-size:18px}.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(245px,1fr));gap:12px}.construction-card{min-height:130px;padding:17px;text-align:left;border:1px solid var(--line);border-radius:16px;background:#fff;box-shadow:0 4px 14px rgba(25,48,90,.05);cursor:pointer}.construction-card:hover,.construction-card:focus-visible{border-color:#91a9d5;transform:translateY(-2px);outline:none;box-shadow:var(--shadow)}.construction-card small{display:block;color:var(--blue);font-weight:700}.construction-card strong{display:block;margin:6px 0;font-size:17px;line-height:1.35;overflow-wrap:anywhere}.construction-card span{display:block;color:var(--muted);font-size:13px;overflow-wrap:anywhere}.empty{margin-top:24px;padding:24px;border:1px dashed #aab8d2;border-radius:15px;background:#fff}.lesson-page{max-width:900px;margin:0 auto}.lesson-head{margin-bottom:18px}.back,.choice,.primary{border-radius:999px;padding:9px 15px;cursor:pointer}.back,.choice{border:1px solid var(--line);background:#fff}.primary{border:1px solid var(--navy);background:var(--navy);color:#fff}.head-row{display:flex;align-items:flex-end;justify-content:space-between;gap:18px;margin-top:18px}.topic-label{display:inline-block;padding:4px 9px;border-radius:999px;background:var(--accent);color:var(--navy);font-size:13px;font-weight:750}.lesson-head h1{margin:8px 0 0;font-size:clamp(29px,5vw,44px);line-height:1.2;overflow-wrap:anywhere}.progress-note{color:var(--muted);font-size:14px}.lesson-flow{display:grid;gap:16px}.learning-section,.structure-bridge,.related-section{padding:clamp(18px,4vw,28px);border-radius:18px;background:#fff;border:1px solid var(--line);box-shadow:0 5px 18px rgba(25,48,90,.05)}.learning-section h2,.related-section h2{margin:0 0 14px;font-size:21px}.pattern-section{border-top:5px solid #557bc1}.pattern{margin:0;font-family:"SFMono-Regular",Consolas,monospace;font-size:clamp(18px,3vw,24px);font-weight:750;overflow-wrap:anywhere;white-space:pre-wrap}.example-section{border-top:5px solid #65a985}.example-list{display:grid;gap:13px}.example{padding:14px;border-radius:12px;background:#f7fafc}.english{margin:0;font-size:18px;font-weight:650;overflow-wrap:anywhere}.korean{margin:5px 0 0;color:#536078}.textbook-notes{display:grid;grid-template-columns:1fr 1fr;gap:12px}.note{padding:15px;border-radius:13px;background:var(--pale)}.note h3{margin:0 0 7px;font-size:16px}.note p{margin:0}.caution{margin:14px 0 0;padding-left:13px;border-left:4px solid #df9847}.practice-section{border-top:5px solid #d69b4f}.practice-prompt{padding:14px;border-radius:12px;background:var(--orange)}.actions{display:flex;gap:9px;flex-wrap:wrap;margin-top:13px}.feedback{margin-top:13px;padding:13px;border-radius:12px;background:var(--green)}.feedback.retry{background:var(--orange)}.structure-bridge{padding:0}.structure-bridge summary{padding:17px 20px;font-weight:800;cursor:pointer}.structure-body{padding:0 20px 20px}.bridge-note{color:var(--muted)}.link-list{display:flex;gap:9px;flex-wrap:wrap}.grammar-link,.construction-link{display:inline-flex;align-items:center;min-height:40px;padding:8px 13px;border-radius:999px;border:1px solid #aec0df;background:#f7f9fd;color:var(--navy);text-decoration:none;cursor:pointer}.related-section p{color:var(--muted)}.lesson-footer{display:flex;justify-content:space-between;gap:12px;padding-top:4px}.badges{display:flex;gap:7px;flex-wrap:wrap;margin-top:12px}.badge{font-size:12px;padding:4px 8px;border-radius:999px;background:#eef2f8;color:#58657a}@media(max-width:700px){.site-header{align-items:stretch;flex-direction:column;gap:9px}.search-wrap{width:100%}#app{padding-top:20px}.hero{border-radius:16px}.grid{grid-template-columns:1fr}.head-row{align-items:flex-start;flex-direction:column}.textbook-notes{grid-template-columns:1fr}.learning-section,.related-section{padding:17px}.pattern{font-size:17px}.english{font-size:17px}.lesson-footer{flex-direction:column}.lesson-footer button{width:100%}}