:root{
  --bg:#f6f8fb;
  --panel:#ffffff;
  --ink:#172033;
  --muted:#697386;
  --line:#e3e8ef;
  --brand:#155eef;
  --brand-soft:#eaf1ff;
  --accent:#0e9384;
  --warn:#b54708;
  --danger:#b42318;
  --shadow:0 12px 30px rgba(16,24,40,.08);
  --radius:18px;
}
*{box-sizing:border-box}
body{margin:0;font-family:Pretendard,"Noto Sans KR",system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;background:var(--bg);color:var(--ink)}
button,input,textarea,select{font:inherit}
button{cursor:pointer}
a{color:inherit}
.topbar{position:sticky;top:0;z-index:20;background:rgba(255,255,255,.94);backdrop-filter:blur(14px);border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;gap:16px;padding:14px max(22px,calc((100vw - 1280px)/2))}
.brand{display:flex;align-items:center;gap:12px;cursor:pointer;min-width:0}.brand-mark{width:42px;height:42px;border-radius:13px;background:linear-gradient(135deg,#155eef,#0e9384);display:grid;place-items:center;color:white;font-weight:900;letter-spacing:-.04em;box-shadow:0 8px 20px rgba(21,94,239,.24)}
.brand strong{display:block;font-size:16px}.brand span{display:block;color:var(--muted);font-size:11px;margin-top:2px}.top-actions{display:flex;gap:8px}
.primary-btn,.ghost-btn,.danger-btn,.small-btn,.icon-btn{border:0;border-radius:10px;padding:10px 14px;font-weight:700}.primary-btn{background:var(--brand);color:#fff}.primary-btn:hover{filter:brightness(.96)}.ghost-btn{background:#fff;color:var(--ink);border:1px solid var(--line)}.ghost-btn:hover{background:#f8fafc}.danger-btn{background:#fff0ee;color:var(--danger);border:1px solid #fecdca}.small-btn{padding:7px 10px;background:#f8fafc;border:1px solid var(--line);color:var(--ink);font-size:12px}.icon-btn{padding:4px 10px;background:transparent;color:var(--muted);font-size:26px;font-weight:400}
.app-shell{max-width:1280px;margin:0 auto;padding:34px 22px 64px}.hero{background:linear-gradient(135deg,#102a56,#155eef 55%,#0e9384);border-radius:28px;color:#fff;padding:42px;box-shadow:var(--shadow);overflow:hidden;position:relative}.hero:after{content:"";position:absolute;width:360px;height:360px;border:60px solid rgba(255,255,255,.08);border-radius:50%;right:-120px;top:-160px}.hero .eyebrow{color:#d6e4ff}.hero h1{font-size:clamp(30px,5vw,52px);line-height:1.12;margin:7px 0 14px;max-width:760px;letter-spacing:-.04em}.hero p{max-width:700px;margin:0;color:#e7efff;line-height:1.75}.hero-stats{display:flex;gap:28px;margin-top:28px;flex-wrap:wrap}.stat strong{font-size:24px;display:block}.stat span{font-size:12px;color:#d6e4ff}
.section-head{display:flex;align-items:end;justify-content:space-between;gap:16px;margin:34px 0 16px}.section-head h2{margin:0;font-size:24px}.section-head p{margin:5px 0 0;color:var(--muted);font-size:13px}.eyebrow{font-size:11px;font-weight:900;letter-spacing:.14em;color:var(--brand);margin:0 0 4px;text-transform:uppercase}
.course-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.course-card{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:22px;box-shadow:0 4px 16px rgba(16,24,40,.04);transition:.2s}.course-card:hover{transform:translateY(-2px);box-shadow:var(--shadow);border-color:#c8d7f5}.course-card h3{font-size:20px;line-height:1.4;margin:14px 0 8px}.course-card p{color:var(--muted);font-size:13px;line-height:1.7;margin:0 0 18px}.card-top,.meta-row{display:flex;align-items:center;justify-content:space-between;gap:8px}.badge{display:inline-flex;align-items:center;border-radius:999px;padding:5px 9px;font-size:11px;font-weight:800;background:var(--brand-soft);color:var(--brand)}.badge.green{background:#e7f6f2;color:#087669}.badge.gray{background:#f2f4f7;color:#667085}.meta-row{border-top:1px solid var(--line);padding-top:14px;color:var(--muted);font-size:12px}
.course-layout{display:grid;grid-template-columns:300px minmax(0,1fr);gap:20px;align-items:start}.sidebar,.content-panel,.admin-bar{background:#fff;border:1px solid var(--line);border-radius:var(--radius);box-shadow:0 4px 16px rgba(16,24,40,.04)}.sidebar{position:sticky;top:86px;overflow:hidden}.course-summary{padding:20px;border-bottom:1px solid var(--line)}.course-summary h2{margin:8px 0 8px;font-size:20px;line-height:1.35}.course-summary p{font-size:12px;color:var(--muted);line-height:1.6}.lesson-nav{padding:10px}.lesson-btn{width:100%;text-align:left;border:0;background:transparent;border-radius:12px;padding:12px;display:flex;gap:10px;color:var(--ink)}.lesson-btn:hover{background:#f8fafc}.lesson-btn.active{background:var(--brand-soft);color:#0f4cc4}.lesson-no{font-size:11px;font-weight:900;opacity:.75;padding-top:2px}.lesson-title{font-size:13px;line-height:1.45;font-weight:800}
.content-panel{padding:30px;min-height:620px}.breadcrumb{font-size:12px;color:var(--muted);margin-bottom:18px}.lesson-header{border-bottom:1px solid var(--line);padding-bottom:24px;margin-bottom:26px}.lesson-header h1{font-size:32px;margin:8px 0 12px;letter-spacing:-.03em}.lesson-header p{color:var(--muted);line-height:1.7;margin:0}.article{font-size:15px;line-height:1.8}.article h2{font-size:20px;margin:28px 0 10px}.article p{white-space:pre-line}.resource-section{margin-top:32px;padding-top:26px;border-top:1px solid var(--line)}.resource-section h2{font-size:18px;margin:0 0 13px}.resource-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}.resource-card{display:flex;align-items:center;justify-content:space-between;gap:14px;border:1px solid var(--line);border-radius:13px;padding:13px 14px;text-decoration:none;background:#fff}.resource-card:hover{border-color:#adc5f5;background:#fbfdff}.resource-info{min-width:0}.resource-info strong{display:block;font-size:13px}.resource-info span{display:block;color:var(--muted);font-size:11px;margin-top:3px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;max-width:420px}.resource-action{font-size:12px;color:var(--brand);font-weight:800;white-space:nowrap}.empty{padding:18px;border:1px dashed #cfd6e0;border-radius:14px;color:var(--muted);font-size:13px;background:#fbfcfe}
.admin-bar{margin-bottom:18px;padding:14px 16px;display:flex;align-items:center;justify-content:space-between;gap:12px;border-color:#b7cdf7;background:#f8fbff}.admin-actions{display:flex;gap:6px;flex-wrap:wrap}.admin-note{font-size:12px;color:#475467}.admin-note strong{color:#1849a9}
.dialog{width:min(760px,calc(100vw - 28px));border:0;border-radius:20px;padding:0;box-shadow:0 30px 80px rgba(16,24,40,.28)}.dialog::backdrop{background:rgba(15,23,42,.52);backdrop-filter:blur(3px)}.dialog form{padding:22px}.dialog-head{display:flex;justify-content:space-between;align-items:start;border-bottom:1px solid var(--line);padding-bottom:14px;margin-bottom:18px}.dialog-head h2{margin:3px 0 0}.form-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px}.field{display:flex;flex-direction:column;gap:6px}.field.full{grid-column:1/-1}.field label{font-size:12px;font-weight:800;color:#344054}.field input,.field textarea,.field select{width:100%;border:1px solid #d0d5dd;border-radius:10px;padding:10px 11px;background:white;color:var(--ink)}.field textarea{min-height:130px;resize:vertical;line-height:1.6}.field small{color:var(--muted);font-size:11px}.dialog-actions{display:flex;justify-content:flex-end;gap:8px;margin-top:20px;padding-top:15px;border-top:1px solid var(--line)}
.footer{max-width:1280px;margin:0 auto 30px;padding:0 22px;color:var(--muted);font-size:11px;display:flex;justify-content:space-between;gap:20px}.toast{position:fixed;right:22px;bottom:22px;z-index:100;background:#101828;color:#fff;padding:11px 14px;border-radius:11px;box-shadow:var(--shadow);font-size:12px;animation:toastIn .2s ease}.toast.error{background:#912018}@keyframes toastIn{from{transform:translateY(8px);opacity:0}to{transform:none;opacity:1}}
@media(max-width:900px){.course-grid{grid-template-columns:1fr 1fr}.course-layout{grid-template-columns:1fr}.sidebar{position:static}.lesson-nav{display:flex;overflow:auto}.lesson-btn{min-width:190px}.resource-grid{grid-template-columns:1fr}.form-grid{grid-template-columns:1fr}.field.full{grid-column:auto}.hero{padding:30px}.content-panel{padding:22px}}
@media(max-width:600px){.topbar{padding:10px 14px}.brand span{display:none}.top-actions .ghost-btn{display:none}.app-shell{padding:20px 14px 48px}.course-grid{grid-template-columns:1fr}.hero{border-radius:20px;padding:24px}.hero h1{font-size:31px}.content-panel{padding:18px}.lesson-header h1{font-size:25px}.admin-bar{align-items:flex-start;flex-direction:column}.footer{padding:0 14px;flex-direction:column;gap:4px}}