:root{
  --bg:#0b0e12;--panel:#12171e;--panel2:#171d25;--text:#eef3f8;--muted:#9aa7b5;
  --line:#26303b;--accent:#7fd1ae;--accent2:#8ab4f8;--warn:#e7be77;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;font-family:Inter,ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto,Arial,sans-serif;background:var(--bg);color:var(--text)}
body.light{--bg:#f6f8fb;--panel:#fff;--panel2:#f0f4f8;--text:#17202a;--muted:#5f6b77;--line:#d9e0e7;--accent:#167b5d;--accent2:#285fb8;--warn:#8a5a00}
.app-shell{display:grid;grid-template-columns:340px 1fr;min-height:100vh}
.sidebar{position:sticky;top:0;height:100vh;overflow:auto;border-right:1px solid var(--line);background:var(--panel);padding:22px}
.brand{display:flex;gap:12px;align-items:center;margin-bottom:18px}
.mark{width:48px;height:48px;display:grid;place-items:center;border-radius:14px;background:var(--accent);color:#07110d;font-weight:900}
.brand h1{font-size:18px;margin:0}
.brand p{margin:3px 0 0;color:var(--muted);font-size:12px}
.search{width:100%;padding:12px 14px;border-radius:12px;border:1px solid var(--line);background:var(--panel2);color:var(--text);outline:none}
.level-filter{display:flex;gap:6px;flex-wrap:wrap;margin:14px 0}
.level-filter button,.theme-btn,#menuBtn{border:1px solid var(--line);background:var(--panel2);color:var(--text);border-radius:10px;padding:8px 10px;cursor:pointer}
.level-filter button.active{border-color:var(--accent);color:var(--accent)}
.module{margin-top:14px}
.module-title{font-size:12px;text-transform:uppercase;letter-spacing:.08em;color:var(--muted);margin:14px 0 6px}
.lesson-link{display:block;width:100%;text-align:left;border:0;background:transparent;color:var(--text);padding:8px 10px;border-radius:8px;cursor:pointer;font-size:13px}
.lesson-link:hover,.lesson-link.active{background:var(--panel2);color:var(--accent)}
.content{min-width:0}
.topbar{position:sticky;top:0;z-index:5;display:flex;align-items:center;gap:12px;justify-content:space-between;padding:14px 28px;border-bottom:1px solid var(--line);background:color-mix(in srgb,var(--bg) 88%, transparent);backdrop-filter:blur(12px)}
.crumb{font-size:13px;color:var(--muted)}
.progress-text{font-size:12px;color:var(--accent)}
#menuBtn{display:none}
.hero{max-width:980px;margin:48px auto 18px;padding:0 34px}
.eyebrow{font-size:12px;letter-spacing:.14em;color:var(--accent);font-weight:800}
.hero h2{font-size:42px;line-height:1.05;margin:10px 0}
.hero>p{max-width:820px;color:var(--muted);font-size:18px;line-height:1.65}
.stats{display:flex;gap:14px;flex-wrap:wrap;margin-top:24px}
.stats div{background:var(--panel);border:1px solid var(--line);padding:14px 18px;border-radius:14px;min-width:130px}
.stats strong{display:block;font-size:25px}
.stats span{color:var(--muted);font-size:12px}
.reader{max-width:980px;margin:0 auto;padding:20px 34px 80px}
.lesson-card{background:var(--panel);border:1px solid var(--line);border-radius:18px;padding:34px;margin:22px 0;box-shadow:0 14px 50px rgba(0,0,0,.12)}
.level-badge{display:inline-flex;padding:6px 10px;border-radius:999px;background:var(--panel2);color:var(--accent);font-size:12px;font-weight:800;letter-spacing:.04em}
.lesson-card h2{font-size:30px;margin:14px 0 8px}
.module-name{color:var(--muted);margin-bottom:22px}
.lesson-card p{font-size:17px;line-height:1.82;color:var(--text);margin:0 0 18px}
.lesson-card p:last-child{margin-bottom:0}
.empty{padding:40px;text-align:center;color:var(--muted)}
.reading-note{border-left:3px solid var(--accent2);background:var(--panel2);padding:14px 16px;border-radius:10px;margin-bottom:22px;color:var(--muted)}
@media (max-width:900px){
  .app-shell{grid-template-columns:1fr}
  .sidebar{position:fixed;left:-360px;top:0;width:330px;z-index:20;transition:left .2s ease;box-shadow:18px 0 60px rgba(0,0,0,.35)}
  .sidebar.open{left:0}
  #menuBtn{display:inline-block}
  .hero,.reader{padding-left:20px;padding-right:20px}
  .hero h2{font-size:34px}
  .lesson-card{padding:24px}
}