:root{
  --bg:#f4f6fb; --card:#fff; --ink:#16203a; --muted:#67718c;
  --accent:#3457d5; --accent-dark:#2742a8; --accent-soft:#e7ecfd;
  --ok:#17966b; --line:#e2e7f2;
}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--ink);
  font:16px/1.6 "Segoe UI",Roboto,Helvetica,Arial,sans-serif}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}
.container{max-width:1080px;margin:0 auto;padding:0 20px}

.site-header{background:#fff;border-bottom:1px solid var(--line);
  position:sticky;top:0;z-index:10}
.header-inner{display:flex;align-items:center;justify-content:space-between;
  gap:16px;padding:14px 20px;flex-wrap:wrap}
.logo{font-size:20px;font-weight:700;color:var(--ink)}
.logo span{color:var(--accent)}
.nav{display:flex;align-items:center;gap:16px;flex-wrap:wrap}
.nav a{color:var(--ink);font-size:15px}
.btn{display:inline-block;background:var(--accent);color:#fff!important;
  padding:9px 18px;border-radius:9px;border:0;cursor:pointer;font:inherit;
  font-size:15px}
.btn:hover{background:var(--accent-dark);text-decoration:none}
.btn-ghost{background:transparent;color:var(--accent)!important;
  border:1px solid var(--accent)}
.btn-ghost:hover{background:var(--accent-soft)}
.btn-sm{padding:6px 12px;font-size:14px}

main{padding:28px 20px 64px}
h1{margin:.2em 0 .4em;font-size:32px}
h2{font-size:23px;margin-top:1.6em}
.muted{color:var(--muted)}

.hero{background:linear-gradient(135deg,#eaf0ff,#fdfdff);
  border:1px solid var(--line);border-radius:18px;padding:44px 34px;margin-bottom:26px}
.hero p{max-width:640px;color:#41496b}

.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:18px}
.card{background:var(--card);border:1px solid var(--line);border-radius:14px;
  padding:20px;display:flex;flex-direction:column;gap:6px}
.card h3{margin:0;font-size:18px}
.tag{display:inline-block;background:var(--accent-soft);color:var(--accent-dark);
  border-radius:999px;padding:3px 11px;font-size:12px;font-weight:600}
.tag-alt{background:#e6f7f0;color:var(--ok)}
.chips{display:flex;gap:8px;flex-wrap:wrap}

.stats{display:flex;gap:16px;flex-wrap:wrap;margin:22px 0}
.stat{flex:1;min-width:140px;background:#fff;border:1px solid var(--line);
  border-radius:14px;padding:16px;text-align:center}
.stat b{display:block;font-size:28px;color:var(--accent)}

.panel{background:#fff;border:1px solid var(--line);border-radius:14px;padding:24px}
.form-narrow{max-width:470px;margin:0 auto}
.field{margin-bottom:14px}
.field label{display:block;font-size:14px;margin-bottom:5px;color:#3c4666}
input[type=text],input[type=email],input[type=password],input[type=number],
select,textarea{width:100%;padding:10px 12px;border:1px solid #cfd6e6;
  border-radius:9px;background:#fbfcff;font:inherit;color:var(--ink)}
input:focus,select:focus,textarea:focus{outline:2px solid var(--accent);
  border-color:transparent}
textarea{min-height:110px;resize:vertical}
.check{display:flex;align-items:center;gap:8px;font-size:14px;margin-bottom:14px}
.check input{width:auto}
.filters{display:grid;grid-template-columns:repeat(auto-fit,minmax(165px,1fr));
  gap:12px;align-items:end;margin-bottom:8px}

.progress{background:#e8ecf6;border-radius:999px;height:10px;overflow:hidden;
  margin:8px 0}
.progress i{display:block;height:100%;background:var(--accent);border-radius:999px}

.lesson-row{display:flex;align-items:center;justify-content:space-between;
  gap:12px;padding:11px 0;border-top:1px solid var(--line)}
.lesson-row:first-child{border-top:0}
.done{color:var(--ok);font-weight:600}

/* текст урока */
.lesson-body{margin-top:6px;font-size:16.5px;line-height:1.7}
.lesson-body h2{font-size:20px;margin:1.6em 0 .5em;padding-top:.6em;
  border-top:1px solid var(--line)}
.lesson-body p{margin:0 0 1em}
.lesson-body ul,.lesson-body ol{margin:0 0 1em;padding-left:24px}
.lesson-body li{margin-bottom:.35em}
.lesson-body code{background:var(--accent-soft);color:var(--accent-dark);
  padding:1px 6px;border-radius:5px;font-size:.92em;
  font-family:Consolas,"SFMono-Regular",Menlo,monospace}
.lesson-body pre{background:#1f2537;color:#e8ecf6;padding:16px 18px;
  border-radius:10px;overflow-x:auto;margin:0 0 1.1em;font-size:14px;line-height:1.55}
.lesson-body pre code{background:transparent;color:inherit;padding:0;font-size:inherit}
.lesson-actions{margin-top:26px;padding-top:18px;border-top:1px solid var(--line)}
.lesson-actions p{margin-top:0}

.flashes{margin-bottom:18px}
.flash{padding:10px 14px;border-radius:9px;margin-bottom:8px;font-size:15px}
.flash-success{background:#e6f7f0;color:#12784f}
.flash-error{background:#fdeaea;color:#98232b}
.flash-warning{background:#fdf4e0;color:#8a5c10}

.review{border-top:1px solid var(--line);padding:14px 0}
.review:first-child{border-top:0}
.stars{color:#eaa61e;letter-spacing:2px}
table{width:100%;border-collapse:collapse}
td,th{padding:9px;border-bottom:1px solid var(--line);text-align:left}
.site-footer{border-top:1px solid var(--line);background:#fff;padding:22px 0;
  font-size:14px}
.two-col{display:grid;grid-template-columns:2fr 1fr;gap:20px;align-items:start}
@media(max-width:760px){.two-col{grid-template-columns:1fr}}