:root {
  --bg: #ffffff;
  --text: #111827;
  --muted: #6b7280;
  --line: #e5e7eb;
  --brand: #2563eb;
  --card: #f8fafc;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: "Segoe UI", Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
}

.wrap { max-width: 920px; margin: 0 auto; padding: 0 16px; }

header {
  border-bottom: 1px solid var(--line);
  position: sticky;
  top: 0;
  background: rgba(255,255,255,.95);
}

.top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 0;
}

.brand { font-weight: 700; text-decoration: none; color: var(--text); }

nav { display: flex; flex-wrap: wrap; gap: 10px; }
nav a {
  text-decoration: none;
  color: var(--text);
  padding: 6px 10px;
  border-radius: 8px;
}
nav a:hover { background: var(--card); }

.lang-btn {
  border: 1px solid var(--line);
  background: #fff;
  border-radius: 8px;
  padding: 6px 10px;
  cursor: pointer;
}

main { padding: 24px 0; }
h1 { margin-top: 0; }
.muted { color: var(--muted); }
.card {
  border: 1px solid var(--line);
  background: var(--card);
  border-radius: 12px;
  padding: 14px;
}

footer {
  border-top: 1px solid var(--line);
  margin-top: 24px;
  padding: 18px 0 28px;
}

.lang-ru { display: none; }
html[data-lang="ru"] .lang-en { display: none; }
html[data-lang="ru"] .lang-ru { display: inline; }