:root {
  --bg: #0a0b0f; --panel: #14161d; --panel-2: #191c25; --line: #262a36;
  --text: #e8eaf0; --muted: #8b90a0; --accent-a: #6d5efc; --accent-b: #21d4a8;
  --radius: 14px;
}
* { box-sizing: border-box; }
html, body { margin: 0; }
body {
  background: radial-gradient(1200px 600px at 70% -10%, #1a1330 0%, var(--bg) 55%) fixed;
  color: var(--text);
  font: 15px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
}
.topbar { display: flex; align-items: center; justify-content: space-between; padding: 16px 24px; border-bottom: 1px solid var(--line); position: sticky; top: 0; background: rgba(10,11,15,0.85); backdrop-filter: blur(8px); z-index: 10; }
.brand { font-weight: 650; letter-spacing: -0.01em; color: var(--text); text-decoration: none; font-size: 14px; }
.ghlink { color: var(--muted); text-decoration: none; font-size: 13px; }
.ghlink:hover { color: var(--text); }
.wrap { max-width: 980px; margin: 0 auto; padding: 40px 20px 64px; }
h1 { font-size: 26px; margin: 0 0 6px; letter-spacing: -0.02em; background: linear-gradient(90deg, var(--accent-a), var(--accent-b)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero-sub { color: var(--muted); font-size: 14px; max-width: 640px; }
.embed-frame { margin-top: 28px; border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; background: var(--panel); }
.embed-frame iframe { display: block; width: 100%; height: 560px; border: 0; background: var(--bg); }
.embed-label { font-size: 12px; color: var(--muted); padding: 10px 16px; border-top: 1px solid var(--line); display: flex; justify-content: space-between; align-items: center; }
.section-title { font-size: 13px; text-transform: uppercase; letter-spacing: 0.08em; color: var(--muted); margin: 40px 0 14px; }
.grid { display: grid; gap: 14px; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); }
.card { background: linear-gradient(180deg, var(--panel-2), var(--panel)); border: 1px solid var(--line); border-radius: var(--radius); padding: 18px; text-decoration: none; color: var(--text); display: block; transition: border-color 0.2s ease, transform 0.2s ease; }
.card:hover, .card:focus-visible { border-color: #3a3f52; transform: translateY(-2px); outline: none; }
.card .num { color: var(--muted); font-size: 11px; font-variant-numeric: tabular-nums; }
.card .title { font-weight: 650; margin-top: 4px; font-size: 15px; }
.card .concept { color: var(--muted); font-size: 12px; margin-top: 6px; }
.card .proves { font-size: 12px; margin-top: 10px; color: #b8bccb; line-height: 1.5; }
.badge { display: inline-block; font-size: 10px; padding: 2px 8px; border-radius: 999px; margin-top: 10px; letter-spacing: 0.03em; }
.badge.Beginner { background: rgba(33,212,168,0.15); color: var(--accent-b); }
.badge.Intermediate { background: rgba(109,94,252,0.18); color: #b3a8ff; }
.badge.Advanced { background: rgba(255,90,122,0.15); color: #ff9db1; }
.badge.blocked { background: rgba(139,144,160,0.15); color: var(--muted); }
table { border-collapse: collapse; width: 100%; margin: 14px 0; font-size: 13px; }
th, td { border: 1px solid var(--line); padding: 8px 12px; text-align: left; }
th { background: var(--panel); color: var(--muted); font-weight: 600; font-size: 12px; }
code { background: var(--panel); border: 1px solid var(--line); border-radius: 5px; padding: 1px 6px; font-size: 0.9em; }
pre { background: var(--panel); border: 1px solid var(--line); border-radius: 10px; padding: 16px; overflow-x: auto; }
pre code { background: none; border: none; padding: 0; }
.readme a { color: #9b8dff; }
.readme h1 { font-size: 24px; }
.readme h2 { font-size: 18px; margin-top: 32px; border-top: 1px solid var(--line); padding-top: 20px; }
.readme blockquote { border-left: 3px solid var(--accent-a); margin: 16px 0; padding: 4px 16px; color: var(--muted); background: var(--panel); border-radius: 0 8px 8px 0; }
footer { max-width: 980px; margin: 0 auto; color: var(--muted); font-size: 12px; border-top: 1px solid var(--line); padding: 18px 20px 40px; }
a { color: #9b8dff; }