:root {
  --bg: #f6f7f9;
  --panel: #ffffff;
  --ink: #1a1d23;
  --muted: #667085;
  --line: #e6e8ec;
  --accent: #1f6feb;
  --accent-soft: #eef4ff;
  --chip: #f0f2f5;
  --radius: 10px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
  font-size: 15px;
  line-height: 1.6;
}

html[dir="rtl"] body {
  font-family: "Segoe UI", "Noto Naskh Arabic", "Traditional Arabic", Tahoma, sans-serif;
}

body.ar .l.en { display: none !important; }
body:not(.ar) .l.ar { display: none !important; }

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ---- top bar ---- */
.topbar {
  display: flex;
  align-items: center;
  gap: 18px;
  padding: 0 22px;
  height: 60px;
  background: var(--panel);
  border-bottom: 1px solid var(--line);
  position: sticky;
  top: 0;
  z-index: 20;
}
.brand { display: flex; align-items: center; gap: 8px; font-weight: 700; font-size: 17px; color: var(--ink); }
.brand:hover { text-decoration: none; }
.brand .logo {
  background: var(--accent);
  color: #fff;
  border-radius: 7px;
  padding: 3px 9px;
  font-size: 14px;
  letter-spacing: .02em;
}
.topnav { display: flex; gap: 2px; flex: 1; }
.topnav a {
  padding: 8px 13px;
  border-radius: 7px;
  color: var(--muted);
  font-size: 14px;
}
.topnav a:hover { background: var(--chip); color: var(--ink); text-decoration: none; }
.controls { display: flex; align-items: center; gap: 8px; margin-inline-start: auto; }
.search {
  width: 230px;
  padding: 8px 13px;
  border: 1px solid var(--line);
  border-radius: 8px;
  font-size: 14px;
  background: #fff;
}
.langbtn {
  padding: 8px 13px;
  border: 1px solid var(--line);
  background: #fff;
  border-radius: 8px;
  cursor: pointer;
  font-size: 13px;
  white-space: nowrap;
}

/* ---- layout ---- */
.page { display: flex; align-items: flex-start; }

/* ---- sidebar ---- */
.sidenav {
  flex: 0 0 280px;
  width: 280px;
  position: sticky;
  top: 60px;
  height: calc(100vh - 60px);
  overflow-y: auto;
  background: var(--panel);
  border-inline-end: 1px solid var(--line);
  padding: 18px 12px 40px;
}
.sidenav-inner { min-width: 0; }
.navhome {
  display: block;
  font-weight: 600;
  color: var(--ink);
  padding: 8px 12px;
  border-radius: 7px;
  margin-bottom: 8px;
}
.navhome:hover { background: var(--chip); text-decoration: none; }
.navhome.active { background: var(--accent-soft); color: var(--accent); }
.navgroup { margin-bottom: 6px; }
.navcat {
  display: block;
  font-weight: 600;
  font-size: 13px;
  color: var(--muted);
  padding: 8px 12px 3px;
}
.navcat:hover { color: var(--ink); text-decoration: none; }
.navcat.active { color: var(--accent); }
.navlink {
  display: block;
  padding: 5px 12px 5px 22px;
  font-size: 14px;
  color: var(--ink);
  border-radius: 7px;
  margin-inline-start: 8px;
}
.navlink:hover { background: var(--chip); text-decoration: none; }
.navlink.active { background: var(--accent-soft); color: var(--accent); font-weight: 600; }

.content { flex: 1 1 auto; min-width: 0; max-width: 920px; margin: 0 auto; padding: 28px 28px 60px; }
.content.narrow { max-width: 780px; }

/* ---- home ---- */
.hero { padding: 8px 0 6px; }
.hero h1 { font-size: 28px; margin: 0 0 6px; }
.hero .sub { color: var(--muted); font-size: 16px; max-width: 640px; }
.catsec { margin-top: 26px; }
.catsec h2 { font-size: 20px; margin: 0 0 4px; }
.catsec .sub { color: var(--muted); margin: 0 0 12px; font-size: 14px; }
.cat-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 12px; }
.card {
  display: block;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
  color: var(--ink);
  transition: border-color .12s, box-shadow .12s;
}
.card:hover { border-color: var(--accent); box-shadow: 0 2px 10px rgba(31,111,235,.08); text-decoration: none; }
.card h3 { margin: 0 0 5px; font-size: 16px; color: var(--ink); }
.card p { margin: 0; color: var(--muted); font-size: 13.5px; }
.card .count { display: inline-block; margin-top: 10px; font-size: 12px; color: var(--accent); font-weight: 600; }

/* ---- breadcrumbs ---- */
.crumbs { font-size: 13px; color: var(--muted); margin-bottom: 16px; }
.crumbs a { cursor: pointer; }
.crumbs .sep { opacity: .5; margin: 0 4px; }

/* ---- article ---- */
.article h1 { font-size: 26px; margin: 0 0 6px; }
.article .tags { margin: 8px 0 18px; }
.article h2 { font-size: 20px; margin-top: 26px; }
.article h3 { font-size: 16px; margin-top: 20px; }
.article h4 { font-size: 15px; margin-top: 16px; }
.article table { border-collapse: collapse; width: 100%; margin: 12px 0; font-size: 14px; }
.article th, .article td { border: 1px solid var(--line); padding: 8px 11px; text-align: start; }
.article th { background: var(--chip); }
.article code { background: var(--chip); padding: 1px 6px; border-radius: 5px; font-size: 13px; }
.article pre { background: #0f172a; color: #e2e8f0; padding: 14px; border-radius: 8px; overflow-x: auto; }
.article pre code { background: none; color: inherit; padding: 0; }
.article blockquote { border-inline-start: 3px solid var(--line); margin: 12px 0; padding: 4px 14px; color: var(--muted); }
.article ul, .article ol { padding-inline-start: 22px; }
.article img.step {
  display: block;
  max-width: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
  margin: 12px 0;
  cursor: zoom-in;
  background: #fff;
}
.article img.step:hover { border-color: var(--accent); }
.article p:has(> img.step) { margin: 0; }

.chip { display: inline-block; background: var(--chip); border-radius: 999px; padding: 2px 10px; font-size: 12px; color: var(--muted); margin-inline-end: 4px; }
.empty { color: var(--muted); padding: 20px; }

/* ---- rules ---- */
.rule { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px 18px; margin-bottom: 12px; }
.rule .rule-title { font-weight: 700; margin-bottom: 5px; }

/* ---- prev / next ---- */
.prevnext { display: flex; justify-content: space-between; gap: 12px; margin-top: 30px; }
.prevnext a { flex: 1; background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 12px 16px; color: var(--ink); }
.prevnext a:hover { border-color: var(--accent); text-decoration: none; }
.prevnext .dir { font-size: 12px; color: var(--muted); }
.prevnext .next { text-align: end; }

/* ---- overlay / lightbox ---- */
.overlay { display: none; position: fixed; inset: 0; background: rgba(10,12,16,.86); z-index: 100; align-items: center; justify-content: center; padding: 24px; }
.overlay.show { display: flex; }
.overlay-inner { position: relative; max-width: 94vw; max-height: 94vh; }
.overlay img { max-width: 94vw; max-height: 90vh; border-radius: 6px; }
.overlay .close { position: absolute; top: -14px; inset-inline-end: -14px; width: 34px; height: 34px; border-radius: 50%; border: none; background: #fff; font-size: 20px; cursor: pointer; line-height: 1; }
.overlay .caption { color: #d6dae1; text-align: center; margin-top: 8px; font-size: 13px; }

@media (max-width: 720px) {
  .topbar { flex-wrap: wrap; height: auto; padding: 10px 14px; }
  .topnav { order: 3; width: 100%; }
  .page { flex-direction: column; }
  .sidenav { flex: none; width: 100%; position: static; height: auto; max-height: 45vh; border-inline-end: none; border-bottom: 1px solid var(--line); }
  .content { padding: 20px 14px 40px; }
}