:root{
  --bg:#f6f7fb;
  --panel:#ffffff;
  --text:#172033;
  --muted:#6b7485;
  --accent:#5b5ce2;
  --accent-soft:#eeefff;
  --border:#dde2eb;
  --shadow:0 14px 40px rgba(31,42,68,.10);
}
html[data-theme="dark"]{
  --bg:#0d1118;
  --panel:#151b25;
  --text:#eef2f8;
  --muted:#a8b1c1;
  --accent:#8f90ff;
  --accent-soft:#26284b;
  --border:#2b3444;
  --shadow:0 14px 40px rgba(0,0,0,.30);
}
*{box-sizing:border-box}
html{color-scheme:light}
html[data-theme="dark"]{color-scheme:dark}
body{
  margin:0;
  min-height:100vh;
  font-family:-apple-system,BlinkMacSystemFont,"SF Pro Text","Segoe UI",sans-serif;
  background:var(--bg);
  color:var(--text);
}
a{color:inherit;text-decoration:none}
.site-header{
  height:72px;
  display:flex;
  align-items:center;
  justify-content:space-between;
  padding:0 clamp(20px,4vw,56px);
  border-bottom:1px solid var(--border);
  background:color-mix(in srgb,var(--panel) 94%,transparent);
  backdrop-filter:blur(14px);
}
.brand{font-size:22px;font-weight:800;letter-spacing:-.02em}
.theme-toggle{
  display:inline-flex;align-items:center;gap:8px;
  border:1px solid var(--border);background:var(--panel);color:var(--text);
  border-radius:999px;padding:9px 13px;font:inherit;font-weight:650;cursor:pointer;
}
.theme-toggle:hover{border-color:var(--accent)}
.home-shell{max-width:1100px;margin:0 auto;padding:72px clamp(20px,4vw,56px)}
.home-heading h1{font-size:clamp(34px,5vw,58px);margin:0 0 36px;letter-spacing:-.045em}
.course-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(290px,1fr));gap:18px}
.course-card{
  display:block;background:var(--panel);border:1px solid var(--border);border-radius:22px;
  padding:26px;box-shadow:var(--shadow);transition:.18s transform,.18s border-color;
}
.course-card:hover{transform:translateY(-2px);border-color:var(--accent)}
.course-card .eyebrow{color:var(--accent);font-size:13px;font-weight:800;text-transform:uppercase;letter-spacing:.08em}
.course-card h2{font-size:29px;margin:10px 0 14px;letter-spacing:-.03em}
.course-card p{margin:0;color:var(--muted);line-height:1.55}
.course-card .meta{margin-top:20px;display:flex;gap:8px;flex-wrap:wrap}
.chip{font-size:12px;border:1px solid var(--border);border-radius:999px;padding:6px 9px;background:var(--bg)}
.empty{color:var(--muted)}
@media(max-width:640px){
  .site-header{height:64px}
  .home-shell{padding-top:48px}
}