:root{
  --bg:#0b1220;
  --card:#111a2e;
  --muted:#9aa4b2;
  --text:#e6edf3;
  --primary:#4d96ff;
  --danger:#ff6b6b;
  --ok:#6bcb77;
  --border: rgba(255,255,255,.10);
  --shadow: 0 10px 24px rgba(0,0,0,.30);
  --radius: 14px;
}

*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  min-height:100vh;
  display:flex;
  flex-direction:column;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji","Segoe UI Emoji";
  background: radial-gradient(1200px 600px at 20% 0%, rgba(77,150,255,.18), transparent 60%),
              radial-gradient(900px 500px at 80% 10%, rgba(255,107,107,.16), transparent 55%),
              var(--bg);
  color:var(--text);
}
main.container{flex:1}

a{color:inherit;text-decoration:none}
a:hover{opacity:.9}

.container{max-width:1100px;margin:0 auto;padding:18px}

.topbar{
  position:sticky;top:0;z-index:5;
  background: rgba(11,18,32,.75);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.topbar__inner{display:flex;align-items:center;justify-content:space-between;gap:14px}
.brand{font-weight:800;letter-spacing:.2px}
.nav{display:flex;gap:12px;flex-wrap:wrap}
.nav a{padding:8px 10px;border-radius:10px;border:1px solid transparent}
.nav a:hover{border-color:var(--border);background:rgba(255,255,255,.04)}

.footer{border-top:1px solid var(--border);margin-top:24px;background:rgba(255,255,255,.02)}

.page-title{display:flex;align-items:flex-end;justify-content:space-between;gap:12px;flex-wrap:wrap;margin:12px 0 14px}
.page-title h1{margin:0;font-size:26px}
.muted{color:var(--muted)}

.card{
  background: linear-gradient(180deg, rgba(255,255,255,.04), rgba(255,255,255,.02));
  border:1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.toolbar{display:flex;gap:12px;flex-wrap:wrap;align-items:center;padding:14px}
main.container > section.card.toolbar{margin-bottom:24px}
.grid{
  display:grid;
  grid-template-columns: repeat(12, 1fr);
  gap:14px;
}
.col-12{grid-column: span 12}
.col-6{grid-column: span 6}
.col-4{grid-column: span 4}
@media (max-width: 900px){.col-6,.col-4{grid-column:span 12}}

.input, select{
  width:100%;
  padding:10px 12px;
  border-radius: 12px;
  border:1px solid var(--border);
  background: rgba(0,0,0,.20);
  color: var(--text);
  outline:none;
}
label{font-size:13px;color:var(--muted)}

.btn{
  display:inline-flex;align-items:center;justify-content:center;
  gap:8px;
  padding:10px 12px;
  border-radius: 12px;
  border:1px solid var(--border);
  background: rgba(255,255,255,.05);
  color: var(--text);
  cursor:pointer;
  user-select:none;
  font-weight:600;
}
.btn:hover{background:rgba(255,255,255,.08)}
.btn-primary{background: rgba(77,150,255,.18); border-color: rgba(77,150,255,.35)}
.btn-danger{background: rgba(255,107,107,.15); border-color: rgba(255,107,107,.35)}
.btn:disabled{opacity:.5;cursor:not-allowed}

.badge{
  display:inline-flex;align-items:center;gap:8px;
  padding:6px 10px;
  border-radius: 999px;
  border:1px solid var(--border);
  background: rgba(255,255,255,.04);
  font-size:12px;
  color: var(--muted);
}
.badge-dot{width:10px;height:10px;border-radius:50%}

.course{
  padding:14px;
  display:flex;
  flex-direction:column;
  gap:10px;
}
.course__top{display:flex;justify-content:space-between;gap:10px}
.course__title{margin:0;font-size:16px}
.course__desc{margin:0;color:var(--muted);font-size:13px;line-height:1.4}
.course__meta{display:flex;gap:10px;flex-wrap:wrap;color:var(--muted);font-size:13px}
.course__actions{display:flex;gap:10px;flex-wrap:wrap;align-items:center}

.alert{
  margin:12px 0;
  padding:12px 14px;
  border-radius: 14px;
  border:1px solid var(--border);
  background: rgba(255,255,255,.04);
}
.alert.ok{border-color: rgba(107,203,119,.35); background: rgba(107,203,119,.10)}
.alert.err{border-color: rgba(255,107,107,.35); background: rgba(255,107,107,.10)}