:root{
  --bg: #0b1220;
  --card: rgba(255,255,255,.06);
  --text: rgba(255,255,255,.92);
  --muted: rgba(255,255,255,.65);
  --border: rgba(255,255,255,.12);
  --shadow: 0 16px 50px rgba(0,0,0,.45);

  --radius: 18px;
  --radius2: 14px;
  --max: 1100px;

  --mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
  --sans: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
}

*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  font-family: var(--sans);
  color: var(--text);
  background:
    radial-gradient(1200px 700px at 20% 10%, rgba(56,189,248,.18), transparent 60%),
    radial-gradient(900px 650px at 90% 30%, rgba(34,197,94,.18), transparent 55%),
    radial-gradient(900px 650px at 50% 110%, rgba(255,255,255,.06), transparent 55%),
    var(--bg);
}

a{color:inherit; text-decoration:none}
.app{
  max-width: var(--max);
  margin: 0 auto;
  padding: 26px 18px 36px;
}

.topbar{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:16px;
  margin-bottom: 16px;
}

.brand{display:flex; align-items:center; gap:12px}
.logo{
  width:44px; height:44px;
  border-radius: 14px;
  background: linear-gradient(135deg, rgba(34,197,94,.25), rgba(56,189,248,.25));
  border: 1px solid var(--border);
  display:flex; align-items:center; justify-content:center;
  font-weight: 800;
  letter-spacing:.5px;
}
.brand-text h1{font-size: 18px; margin:0; line-height:1.05;}
.brand-text p{margin:2px 0 0; font-size: 12.5px; color: var(--muted);}

.card{
  background: linear-gradient(180deg, var(--card), rgba(255,255,255,.04));
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 18px;
}

h2{margin:0 0 8px; font-size: 18px}
.muted{color: var(--muted)}
.sep{border:0; border-top:1px solid var(--border); margin: 16px 0;}

.grid{
  display:grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin-top: 12px;
}
@media (max-width: 900px){ .grid{grid-template-columns: repeat(2, minmax(0, 1fr));} }
@media (max-width: 620px){ .grid{grid-template-columns: 1fr;} }

.course{
  padding: 14px;
  border-radius: var(--radius2);
  border: 1px solid var(--border);
  background: linear-gradient(180deg, rgba(255,255,255,.08), rgba(255,255,255,.04));
  transition: transform .15s ease, border-color .15s ease, background .15s ease;
  display:block;
}
.course:hover{
  transform: translateY(-1px);
  border-color: rgba(255,255,255,.22);
  background: linear-gradient(180deg, rgba(255,255,255,.10), rgba(255,255,255,.05));
}
.course-title{font-weight: 750; margin-bottom: 4px}
.course-desc{font-size: 13px; color: var(--muted); margin-bottom: 6px}
.course-meta{font-size: 12.5px; color: rgba(255,255,255,.74)}
.course.disabled{opacity:.45; cursor:not-allowed; pointer-events:none;}

.row{display:flex; align-items:center; justify-content:space-between; gap: 12px;}
.right{display:flex; gap:10px; align-items:center}

.label{
  font-size: 12px;
  letter-spacing:.3px;
  color: rgba(255,255,255,.78);
  margin-bottom: 6px;
  text-transform: uppercase;
}

.btn{
  border: 1px solid rgba(255,255,255,.16);
  background: linear-gradient(135deg, rgba(34,197,94,.22), rgba(56,189,248,.18));
  padding: 10px 12px;
  border-radius: 14px;
  color: var(--text);
  cursor:pointer;
  font-weight: 650;
  transition: transform .12s ease, filter .12s ease, border-color .12s ease;
  display:inline-flex;
  align-items:center;
  gap:8px;
}
.btn:hover{transform: translateY(-1px); border-color: rgba(255,255,255,.24); filter: brightness(1.06)}
.btn:active{transform: translateY(0px)}
.btn.ghost{background: rgba(255,255,255,.06);}

.footer{margin-top: 14px; text-align:center; font-size: 12px;}

.form{
  display:grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: 12px;
  margin-top: 12px;
}
.field{
  grid-column: span 6;
  background: rgba(255,255,255,.04);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 12px;
}
.field.full{grid-column: 1 / -1}
.field.small{grid-column: span 4}
@media (max-width: 900px){
  .field, .field.small{grid-column: 1 / -1}
}
.input, select, textarea{
  width:100%;
  margin-top: 8px;
  padding: 10px 10px;
  border-radius: 12px;
  border: 1px solid rgba(255,255,255,.14);
  background: rgba(0,0,0,.20);
  color: var(--text);
  outline:none;
}
textarea{min-height: 110px; resize: vertical}
.hint{font-size: 12px; color: var(--muted); margin-top: 6px}
.pill{
  display:inline-flex;
  align-items:center;
  gap:8px;
  padding: 8px 10px;
  border-radius: 999px;
  background: rgba(255,255,255,.06);
  border: 1px solid var(--border);
  font-size: 12.5px;
  color: rgba(255,255,255,.78);
}
.kbd{
  font-family: var(--mono);
  font-size: 11.5px;
  padding: 2px 6px;
  border-radius: 8px;
  background: rgba(255,255,255,.08);
  border: 1px solid rgba(255,255,255,.12);
}

.output{
  margin-top: 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: rgba(0,0,0,.22);
  padding: 14px;
}
.output pre{
  margin:0;
  white-space: pre-wrap;
  word-break: break-word;
  font-family: var(--mono);
  font-size: 12.5px;
  line-height: 1.35;
}
.notice{
  margin-top: 10px;
  padding: 10px 12px;
  border-radius: 14px;
  border: 1px solid rgba(255,255,255,.14);
  background: rgba(255,255,255,.06);
  color: rgba(255,255,255,.78);
  font-size: 12.5px;
}
.notice.warn{
  border-color: rgba(245,158,11,.35);
  background: rgba(245,158,11,.10);
}