:root {
  --bg: #eef4fb;
  --card: #ffffff;
  --text: #0f1a2a;
  --muted: #5a6b84;
  --brand: #0c97e2;
  --brand-dark: #0a78b4;
  --accent: #0cc4a1;
  --border: #d8e3f0;
  --danger: #d63636;
  --warning: #e39f07;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: "DM Sans", "Segoe UI", Tahoma, sans-serif;
  background: radial-gradient(circle at top right, #dff0ff, #eff5fc 50%, #edf3fb);
  color: var(--text);
}
.hidden { display: none !important; }
body.busy { cursor: wait; }

.global-loader {
  position: fixed;
  inset: 0;
  display: grid;
  place-items: center;
  background: rgba(255, 255, 255, 0.75);
  backdrop-filter: blur(2px);
  z-index: 100;
}
.global-loader .loader-card {
  display: inline-flex;
  gap: 10px;
  align-items: center;
  padding: 10px 14px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: #fff;
}
.spinner {
  width: 16px;
  height: 16px;
  border: 2px solid #dce8f5;
  border-top-color: var(--brand);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

.auth-wrap {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 20px;
}
.auth-shell {
  width: min(980px, 100%);
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 14px;
}
@media (max-width: 960px) {
  .auth-shell { grid-template-columns: 1fr; }
}
.hero-card, .card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 18px;
  box-shadow: 0 12px 28px rgba(7, 20, 40, 0.06);
}
.hero-card {
  background: linear-gradient(165deg, #0d1320, #12233d);
  color: #fff;
}
.hero-card h1 { margin: 0; font-size: 34px; letter-spacing: 0.5px; }
.hero-card p { opacity: 0.9; }
.hero-list { margin: 20px 0 0; padding: 0; list-style: none; display: grid; gap: 10px; }
.hero-list li { padding: 8px 10px; border: 1px solid rgba(255,255,255,0.15); border-radius: 10px; }
.auth-card { display: grid; gap: 9px; }

label { font-size: 13px; color: var(--muted); margin-top: 4px; display: block; }
input, textarea, select, button {
  width: 100%;
  margin-top: 4px;
  padding: 10px;
  border-radius: 10px;
  border: 1px solid var(--border);
  font-size: 14px;
  background: #fff;
}
textarea { min-height: 84px; resize: vertical; }
button {
  background: linear-gradient(90deg, var(--brand), #22afea);
  color: #fff;
  border: none;
  cursor: pointer;
  font-weight: 700;
}
button:hover { background: linear-gradient(90deg, var(--brand-dark), var(--brand)); }
button.secondary {
  background: #f4f8fc;
  color: var(--text);
  border: 1px solid var(--border);
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 20px;
  border-bottom: 1px solid var(--border);
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(8px);
  position: sticky;
  top: 0;
  z-index: 3;
}
.topbar h2 { margin: 0; }
.tabs {
  display: flex;
  gap: 8px;
  padding: 10px 20px;
  border-bottom: 1px solid var(--border);
  background: rgba(255,255,255,0.92);
  position: sticky;
  top: 68px;
  z-index: 2;
  overflow-x: auto;
}
.tabs button {
  width: auto;
  border: 1px solid var(--border);
  background: #fff;
  color: #111;
  padding: 8px 12px;
  border-radius: 10px;
}
.tabs button.active { background: var(--brand); color: #fff; border-color: var(--brand); }

.notice {
  margin: 12px 20px 0;
  padding: 10px 12px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: #fff;
  font-size: 13px;
}
.notice.error { border-color: #f0c5c5; background: #fff2f2; color: var(--danger); }
.notice.success { border-color: #b8ead6; background: #effcf6; color: #1d7d57; }
.notice.info { border-color: #bcdff8; background: #f0f8ff; color: #116ea8; }

main { padding: 16px 20px 28px; }
.tab { display: none; }
.tab.active { display: block; }
.grid { display: grid; gap: 12px; }
.stats { grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); }
.stat { padding: 14px; border: 1px solid var(--border); border-radius: 12px; background: #fff; }
.stat .value { font-size: 24px; font-weight: 800; color: #0b3656; }
.split { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
@media (max-width: 980px) { .split { grid-template-columns: 1fr; } }
.row { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.row.between { display: flex; justify-content: space-between; align-items: center; }
.actions { display: flex; gap: 8px; margin-top: 8px; }
.actions button { margin-top: 0; }
.muted { color: var(--muted); font-size: 13px; }
.error { color: var(--danger); font-size: 13px; margin: 4px 0 0; }
.table-wrap { overflow: auto; }
table { width: 100%; border-collapse: collapse; font-size: 13px; }
th, td { border-bottom: 1px solid var(--border); text-align: left; padding: 8px; vertical-align: top; }
.list { display: grid; gap: 8px; }
.course-card { border: 1px solid var(--border); border-radius: 10px; padding: 10px; background: #fff; }
.link-btn { border: none; background: transparent; color: #0a5ea8; cursor: pointer; padding: 0; margin: 0; width: auto; }
.inline-actions { display: flex; gap: 6px; }
.inline-actions button { width: auto; padding: 6px 8px; font-size: 12px; }