*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
:root {
  --primary: #4F46E5;
  --primary-light: #818CF8;
  --bg: #F5F6FA;
  --card-bg: #FFF;
  --text: #1F2937;
  --text-muted: #6B7280;
  --border: #E5E7EB;
  --radius: 12px;
}
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}
.loading { text-align: center; padding: 60px 20px; color: var(--text-muted); font-size: 14px; }
.card { background: var(--card-bg); border-radius: var(--radius); padding: 16px; box-shadow: 0 1px 3px rgba(0,0,0,0.06); }
.btn {
  border: 1px solid var(--border); border-radius: 8px; padding: 8px 16px;
  font-size: 13px; cursor: pointer; font-family: inherit; background: #FFF; transition: background .15s;
  display: inline-flex; align-items: center; gap: 4px;
}
.btn:hover { background: #F9FAFB; }
.btn:active { background: #F3F4F6; }
.btn-primary { background: var(--primary); color: #FFF; border-color: var(--primary); }
.btn-primary:hover { background: #4338CA; }
.btn-danger { color: #DC2626; border-color: #FCA5A5; }
.btn-danger:hover { background: #FEF2F2; border-color: #DC2626; }
.btn-sm { padding: 4px 10px; font-size: 12px; }
.btn-block { width: 100%; }
.admin-input {
  width:100%; box-sizing:border-box;
  border: 1px solid var(--border); border-radius: 8px;
  padding: 10px 12px; font-size: 14px; font-family: inherit;
  outline: none; transition: border-color .2s;
}
.admin-input:focus { border-color: var(--primary); }
/* Dashboard */
.dash { max-width: 640px; margin: 0 auto; padding: 16px; position: relative; }
.dash-header { text-align: center; margin-bottom: 20px; position: relative; }
.dash-header h1 { font-size: 22px; }
.dash-subtitle { font-size: 13px; color: var(--text-muted); margin-top: 2px; }
.stats-row { display: flex; gap: 10px; }
.stat-card {
  flex: 1; background: var(--card-bg); border-radius: var(--radius);
  padding: 16px; text-align: center; box-shadow: 0 1px 3px rgba(0,0,0,0.06);
}
.stat-num { display: block; font-size: 28px; font-weight: 700; color: var(--primary); }
.stat-label { font-size: 12px; color: var(--text-muted); margin-top: 2px; display: block; }
.student-row {
  display: flex; align-items: center; justify-content: space-between;
  padding: 10px 0; border-bottom: 1px solid var(--border); font-size: 13px;
}
.student-row:last-child { border-bottom: none; }
.alert-error { color: #DC2626; background: #FEF2F2; border: 1px solid #FECACA; border-radius: var(--radius); padding: 12px 16px; }