:root{--bg:#f4f6fb;--card:#fff;--line:#e6eaf2;--line2:#d7deea;--tx:#0f172a;--tx2:#475569;--mute:#94a3b8;
  --blue:#2563eb;--blue2:#1d4ed8;--ok:#16a34a;--err:#dc2626;--shadow:0 1px 2px rgba(15,23,42,.04),0 8px 24px -12px rgba(15,23,42,.12);color-scheme:light}
*{box-sizing:border-box;margin:0;padding:0}
body{font-family:Inter,system-ui,-apple-system,"Segoe UI",sans-serif;background:var(--bg);color:var(--tx);font-size:14.5px;line-height:1.5}
[hidden]{display:none!important}
h1{font-size:24px;letter-spacing:-.02em}h2{font-size:18px}
.muted{color:var(--tx2)}code{background:#f1f5f9;padding:1px 6px;border-radius:5px;font-size:13px}
.card{background:var(--card);border:1px solid var(--line);border-radius:16px;box-shadow:var(--shadow);padding:20px}
.center{min-height:100vh;display:grid;place-items:center;padding:16px;background:linear-gradient(120deg,#dbeafe,#ede9fe 55%,#e0e7ff)}
.auth{width:100%;max-width:400px;padding:30px;display:flex;flex-direction:column;gap:12px}
.brand{display:flex;align-items:center;gap:10px}
.brand .mark{width:40px;height:40px;border-radius:12px;display:grid;place-items:center;font-size:20px;background:#eff6ff}
.brand b{display:block;font-size:16px}.brand small{color:var(--tx2);font-size:12px}
label{display:flex;flex-direction:column;gap:5px;font-size:13px;font-weight:600;color:#334155}
input,select,textarea{font:inherit;font-weight:400;padding:9px 11px;border-radius:10px;border:1px solid var(--line2);background:#fff;color:var(--tx);outline:0;width:100%}
input:focus,select:focus,textarea:focus{border-color:var(--blue);box-shadow:0 0 0 4px rgba(37,99,235,.12)}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;padding:9px 15px;border-radius:10px;border:1px solid var(--line2);background:#fff;color:var(--tx);font:inherit;font-weight:600;cursor:pointer;text-decoration:none;white-space:nowrap}
.btn:hover{background:#f8fafc}
.btn.primary{background:var(--blue);border-color:var(--blue);color:#fff}.btn.primary:hover{background:var(--blue2)}
.btn.danger{color:var(--err);border-color:#fecaca}.btn.danger:hover{background:#fef2f2}
.btn.sm{padding:5px 10px;font-size:13px}.btn.wide{width:100%}
.btn:disabled{opacity:.5;cursor:not-allowed}
.alert{padding:10px 12px;border-radius:10px;background:#fef2f2;border:1px solid #fecaca;color:#b91c1c;font-size:13.5px}
.top{position:sticky;top:0;z-index:5;display:flex;align-items:center;gap:12px;padding:12px 24px;background:rgba(255,255,255,.9);backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}
.sp{flex:1}
.tag{font-size:12px;color:var(--tx2);background:#f1f5f9;padding:3px 9px;border-radius:999px}
.wrap{max-width:1200px;margin:0 auto;padding:22px 24px 60px;display:flex;flex-direction:column;gap:18px}
.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}
.stat{padding:16px 18px}.stat .v{font-size:26px;font-weight:800;letter-spacing:-.02em}.stat .l{color:var(--tx2);font-size:13px}
.classes{grid-column:1/-1;display:flex;flex-wrap:wrap;gap:8px;align-items:center}
.chip{font-size:12.5px;padding:4px 10px;border-radius:999px;background:#eff6ff;color:#1e40af;border:1px solid #dbeafe;cursor:pointer}
.chip b{margin-left:4px}
.toolbar{display:flex;align-items:center;gap:10px;flex-wrap:wrap;margin-bottom:12px}
.filters{display:grid;grid-template-columns:1fr 180px 160px;gap:10px;margin-bottom:12px}
.twrap{overflow-x:auto}
table{width:100%;border-collapse:collapse}
th{text-align:left;font-size:11.5px;text-transform:uppercase;letter-spacing:.05em;color:var(--mute);padding:10px;border-bottom:1px solid var(--line);white-space:nowrap}
td{padding:11px 10px;border-bottom:1px solid var(--line);color:var(--tx2);vertical-align:middle}
tr:last-child td{border-bottom:0}
tbody tr{cursor:pointer}tbody tr:hover td{background:#fafbff}
td b{color:var(--tx)}td small{display:block;color:var(--mute);font-size:12px}
.pill{font-size:12px;font-weight:600;padding:2px 9px;border-radius:999px}
.pill.active{background:#dcfce7;color:#15803d}.pill.alumni{background:#ede9fe;color:#6d28d9}.pill.left{background:#f1f5f9;color:#64748b}
.empty{text-align:center;padding:36px;color:var(--mute)}
.pager{display:flex;align-items:center;gap:8px;margin-top:12px}
.overlay{position:fixed;inset:0;background:rgba(15,23,42,.45);display:flex;align-items:center;justify-content:center;padding:16px;z-index:20}
.modal{width:100%;max-width:640px;max-height:92vh;overflow:auto;display:flex;flex-direction:column;gap:14px}
.grid{display:grid;grid-template-columns:1fr 1fr;gap:12px}.grid .full{grid-column:1/-1}
.acts{display:flex;gap:8px;align-items:center}
.toast{position:fixed;right:18px;bottom:18px;background:#0f172a;color:#fff;padding:11px 15px;border-radius:12px;font-size:13.5px;opacity:0;transform:translateY(8px);transition:.25s;pointer-events:none;z-index:30}
.toast.show{opacity:1;transform:none}
@media(max-width:800px){.stats{grid-template-columns:1fr 1fr}.filters{grid-template-columns:1fr}.grid{grid-template-columns:1fr}.top,.wrap{padding-left:14px;padding-right:14px}}