:root{--bg:#071321;--card:#102239;--card2:#0b1b2e;--border:#27517b;--blue:#208ee8;--text:#f7fbff;--muted:#b8c8dc;--danger:#ff4d6d;--green:#22c55e;--gold:#fbbf24;--purple:#7c3aed}
*{box-sizing:border-box} body{margin:0;font-family:Arial,Helvetica,sans-serif;background:radial-gradient(circle at top,#0d2741,var(--bg));color:var(--text)} a{color:#7dd3fc;text-decoration:none} a:hover{text-decoration:underline}.wrap{width:min(1120px,94%);margin:0 auto;padding:28px 0}.top{display:flex;justify-content:space-between;align-items:center;gap:15px;margin-bottom:25px}.brand{display:flex;align-items:center;gap:14px}.logo{width:54px;height:54px;border-radius:16px;background:linear-gradient(135deg,#1d8fe3,#0f2c48);display:grid;place-items:center;font-weight:900;font-size:26px;box-shadow:0 14px 35px rgba(0,0,0,.28)}h1{font-size:40px;margin:12px 0}.subtle,.muted{color:var(--muted)}.card{background:rgba(16,34,57,.94);border:1px solid var(--border);border-radius:18px;padding:24px;box-shadow:0 20px 50px rgba(0,0,0,.22)}.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}.grid2{display:grid;grid-template-columns:1fr 1fr;gap:18px}.lab-card{min-height:180px;display:flex;flex-direction:column;justify-content:space-between}.badge{display:inline-block;background:#0f2c48;border:1px solid var(--border);border-radius:999px;padding:7px 12px;color:#a7f3d0;font-weight:700;font-size:13px}.locked{opacity:.55;filter:grayscale(1)}label{display:block;margin:15px 0 7px;color:#dbeafe;font-weight:700}input,textarea,select{width:100%;padding:14px 15px;border:1px solid #3b6a9a;border-radius:10px;background:#06111e;color:white;outline:none}textarea{min-height:120px}input:focus,textarea:focus{border-color:#60a5fa}button,.btn{display:inline-block;margin-top:16px;padding:13px 18px;border:0;border-radius:10px;background:var(--blue);color:white;font-weight:800;cursor:pointer;text-align:center}.btn.secondary{background:#0b1b2e;border:1px solid var(--border)}button:hover,.btn:hover{filter:brightness(1.07);text-decoration:none}.alert{background:#351326;border:1px solid #7f1d1d;color:#fecdd3;padding:12px;border-radius:10px;margin:14px 0}.ok{background:#052e1a;border:1px solid #166534;color:#bbf7d0;padding:12px;border-radius:10px;margin:14px 0}.flag{display:inline-block;background:#020617;color:#86efac;border:1px dashed #22c55e;border-radius:10px;padding:13px;font-size:20px;font-weight:900}.login-page{min-height:100vh;display:grid;place-items:center;padding:28px}.login-shell{width:min(460px,94%)}.login-card h2{font-size:31px;margin:0 0 7px}.row-between{display:flex;justify-content:space-between;align-items:center;gap:10px;margin-top:14px}.check{display:flex;align-items:center;gap:8px;margin:0;font-weight:400;color:var(--muted)}footer{text-align:center;color:#91a8c0;font-size:13px;margin-top:18px}.dashboard-wrap{display:grid;grid-template-columns:250px 1fr;min-height:100vh}.sidebar{background:#07111f;border-right:1px solid var(--border);padding:28px;position:sticky;top:0;height:100vh}.sidebar nav{display:grid;gap:9px}.sidebar nav a,.logout{padding:12px 14px;border-radius:12px;color:#dbeafe;background:#0b1b2e}.sidebar nav a.active{background:#1d8fe3;color:white}.logout{display:block;margin-top:30px;text-align:center;background:#3b1220}.main{padding:32px}.main-header{display:flex;justify-content:space-between;align-items:flex-start;gap:20px}.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:16px;margin:28px 0}.stat,.panel{background:rgba(16,34,57,.92);border:1px solid var(--border);border-radius:16px;padding:22px;box-shadow:0 18px 50px rgba(0,0,0,.18)}.stat span{color:var(--muted)}.stat strong{display:block;font-size:34px;margin-top:8px}.panel{margin-bottom:20px}table{width:100%;border-collapse:collapse;color:white}th,td{padding:13px 11px;border-top:1px solid #27517b;text-align:left}th{background:#0b1b2e;border-top:0}.tag{background:#08331d;color:#bbf7d0;border:1px solid #166534;border-radius:999px;padding:5px 9px;font-size:12px}.notice{background:#07182b;border:1px solid #294d74;border-radius:12px;padding:13px;margin-bottom:12px}.comment{background:#06111e;border:1px solid #294d74;border-radius:12px;padding:13px;margin:12px 0}.codebox{background:#020617;border:1px solid #294d74;border-radius:12px;padding:16px;font-family:monospace;color:#a7f3d0;overflow:auto}.teacher-wrap{width:min(1180px,94%);margin:0 auto;padding:28px 0}@media(max-width:900px){.grid,.grid2{grid-template-columns:1fr}.dashboard-wrap{grid-template-columns:1fr}.sidebar{height:auto;position:relative}.stats{grid-template-columns:1fr 1fr}}@media(max-width:560px){.stats{grid-template-columns:1fr}.row-between{align-items:flex-start;flex-direction:column}.main{padding:20px}h1{font-size:30px}}.locked {
  opacity: 0.55;
  filter: grayscale(0.4);
}

.locked .btn {
  cursor: not-allowed;
}