* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif; background: #f9fafb; color: #111827; }
nav { background: white; padding: 12px 0; box-shadow: 0 1px 3px rgba(0,0,0,0.1); position: sticky; top: 0; z-index: 50; }
.container { max-width: 1200px; margin: 0 auto; padding: 24px 20px; }
.card { background: white; border-radius: 12px; padding: 24px; box-shadow: 0 1px 3px rgba(0,0,0,0.1); margin-bottom: 16px; }
.btn { padding: 10px 20px; border: none; border-radius: 8px; cursor: pointer; font-size: 14px; font-weight: 600; transition: all 0.2s; }
.btn-primary { background: #6366f1; color: white; }
.btn-primary:hover { background: #4f46e5; }
.btn-success { background: #10b981; color: white; }
.btn-danger { background: #ef4444; color: white; }
.btn-secondary { background: #e5e7eb; color: #374151; }
.btn-sm { padding: 6px 12px; font-size: 12px; }
input, select { width: 100%; padding: 10px 14px; border: 1px solid #d1d5db; border-radius: 8px; font-size: 14px; margin-bottom: 12px; }
input:focus, select:focus { outline: none; border-color: #6366f1; box-shadow: 0 0 0 3px rgba(99,102,241,0.1); }
label { display: block; font-weight: 600; margin-bottom: 4px; font-size: 14px; color: #374151; }
table { width: 100%; border-collapse: collapse; }
th, td { padding: 10px 12px; text-align: left; border-bottom: 1px solid #e5e7eb; font-size: 13px; }
th { background: #f9fafb; font-weight: 600; color: #6b7280; }
.badge { display: inline-block; padding: 2px 8px; border-radius: 12px; font-size: 11px; font-weight: 600; }
.badge-green { background: #d1fae5; color: #065f46; }
.badge-yellow { background: #fef3c7; color: #92400e; }
.badge-red { background: #fee2e2; color: #991b1b; }
.badge-blue { background: #dbeafe; color: #1e40af; }
.badge-purple { background: #ede9fe; color: #5b21b6; }
.badge-gray { background: #f3f4f6; color: #374151; }
.tabs { display: flex; gap: 8px; margin-bottom: 20px; flex-wrap: wrap; }
.tab { padding: 8px 16px; border-radius: 8px; cursor: pointer; font-size: 14px; font-weight: 500; background: #f3f4f6; color: #374151; border: none; transition: all 0.2s; }
.tab.active { background: #6366f1; color: white; }
.stat-card { text-align: center; padding: 20px; }
.stat-card h3 { font-size: 28px; color: #6366f1; margin-bottom: 4px; }
.stat-card p { color: #6b7280; font-size: 14px; }
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
@media (max-width: 768px) { .grid-2, .grid-4 { grid-template-columns: 1fr; } }
.alert { padding: 12px 16px; border-radius: 8px; margin-bottom: 16px; font-size: 14px; }
.alert-error { background: #fee2e2; color: #991b1b; }
.alert-success { background: #d1fae5; color: #065f46; }
.hero { text-align: center; padding: 60px 20px; background: linear-gradient(135deg, #6366f1, #8b5cf6); color: white; border-radius: 16px; margin-bottom: 32px; }
.hero h1 { font-size: 36px; margin-bottom: 12px; }
.hero p { font-size: 18px; opacity: 0.9; }
.locked { opacity: 0.6; cursor: pointer; }
.locked:hover { opacity: 0.8; }
.grade-ap { background: #dc2626; color: white; }
.grade-a { background: #f97316; color: white; }
.grade-b { background: #3b82f6; color: white; }
.grade-c { background: #6b7280; color: white; }