:root{--primary-color: #4f46e5;--primary: #4f46e5;--secondary-color: #10b981;--secondary: #10b981;--accent-color: #f59e0b;--error-color: #ef4444;--danger: #ef4444;--background-color: #f9fafb;--surface-color: #ffffff;--text-primary: #111827;--text-secondary: #6b7280;--border-color: #e5e7eb;--shadow-sm: 0 1px 2px 0 rgb(0 0 0 / .05);--shadow-md: 0 4px 6px -1px rgb(0 0 0 / .1), 0 2px 4px -2px rgb(0 0 0 / .1);--shadow-lg: 0 10px 15px -3px rgb(0 0 0 / .1), 0 4px 6px -4px rgb(0 0 0 / .1);--border-radius: .5rem;--font-sans: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;--text-danger: #ef4444;--bg-primary: #4f46e5;--bg-secondary: #10b981;--bg-danger: #ef4444;--ring-primary: #4f46e5;--ring-secondary: #10b981;--ring-danger: #ef4444;--opacity-50: .5;--opacity-90: .9;--transition-all: all .2s ease;--focus-outline: none;--focus-ring: 2px;--focus-offset: 2px;--duration-200: .2s}*{box-sizing:border-box;margin:0;padding:0}body{font-family:var(--font-sans);background-color:var(--background-color);color:var(--text-primary);line-height:1.5;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}#root{min-height:100vh}.container{width:100%;max-width:1200px;margin:0 auto;padding:0 1rem}.btn{display:inline-flex;align-items:center;justify-content:center;padding:.5rem 1rem;border-radius:var(--border-radius);font-weight:500;cursor:pointer;transition:all .2s ease;border:none;font-size:1rem}.btn-primary{background-color:var(--primary-color);color:#fff}.btn-primary:hover{background-color:#4338ca}.btn-secondary{background-color:var(--secondary-color);color:#fff}.btn-secondary:hover{background-color:#059669}.btn-outline{background-color:transparent;border:1px solid var(--border-color);color:var(--text-primary)}.btn-outline:hover{background-color:var(--background-color)}.form-group{margin-bottom:1rem}.form-label{display:block;margin-bottom:.5rem;font-weight:500;color:var(--text-primary)}.form-input{width:100%;padding:.5rem;border:1px solid var(--border-color);border-radius:var(--border-radius);font-size:1rem;transition:border-color .2s ease}.form-input:focus{outline:none;border-color:var(--primary-color);box-shadow:0 0 0 3px #4f46e51a}.card{background-color:var(--surface-color);border-radius:var(--border-radius);box-shadow:var(--shadow-sm);padding:1.5rem;margin-bottom:1rem}h1,h2,h3,h4,h5,h6{font-weight:600;line-height:1.25;margin-bottom:.75rem}h1{font-size:1.875rem}h2{font-size:1.5rem}h3{font-size:1.25rem}a{color:var(--primary-color);text-decoration:none}a:hover{text-decoration:underline}@media (max-width: 768px){.container{padding:0 .75rem}h1{font-size:1.5rem}h2{font-size:1.25rem}h3{font-size:1.125rem}}.loading{display:flex;align-items:center;justify-content:center;padding:2rem}.loading-spinner{width:2rem;height:2rem;border:2px solid var(--border-color);border-top:2px solid var(--primary-color);border-radius:50%;animation:spin 1s linear infinite}@keyframes spin{0%{transform:rotate(0)}to{transform:rotate(360deg)}}.error{color:var(--error-color);font-size:.875rem;margin-top:.25rem}.success{color:var(--secondary-color);font-size:.875rem;margin-top:.25rem}.navbar{background-color:var(--surface-color);box-shadow:var(--shadow-sm);padding:1rem 0;position:sticky;top:0;z-index:100}.navbar-container{display:flex;align-items:center;justify-content:space-between}.navbar-brand{font-size:1.25rem;font-weight:600;color:var(--primary-color)}.navbar-nav{display:flex;gap:1rem}.navbar-link{color:var(--text-primary);font-weight:500;padding:.5rem;border-radius:var(--border-radius);transition:background-color .2s ease}.navbar-link:hover{background-color:var(--background-color);text-decoration:none}.navbar-link.active{color:var(--primary-color)}.navbar-toggle{display:none;background:none;border:none;font-size:1.25rem;cursor:pointer}@media (max-width: 768px){.navbar-toggle{display:block}.navbar-nav{position:fixed;top:64px;left:0;right:0;background-color:var(--surface-color);box-shadow:var(--shadow-md);flex-direction:column;padding:1rem;gap:.5rem;transform:translateY(-100%);transition:transform .3s ease}.navbar-nav.open{transform:translateY(0)}}.dashboard{padding:2rem 0}.dashboard-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));gap:1.5rem;margin-bottom:2rem}.dashboard-card{background-color:var(--surface-color);border-radius:var(--border-radius);box-shadow:var(--shadow-sm);padding:1.5rem}.dashboard-card h3{margin-bottom:1rem;color:var(--text-primary)}.chart-container{height:300px;margin:1rem 0}.grade-management{padding:2rem 0}.grade-table{width:100%;border-collapse:collapse;margin:1rem 0;background-color:var(--surface-color);border-radius:var(--border-radius);overflow:hidden;box-shadow:var(--shadow-sm)}.grade-table th,.grade-table td{padding:1rem;text-align:left;border-bottom:1px solid var(--border-color)}.grade-table th{background-color:var(--background-color);font-weight:600;color:var(--text-primary)}.grade-table tr:hover{background-color:var(--background-color)}.upload-page{padding:2rem 0}.upload-container{max-width:800px;margin:0 auto;background-color:var(--surface-color);border-radius:var(--border-radius);box-shadow:var(--shadow-sm);padding:2rem}.upload-area{border:2px dashed var(--border-color);border-radius:var(--border-radius);padding:3rem;text-align:center;margin:1rem 0;transition:all .2s ease}.upload-area:hover{border-color:var(--primary-color);background-color:#4f46e50d}.upload-area.active{border-color:var(--primary-color);background-color:#4f46e51a}.profile-page{padding:2rem 0}.profile-container{max-width:800px;margin:0 auto;background-color:var(--surface-color);border-radius:var(--border-radius);box-shadow:var(--shadow-sm);padding:2rem}.profile-avatar{width:100px;height:100px;border-radius:50%;object-fit:cover;margin-bottom:1rem}.pagination{display:flex;align-items:center;justify-content:center;gap:.5rem;margin:2rem 0}.pagination-btn{padding:.5rem 1rem;border:1px solid var(--border-color);border-radius:var(--border-radius);background-color:var(--surface-color);color:var(--text-primary);cursor:pointer;transition:all .2s ease}.pagination-btn:hover{background-color:var(--background-color)}.pagination-btn.active{background-color:var(--primary-color);color:#fff;border-color:var(--primary-color)}.search-filter{display:flex;gap:1rem;margin-bottom:1rem;flex-wrap:wrap}.search-input{flex:1;min-width:200px;padding:.5rem;border:1px solid var(--border-color);border-radius:var(--border-radius);font-size:1rem}.filter-select{padding:.5rem;border:1px solid var(--border-color);border-radius:var(--border-radius);font-size:1rem}@media (max-width: 640px){.dashboard-grid{grid-template-columns:1fr}.search-filter{flex-direction:column}.search-input,.filter-select{width:100%}.grade-table{font-size:.875rem}.grade-table th,.grade-table td{padding:.75rem}.upload-container{padding:1.5rem}.upload-area{padding:2rem}}.flex{display:flex}.flex-col{flex-direction:column}.items-center{align-items:center}.justify-center{justify-content:center}.justify-between{justify-content:space-between}.mt-2{margin-top:.5rem}.mb-4{margin-bottom:1rem}.p-4{padding:1rem}.p-6{padding:1.5rem}.p-8{padding:2rem}.text-lg{font-size:1.125rem}.font-semibold{font-weight:600}.text-sm{font-size:.875rem}.text-gray-600{color:#6b7280}.w-full{width:100%}.h-4{height:1rem}.w-4{width:1rem}.h-8{height:2rem}.w-8{width:2rem}.h-12{height:3rem}.w-12{width:3rem}.fixed{position:fixed}.inset-0{top:0;right:0;bottom:0;left:0}.z-50{z-index:50}.bg-black{background-color:#000}.bg-opacity-50{opacity:.5}.animate-spin{animation:spin 1s linear infinite}.rounded-full{border-radius:9999px}.border-2{border-width:2px}.border-t-transparent{border-top-color:transparent}