:root{--primary-color: #4F46E5;--primary-hover: #4338CA;--text-color: #333333;--light-gray: #f3f4f6;--medium-gray: #e5e7eb;--dark-gray: #9ca3af;--danger-color: #ef4444;--success-color: #10b981;--border-radius: 8px;--box-shadow: 0 4px 6px rgba(0, 0, 0, .1);--transition: all .3s ease}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica,Arial,sans-serif;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;margin:0;padding:0;color:var(--text-color);background-color:#f9fafb}.container{max-width:800px;margin:0 auto;padding:2rem 1rem}.btn{display:inline-block;padding:.5rem 1rem;border-radius:var(--border-radius);font-weight:500;cursor:pointer;transition:var(--transition);border:none;outline:none}.btn-primary{background-color:var(--primary-color);color:#fff}.btn-primary:hover{background-color:var(--primary-hover)}.btn-secondary{background-color:var(--medium-gray);color:var(--text-color)}.btn-secondary:hover{background-color:var(--dark-gray)}input[type=text],input[type=email],input[type=password]{width:100%;padding:.75rem 1rem;border:1px solid var(--medium-gray);border-radius:var(--border-radius);font-size:1rem;transition:var(--transition)}input[type=text]:focus,input[type=email]:focus,input[type=password]:focus{border-color:var(--primary-color);box-shadow:0 0 0 2px #4f46e533;outline:none}.card{background-color:#fff;border-radius:var(--border-radius);box-shadow:var(--box-shadow);overflow:hidden}.text-center{text-align:center}.mb-1{margin-bottom:.25rem}.mb-2{margin-bottom:.5rem}.mb-3{margin-bottom:1rem}.mb-4{margin-bottom:1.5rem}.mb-5{margin-bottom:2rem}.mt-1{margin-top:.25rem}.mt-2{margin-top:.5rem}.mt-3{margin-top:1rem}.mt-4{margin-top:1.5rem}.mt-5{margin-top:2rem}::-webkit-scrollbar{width:8px}::-webkit-scrollbar-track{background:#f1f1f1}::-webkit-scrollbar-thumb{background:#c5c5c5;border-radius:4px}::-webkit-scrollbar-thumb:hover{background:#a8a8a8}.todo-container{width:100%}.todo-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:1.5rem}.todo-title{font-size:1.5rem;font-weight:700;color:#1f2937;margin:0}.todo-form{display:flex;gap:.5rem;margin-bottom:1.5rem}.todo-input{flex:1}.todo-list{list-style:none;padding:0;margin:0;border:1px solid var(--medium-gray);border-radius:var(--border-radius);overflow:hidden}.todo-item{display:flex;align-items:center;padding:1rem;border-bottom:1px solid var(--medium-gray);transition:var(--transition)}.todo-item:last-child{border-bottom:none}.todo-item.completed{background-color:var(--light-gray)}.todo-checkbox{margin-right:1rem;width:1.25rem;height:1.25rem;cursor:pointer}.todo-text{flex:1;font-size:.875rem;margin:0}.todo-text.completed{text-decoration:line-through;color:var(--dark-gray)}.todo-delete{background:none;border:none;cursor:pointer;color:var(--dark-gray);padding:.25rem;border-radius:50%;display:flex;align-items:center;justify-content:center;transition:var(--transition)}.todo-delete:hover{background-color:var(--light-gray);color:var(--danger-color)}.todo-empty{text-align:center;padding:2.5rem 0;color:var(--dark-gray)}.alert{padding:1rem;margin:1rem 0;border-radius:var(--border-radius);display:flex;align-items:flex-start}.alert-error{background-color:#fee2e2;border:1px solid #fecaca}.alert-icon{margin-right:.75rem;flex-shrink:0}.alert-message{color:#b91c1c;font-size:.875rem}.home-container{min-height:100vh;background:linear-gradient(135deg,#e0f2fe,#e0e7ff);padding:2rem 1rem}.home-card{max-width:600px;margin:0 auto;background-color:#fff;border-radius:var(--border-radius);box-shadow:var(--box-shadow);overflow:hidden}.home-content{padding:2rem}.home-header{text-align:center;margin-bottom:2rem}.home-title{font-size:1.875rem;font-weight:700;color:#1f2937;margin-bottom:.5rem}.home-subtitle{color:#6b7280;font-size:1rem}.auth-container{background-color:#fff;padding:1.5rem;border-radius:var(--border-radius);box-shadow:0 1px 3px #0000001a}@media (max-width: 640px){.home-card{max-width:100%}.home-content{padding:1.5rem}.home-title{font-size:1.5rem}}.app{display:flex;flex-direction:column;min-height:100vh}.main-content{flex:1}.footer{margin-top:auto;padding:1rem;background-color:#f3f4f6;text-align:center;font-size:.875rem;color:#6b7280}