:root{--primary-color: #667eea;--secondary-color: #764ba2;--success-color: #4caf50;--danger-color: #f44336;--warning-color: #ff9800;--info-color: #2196f3;--text-primary: #212121;--text-secondary: #757575;--bg-white: #ffffff;--bg-light: #f5f5f5;--border-color: #e0e0e0;--shadow-sm: 0 2px 4px rgba(0,0,0,.1);--shadow-md: 0 4px 6px rgba(0,0,0,.1);--shadow-lg: 0 10px 20px rgba(0,0,0,.15)}*{margin:0;padding:0;box-sizing:border-box}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen,Ubuntu,Cantarell,Fira Sans,Droid Sans,Helvetica Neue,sans-serif;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;background:linear-gradient(135deg,var(--primary-color) 0%,var(--secondary-color) 100%);min-height:100vh;color:var(--text-primary)}.container{max-width:1200px;margin:0 auto;padding:0 20px}.auth-container{min-height:100vh;display:flex;align-items:center;justify-content:center;padding:20px}.auth-card{background:var(--bg-white);border-radius:12px;padding:40px;width:100%;max-width:400px;box-shadow:var(--shadow-lg)}.auth-card h2{text-align:center;margin-bottom:30px;color:var(--text-primary);font-size:28px}.form-group{margin-bottom:20px}.form-group label{display:block;margin-bottom:8px;color:var(--text-secondary);font-size:14px;font-weight:500}.form-group input{width:100%;padding:12px;border:1px solid var(--border-color);border-radius:6px;font-size:16px;transition:border-color .3s}.form-group input:focus{outline:none;border-color:var(--primary-color)}.btn{display:inline-block;padding:12px 24px;font-size:16px;font-weight:500;text-align:center;text-decoration:none;border:none;border-radius:6px;cursor:pointer;transition:all .3s}.btn-primary{background:linear-gradient(135deg,var(--primary-color),var(--secondary-color));color:#fff}.btn-primary:hover{transform:translateY(-2px);box-shadow:var(--shadow-md)}.btn-secondary{background:transparent;color:var(--primary-color);border:2px solid var(--primary-color)}.btn-secondary:hover{background:var(--primary-color);color:#fff}.btn-block{width:100%;display:block}.btn-danger{background:var(--danger-color);color:#fff}.btn-success{background:var(--success-color);color:#fff}.auth-links{margin-top:20px;text-align:center}.auth-links a{color:var(--primary-color);text-decoration:none;font-size:14px;transition:color .3s}.auth-links a:hover{color:var(--secondary-color);text-decoration:underline}.error-message{background:#ffebee;color:var(--danger-color);padding:10px;border-radius:4px;margin-bottom:20px;font-size:14px}.success-message{background:#e8f5e9;color:var(--success-color);padding:10px;border-radius:4px;margin-bottom:20px;font-size:14px}.navbar{background:var(--bg-white);box-shadow:var(--shadow-sm);padding:15px 0;margin-bottom:30px}.navbar-content{display:flex;justify-content:space-between;align-items:center}.navbar-brand{font-size:24px;font-weight:700;background:linear-gradient(135deg,var(--primary-color),var(--secondary-color));-webkit-background-clip:text;-webkit-text-fill-color:transparent;text-decoration:none}.navbar-nav{display:flex;gap:20px;align-items:center}.navbar-nav a{color:var(--text-primary);text-decoration:none;font-weight:500;transition:color .3s}.navbar-nav a:hover,.navbar-nav a.active{color:var(--primary-color)}.tasks-container{background:var(--bg-white);border-radius:12px;padding:30px;margin-top:30px;box-shadow:var(--shadow-md)}.tasks-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:30px}.task-input{display:flex;gap:10px;margin-bottom:30px}.task-input input{flex:1;padding:12px;border:1px solid var(--border-color);border-radius:6px;font-size:16px}.task-list{list-style:none}.task-item{background:var(--bg-light);border-radius:8px;padding:15px;margin-bottom:10px;display:flex;align-items:center;gap:15px;transition:background .3s}.task-item:hover{background:#eee}.task-checkbox{width:20px;height:20px;cursor:pointer}.task-content{flex:1}.task-title{font-size:16px;font-weight:500;margin-bottom:4px}.task-title.completed{text-decoration:line-through;color:var(--text-secondary)}.task-description{font-size:14px;color:var(--text-secondary)}.task-actions{display:flex;gap:10px}.task-actions button{padding:6px 12px;font-size:14px;background:transparent;border:1px solid var(--border-color);border-radius:4px;cursor:pointer;transition:all .3s}.task-actions button:hover{background:var(--bg-light)}.task-actions button.delete{color:var(--danger-color);border-color:var(--danger-color)}.task-actions button.delete:hover{background:var(--danger-color);color:#fff}.loading,.empty-state{text-align:center;padding:40px;color:var(--text-secondary)}.empty-state h3{font-size:20px;margin-bottom:10px}.admin-panel{background:var(--bg-white);border-radius:12px;padding:30px;margin-top:30px;box-shadow:var(--shadow-md)}.stats-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:20px;margin-bottom:30px}.stat-card{background:linear-gradient(135deg,var(--primary-color),var(--secondary-color));color:#fff;padding:20px;border-radius:8px;text-align:center}.stat-card h3{font-size:32px;margin-bottom:5px}.stat-card p{font-size:14px;opacity:.9}