:root{--bg-color: #f9f9f9;--primary-color: #4f46e5;--secondary-color: #6366f1;--text-color: #333;--card-bg: #ffffff;--shadow: rgba(0, 0, 0, .1) 0px 4px 12px;--font: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif}body{margin:0;font-family:var(--font);background-color:var(--bg-color);color:var(--text-color)}.app-container{display:flex;flex-direction:column;min-height:100vh}.header{background:var(--primary-color);color:#fff;padding:2rem;text-align:center;box-shadow:var(--shadow)}.header h1{margin:0;font-size:2rem}.header p{margin-top:.5rem;font-size:1rem}.main-content{flex:1;display:flex;justify-content:center;align-items:center;padding:2rem}.tracker-card{background:var(--card-bg);padding:2rem 3rem;border-radius:1rem;box-shadow:var(--shadow);text-align:center;width:100%;max-width:400px}.tracker-card h2{font-size:2rem;color:var(--primary-color);margin-bottom:1rem}.tracker-card p{font-size:1.1rem;color:#555}.footer{text-align:center;padding:1rem;background-color:#e0e7ff;font-size:.9rem}