*{margin:0;padding:0;box-sizing:border-box;font-family:"Segoe UI",Tahoma,Geneva,Verdana,sans-serif}body{background:linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);min-height:100vh;display:flex;justify-content:center;align-items:center;padding:20px}.container{max-width:800px;width:100%;background:white;border-radius:16px;box-shadow:0 10px 30px rgba(0, 0, 0, 0.1);overflow:hidden}.app-header{background:linear-gradient(135deg, #4b6cb7 0%, #182848 100%);color:white;padding:30px;text-align:center}.app-header h1{font-size:2.2rem;margin-bottom:10px}.app-header p{font-size:1.1rem;opacity:.9}.content{padding:30px;min-height:400px;display:flex;flex-direction:column}.intro-screen,.challenge-screen{display:flex;flex-direction:column;align-items:center;justify-content:center;flex-grow:1}.intro-screen button,.btn-complete{margin:30px auto 0 auto;display:block}.intro-screen h2{color:#2c3e50;margin-bottom:20px;font-size:1.8rem}.intro-screen p{color:#555;line-height:1.6;margin-bottom:30px;max-width:600px}.btn{background:linear-gradient(135deg, #4b6cb7 0%, #182848 100%);color:white;border:none;padding:14px 30px;font-size:1.1rem;border-radius:50px;cursor:pointer;transition:transform .3s,box-shadow .3s;font-weight:600;margin-top:10px}.btn:hover{transform:translateY(-3px);box-shadow:0 7px 15px rgba(0, 0, 0, 0.1)}.btn-complete{background:linear-gradient(135deg, #2ecc71 0%, #27ae60 100%)}.btn-reset{background:none;border:1px solid #e74c3c;color:#e74c3c;padding:4px 8px;border-radius:4px;cursor:pointer;font-size:.8rem;margin-left:10px;transition:all .3s}.btn-reset:hover{background:#e74c3c;color:white}.challenge-header{display:flex;justify-content:space-between;width:100%;margin-bottom:30px;align-items:center}.day-indicator{background:#4b6cb7;color:white;padding:8px 20px;border-radius:50px;font-weight:bold}.progress{font-size:.9rem;color:#7f8c8d}.challenge-card{background:#f8f9fa;border-radius:12px;padding:30px;width:100%;box-shadow:0 5px 15px rgba(0, 0, 0, 0.05);margin-bottom:20px}.challenge-title{color:#2c3e50;font-size:1.5rem;margin-bottom:15px}.challenge-description{color:#555;line-height:1.6;margin-bottom:20px}.challenge-tip{background:#e8f4fc;border-left:4px solid #4b6cb7;padding:15px;border-radius:4px;margin-top:20px;font-style:italic}.completion-message{background:#d4edda;color:#155724;padding:15px;border-radius:8px;margin-top:20px;display:none}.info-footnote{margin-top:25px;padding-top:15px;border-top:1px solid #e0e0e0;text-align:center}.info-footnote a{color:#4b6cb7;text-decoration:none;font-size:.9rem;transition:color .3s}.info-footnote a:hover{color:#182848;text-decoration:underline}.navigation{display:flex;justify-content:space-between;width:100%;margin-top:20px}.btn-prev{background:#95a5a6}.hidden{display:none}@media(max-width: 600px){.container{border-radius:10px}.app-header{padding:20px}.app-header h1{font-size:1.8rem}.content{padding:20px}.challenge-card{padding:20px}}