* {
                box-sizing: border-box;
                font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
            }

            body {
                background: linear-gradient(135deg, #f0f4ff, #dbe6ff);
                height: 100vh;
                margin: 0;
                display: flex;
                flex-direction: column;
                align-items: center;
                justify-content: flex-start;
                padding: 1rem;
            }

            #game-container {
                background: white;
                padding: 0px 20px 20px 20px;
                border-radius: 20px;
                box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
                text-align: center;
                width: 90%;
                max-width: 400px;
                position: relative;
            }

            h1 {
                margin-bottom: 1rem;
                line-height: 1.2;
            }

            #mainTitle {
                font-size: 3.2rem;
                font-weight: 800;
                color: #4e89ff;
                text-shadow: 2px 2px 0 rgba(0, 0, 0, 0.1);
                letter-spacing: 2px;
            }

            #subTitle {
                font-size: 2rem;
                font-weight: 500;
                color: #333;
                background: linear-gradient(to right, #4e89ff, #9b59b6);
                -webkit-background-clip: text;
                -webkit-text-fill-color: transparent;
            }

            #levelBox {
                padding: 0.7rem 1rem;
                margin-bottom: 1.2rem;
                margin-top: 10px;
                border-radius: 10px;
                display: inline-block;
                text-align: left;
                transition:
                    background-color 0.3s ease,
                    border-left 0.3s ease;
            }

            #levelLabel {
                font-size: 1.2rem;
                font-weight: bold;
                display: block;
            }

            #toleranceInfo {
                font-size: 0.9rem;
                color: #555;
                margin-top: 2px;
                display: block;
            }

            #timer {
                font-size: 3.5rem;
                font-weight: bold;
                color: #3a3a3a;
                margin-bottom: 1.2rem;
            }

            button {
                padding: 1rem 2rem;
                font-size: 1.2rem;
                background-color: #4e89ff;
                color: white;
                border: none;
                border-radius: 10px;
                box-shadow: 0 5px 15px rgba(78, 137, 255, 0.3);
                cursor: pointer;
                transition: background-color 0.2s ease;
                margin: 0.5rem;
            }

            button:hover {
                background-color: #3a6edc;
            }

            #result {
                margin-top: 1.5rem;
                font-size: 1.2rem;
                color: #444;
            }

            #gameOverArea {
                display: none;
                margin-top: 2rem;
                background: #ffeaea;
                border: 2px solid #ff4d4f;
                padding: 1.5rem;
                border-radius: 15px;
                color: #c0392b;
                animation: fadeIn 0.3s ease-in;
            }

            #gameOverArea p {
                font-size: 1.3rem;
                margin-bottom: 1rem;
            }

            #finalLevelBox {
                margin-top: 0.5rem;
                font-size: 1.1rem;
                background: #ff4d4f;
                color: white;
                padding: 0.5rem 1rem;
                border-radius: 30px;
                font-weight: bold;
                display: inline-block;
            }

            #finalDiff {
                font-size: 1rem;
                color: #333;
                margin-top: 0.5rem;
            }

            @keyframes fadeIn {
                from {
                    opacity: 0;
                    transform: translateY(20px);
                }
                to {
                    opacity: 1;
                    transform: translateY(0);
                }
            }

            #levelUpBanner {
                position: absolute;
                top: -10px;
                left: 50%;
                transform: translateX(-50%);
                background: #fff8c5;
                border: 2px solid #f5c518;
                padding: 0.5rem 1rem;
                border-radius: 20px;
                font-size: 1rem;
                font-weight: bold;
                color: #b38f00;
                opacity: 0;
                transition: opacity 0.3s ease;
                pointer-events: none;
            }

            .animate {
                animation: scaleUp 0.4s ease-in-out;
            }

            @keyframes scaleUp {
                0% {
                    transform: scale(1);
                }
                50% {
                    transform: scale(1.15);
                }
                100% {
                    transform: scale(1);
                }
            }