:root{font-family:system-ui,Avenir,Helvetica,Arial,sans-serif;line-height:1.5;font-weight:400;color-scheme:light dark;color:#ffffffde;background-color:#242424;font-synthesis:none;text-rendering:optimizeLegibility;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}a{font-weight:500;color:#646cff;text-decoration:inherit}a:hover{color:#535bf2}body{margin:0;display:flex;place-items:center;min-width:320px;min-height:100vh}h1{font-size:3.2em;line-height:1.1}button{border-radius:8px;border:1px solid transparent;padding:.6em 1.2em;font-size:1em;font-weight:500;font-family:inherit;background-color:#1a1a1a;cursor:pointer;transition:border-color .25s}button:hover{border-color:#646cff}button:focus,button:focus-visible{outline:4px auto -webkit-focus-ring-color}@media (prefers-color-scheme: light){:root{color:#213547;background-color:#fff}a:hover{color:#747bff}button{background-color:#f9f9f9}}body{font-family:Arial,sans-serif;background-color:#f0f8ff;color:#333;display:flex;justify-content:center;align-items:center;min-height:100vh;margin:0;padding:20px;box-sizing:border-box}.app-container{background-color:#fff;padding:30px;border-radius:20px;box-shadow:0 10px 25px #0000001a;text-align:center;width:100%;max-width:900px}.game-header{margin-bottom:30px;display:flex;justify-content:space-between;align-items:center;padding-bottom:20px;border-bottom:2px solid #e0e0e0}.game-header h1{font-size:2.5rem;color:#007bff;margin:0}.display-mode-selector button{font-size:1.3rem;padding:10px 18px;margin:0 8px;border:2px solid #007bff;background-color:#fff;color:#007bff;border-radius:10px;cursor:pointer;transition:background-color .3s,color .3s}.display-mode-selector button:hover{background-color:#0056b3;color:#fff}.display-mode-selector button.active{background-color:#007bff;color:#fff}.score-display{font-size:1.6rem;font-weight:700;color:#28a745}.game-area{padding:20px}.question-container-new{display:flex;justify-content:space-around;align-items:flex-start;background-color:#fffacd;padding:20px;border-radius:15px;margin-bottom:30px;border:1px solid #ddd}.operand-column,.result-column{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:15px;flex:1;padding:10px;min-height:150px}.number-box{background-color:#fff;border:1px solid #ccc;border-radius:10px;padding:20px 30px;min-width:80px;box-shadow:0 2px 4px #0000001a;display:inline-flex;justify-content:center;align-items:center}.number-text{font-size:3.5rem;font-weight:700;color:#333}.objects-display{display:flex;flex-direction:column;justify-content:center;align-items:center;gap:8px;min-height:60px;width:100%}.item-object{font-size:2.5rem!important;padding:2px}.operator-cell{display:flex;flex-direction:column;align-items:center;justify-content:center;position:relative;align-self:stretch;padding:0 20px}.operator-cell:before,.operator-cell:after{content:"";position:absolute;left:50%;transform:translate(-50%);width:2px;background-color:#bdbdbd;height:calc(50% - 25px)}.operator-cell:before{top:0}.operator-cell:after{bottom:0}.operator-symbol{font-size:2rem;font-weight:700;color:#555;background-color:#fff;border:2px solid #bdbdbd;border-radius:50%;width:40px;height:40px;display:flex;justify-content:center;align-items:center;z-index:1}.answer-placeholder-new{font-size:4rem;font-weight:700;color:#dc3545;display:flex;justify-content:center;align-items:center}.options-container{display:flex;justify-content:center;gap:20px;margin-bottom:30px}.option-button{font-size:2.5rem;font-weight:700;padding:20px 35px;border:3px solid #28a745;background-color:#fff;color:#28a745;border-radius:15px;cursor:pointer;transition:background-color .3s,color .3s,transform .2s;min-width:90px}.option-button:hover{background-color:#218838;color:#fff;transform:translateY(-3px)}.feedback-message{font-size:1.8rem;font-weight:700;margin-top:25px;padding:15px;border-radius:10px;color:#fff}.feedback-message:empty{display:none}.loading{font-size:2rem;text-align:center;padding:50px;color:#007bff}@media (max-width: 768px){.game-header h1{font-size:2rem}.display-mode-selector button{font-size:1.1rem;padding:8px 12px}.score-display{font-size:1.3rem}.question-container-new{flex-direction:column;align-items:center;padding:15px}.operand-column,.result-column{width:100%;max-width:300px;gap:10px}.operator-cell{flex-direction:row;align-self:auto;padding:10px 0;width:80%;max-width:250px}.operator-cell:before,.operator-cell:after{width:calc(50% - 25px);height:2px;top:50%;transform:translateY(-50%)}.operator-cell:before{left:0}.operator-cell:after{right:0;left:auto}.number-text{font-size:2.8rem}.item-object{font-size:2rem!important}.operator-symbol{font-size:1.5rem;width:35px;height:35px}.options-container{flex-direction:column;gap:10px}.option-button{font-size:2rem;padding:15px 25px}.feedback-message{font-size:1.5rem}}@media (max-width: 480px){.game-header{flex-direction:column;gap:10px}.game-header h1{font-size:1.6rem}.display-mode-selector button{font-size:1rem;padding:6px 10px}.number-text{font-size:2.2rem}.item-object{font-size:1.8rem!important}.operator-symbol{font-size:1.3rem;width:30px;height:30px}.option-button{font-size:1.6rem;padding:12px 20px}}.question-container,.operand-stack,.operator,.answer-placeholder,.result-objects-display{display:none!important}