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0}.solution-locked-icon{font-size:3rem;color:var(--secondary-color);margin-bottom:1rem}.solution-content{animation:fadeIn .5s ease}.solution-section{margin-bottom:2rem}.solution-section h3{color:var(--primary-color);margin-bottom:1rem;font-size:1.4rem}.solution-image{max-width:100%;height:auto;border-radius:var(--border-radius);margin:1.5rem 0;box-shadow:var(--card-shadow)}.solution-equation{font-family:"Cambria Math",serif;background-color:#e0e7ef4d;padding:1rem;margin:1rem 0;border-radius:var(--border-radius);text-align:center;font-size:1.2rem;border-left:3px solid var(--accent-color)}.solution-calculation{background-color:#e0e7ef33;padding:1rem;margin:1rem 0;border-radius:var(--border-radius);font-family:monospace;line-height:1.5}.solution-table{width:100%;border-collapse:collapse;margin:1rem 0}.solution-table th,.solution-table td{padding:.7rem;border:1px solid var(--secondary-color)}.solution-table th{background-color:var(--primary-color);color:#fff;text-align:left}.solution-table tr:nth-child(2n){background-color:#e0e7ef33}@media (max-width: 768px){.tab-content{padding:1rem}.parameters-table td{padding:.5rem}.parameters-table td:first-child{width:auto}.harvard-references li{padding-left:.8rem}.chart-container{height:300px;padding-bottom:40px}.visualization-options{flex-direction:column}.formula{font-size:1rem;padding:.4rem .8rem}.quiz-option{padding:.5rem .8rem}.solution-equation{font-size:1rem;padding:.8rem}.solution-calculation{font-size:.9rem;overflow-x:auto}.solution-table{font-size:.9rem}}@media (max-width: 480px){.tab-content h2{font-size:1.5rem}.tab-content h3{font-size:1.3rem}.parameters-table{font-size:.9rem}.chart-container{height:250px;padding-bottom:50px}}:root{--primary-color: #2a5d8f;--secondary-color: #e0e7ef;--accent-color: #f9b233;--danger-color: #d7263d;--success-color: #3bb273;--text-color: #222;--background-color: #fff;--tab-active-bg: #f9b233;--tab-inactive-bg: #e0e7ef;--tab-active-color: #222;--tab-inactive-color: #2a5d8f;--footer-bg: #2a5d8f;--footer-text: #fff;--border-radius: 8px;--transition: .2s;--card-shadow: 0 2px 8px rgba(42,93,143,.1);--font-main: "Segoe UI", Arial, sans-serif;--header-height: 60px;--footer-height: 80px}*{box-sizing:border-box;margin:0;padding:0}body{font-family:var(--font-main);background:var(--background-color);color:var(--text-color);line-height:1.6;overflow-x:hidden}a{color:var(--primary-color);text-decoration:none;transition:all var(--transition) ease}a:hover{color:var(--accent-color)}button{cursor:pointer;font-family:var(--font-main);border:none;outline:none}h1,h2,h3,h4,h5,h6{margin-bottom:.5em;line-height:1.3;color:var(--primary-color)}.container{max-width:1200px;margin:0 auto;padding:0 1rem}@media (max-width: 768px){:root{--header-height: 120px}.container{padding:0 .5rem}}@media (max-width: 480px){h1{font-size:1.8rem}h2{font-size:1.5rem}}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}.fade-in{animation:fadeIn .3s ease-in-out}