:root{--pearson-blue: #00467f;--pearson-blue-light: #005a9e;--pearson-grey-dark: #333333;--pearson-grey-medium: #666666;--pearson-grey-light: #f1f1f1;--pearson-border: #cccccc;--primary: var(--pearson-blue);--primary-hover: var(--pearson-blue-light);--bg-dark: #e0e0e0;--bg-card: #ffffff;--text-main: #333333;--text-muted: #666666;--accent: #2d8134;--error: #c73a3a;--warning: #ffcc00;--border: var(--pearson-border);--header-bg: var(--pearson-blue);--header-text: #ffffff;--footer-bg: #e0e0e0}.dark-theme{--bg-dark: #121212 !important;--bg-card: #1e1e1e !important;--text-main: #e0e0e0 !important;--text-muted: #aaaaaa !important;--border: #333333 !important;--header-bg: #1a1a1a !important;--footer-bg: #1a1a1a !important}*{margin:0;padding:0;box-sizing:border-box;font-family:Segoe UI,Tahoma,Geneva,Verdana,sans-serif}body{background-color:var(--bg-dark);color:var(--text-main);min-height:100vh;overflow-x:hidden;line-height:1.5}#root{width:100%;min-height:100vh;display:flex;flex-direction:column}button{cursor:pointer;border:none;outline:none;transition:all .2s cubic-bezier(.4,0,.2,1);font-size:.95rem}button:hover:not(:disabled){transform:translateY(-1px);filter:brightness(1.1)}button:active:not(:disabled){transform:translateY(0)}button:disabled{opacity:.5;cursor:not-allowed}.option-row:disabled{opacity:1!important}.container{max-width:1200px;margin:0 auto;padding:0 1rem;width:100%}.card{background:var(--bg-card);padding:2.5rem;border:1px solid var(--border);box-shadow:0 4px 6px -1px #0000001a,0 2px 4px -1px #0000000f;transition:transform .2s ease,box-shadow .2s ease}.card:hover{box-shadow:0 10px 15px -3px #0000001a,0 4px 6px -2px #0000000d}h1,h2,h3,h4{font-weight:600;color:var(--text-main)}.btn-primary{background-color:var(--primary);color:#fff;padding:.6rem 1.5rem;border-radius:2px;font-weight:500;border-bottom:2px solid rgba(0,0,0,.2)}.btn-primary:hover:not(:disabled){background-color:var(--primary-hover)}.btn-primary:active:not(:disabled){transform:translateY(1px);border-bottom-width:0;margin-bottom:2px}.btn-outline{background:var(--bg-card);border:1px solid var(--border);color:var(--text-main);padding:.6rem 1.5rem;border-radius:2px;box-shadow:0 1px 2px #0000000d}.btn-outline:hover:not(:disabled){background:#f8f8f8;border-color:#999}.pvue-header{background:var(--header-bg);color:var(--header-text);padding:.75rem 1.5rem;display:flex;justify-content:space-between;align-items:center;font-size:.9rem}.pvue-sub-header{background:#fff;border-bottom:1px solid var(--border);padding:.5rem 1.5rem;display:flex;justify-content:space-between;align-items:center;font-size:.85rem;color:var(--pearson-grey-medium)}.pvue-footer{background:var(--footer-bg);border-top:1px solid var(--border);padding:1rem 1.5rem;display:flex;justify-content:space-between;align-items:center;position:fixed;bottom:0;left:0;right:0}.light-only{display:block}:root.dark-theme .light-only{display:none}.dark-only{display:none}:root.dark-theme .dark-only{display:block}pre{background:#f4f6f8;border:1px solid var(--border);padding:1.25rem;border-radius:4px;overflow-x:auto;font-family:Consolas,Monaco,Courier New,monospace;font-size:.9rem;line-height:1.45;margin:1.5rem 0;color:#24292e;white-space:pre-wrap;word-wrap:break-word}code{background:#afb8c133;padding:.2rem .4rem;border-radius:3px;font-family:Consolas,Monaco,Courier New,monospace;font-size:.9em;color:var(--pearson-blue-light)}.dark-theme pre{background:#0d1117!important;color:#c9d1d9!important;border-color:#30363d!important}.dark-theme code{background:#6e768166!important;color:#58a6ff!important}.custom-scrollbar::-webkit-scrollbar{width:6px}.custom-scrollbar::-webkit-scrollbar-track{background:transparent}.custom-scrollbar::-webkit-scrollbar-thumb{background:var(--border);border-radius:10px}.custom-scrollbar::-webkit-scrollbar-thumb:hover{background:var(--text-muted)}.animate-fade-in{animation:fadeIn .3s ease-out forwards}@keyframes fadeIn{0%{opacity:0;transform:translateY(5px)}to{opacity:1;transform:translateY(0)}}.option-row:hover:not(:disabled){background:#f1f7fb!important}.question-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(35px,1fr));gap:.5rem}.question-dot{position:absolute;top:-4px;right:-4px;width:8px;height:8px;background:var(--warning);border-radius:50%;border:1px solid white}@keyframes spin{0%{transform:rotate(0)}to{transform:rotate(360deg)}}.rich-text-explanation{margin-top:1rem}.rich-text-explanation img{display:block;max-width:100%;height:auto;margin:1.5rem auto;border:1px solid var(--border);padding:5px;background:#fff}.rich-text-explanation p{margin-bottom:1rem}.rich-text-explanation ul,.rich-text-explanation ol{padding-left:1.5rem;margin-bottom:1rem}.rich-text-explanation a{color:var(--pearson-blue);text-decoration:underline}.spinner{border:3px solid rgba(0,0,0,.1);border-top:3px solid var(--pearson-blue);border-radius:50%;width:40px;height:40px;animation:spin 1s linear infinite}.overlay-loading{position:fixed;inset:0;z-index:1000;display:flex;flex-direction:column;align-items:center;justify-content:center;background:#ffffffe6}@media(max-width:768px){.pvue-header{padding:.5rem 1rem!important;font-size:.8rem!important}.pvue-sub-header{padding:.5rem 1rem!important;font-size:.75rem!important}.card{padding:1.5rem!important}.question-grid{grid-template-columns:repeat(auto-fill,minmax(30px,1fr))!important;gap:.35rem!important}pre,code{font-size:.8rem!important;padding:.75rem!important}.lobby-grid{grid-template-columns:1fr!important}.bottom-nav{padding:.75rem 1rem 1.5rem!important}.search-container{width:100%!important}}@media(max-width:480px){h1{font-size:1.5rem!important}h2{font-size:1.25rem!important}.option-row{padding:.75rem 1rem!important;font-size:.95rem!important}.btn-primary,.btn-outline{padding:.5rem 1rem!important;font-size:.85rem!important}}