:root{--neutral-900: #18181b;--neutral-800: #27272a;--neutral-700: #3f3f46;--neutral-600: #52525b;--neutral-500: #71717a;--neutral-400: #a1a1aa;--neutral-300: #d4d4d8;--neutral-200: #e4e4e7;--neutral-100: #f4f4f5;--neutral-50: #fafafa;--glass-bg: rgba(255, 255, 255, .98);--glass-border: #e4e4e7;--accent-gradient: linear-gradient(135deg, #18181b 0%, #3f3f46 100%);--text-dark: #18181b;--text-light: #52525b}body.dark-mode{--glass-bg: rgba(24, 24, 27, .95);--glass-border: #3f3f46;--neutral-900: #fafafa;--neutral-800: #f4f4f5;--neutral-700: #e4e4e7;--neutral-600: #a1a1aa;--neutral-500: #71717a;--neutral-400: #52525b;--neutral-300: #3f3f46;--neutral-200: #27272a;--neutral-100: #18181b;--neutral-50: #161214;--accent-gradient: linear-gradient(135deg, #ffffff 0%, #a1a1aa 100%);--text-dark: #fafafa;--text-light: #a1a1aa}.topic-header{margin-bottom:2rem}.topic-header h1{color:var(--neutral-900)!important;font-family:Outfit,sans-serif!important;font-weight:800!important;font-size:2.25rem!important;margin:.5rem 0 .6rem!important;letter-spacing:-.02em}.topic-header p{color:var(--neutral-600)!important;font-size:1.05rem!important;margin:0;line-height:1.6}.neutral-badge{display:inline-flex;align-items:center;gap:6px;padding:4px 12px;background:var(--neutral-100);border:1px solid var(--neutral-200);color:var(--neutral-800);border-radius:20px;font-weight:700;font-size:.82rem;margin-bottom:.75rem}body.dark-mode .neutral-badge{background:var(--neutral-200);border-color:var(--neutral-300);color:var(--neutral-800)}.subject-nav{display:flex;gap:8px;margin-bottom:2.25rem;flex-wrap:wrap;border-bottom:1px solid var(--neutral-200);padding-bottom:1.25rem}body.dark-mode .subject-nav{border-bottom-color:var(--neutral-700)}.sub-nav-item{background:var(--neutral-50)!important;border:1px solid var(--neutral-200)!important;color:var(--neutral-600)!important;border-radius:30px!important;padding:.6rem 1.25rem!important;font-weight:600!important;font-family:Outfit,sans-serif!important;font-size:.92rem!important;cursor:pointer;transition:all .2s ease!important;display:inline-flex!important;align-items:center!important;gap:8px!important}.sub-nav-item:hover{background:var(--neutral-100)!important;color:var(--neutral-900)!important;border-color:var(--neutral-400)!important}.sub-nav-item.active{background:var(--neutral-900)!important;color:#fff!important;border-color:var(--neutral-900)!important;box-shadow:0 4px 12px #18181b33!important}body.dark-mode .sub-nav-item.active{background:#fff!important;color:#18181b!important;border-color:#fff!important}.card-premium{background:var(--glass-bg)!important;border:1px solid var(--glass-border)!important;box-shadow:0 6px 20px -4px #0000000a!important;border-radius:12px!important;padding:1.6rem!important;margin-bottom:1.75rem!important}.card-title{color:var(--neutral-900)!important;font-family:Outfit,sans-serif!important;font-weight:700!important;font-size:1.25rem!important;margin:0 0 .85rem!important;display:flex;align-items:center;gap:8px}.card-title i{color:var(--neutral-500)}.theory-para{color:var(--neutral-700)!important;line-height:1.7!important;font-size:.96rem!important;margin:0 0 1rem!important}.theory-highlight{background:var(--neutral-100)!important;border:1px solid var(--neutral-200)!important;color:var(--neutral-900)!important;border-radius:8px!important;padding:12px 16px!important;margin:14px 0!important;font-family:Fira Code,monospace!important;font-size:.92rem!important}body.dark-mode .theory-highlight{background:var(--neutral-200)!important;border-color:var(--neutral-300)!important}.example-box{background:var(--neutral-50);border:1px solid var(--neutral-200);border-left:4px solid var(--neutral-800);border-radius:0 10px 10px 0;padding:1.25rem;margin:1.25rem 0}body.dark-mode .example-box{background:var(--neutral-100);border-color:var(--neutral-300);border-left-color:var(--neutral-400)}details.solution-details{background:var(--glass-bg);border:1px solid var(--neutral-200);border-radius:8px;padding:.75rem 1.1rem;margin-top:.9rem;transition:all .2s ease}body.dark-mode details.solution-details{background:var(--neutral-100);border-color:var(--neutral-300)}details.solution-details[open]{border-color:var(--neutral-400);box-shadow:0 2px 8px #00000008}details.solution-details summary{font-family:Outfit,sans-serif;font-weight:700;font-size:.88rem;color:var(--neutral-800);cursor:pointer;user-select:none;display:flex;align-items:center;gap:8px}body.dark-mode details.solution-details summary{color:var(--neutral-800)}details.solution-details summary:before{content:"\f05a";font-family:"Font Awesome 6 Free";font-weight:900;color:var(--neutral-500);font-size:.85rem}.solution-explanation{margin-top:.75rem;padding-top:.75rem;border-top:1px dashed var(--neutral-200);font-size:.93rem;color:var(--neutral-700);line-height:1.7}body.dark-mode .solution-explanation{border-top-color:var(--neutral-300);color:var(--neutral-700)}.q-card{background:var(--glass-bg);border:1px solid var(--glass-border);border-radius:12px;padding:1.35rem;margin-bottom:1.25rem;box-shadow:0 4px 12px -2px #00000005}.q-header-meta{display:flex;justify-content:space-between;align-items:center;margin-bottom:.6rem}.q-number-pill{font-family:Fira Code,monospace;font-size:.8rem;font-weight:700;background:var(--neutral-100);border:1px solid var(--neutral-200);color:var(--neutral-800);padding:2px 8px;border-radius:6px}body.dark-mode .q-number-pill{background:var(--neutral-200);border-color:var(--neutral-300)}.q-marks-pill{font-size:.8rem;font-weight:600;color:var(--neutral-500)}.q-prompt{font-size:.97rem;font-weight:600;color:var(--neutral-900);margin:0 0 .75rem;line-height:1.6}.mock-section-title{background:var(--neutral-100);border:1px solid var(--neutral-200);border-radius:8px;padding:.75rem 1.25rem;margin:2rem 0 1.25rem;font-family:Outfit,sans-serif;font-weight:700;font-size:1.05rem;color:var(--neutral-900);display:flex;justify-content:space-between;align-items:center}body.dark-mode .mock-section-title{background:var(--neutral-200);border-color:var(--neutral-300)}.test-opt{border:1px solid var(--neutral-200)!important;background:var(--neutral-50)!important;color:var(--neutral-800)!important;border-radius:8px!important;padding:9px 14px!important;margin-bottom:8px!important;cursor:pointer;transition:all .15s ease!important;display:flex!important;align-items:center!important;gap:10px!important}.test-opt:hover{border-color:var(--neutral-400)!important;background:var(--neutral-100)!important}.next-tab-btn,.btn-grade-test{background:var(--neutral-900)!important;color:#fff!important;border:1px solid var(--neutral-900)!important;border-radius:8px!important;padding:10px 22px!important;font-weight:700!important;font-family:Outfit,sans-serif!important;cursor:pointer;transition:all .2s ease!important;display:inline-flex;align-items:center;gap:8px;text-decoration:none}.next-tab-btn:hover,.btn-grade-test:hover{background:var(--neutral-700)!important;border-color:var(--neutral-700)!important}body.dark-mode .next-tab-btn,body.dark-mode .btn-grade-test{background:#fff!important;color:#18181b!important;border-color:#fff!important}.rubric-tag{display:inline-block;background:var(--neutral-200);color:var(--neutral-800);font-family:Fira Code,monospace;font-size:.74rem;padding:1px 6px;border-radius:4px;font-weight:700;margin-right:6px}