:root{--primary: #8e44ad;--primary-dark: #6c3483;--primary-light: #a569bd;--secondary: #e74c3c;--accent: #f39c12;--text-dark: #2c3e50;--text-light: #555;--bg-gradient: linear-gradient(135deg, #fdfbfd 0%, #f4ecf7 100%);--white: #ffffff;--card-bg: #ffffff;--box-bg: #f4f6f7;--header-bg: rgba(255, 255, 255, .95);--border-color: #eee;--success: #27ae60;--error: #c0392b;--shadow: 0 10px 30px rgba(0, 0, 0, .05);--accordion-header: #f8f9fa;--focus-ring: 2px solid var(--accent)}body.dark-mode{--primary: #9b59b6;--primary-dark: #8e44ad;--primary-light: #be93d4;--secondary: #e74c3c;--accent: #f39c12;--text-dark: #ecf0f1;--text-light: #bdc3c7;--bg-gradient: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);--white: #1f2937;--card-bg: #1f2937;--box-bg: #2c3e50;--header-bg: rgba(31, 41, 55, .95);--border-color: #374151;--shadow: 0 10px 30px rgba(0, 0, 0, .3);--accordion-header: #374151}*{margin:0;padding:0;box-sizing:border-box;font-family:Poppins,sans-serif;scroll-behavior:smooth}body{background:var(--bg-gradient);color:var(--text-dark);overflow-x:hidden;line-height:1.6;transition:background .3s,color .3s}:focus-visible{outline:var(--focus-ring);outline-offset:2px}.progress-container{position:fixed;top:0;left:0;width:100%;height:5px;background:#0000001a;z-index:2000}.progress-bar{height:5px;background:var(--secondary);width:0%;transition:width .1s}header{background:var(--header-bg);backdrop-filter:blur(12px);padding:.8rem 5%;display:flex;justify-content:space-between;align-items:center;box-shadow:0 4px 20px #0000000a;position:sticky;top:0;z-index:1000;transition:background .3s}.logo{font-size:1.4rem;font-weight:800;display:flex;align-items:center;gap:10px;text-decoration:none;background:linear-gradient(45deg,var(--primary),#c0392b);background-clip:text;color:transparent}.nav-controls{display:flex;justify-content:space-between;max-width:900px;margin:2rem auto;padding:0 1rem;flex-wrap:wrap;align-items:stretch}.nav-btn{padding:10px 20px;background:var(--card-bg);color:var(--primary);border:2px solid var(--primary);border-radius:50px;font-weight:600;text-decoration:none;transition:all .3s;display:flex;align-items:center;gap:8px;font-size:.9rem;cursor:pointer}.nav-btn:hover{background:var(--primary);color:#fff;transform:translateY(-2px);box-shadow:0 5px 15px #8e44ad33}.content-wrapper{max-width:900px;margin:0 auto 4rem;padding:0 1.5rem;overflow-x:hidden}h1.chapter-title{font-size:2.5rem;color:var(--primary-dark);text-align:center;margin-bottom:.5rem}body.dark-mode h1.chapter-title{color:var(--primary-light)}.chapter-subtitle{text-align:center;color:var(--text-light);margin-bottom:3rem;font-size:1.1rem}.note-section{background:var(--card-bg);border-radius:20px;padding:2.5rem;margin-bottom:2.5rem;box-shadow:var(--shadow);border:1px solid rgba(0,0,0,.03);transition:transform .3s,background .3s;overflow-wrap:break-word;width:100%}.note-section h2{font-size:1.6rem;color:var(--primary);margin-bottom:1.5rem;border-bottom:2px solid var(--border-color);padding-bottom:.5rem;display:inline-block}.note-section h3{font-size:1.2rem;color:var(--text-dark);margin-top:1.5rem;margin-bottom:.8rem}.calc-box{background:var(--box-bg);padding:25px;border-radius:15px;text-align:center;margin:20px 0;border:1px dashed var(--primary);width:100%;box-sizing:border-box;overflow-wrap:break-word}.input-group{display:flex;justify-content:center;gap:15px;margin:20px 0;flex-wrap:wrap}.set-input,.calc-input{width:100%;max-width:300px;padding:12px;border-radius:8px;border:1px solid var(--border-color);text-align:center;background:var(--card-bg);color:var(--text-dark);font-size:1rem;margin-bottom:10px}.calc-btn{padding:12px 30px;background:var(--success);color:#fff;border:none;border-radius:8px;cursor:pointer;font-weight:700;font-size:1.1rem;transition:transform .2s;margin-top:10px}.calc-btn:hover{transform:scale(1.05)}.result-panel{background:var(--card-bg);margin-top:25px;padding:20px;border-radius:8px;text-align:left;display:none;border-left:5px solid var(--accent)}.result-code{font-family:monospace;background:var(--box-bg);padding:15px;border-radius:5px;display:block;margin-top:10px;color:var(--primary);font-size:1rem}.result-row{padding:8px 0;border-bottom:1px solid var(--border-color);font-size:.95rem}.res-label{font-weight:600;color:var(--text-light);margin-right:10px}.res-val{font-weight:700;color:var(--primary);font-family:monospace;font-size:1.1em}.visual-container,.graph-canvas-container,.venn-container{width:100%;max-width:450px;margin:0 auto 20px;background:var(--card-bg);border:1px solid var(--border-color);border-radius:15px;position:relative;text-align:center}.graph-canvas-container,.visual-container{height:350px}.graph-controls,.venn-btn-group{display:flex;gap:10px;justify-content:center;flex-wrap:wrap;margin-bottom:25px}.graph-btn,.venn-btn{padding:10px 18px;background:var(--card-bg);border:1px solid var(--border-color);color:var(--text-dark);border-radius:50px;cursor:pointer;transition:.3s;font-weight:600;font-size:.9rem}.graph-btn.active,.venn-btn:hover{background:var(--primary);color:#fff;border-color:var(--primary)}.flip-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:20px;margin:20px 0}.flip-card{background-color:transparent;height:200px;perspective:1000px;cursor:pointer}.flip-card-inner{position:relative;width:100%;height:100%;text-align:center;transition:transform .6s;transform-style:preserve-3d;box-shadow:var(--shadow);border-radius:15px}.flip-card.flipped .flip-card-inner{transform:rotateY(180deg)}.flip-card-front,.flip-card-back{position:absolute;width:100%;height:100%;-webkit-backface-visibility:hidden;backface-visibility:hidden;border-radius:15px;display:flex;flex-direction:column;justify-content:center;align-items:center;padding:20px;box-sizing:border-box}.flip-card-front{background:var(--card-bg);color:var(--text-dark);border:1px solid var(--border-color)}.flip-card-back{background-color:var(--primary);color:#fff;transform:rotateY(180deg)}.accordion-item{border:1px solid var(--border-color);border-radius:8px;margin-bottom:10px;overflow:hidden}.accordion-header{width:100%;text-align:left;background:var(--accordion-header);padding:15px;cursor:pointer;font-weight:600;display:flex;justify-content:space-between;align-items:center;color:var(--text-dark);transition:background .3s;border:none;font-family:inherit;font-size:1.05rem}.accordion-header:hover{background:var(--border-color)}.accordion-body{display:none;padding:20px;background:var(--card-bg);border-top:1px solid var(--border-color);color:var(--text-dark)}.table-container{width:100%;overflow:hidden;margin:25px 0}.styled-table{width:100%;border-collapse:collapse;font-size:1rem;background-color:var(--card-bg);border-radius:10px;overflow:hidden}.styled-table thead tr{background-color:var(--primary);color:#fff;text-align:left}.styled-table th,.styled-table td{padding:15px 20px;border-bottom:1px solid var(--border-color);color:var(--text-dark)}@media(max-width:992px){.styled-table thead{display:none}.styled-table,.styled-table tbody,.styled-table tr,.styled-table td{display:block;width:100%}.styled-table tr{margin-bottom:20px;border:1px solid var(--border-color);border-radius:12px;box-shadow:var(--shadow);background:var(--card-bg)}.styled-table td{text-align:left;padding:20px;position:relative;border-bottom:1px solid var(--border-color)}.styled-table td:before{content:attr(data-label);display:block;font-weight:800;color:var(--primary);margin-bottom:10px;text-transform:uppercase;font-size:.9em}}.quiz-container{background:var(--box-bg);border:2px solid var(--accent)}.quiz-option{display:block;width:100%;text-align:left;background:var(--card-bg);padding:15px;margin:10px 0;border-radius:10px;cursor:pointer;border:1px solid var(--border-color);transition:all .2s;color:var(--text-dark);font-family:inherit;font-size:1.05rem}.quiz-option:hover{background:var(--accordion-header)}.quiz-option.correct{background:#d4edda;border-color:#28a745;color:#155724}.quiz-option.wrong{background:#f8d7da;border-color:#dc3545;color:#721c24}mjx-container{font-size:110%!important;white-space:normal!important;overflow:visible!important;max-width:100%}body.dark-mode mjx-container{color:#ecf0f1!important}body.dark-mode line,body.dark-mode path,body.dark-mode circle,body.dark-mode rect{stroke:#ecf0f1}body.dark-mode text{fill:#ecf0f1}body.dark-mode .axis{stroke:#7f8c8d!important}body.dark-mode .grid{stroke:#374151!important}.note-section p,.note-section li{max-width:70ch;line-height:1.75;margin-left:auto;margin-right:auto}svg{max-width:100%;height:auto}@media(max-width:600px){h1.chapter-title{font-size:2rem}.note-section{padding:1.5rem 1rem}.content-wrapper{padding:0 .8rem}mjx-container{font-size:100%!important}}.comparison-grid{display:grid;grid-template-columns:1fr 1fr;gap:15px;margin-top:15px}.comp-card{background:var(--box-bg);padding:15px;border-radius:8px;text-align:center;border:1px solid var(--border-color)}@media(max-width:600px){.comparison-grid{grid-template-columns:1fr}}