:root{--bg-primary: #000000;--bg-secondary: #121212;--bg-tertiary: #1E1E1E;--text-primary: #FFFFFF;--text-secondary: #B3B3B3;--accent: #FFD700;--accent-light: #FFE44D;--accent-dark: #D4AF37;--white: #FFFFFF;--black: #000000;--gray-100: #F5F5F5;--gray-200: #EEEEEE;--gray-300: #E0E0E0;--gray-400: #BDBDBD;--gray-500: #9E9E9E;--gray-600: #757575;--gray-700: #616161;--gray-800: #424242;--gray-900: #212121;--bg-gradient-start: #000000;--bg-gradient-end: #121212;--header-height: 100px;--logo-height: 160px;--mobile-logo-height: 80px;--border-radius: 8px;--box-shadow: 0 4px 20px rgba(0, 0, 0, .3);--transition: all .3s ease}*{margin:0;padding:0;box-sizing:border-box;font-family:Segoe UI,Roboto,Helvetica Neue,Arial,sans-serif}html{scroll-behavior:smooth}body{background-color:var(--bg-primary);color:var(--text-primary);transition:var(--transition);line-height:1.6;overflow-x:hidden}a{text-decoration:none;color:inherit;transition:var(--transition)}ul,ol{list-style:none}img{max-width:100%;height:auto;display:block}.container{width:90%;max-width:1200px;margin:0 auto;padding:20px 0}.section-subtitle{color:var(--text-secondary);text-align:center;max-width:800px;margin:0 auto 50px;font-size:1.2rem}h1{font-size:3.2rem;line-height:1.2;font-weight:700}h2{font-size:2.8rem;margin-bottom:20px;text-align:center;position:relative;font-weight:600}h3{font-size:1.8rem;margin-bottom:15px;font-weight:500}p{margin-bottom:1rem;font-size:1.1rem}.accent{color:var(--accent)}h2:after{content:"";display:block;width:80px;height:4px;background-color:var(--accent);margin:15px auto 30px}header{background-color:var(--bg-secondary);height:var(--header-height);position:fixed;width:100%;z-index:1000;box-shadow:var(--box-shadow);display:flex;align-items:center;transition:var(--transition)}.header-container{width:100%;display:flex;justify-content:space-between;align-items:center;padding:0 5%}.logo img{height:var(--logo-height);width:auto;transition:transform .3s;object-fit:contain}.logo img:hover{height:175px;width:auto;transition:transform .3s;object-fit:contain}nav.desktop-menu ul{display:flex;gap:30px}nav.desktop-menu a{font-weight:600;font-size:1.1rem;position:relative;padding:5px 0;transition:var(--transition)}nav.desktop-menu a:after{content:"";position:absolute;bottom:0;left:0;width:0;height:2px;background-color:var(--accent);transition:width .1s}nav.desktop-menu a:hover,nav.desktop-menu a.active{color:var(--accent)}nav.desktop-menu a:hover:after,nav.desktop-menu a.active:after{width:100%}.mobile-menu-button{display:none;background:none;border:none;color:var(--text-primary);font-size:1.8rem;cursor:pointer;z-index:1001;padding:10px;transition:var(--transition)}.mobile-menu-button:hover,.mobile-menu-button[aria-expanded=true]{color:var(--accent)}nav.mobile-menu{position:fixed;top:var(--header-height);right:-100%;width:80%;max-width:300px;height:calc(100vh - var(--header-height));background-color:var(--bg-secondary);box-shadow:-5px 0 15px #0003;transition:right .3s ease-in-out;z-index:1000;overflow-y:auto}nav.mobile-menu.active{right:0}nav.mobile-menu ul{padding:30px;display:flex;flex-direction:column;gap:15px}nav.mobile-menu a{font-size:1.2rem;font-weight:500;display:block;padding:12px 15px;border-radius:var(--border-radius);transition:var(--transition)}nav.mobile-menu a:hover{background-color:var(--bg-tertiary);color:var(--accent)}.btn{display:inline-block;padding:12px 24px;border-radius:var(--border-radius);font-weight:600;font-size:1.1rem;transition:var(--transition);text-align:center;cursor:pointer;border:2px solid transparent;text-decoration:none;display:inline-flex;align-items:center;gap:8px}.btn-primary{background-color:var(--accent);color:var(--black);padding:5px;border-radius:8px}.btn-primary:hover{background-color:transparent;color:var(--accent);border-radius:8px;transform:translateY(-3px);box-shadow:0 10px 20px #ffd7004d}.btn-secondary{background-color:transparent;color:var(--accent);border-color:var(--accent)}.btn-secondary:hover{background-color:var(--accent);color:var(--black);transform:translateY(-3px);box-shadow:0 5px 15px #ffd7004d}.btn-outline{background-color:transparent;color:var(--accent);border:2px solid var(--accent);padding:12px 25px}.btn-outline:hover{background-color:var(--accent);color:var(--black)}.btn-ghost{background-color:transparent;color:var(--text-primary);border:2px solid var(--gray-600)}.btn-ghost:hover{border-color:var(--accent);color:var(--accent)}.btn-outline-white{background-color:transparent;color:var(--text-primary);border:2px solid var(--text-primary)}.btn-outline-white:hover{background-color:#ffffff1a}.btn-card{padding:12px 25px;font-size:1rem}.cta-buttons{display:flex;justify-content:center;gap:20px;flex-wrap:wrap;margin-top:30px}.ebook-hero{padding:calc(var(--header-height) + 80px) 0 100px;text-align:center;background:linear-gradient(135deg,var(--bg-gradient-start) 0%,var(--bg-gradient-end) 100%),url(assets/ebook-bg.jpg) no-repeat center/cover;position:relative;overflow:hidden}.ebook-hero:before{content:"";position:absolute;top:0;left:0;width:100%;height:100%;background-color:#00000080;z-index:0}.ebook-hero .container{position:relative;z-index:1}.ebook-hero h1{font-size:3.5rem;margin-bottom:20px;line-height:1.2;text-shadow:0 2px 10px rgba(0,0,0,.5)}.ebook{padding:100px 0;background-color:var(--bg-primary)}.ebook-content{display:flex;gap:60px;align-items:center}.ebook-text{flex:1}.ebook-text h2{margin-bottom:25px;position:relative;display:inline-block;text-align:left}.ebook-text h2:after{content:"";display:block;width:100%;height:3px;background:linear-gradient(90deg,var(--accent) 0%,transparent 100%);margin:10px 0 20px}.ebook-text ul{margin:30px 0;list-style:none;padding:0}.ebook-text li{margin-bottom:18px;display:flex;align-items:flex-start;gap:12px;padding:12px 15px;background-color:var(--bg-secondary);border-radius:var(--border-radius);transition:var(--transition)}.ebook-text li:hover{background-color:#ffd7000d;transform:translate(5px)}.ebook-text i{color:var(--accent);margin-top:3px;flex-shrink:0;font-size:1.2rem}.ebook-image{flex:1;position:relative;border-radius:var(--border-radius);overflow:visible;box-shadow:var(--box-shadow);transition:var(--transition);border:1px solid rgba(255,215,0,.2);max-width:100%;display:flex;justify-content:center;align-items:center}.ebook-image:hover{transform:translateY(-5px);box-shadow:0 15px 35px #ffd70033}.ebook-image img{max-width:100%;height:auto;display:block;transition:transform .5s ease;object-fit:contain}.ebook-image:hover img{transform:scale(1.03)}.ebook-badge{position:absolute;top:20px;right:20px;background-color:var(--accent);color:var(--black);padding:10px 20px;border-radius:30px;font-weight:700;box-shadow:0 5px 15px #ffd7004d;z-index:1;font-size:.9rem}.testimonials{padding:100px 0;background-color:var(--bg-tertiary);position:relative}.testimonials:before{content:"";position:absolute;top:0;left:0;width:100%;height:100%;background:url(assets/dots-pattern.png) repeat;opacity:.03;z-index:0}.testimonials .container{position:relative;z-index:1}.testimonial-cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(350px,1fr));gap:40px;margin-top:60px}.testimonial-card{background-color:var(--bg-secondary);padding:40px 30px;border-radius:var(--border-radius);box-shadow:var(--box-shadow);transition:var(--transition);position:relative;overflow:hidden;border:1px solid rgba(255,215,0,.1)}.testimonial-card:before{content:"";position:absolute;top:0;left:0;width:100%;height:4px;background:linear-gradient(90deg,var(--accent) 0%,transparent 100%);opacity:0;transition:var(--transition)}.testimonial-card:hover{transform:translateY(-10px);box-shadow:0 20px 40px #ffd70026}.testimonial-card:hover:before{opacity:1}.testimonial-rating{color:var(--accent);margin-bottom:20px;font-size:1.1rem}.testimonial-card p{font-style:italic;position:relative;z-index:1;line-height:1.7;margin-bottom:25px}.testimonial-author{display:flex;align-items:center;gap:20px}.testimonial-author img{width:70px;height:70px;border-radius:50%;object-fit:cover;border:3px solid var(--accent);transition:var(--transition)}.testimonial-card:hover .testimonial-author img{transform:scale(1.1)}.testimonial-author strong{display:block;font-size:1.1rem;margin-bottom:5px}.testimonial-author span{font-size:.9rem;color:var(--text-secondary)}.ebook-contents{padding:100px 0;background-color:var(--bg-secondary);position:relative}.ebook-contents:after{content:"";position:absolute;bottom:0;left:0;width:100%;height:1px;background:linear-gradient(90deg,transparent 0%,var(--accent) 50%,transparent 100%);opacity:.3}.contents-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));gap:30px;margin-top:60px}.chapter{background-color:var(--bg-tertiary);padding:30px;border-radius:var(--border-radius);transition:var(--transition);box-shadow:var(--box-shadow);border:1px solid rgba(255,215,0,.1);position:relative;overflow:hidden}.chapter:before{content:"";position:absolute;top:0;left:0;width:100%;height:4px;background:linear-gradient(90deg,var(--accent) 0%,transparent 100%);opacity:0;transition:var(--transition)}.chapter:hover{transform:translateY(-10px);box-shadow:0 20px 40px #ffd70026}.chapter:hover:before{opacity:1}.chapter h3{display:flex;align-items:center;gap:10px;margin-bottom:15px;font-size:1.3rem}.chapter h3 i{color:var(--accent);font-size:1.5rem}.chapter p{color:var(--text-secondary);line-height:1.6}.faq-contact{padding:80px 0;background-color:var(--bg-primary)}.faq-grid{display:grid;grid-template-columns:1fr;gap:20px;margin-top:40px}.faq-item{background-color:var(--bg-secondary);padding:25px;border-radius:var(--border-radius);box-shadow:var(--box-shadow);border-left:4px solid var(--accent)}.faq-item h3{display:flex;align-items:center;gap:10px;color:var(--accent);margin-bottom:15px}.faq-item p{color:var(--text-secondary);line-height:1.6}.cta-faq{text-align:center;margin-top:40px}.ebook-catalog{padding:80px 0;background-color:var(--bg-primary)}.catalog-filters{display:flex;justify-content:center;gap:20px;margin-bottom:40px;flex-wrap:wrap}.filter-group{display:flex;align-items:center;gap:10px}.filter-group label{color:var(--text-secondary)}.filter-select{padding:10px 15px;border-radius:var(--border-radius);border:1px solid var(--bg-tertiary);background-color:var(--bg-secondary);color:var(--text-primary);cursor:pointer}.catalog-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:30px;margin-top:30px}.ebook-card{background-color:var(--bg-secondary);border-radius:var(--border-radius);overflow:hidden;box-shadow:var(--box-shadow);transition:var(--transition);position:relative}.ebook-card.highlight{border:2px solid var(--accent)}.ebook-card:hover{transform:translateY(-10px);box-shadow:0 15px 30px #ffd70033}.ebook-badge{position:absolute;top:15px;right:15px;background-color:var(--accent);color:var(--black);padding:5px 15px;border-radius:20px;font-size:.8rem;font-weight:600;z-index:1}.ebook-image{height:auto;min-height:200px;display:flex;justify-content:center;align-items:center;overflow:hidden}.ebook-image img{width:100%;height:auto;object-fit:contain;transition:transform .5s ease}.ebook-card:hover .ebook-image img{transform:scale(1.05)}.ebook-info{padding:20px}.ebook-category{display:inline-block;padding:5px 10px;border-radius:4px;font-size:.8rem;font-weight:600;margin-bottom:10px}.ebook-category.beginner{background-color:#00800033;color:#90ee90}.ebook-category.intermediate{background-color:#ffa50033;color:orange}.ebook-category.advanced{background-color:#f003;color:#f08080}.ebook-category.algorithms{background-color:#00f3;color:#add8e6}.ebook-info h3{font-size:1.3rem;margin-bottom:10px}.ebook-excerpt{color:var(--text-secondary);font-size:.9rem;margin-bottom:15px;line-height:1.5}.ebook-meta{display:flex;gap:15px;margin-bottom:15px;font-size:.8rem;color:var(--text-secondary)}.ebook-meta span{display:flex;align-items:center;gap:5px}.ebook-actions{display:flex;gap:10px}.catalog-cta{text-align:center;margin-top:50px;padding:30px;background-color:var(--bg-secondary);border-radius:var(--border-radius)}.catalog-cta h3{margin-bottom:15px}.catalog-cta p{color:var(--text-secondary);margin-bottom:20px}.footer-container{background:var(--bg-secondary);padding-top:60px;color:var(--text-primary)}.footer-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:40px;max-width:1200px;margin:0 auto;padding:0 20px}.footer-logo img{margin-bottom:20px;width:200px}.footer-logo p{font-size:.9rem;color:var(--text-secondary);margin-bottom:20px}.footer-social{display:flex;gap:15px}.footer-social a{color:var(--text-primary);width:35px;height:35px;border-radius:50%;display:flex;align-items:center;justify-content:center;background-color:var(--bg-tertiary);transition:var(--transition)}.footer-social a:hover{color:var(--accent);transform:translateY(-3px)}.footer-links h3,.footer-contact h3,.footer-newsletter h3{color:var(--accent);margin-bottom:20px;font-size:1.1rem}.footer-links ul{list-style:none;padding:0}.footer-links li{margin-bottom:10px}.footer-links a{color:var(--text-secondary);transition:var(--transition);text-decoration:none}.footer-links a:hover{color:var(--accent);padding-left:5px}.footer-contact ul{list-style:none;padding:0}.footer-contact li{margin-bottom:15px;display:flex;align-items:flex-start;gap:10px}.footer-contact i{color:var(--accent);margin-top:3px}.footer-bottom{text-align:center;padding:20px;margin-top:40px;border-top:1px solid var(--bg-tertiary);font-size:.9rem;color:var(--text-secondary)}.footer-legal{display:flex;justify-content:center;gap:20px;margin-top:15px}.footer-legal a{color:var(--text-secondary);text-decoration:none;transition:var(--transition)}.footer-legal a:hover{color:var(--accent)}.theme-float{position:fixed;bottom:30px;right:30px;z-index:999}#theme-toggle{width:50px;height:50px;border-radius:50%;background-color:var(--accent);color:var(--black);border:none;cursor:pointer;display:flex;align-items:center;justify-content:center;font-size:1.2rem;box-shadow:0 5px 15px #0003;transition:var(--transition)}#theme-toggle:hover{transform:scale(1.1)}#back-to-top{position:fixed;bottom:90px;right:30px;width:50px;height:50px;border-radius:50%;background-color:var(--bg-secondary);color:var(--text-primary);border:none;cursor:pointer;display:flex;align-items:center;justify-content:center;font-size:1.2rem;box-shadow:0 5px 15px #0003;transition:var(--transition);z-index:998;opacity:0;visibility:hidden;border:2px solid var(--accent)}#back-to-top.visible{opacity:1;visibility:visible}#back-to-top:hover{background-color:var(--accent);color:var(--black);transform:translateY(-5px)}@media (max-width: 1200px){.ebook-hero h1,.hero h1{font-size:3rem}h2{font-size:2.4rem}}@media (max-width: 992px){.ebook-content,.about-content,.contact-content{flex-direction:column;gap:40px}.ebook-image,.about-image{order:-1;max-width:500px;margin:0 auto}.form-group{flex-direction:column;gap:15px}}@media (max-width: 768px){:root{--header-height: 80px;--logo-height: 120px}nav.desktop-menu{display:none}.mobile-menu-button{display:block}.ebook-hero,.hero{padding:calc(var(--header-height) + 30px) 0 80px}.ebook-hero h1,.hero h1{font-size:2.4rem}.hero-subtitle{font-size:1.1rem}h2{font-size:2rem}.testimonial-cards{grid-template-columns:1fr}.testimonial-author{flex-direction:column;text-align:center}.contact-info{margin-top:40px;text-align:center}.info-card{flex-direction:column;align-items:center;text-align:center}.social-icons{justify-content:center}.about-cta{flex-direction:column}.ebook-image{max-width:100%;padding:0 20px}.ebook-image img{max-height:400px}}@media (max-width: 576px){:root{--header-height: 70px;--mobile-logo-height: 70px}h1{font-size:2rem;line-height:1.3}h2{font-size:1.8rem;margin-bottom:15px}h3{font-size:1.4rem}p{font-size:1rem}.header-container{padding:0 15px}.logo img{height:var(--mobile-logo-height)}.logo img:hover{height:calc(var(--mobile-logo-height) + 10px)}.ebook-hero{padding:calc(var(--header-height) + 20px) 0 40px;background-position:center}.ebook-hero h1{font-size:1.8rem;margin-bottom:15px}.ebook{padding:60px 0}.ebook-content{gap:30px}.ebook-text li{padding:10px;margin-bottom:12px;font-size:.95rem}.testimonials{padding:60px 0}.testimonial-cards{grid-template-columns:1fr;gap:20px}.testimonial-card{padding:25px 20px}.ebook-contents{padding:60px 0}.contents-grid{gap:20px}.chapter{padding:20px}.faq-contact{padding:60px 0}.faq-item{padding:20px}.ebook-catalog{padding:60px 0}.catalog-grid{grid-template-columns:1fr}.ebook-card{max-width:100%}.footer-grid{grid-template-columns:1fr;gap:30px}.footer-logo,.footer-links,.footer-contact,.footer-newsletter{text-align:center}.footer-social{justify-content:center}#back-to-top,#theme-toggle{width:45px;height:45px;font-size:1.1rem}#back-to-top{bottom:85px;right:15px}#theme-toggle{bottom:15px;right:15px}.filter-select,.btn{padding:10px 15px;font-size:.95rem}.cta-buttons{flex-direction:column;gap:15px}.ebook-badge{font-size:.7rem;padding:5px 10px}.ebook-image{min-height:180px}.ebook-image img{max-height:250px}}@media (max-width: 400px){:root{--header-height: 60px;--mobile-logo-height: 60px}.container{width:95%}h1{font-size:1.6rem}h2{font-size:1.5rem}.ebook-hero{padding:calc(var(--header-height) + 15px) 0 30px}.ebook-text h2:after,h2:after{margin:10px auto 20px;height:3px}.testimonial-author{flex-direction:column;align-items:center;text-align:center;gap:10px}.testimonial-author img{width:50px;height:50px}.ebook-meta{flex-direction:column;gap:8px}.ebook-actions{flex-direction:column;gap:10px}.btn{width:100%}}