.about-book{padding:80px 0 120px}.about-container{width:min(920px,calc(100% - 48px));margin:0 auto}.book-cover{text-align:center;padding:70px 0 90px}.book-label{font-size:0.9rem;letter-spacing:0.25em;text-transform:uppercase;color:var(--accent-color);margin-bottom:18px}.book-title{margin:0;font-size:clamp(3rem,6vw,4.8rem);font-weight:700}.book-subtitle{max-width:700px;margin:35px auto 0;font-size:1.15rem;line-height:1.9;color:rgba(255,255,255,0.72)}.book-intro{max-width:760px;margin:0 auto 80px}.book-intro-text{font-size:1.18rem;line-height:2;text-align:center}.book-toc{margin:100px auto;max-width:520px;padding:40px;border:1px solid rgba(255,255,255,0.08);border-radius:16px;background:rgba(255,255,255,0.02)}.book-toc h2{margin-bottom:30px;text-align:center}.book-toc ul{list-style:none;margin:0;padding:0}.book-toc li{margin:14px 0}.book-toc a{color:inherit;text-decoration:none;transition:0.25s}.book-toc a:hover{color:var(--accent-color);padding-left:8px}.book-chapter{max-width:760px;margin:0 auto;padding:90px 0}.chapter-header{text-align:center}.chapter-header h2{margin-top:20px}.chapter-number{text-transform:uppercase;letter-spacing:0.22em;color:var(--accent-color);font-size:0.92rem}.chapter-title{margin:0;font-size:clamp(2rem,4vw,3rem)}.chapter-content p{margin-bottom:22px;line-height:2.1;font-size:1.08rem}.chapter-content p:first-child{font-size:1.15rem}.book-quote{margin:60px 0;padding:30px 36px;border-left:4px solid var(--accent-color);background:rgba(255,255,255,0.03);font-style:italic;line-height:1.9}.book-formula-section{padding:120px 0 70px}.book-formula{max-width:760px;margin:auto;padding:50px;border:1px solid rgba(255,255,255,0.08);border-radius:18px;text-align:center;background:rgba(255,255,255,0.02)}.book-formula p{margin:20px 0;font-size:1.18rem;font-weight:500}.chapter-divider{display:flex;align-items:center;justify-content:center;margin:0 auto;width:180px;height:60px}.chapter-divider::before{content:"✦";color:var(--accent-color);font-size:1.2rem;opacity:0.85}.book-closing{padding:90px 0 30px;text-align:center}.closing-text{max-width:700px;margin:auto auto 65px;line-height:1.9;font-size:1.15rem}.book-closing .btn-primary{display:inline-block}.book-edition{margin-top:80px;font-size:0.85rem;letter-spacing:0.15em;text-transform:uppercase;color:rgba(255,255,255,0.45);text-align:center}@media (max-width:768px){.book-cover{padding:40px 0 60px}.book-chapter{padding:60px 0}.book-formula{padding:32px}.book-toc{padding:28px}.chapter-content p{font-size:1rem;line-height:1.85}}