@font-face{font-family:Sarabun;src:url('fonts/Sarabun-Regular.ttf') format('truetype');font-weight:400;font-display:swap}@font-face{font-family:Sarabun;src:url('fonts/Sarabun-SemiBold.ttf') format('truetype');font-weight:600;font-display:swap}@font-face{font-family:Sarabun;src:url('fonts/Sarabun-Bold.ttf') format('truetype');font-weight:700;font-display:swap}
:root{--bg:#fff9ef;--paper:#fffefa;--ink:#342d48;--muted:#776b80;--line:#e8dfe4;--green:#256d60;--soft:#e8f3eb;--gold:#b84931;--warning:#fff0da;--blue:#e9f3fc;--primary:#ba4732;--purple:#69489c;--lilac:#f2ecfc;--shadow:0 10px 0 #342d4805,0 18px 40px #342d4806}
:root[data-theme=dark]{--bg:#211d2b;--paper:#2d2638;--ink:#fff2e7;--muted:#c6b8ce;--line:#514257;--green:#94d7c1;--soft:#273e37;--gold:#ffb18f;--warning:#473627;--blue:#263a50;--primary:#f5a28a;--purple:#cbb0f5;--lilac:#393048;--shadow:0 10px 24px #100c1824}
body{font-family:Sarabun,Tahoma,sans-serif}button,input,select{font-family:inherit}.hub{background-image:radial-gradient(#e9ddcb 1px,transparent 1px);background-size:24px 24px}.topbar,.reader .topbar{height:90px;max-width:none;background:var(--paper);padding:0 max(28px,calc((100vw - 1280px)/2));border-bottom:1px solid var(--line);position:relative;z-index:25}.reader .topbar{position:sticky;top:0;height:80px;padding:0 32px}.brand{font-family:Sarabun,sans-serif;font-size:24px;font-weight:700}.brand-mark{background:#5a437b;box-shadow:3px 4px 0 #d8bbf2;color:#fff4e8;border-radius:16px;transform:rotate(-5deg)}.brand small{letter-spacing:1.8px;font-size:9px;color:var(--muted)}.topbar nav{gap:15px}.desktop-nav{display:flex;align-items:center;gap:9px}.desktop-nav>a{font-size:14px;font-weight:600;padding:10px 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1px,transparent 1px);background-size:20px 20px}.scene-orbit{position:absolute;border:1px dashed #bb9fd2;border-radius:50%;width:275px;height:275px;left:50%;top:15px;margin-left:-137px;transform:rotate(-25deg) scaleY(.5)}.orbit-two{transform:rotate(45deg) scaleY(.65);width:300px;height:300px;top:-15px;margin-left:-150px}.scene-star{position:absolute;color:#bb7134}.star-one{left:13%;top:44%;font-size:27px;animation:floaty 5s ease-in-out infinite}.star-two{right:8%;top:15%;font-size:37px;color:#8b63af;animation:sparkle 7s linear infinite}.star-three{right:15%;bottom:13%;font-size:22px;color:#9d74bb}.scene-platform{position:absolute;bottom:58px;left:14%;right:14%;height:11px;background:#8970a5;border-radius:10px;box-shadow:0 7px 0 #b7a5ce}.scene-spring{width:22%;height:33px;position:absolute;left:14%;bottom:70px;background:repeating-linear-gradient(115deg,transparent 0 8px,#88719f 9px 12px,transparent 13px 20px);transform-origin:left;animation:spring-stretch 4s ease-in-out infinite}.spring-mascot{position:absolute;left:36%;bottom:70px;width:98px;height:88px;border-radius:22px 22px 17px 17px;background:#edaa70;border:2px solid #cb8d5a;box-shadow:inset -8px -8px 0 #df985c,0 7px 10px #51406112;animation:spring-slide 4s ease-in-out infinite;transform:translateX(25px)}.mascot-eyes{position:absolute;top:17px;left:27px;font-family:Arial,sans-serif;font-size:23px;font-weight:bold;letter-spacing:7px;color:#583e48;white-space:nowrap}.mascot-smile{width:19px;height:11px;border:2px solid #583e48;border-top:0;border-radius:0 0 15px 15px;position:absolute;top:47px;left:39px}.mascot-blush{position:absolute;top:43px;width:13px;height:7px;border-radius:50%;background:#d97e6b}.blush-left{left:13px}.blush-right{right:13px}.floating-note{position:absolute;background:#fffaf0;border:1px solid #e7d6c8;border-radius:13px;padding:12px 15px;box-shadow:0 6px 0 #624d8210;z-index:2;color:#4d4059;animation:floaty 6s ease-in-out infinite}.floating-note span{display:block;font:700 8px 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12px}.quiz-tag{font-size:10px;color:var(--purple);font-weight:700}.quiz-options{display:flex;gap:9px}.quiz-options button{flex:1;border:1.5px solid var(--line);background:var(--bg);color:var(--ink);border-radius:10px;padding:8px;font-size:12px;min-height:40px}.quiz-options button:hover{border-color:var(--purple);background:var(--lilac)}.quiz-options button.correct{background:var(--soft);border-color:var(--green);color:var(--green)}.quiz-options button.try-again{background:var(--warning);border-color:var(--gold)}#quiz-feedback{font-size:11px;color:var(--muted);margin:10px 0 0;min-height:36px;line-height:1.6}.journey-strip{max-width:1280px;margin:0 auto 62px;background:var(--paper);border:1px solid var(--line);border-radius:20px;padding:21px 28px;display:flex;align-items:center;gap:21px;box-shadow:var(--shadow)}.journey-icon{background:var(--lilac);color:var(--purple);font-size:24px;border-radius:16px;min-width:53px;height:53px;text-align:center;line-height:53px}.journey-strip strong{font-size:15px}.journey-strip p{margin:3px 0 0;color:var(--muted);font-size:12px}.journey-progress{margin-left:auto;min-width:180px;max-width:240px;width:24%}.journey-progress>span{font-size:12px;color:var(--purple);display:block;margin-bottom:7px}.journey-progress [role=progressbar]{height:8px;background:var(--lilac);border-radius:8px;overflow:hidden}.journey-progress [role=progressbar]>span{display:block;height:100%;width:0;background:#a18bd4;border-radius:8px}.chapter-section,.labs-section{max-width:1280px;margin:auto}.section-heading{margin-bottom:28px}.section-heading h2{font-size:31px;margin-top:7px}.section-heading p{font-size:14px;color:var(--muted);margin:9px 0 0}.search-box{border-radius:14px;padding:10px 16px;min-width:340px}.search-box input{font-size:13px}.chapter-grid{gap:25px}.chapter-card{border-radius:23px;border:1.5px solid var(--line);box-shadow:var(--shadow);padding:25px 25px 0;position:relative;background:var(--paper)}.chapter-card:hover{transform:translateY(-6px);border-color:#b7a0d0;box-shadow:0 14px 35px #66517a14}.card-top{gap:13px}.card-number{font:700 20px Sarabun;color:var(--muted)}.chapter-icon{margin-left:auto;display:flex;align-items:center;justify-content:center;width:43px;height:43px;background:var(--lilac);border-radius:13px;font-size:27px;color:var(--purple);order:-1}.card-status{margin-left:auto;font-size:10px}.card-status.complete{background:var(--soft);padding:5px 8px;border-radius:7px}.card-formula{font-size:29px;padding:25px 9px;margin:22px 0;border-radius:15px;background:var(--soft);color:var(--green);border:1px solid #256d6010}.chapter-card:nth-child(2n) .card-formula{background:var(--lilac);color:var(--purple);border-color:#69489c15}.chapter-card:nth-child(3n) .card-formula{background:var(--blue);color:#306286;border-color:#30628615}.card-title h3{font-size:23px;line-height:1.5;min-height:68px;color:var(--ink);font-weight:700}.card-english{font-size:11px;min-height:33px;margin-bottom:10px}.card-description{font-size:14px;line-height:1.8;min-height:76px}.card-meta{font-size:10px;gap:9px;flex-wrap:wrap}.card-meta span{background:var(--bg);padding:3px 7px;border-radius:6px}.card-meta span:before{display:none}.card-links{display:grid;grid-template-columns:1fr 1fr;gap:9px;padding:18px 0;border-top-style:dashed}.card-button{display:flex;align-items:center;justify-content:center;border:1px solid var(--line);background:var(--bg);padding:9px 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a>span{grid-row:1/3;width:48px;height:48px;display:flex;align-items:center;justify-content:center;font-size:28px;border-radius:14px;background:var(--blue);color:#356789}.lab-card-grid strong{font-size:15px}.lab-card-grid small{color:var(--muted);font-size:11px;margin-top:5px}.creator-section{max-width:1280px;margin:65px auto;display:flex;align-items:center;justify-content:center;gap:24px;padding:32px;border:1px dashed #d4bbc5;border-radius:23px;background:var(--paper)}.creator-avatar{width:83px;height:83px;min-width:83px;border-radius:25px;background:#e9cbb2;color:#624651;font-size:30px;font-weight:700;display:flex;align-items:center;justify-content:center;position:relative;transform:rotate(-5deg)}.creator-avatar span{position:absolute;right:-10px;top:-10px;background:#f5d879;border:3px solid var(--paper);border-radius:50%;width:32px;height:32px;font-size:21px;text-align:center;line-height:27px}.creator-section h2{font-size:25px;margin:4px 0 8px}.creator-section p{font-size:14px;margin:0;color:var(--muted)}.creator-section small{font-size:12px;color:var(--muted)}.site-footer{max-width:1280px;font-size:12px;padding:30px 0;background:transparent;align-items:center}.footer-brand{font-weight:700;color:var(--purple);letter-spacing:1px}.site-footer p{font-size:12px;margin:7px 0 0}.site-footer small{font-size:10px}.footer-links{display:flex;gap:9px;flex-wrap:wrap}.footer-links a{padding:8px 13px;border:1px solid var(--line);background:var(--paper);border-radius:10px;min-height:38px}.reader-layout{max-width:1360px;gap:45px;grid-template-columns:265px minmax(0,1fr)}.sidebar{padding-right:20px}.toc-panel nav a{border-radius:10px;padding:9px 10px;font-size:13px}.toc-panel nav a.active{background:var(--lilac);border-color:var(--purple)}.sidebar-title{font-size:19px}.chapter-label{color:var(--primary)}.back-link,.sidebar-other,.sidebar-math{display:block;background:var(--paper);border:1px solid var(--line);padding:9px 12px;border-radius:10px;font-size:12px}.sidebar-other{margin-top:20px}.sidebar-math{margin-top:10px;background:var(--lilac);color:var(--purple);font-size:12px}.chapter-header{padding:35px 0}.chapter-header h1{font-size:38px;font-weight:700}.chapter-number{font:700 65px Sarabun;color:var(--purple);letter-spacing:-3px}.english-title{font-family:Georgia,serif}.chapter-header .author-credit{font-size:12px!important;margin:23px 0 0;color:var(--muted);border-top:1px dashed var(--line);padding-top:14px}.reader-toolbar button{background:var(--paper);padding:7px 12px;border-radius:9px;min-height:39px;font-size:13px}.reading-progress{top:79px}.reading-progress span{background:var(--primary)}.book-content{line-height:1.95}.book-content h2{font-size:1.5em;font-weight:700;color:var(--ink);border-top-style:dashed}.book-content h3{color:var(--purple);font-weight:700}.book-content strong{color:inherit}.color-guide{border:1px solid var(--line);background:var(--paper);border-radius:16px;padding:16px 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25px}.callout.warning{background:var(--warning);border-left-color:var(--gold)}.callout.math-note{background:var(--lilac);border-left-color:var(--purple)}.callout-title{color:inherit;font-weight:700}.book-content figure{border-radius:19px;box-shadow:var(--shadow);padding:20px}.book-content figure img{border-radius:12px;max-height:none}.book-content figcaption{font-family:Sarabun,sans-serif;font-size:14px;line-height:1.8;margin-top:16px}.table-scroll{border-radius:14px}.book-content table{font-size:.91em}.book-content th{background:var(--lilac)}.solution{border-radius:17px;padding:0 24px;box-shadow:var(--shadow);margin:17px 0}.solution summary{color:var(--purple);font-size:1.12em;min-height:64px}.solution[open] summary{border-bottom-style:dashed}.solution-expansion{margin:24px 0 8px;padding:23px 24px;background:var(--lilac);border:1px solid #cbb8e3;border-radius:15px}.solution-expansion h3{margin:0 0 16px;font-size:1.08em;color:var(--purple)}.solution-expansion ol{padding-left:24px}.solution-expansion li{margin:12px 0}.solution-expansion .equation{background:var(--paper)}.solution-expansion .math-link{font-size:13px;display:inline-flex;align-items:center;gap:8px;padding:8px 13px;border:1px solid #c0a8db;background:var(--paper);border-radius:10px;color:var(--purple);margin-top:10px}.simulation{background:var(--blue);border:1.5px solid #bad6e7;border-radius:20px;padding:27px}.simulation .eyebrow{color:#366e93}.simulation h2{font-size:27px}.simulation>p{font-size:15px}.lab-canvas{border-radius:15px;border-color:#bdd1df}.lab-controls label{font-size:13px}.lab-controls input{height:25px;accent-color:#3b759b}.lab-values{font-size:13px}.lab-actions .button{background:#356d91;border-color:#356d91;color:#fff}.lab-actions .button.secondary{background:var(--paper);color:#356d91;border-color:#accadd}.simulation .assumptions{font-size:12px}.chapter-pagination a{background:var(--paper);border:1px solid var(--line);border-radius:12px;padding:10px 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