/* Draft design tokens: forest #064c3b, ivory #fffdf3, emerald #00856c, gold #d6bf68.
   Existing approved sidebar/logo are reused; no live stylesheet is modified. */
:root{--book-ink:#123e33;--book-muted:#587266;--book-paper:#fffdf3;--book-edge:#c8d7af;--book-radius:18px;--book-shadow:inset 0 2px 2px #fff,0 4px 0 #c4d4ac,0 7px 0 #8aa278,0 14px 24px #0a42362b}
*{box-sizing:border-box}.book-preview{background:#d8edda url('/assets/nature-tech-energy.webp') center/cover fixed;color:var(--book-ink);font:16px/1.75 'Segoe UI',Arial,sans-serif}.book-preview::before{content:'';position:fixed;inset:0;pointer-events:none;background:linear-gradient(110deg,#f4fbe9c9,#f4fbe92b 75%);z-index:-1}.book-preview .workspace-content{position:relative}.book-preview .workspace-sidebar{background-color:#064c3b}.book-preview .workspace-nav a{min-height:48px;margin-bottom:3px;border:1px solid #a8c39a65;border-radius:12px;background:linear-gradient(145deg,#216b52c9,#003d35)}.book-preview .workspace-nav a[aria-current]{background:linear-gradient(145deg,#049779,#006154);color:#fffbe5}.book-preview .workspace-nav a[data-workspace-book]{background:linear-gradient(#fffff3,#e6edce);color:#174738;box-shadow:inset 0 2px 1px #fff,0 4px 0 #8fa97c}.book-preview .workspace-sidebar-bottom>a{padding:12px;border:1px solid #a8cda0;border-radius:12px;background:#0b604b;line-height:1.5}.book-preview .workspace-topbar{position:sticky;gap:14px;background:#f6ffedec;backdrop-filter:blur(12px)}.book-preview .workspace-breadcrumb{font-size:13px}.book-draft{font:600 11px/1.3 'Segoe UI',sans-serif;color:#5b7061;white-space:nowrap}.book-main{max-width:1440px;margin:auto;padding:28px 32px 42px}.book-heading{margin-bottom:22px}.book-preview h1{font:48px/1.12 Georgia,serif;letter-spacing:-1.3px;margin:0 0 14px;color:#113e33;text-wrap:balance}.book-preview h2{font:32px/1.2 Georgia,serif;letter-spacing:-.5px;color:#164334;margin:0 0 14px}.book-heading p{margin:0;color:#4e6c5d}.book-panel{background:linear-gradient(125deg,#fffef5,#fffdf5 65%,#f1f4e3);border:1px solid var(--book-edge);border-radius:var(--book-radius);box-shadow:var(--book-shadow);overflow:hidden}.book-toolbar{display:flex;gap:15px;margin:0 0 26px}.book-search{flex:1;min-width:0}.book-search input{width:100%;height:50px;border:1px solid #b8cca6;border-radius:12px;padding:10px 18px;background:#fffef4;color:var(--book-ink);font:15px 'Segoe UI',sans-serif;box-shadow:inset 0 2px 4px #205c3620,0 3px 0 #b4cba2}.book-filters{display:flex;gap:5px;padding:4px;border:1px solid #baccaa;background:linear-gradient(#f2f6df,#d6e3bf);border-radius:14px;box-shadow:0 4px 0 #9cb58a}.book-filters button{border:1px solid #ced8b9;border-radius:10px;min-height:40px;padding:8px 22px;color:#365746;background:#f9fbed;cursor:pointer;font:600 14px 'Segoe UI',sans-serif}.book-filters [aria-pressed=true]{background:linear-gradient(#009c7b,#006756);color:#fff;box-shadow:inset 0 1px 0 #95e9c8,0 3px 0 #004e40}.book-catalogue{display:grid;gap:25px}.book-card{display:grid;grid-template-columns:29% minmax(0,1fr)}.book-card>img{width:100%;height:100%;min-height:210px;object-fit:cover}.book-card>div{position:relative;padding:21px 25px}.book-card h2{font-size:30px;margin:5px 0 10px}.book-card p{margin:8px 0;color:var(--book-muted);font-size:15px}.book-card-label{font-size:10px;font-weight:600;letter-spacing:2px;color:#637462}.book-card-meta{display:block;margin:14px 0!important;font-size:13px!important}.book-card-meta strong{font-size:22px;color:#104d3b}.book-featured{grid-template-columns:38% minmax(0,1fr)}.book-featured>img{min-height:285px}.book-featured h2{max-width:540px;padding-right:80px;font-size:35px}.book-featured .book-free{position:absolute;top:27px;right:22px}.book-free{display:inline-block;flex-shrink:0;padding:5px 17px;border-radius:30px;background:#ddf4cd;color:#075431;font:700 12px/1.6 'Segoe UI',sans-serif;letter-spacing:.6px}.book-button{display:inline-flex;justify-content:center;align-items:center;gap:20px;min-height:46px;padding:11px 23px;border:1px solid #51c2a0;border-radius:11px;background:linear-gradient(135deg,#009a78,#006b5d);box-shadow:inset 0 2px 1px #a2e9c775,0 4px 0 #064c3b,0 7px 11px #124d3424;color:#fffef1!important;font:600 14px/1.4 'Segoe UI',sans-serif;text-decoration:none;cursor:pointer}.book-button svg{width:20px;height:20px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round;flex-shrink:0}.book-button:hover{filter:brightness(1.07)}.book-button:active{transform:translateY(2px);box-shadow:inset 0 1px 0 #abebc360,0 2px 0 #064c3b}.book-button.secondary{background:linear-gradient(#fffff6,#eaf0db);color:#28523d!important;border-color:#b5c9a4;box-shadow:inset 0 1px 0 #fff,0 3px 0 #a7bc98}.book-hero{display:grid;grid-template-columns:59% 41%;min-height:340px;margin-bottom:27px}.book-hero>div{padding:31px 29px;align-self:center}.book-hero h1{font-size:47px;max-width:650px}.book-hero .book-free{margin:3px 0 12px}.book-hero p{color:var(--book-muted);margin:5px 0 24px}.book-hero img{width:100%;height:100%;object-fit:cover;object-position:60% center;mask-image:linear-gradient(to right,transparent,#000 18%)}.book-hero-actions{display:flex;align-items:center;gap:24px}.book-hero-actions>span{border-left:1px solid #cdd6bd;padding-left:20px;color:#6b7d68;font-size:12px;line-height:1.6}.book-path,.book-intro{padding:26px 29px;margin-bottom:25px}.book-path>p,.book-intro p{color:var(--book-muted);margin:0 0 20px}.book-module-list{display:grid;gap:9px}.book-module-row{display:flex;align-items:center;gap:17px;padding:13px 18px;border:1px solid #d5dfc5;border-radius:11px;text-decoration:none;color:var(--book-ink);background:#fffff6b8;min-height:67px}.book-module-row:hover{border-color:#6dae8b;background:#edf7e5}.book-number{display:grid;place-items:center;flex:0 0 38px;width:38px;height:38px;border-radius:50%;background:#e0f0d7;color:#1c6047;font-size:14px;font-weight:650;line-height:1}.book-module-row strong{display:block;font-size:16px;font-weight:600}.book-module-row small{display:block;font-size:12px;color:#6b7f69;margin-top:2px}.book-module-row>svg{width:19px;height:19px;stroke:#375f49;stroke-width:1.6;fill:none;margin-left:0;flex-shrink:0}.book-complete{width:19px;height:19px;border:1px solid #94a787;border-radius:50%;margin-left:auto;flex-shrink:0}.book-complete.done{background:#087d60;border-color:#087d60;box-shadow:inset 0 0 0 4px #fcfff0}.book-outcome{padding:15px 19px;background:#e0efd3;border-radius:10px;margin:20px 0 7px!important;color:#254f37!important}.book-progress{font-size:12px;margin:11px 0 0!important}.book-intro a{color:#056b54;text-underline-offset:3px;font-size:14px}.book-lesson-layout{display:grid;grid-template-columns:minmax(0,1fr) 235px;align-items:start;gap:22px}.book-lesson{padding:30px;min-width:0}.book-lesson-heading{position:relative}.book-lesson h1{font-size:39px;max-width:850px;padding-right:80px;line-height:1.18;margin:12px 0 19px}.book-lesson-heading>.book-free{position:absolute;right:0;top:52px;padding-inline:12px;font-size:11px}.book-module-label{font-size:12px;background:#e8efe1;border-radius:7px;padding:5px 11px;color:#526e5b;display:inline-block}.book-video-note{background:#e8f3ef;border:1px solid #c1dcd1;border-radius:11px;padding:13px 17px;margin:0 0 24px;font-size:14px;color:#2e6051}.book-toc{border-top:1px solid #dde4ce;border-bottom:1px solid #dde4ce;padding:10px 0;margin:0 0 24px}.book-toc summary{cursor:pointer;font-size:13px;font-weight:650;color:#34634b}.book-toc nav{display:grid;gap:6px;padding:10px 0}.book-toc a{font-size:13px;color:#2a6853;text-underline-offset:3px}.book-prose{max-width:78ch;font-size:16px;line-height:1.9;overflow-wrap:anywhere}.book-prose p{margin:0 0 20px}.book-prose h2{font-size:28px;margin:35px 0 15px;scroll-margin-top:90px}.book-prose h3{font:650 18px/1.5 'Segoe UI',sans-serif;margin:26px 0 12px;scroll-margin-top:90px}.book-prose ul,.book-prose ol{padding-left:25px;margin:12px 0 24px}.book-prose li{margin-bottom:10px;padding-left:3px}.book-prose a{color:#057b5d;text-underline-offset:3px}.table-scroll{max-width:100%;overflow:auto;border:1px solid #cbdabc;border-radius:10px;margin:20px 0 27px;overscroll-behavior-inline:contain}.book-prose table{width:100%;border-collapse:collapse;font-size:14px;line-height:1.65;min-width:440px}.book-prose th{background:#e5eed9;color:#214e38;font-size:13px;text-align:left;font-weight:650}.book-prose td,.book-prose th{padding:12px 14px;vertical-align:top;border-bottom:1px solid #dce3d0;border-right:1px solid #dde4d1}.book-prose tr:last-child td{border-bottom:0}.book-prose tr:nth-child(even){background:#f1f4e7}.book-prose td:first-child{font-weight:600}.book-prose .prompt-block{margin:24px 0;border-radius:12px;overflow:hidden;border:1px solid #83aa89;background:#0b4435;color:#e9f4df}.prompt-block>div{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:10px 15px;background:#195744;font-size:12px}.prompt-block button{border:1px solid #87b795;background:#edf6df;color:#164c36;border-radius:7px;padding:7px 11px;cursor:pointer;font:600 12px 'Segoe UI',sans-serif;min-height:36px}.prompt-block pre{margin:0;padding:19px;white-space:pre-wrap;overflow-wrap:anywhere;font:13px/1.9 Consolas,monospace}.book-prose :not(pre)>code{background:#edf0df;padding:2px 5px;border-radius:4px;font-size:14px}.book-module-nav{padding:22px 19px;position:sticky;top:92px}.book-module-nav h2{font-size:24px;margin-bottom:17px}.book-module-nav nav{display:grid;gap:4px}.book-module-nav nav a{display:flex;align-items:center;gap:11px;padding:10px 4px;color:#3e5c49;border-bottom:1px solid #dbe3cb;text-decoration:none;font-size:13px}.book-module-nav nav a[aria-current]{background:#e3f0d7;color:#134c34;font-weight:650;border-radius:9px;padding-inline:8px}.book-module-nav [aria-current] .book-number{background:#07674e;color:#fff}.book-module-nav .book-number{flex-basis:30px;width:30px;height:30px;font-size:12px}.book-back{display:block;margin-top:19px;color:#3c7257;font-size:12px}.book-finish{background:#eef4de;border:1px solid #d2dfb9;border-radius:13px;padding:22px;margin-top:32px}.book-finish h2{font-size:25px}.book-finish p{font-size:13px;color:#526b50;margin-bottom:17px}.book-finish [data-progress-notice]{margin:11px 0 0;min-height:20px}.book-finish [aria-pressed=true]{background:linear-gradient(#1c7553,#134e38)}.book-pagination{display:flex;align-items:center;justify-content:space-between;gap:15px;margin:28px 0}.book-download{color:#316b4d;text-underline-offset:3px;font-size:13px}.book-footer{display:flex;justify-content:space-between;gap:15px;padding:0 32px 25px;font-size:11px;color:#315c43}.book-footer a{color:#246247}.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap}.book-skip{position:fixed;left:20px;top:-60px;z-index:100;background:#fffef1;padding:12px;color:#063e2b}.book-skip:focus{top:12px}#book-status{position:fixed;bottom:20px;left:50%;transform:translateX(-50%);border-radius:10px;background:#073b2f;color:#fff;padding:12px 18px;max-width:90vw;font-size:13px;box-shadow:0 5px 15px #003a3333;z-index:100}#book-status:empty{display:none}.book-preview [hidden]{display:none!important}.book-preview :is(a,button,input,summary,.table-scroll):focus-visible{outline:3px solid #c9a33d;outline-offset:4px}
@media(min-width:1450px){.book-preview .workspace-sidebar{width:292px}.book-preview .workspace-content{margin-left:292px}.book-main{padding:28px 30px 45px}.book-hero h1{font-size:51px}.book-hero{min-height:360px}.book-lesson-layout{grid-template-columns:minmax(0,1fr) 245px}}
@media(max-width:1150px){.book-lesson-layout{grid-template-columns:minmax(0,1fr)}.book-module-nav{position:static;grid-row:1;padding:14px 17px}.book-module-nav h2{font-size:19px;margin-bottom:9px}.book-module-nav nav{display:flex;overflow-x:auto;gap:8px}.book-module-nav nav a{flex-shrink:0;border:1px solid #d7e0c6;border-radius:8px;padding:7px 9px;font-size:12px}.book-module-nav .book-back{display:none}.book-module-nav .book-number{width:24px;height:24px;flex-basis:24px}.book-toolbar{flex-wrap:wrap}.book-search{min-width:240px}.book-hero{grid-template-columns:63% 37%}.book-hero h1{font-size:41px}.book-hero>div{padding:25px}.book-featured h2{font-size:30px;padding-right:0;margin-top:34px}.book-featured .book-free{left:25px;right:auto;top:42px;font-size:10px}.book-hero-actions{gap:16px}.book-hero-actions>span{font-size:11px;padding-left:14px}}
@media(max-width:900px){.book-preview .workspace-content{margin-left:0}.book-main{padding:23px}.book-preview h1{font-size:40px}.book-hero h1{font-size:42px}.book-draft{margin-left:auto;font-size:10px}.book-preview .workspace-breadcrumb>a:first-child,.book-preview .workspace-breadcrumb>span:first-of-type{display:none}}
@media(max-width:620px){.book-main{padding:19px 15px 32px}.book-preview .workspace-topbar{padding:0 14px;gap:10px;min-height:64px}.book-preview .workspace-breadcrumb{gap:7px;font-size:11px}.book-preview .workspace-breadcrumb>span:last-child{display:none}.book-draft{font-size:9px;max-width:76px;white-space:normal;line-height:1.5}.book-preview h1{font-size:34px;letter-spacing:-.7px}.book-heading p{font-size:14px;line-height:1.65}.book-toolbar{gap:12px}.book-search{min-width:0;flex-basis:100%}.book-filters{width:100%}.book-filters button{flex:1;padding:9px 12px;font-size:13px}.book-card,.book-featured{grid-template-columns:minmax(0,1fr)}.book-card>img{height:170px;min-height:0}.book-card>div{padding:20px}.book-card h2,.book-featured h2{font-size:28px;padding:0;margin:9px 0 12px}.book-featured .book-free{position:static;margin-bottom:4px;font-size:11px}.book-card p{font-size:14px}.book-card .book-button{width:100%;margin-top:5px}.book-hero{grid-template-columns:1fr;min-height:0}.book-hero>div{padding:23px 21px}.book-hero h1{font-size:35px}.book-hero img{height:170px;object-position:center 60%;mask-image:none}.book-hero p{font-size:14px;line-height:1.7}.book-hero-actions{flex-wrap:wrap;gap:17px}.book-hero-actions .book-button{min-width:170px}.book-hero-actions>span{font-size:11px}.book-path,.book-intro{padding:22px 18px}.book-preview .book-path h2,.book-intro h2{font-size:27px}.book-path>p,.book-intro p{font-size:14px}.book-module-row{padding:12px 10px;gap:10px}.book-module-row strong{font-size:14px;line-height:1.5}.book-module-row small{font-size:11px}.book-module-row .book-number{width:31px;height:31px;flex-basis:31px;font-size:12px}.book-complete{width:15px;height:15px}.book-module-row>svg{width:16px;flex-shrink:0}.book-lesson{padding:22px 17px}.book-lesson h1{font-size:32px;max-width:none;padding-right:0;margin-bottom:13px}.book-lesson-heading>.book-free{position:static;margin:0 0 13px}.book-video-note{font-size:12px;padding:11px 13px}.book-lesson-layout{gap:18px}.book-prose{font-size:15px;line-height:1.85}.book-prose h2{font-size:25px;margin-top:29px}.book-prose h3{font-size:17px}.book-prose li{margin-bottom:11px}.book-prose table{font-size:12px;min-width:450px}.book-prose td,.book-prose th{padding:10px 11px}.prompt-block pre{padding:15px;font-size:12px}.prompt-block>div{font-size:10px;padding:9px 11px}.book-pagination{flex-direction:column;align-items:stretch;gap:15px}.book-pagination .book-button{width:100%}.book-finish{padding:19px 15px}.book-finish h2{font-size:23px}.book-finish .book-button{width:100%}.book-footer{padding:0 17px 23px;flex-wrap:wrap;font-size:10px}.book-toc summary{min-height:34px;padding:5px 0}}
/* Keep one meaningful breadcrumb visible instead of an orphan slash on phones. */
@media(max-width:620px){.book-preview .workspace-breadcrumb>a[href="/video-tutorial"]{display:inline}.book-preview .workspace-breadcrumb>span{display:none}.book-module-nav nav{scrollbar-width:thin;scrollbar-color:#82a789 #edf3df}}
@media(prefers-reduced-motion:no-preference){.book-preview::before{animation:book-breathe 12s ease-in-out infinite alternate}.book-button{transition:filter .15s,transform .15s}.book-module-row{transition:background .2s,border-color .2s}@keyframes book-breathe{from{opacity:.8}to{opacity:.97}}}
@media print{.workspace-sidebar,.workspace-topbar,.book-module-nav,.book-toc,.book-pagination,.book-finish,.book-download,.book-footer,#book-status,.book-skip{display:none!important}.book-preview{background:#fff;color:#000}.book-preview .workspace-content{margin:0}.book-main{padding:0;max-width:none}.book-lesson-layout{display:block}.book-panel{box-shadow:none;border:0;background:#fff}.book-lesson{padding:0}.book-prose{max-width:none;font-size:11pt}.table-scroll{overflow:visible}.book-prose table{min-width:0}a{color:#000}.prompt-block{break-inside:avoid}}