:root{--cream:#FFF8F0;--cream-2:#FDEFE0;--peach-50:#FFEFDD;--peach-100:#FFD9B8;--peach-200:#FFB988;--coral-400:#FF8B5A;--coral-500:#FF6B3D;--coral-600:#E8552A;--honey-400:#FFC547;--honey-500:#F5A623;--leaf-400:#6BBE7E;--sky-300:#BCDFF1;--sky-400:#7CC0DE;--plum-700:#2D1F3D;--ink:#1A1814;--ink-2:#3A332B;--ink-3:#6B5F50;--ink-soft:rgba(26,24,20,0.6);--line:rgba(26,24,20,0.08);--line-2:rgba(26,24,20,0.14);--shadow-sm:0 1px 2px rgba(60,30,10,0.04),0 2px 6px rgba(60,30,10,0.04);--shadow-md:0 4px 12px rgba(60,30,10,0.06),0 12px 32px rgba(60,30,10,0.08);--shadow-lg:0 8px 24px rgba(60,30,10,0.08),0 24px 60px rgba(60,30,10,0.10);--radius-sm:10px;--radius-md:16px;--radius-lg:24px;--radius-xl:32px;--font-display:"Unbounded","Manrope",system-ui,sans-serif;--font-body:"Manrope",system-ui,sans-serif;--content-max:1200px;--rail-w:300px;--gap-col:32px;--header-h:68px}.gdz-scope *,.gdz-scope :after,.gdz-scope :before{box-sizing:border-box}.gdz-scope{background:var(--cream);color:var(--ink);font-family:var(--font-body);-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;font-size:16px;line-height:1.5;min-height:100vh}.gdz-scope a{color:inherit;text-decoration:none}.gdz-scope img{max-width:100%;display:block}.gdz-display{font-family:var(--font-display);font-weight:700;letter-spacing:-.03em;line-height:1.05}.gdz-header{position:sticky;top:0;z-index:50;background:rgba(255,248,240,.88);-webkit-backdrop-filter:saturate(140%) blur(12px);backdrop-filter:saturate(140%) blur(12px);border-bottom:1px solid var(--line)}.gdz-header-inner{max-width:var(--content-max);margin:0 auto;height:var(--header-h);padding:0 24px;display:flex;align-items:center;gap:18px}.gdz-logo{display:flex;align-items:center;gap:10px;font-size:19px;letter-spacing:-.02em;color:var(--ink)}.gdz-logo,.gdz-logo-mark{font-family:var(--font-display);font-weight:700;flex-shrink:0}.gdz-logo-mark{width:34px;height:34px;border-radius:9px;background:var(--coral-500);display:grid;place-items:center;color:#fff;font-size:17px;box-shadow:0 2px 0 var(--coral-600),inset 0 1px 0 rgba(255,255,255,.25)}.gdz-logo .muted{opacity:.5;font-weight:500}.gdz-logo .tag{font-family:var(--font-body);font-weight:700;font-size:12px;letter-spacing:.04em;text-transform:uppercase;color:var(--coral-600);background:var(--peach-50);border:1px solid rgba(255,107,61,.2);padding:3px 8px;border-radius:999px;margin-left:2px}.gdz-search{flex:1;max-width:460px;display:flex;align-items:center;gap:10px;background:#fff;border:1px solid var(--line-2);border-radius:999px;padding:9px 16px;color:var(--ink-3);transition:border-color .15s,box-shadow .15s}.gdz-search:focus-within{border-color:var(--coral-400);box-shadow:0 0 0 4px rgba(255,107,61,.12)}.gdz-search svg{flex-shrink:0}.gdz-search input{border:none;outline:none;background:transparent;flex:1;font-family:var(--font-body);font-size:15px;color:var(--ink)}.gdz-header-cta{margin-left:auto;display:flex;align-items:center;gap:10px;flex-shrink:0}.gdz-btn{font-family:var(--font-body);font-weight:600;font-size:14px;border:none;cursor:pointer;border-radius:999px;padding:11px 20px;display:inline-flex;align-items:center;gap:8px;transition:transform .12s ease,box-shadow .12s ease,background .15s;white-space:nowrap}.gdz-btn:active{transform:translateY(1px)}.gdz-btn--primary{background:var(--coral-500);color:#fff;box-shadow:0 3px 0 var(--coral-600),0 6px 18px rgba(255,107,61,.3)}.gdz-btn--primary:hover{background:var(--coral-400)}.gdz-btn--ghost{background:#fff;color:var(--ink);border:1.5px solid var(--line-2)}.gdz-btn--ghost:hover{background:var(--peach-50);border-color:var(--peach-200)}.gdz-shell{max-width:var(--content-max);margin:0 auto;padding:28px 24px 80px;display:grid;grid-template-columns:minmax(0,1fr) var(--rail-w);gap:var(--gap-col);align-items:start}.gdz-main{min-width:0}.gdz-crumbs{display:flex;flex-wrap:wrap;align-items:center;gap:6px;font-size:13.5px;font-weight:600;color:var(--ink-3);margin-bottom:16px}.gdz-crumbs .cur,.gdz-crumbs a{white-space:nowrap}.gdz-crumbs a{color:var(--ink-3);transition:color .12s}.gdz-crumbs a:hover{color:var(--coral-500)}.gdz-crumbs .sep{opacity:.4}.gdz-crumbs .cur{color:var(--ink)}.gdz-pagehead{margin-bottom:24px}.gdz-pagehead h1{font-family:var(--font-display);font-weight:700;letter-spacing:-.03em;font-size:clamp(28px,4vw,40px);line-height:1.05;margin:0 0 10px}.gdz-pagehead .lede{color:var(--ink-3);font-size:16px;line-height:1.55;margin:0;max-width:640px}.gdz-eyebrow{display:inline-flex;align-items:center;gap:8px;font-size:12px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:var(--coral-600);margin-bottom:14px}.gdz-eyebrow .dot{width:6px;height:6px;border-radius:50%;background:var(--coral-500)}.gdz-classbar{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:28px}.gdz-classbar a{display:inline-flex;align-items:center;justify-content:center;min-width:78px;padding:10px 14px;border-radius:999px;background:#fff;border:1.5px solid var(--line-2);font-weight:600;font-size:14px;color:var(--ink-2);transition:all .12s}.gdz-classbar a:hover{border-color:var(--peach-200);background:var(--peach-50);color:var(--coral-600)}.gdz-classbar a.active{background:var(--coral-500);color:#fff;border-color:var(--coral-500);box-shadow:0 3px 0 var(--coral-600)}.gdz-section{margin-bottom:38px}.gdz-section-head{display:flex;align-items:baseline;justify-content:space-between;gap:16px;margin-bottom:16px}.gdz-section-head h2{font-family:var(--font-display);font-weight:600;letter-spacing:-.02em;font-size:22px;margin:0}.gdz-section-head .more{font-size:14px;font-weight:600;color:var(--coral-600)}.gdz-class-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(150px,1fr));gap:14px}.gdz-class-card{position:relative;display:flex;flex-direction:column;gap:4px;background:#fff;border:1px solid var(--line);border-radius:var(--radius-md);padding:18px 18px 16px;box-shadow:var(--shadow-sm);transition:transform .14s ease,box-shadow .14s ease,border-color .14s;overflow:hidden}.gdz-class-card:hover{transform:translateY(-3px);box-shadow:var(--shadow-md);border-color:var(--peach-200)}.gdz-class-num{font-family:var(--font-display);font-weight:700;font-size:40px;line-height:1;letter-spacing:-.04em;color:var(--coral-500)}.gdz-class-card .lbl{font-weight:700;font-size:15px;color:var(--ink)}.gdz-class-card .sub{font-size:12.5px;color:var(--ink-3);font-weight:500}.gdz-class-card .corner{position:absolute;right:-14px;top:-14px;width:60px;height:60px;border-radius:50%;background:var(--peach-50);opacity:.8}.gdz-subj-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:12px}.gdz-subj-card{display:flex;align-items:center;gap:14px;background:#fff;border:1px solid var(--line);border-radius:var(--radius-md);padding:16px 18px;box-shadow:var(--shadow-sm);transition:transform .14s ease,box-shadow .14s ease,border-color .14s}.gdz-subj-card:hover{transform:translateY(-2px);box-shadow:var(--shadow-md);border-color:var(--peach-200)}.gdz-subj-ic{width:46px;height:46px;border-radius:12px;background:var(--peach-50);display:grid;place-items:center;font-size:24px;line-height:1;flex-shrink:0}.gdz-subj-txt{display:flex;flex-direction:column;gap:2px;flex:1;min-width:0}.gdz-subj-card .name{font-weight:700;font-size:15.5px;color:var(--ink);line-height:1.2}.gdz-subj-card .count{font-size:12.5px;color:var(--ink-3);font-weight:500}.gdz-filters{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:22px}.gdz-chip{display:inline-flex;align-items:center;gap:7px;padding:8px 15px;border-radius:999px;background:#fff;border:1.5px solid var(--line-2);font-weight:600;font-size:13.5px;color:var(--ink-2);cursor:pointer;transition:all .12s}.gdz-chip:hover{border-color:var(--peach-200);background:var(--peach-50)}.gdz-chip.active{background:var(--ink);color:var(--cream);border-color:var(--ink)}.gdz-chip .ct{opacity:.55;font-weight:600}.gdz-book-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:18px}.gdz-book-card{display:flex;flex-direction:column;background:#fff;border:1px solid var(--line);border-radius:var(--radius-md);padding:14px;box-shadow:var(--shadow-sm);transition:transform .14s ease,box-shadow .14s ease,border-color .14s}.gdz-book-card:hover{transform:translateY(-3px);box-shadow:var(--shadow-md);border-color:var(--peach-200)}.gdz-book-cover{position:relative;aspect-ratio:3/4;border-radius:12px;overflow:hidden;margin-bottom:12px;background:repeating-linear-gradient(135deg,rgba(255,255,255,.5) 0 10px,rgba(255,255,255,0) 10px 20px),linear-gradient(160deg,var(--peach-100),var(--coral-400));display:flex;flex-direction:column;justify-content:space-between;padding:12px}.gdz-book-cover .cv-subj{font-family:var(--font-display);font-weight:600;font-size:15px;color:#fff;line-height:1.1;letter-spacing:-.01em;text-shadow:0 1px 2px rgba(0,0,0,.18)}.gdz-book-cover .cv-num{align-self:flex-end;font-family:var(--font-display);font-weight:700;font-size:38px;color:rgba(255,255,255,.92);line-height:.9;text-shadow:0 2px 4px rgba(0,0,0,.16)}.gdz-book-card .b-authors{font-weight:700;font-size:14px;color:var(--ink);line-height:1.25}.gdz-book-card .b-meta{font-size:12.5px;color:var(--ink-3);font-weight:500;margin-top:4px}.gdz-badge{display:inline-flex;align-items:center;margin-top:10px;font-size:11px;font-weight:700;letter-spacing:.04em;color:var(--coral-600);background:var(--peach-50);border:1px solid rgba(255,107,61,.2);padding:3px 8px;border-radius:6px;align-self:flex-start}.gdz-bookhead{display:flex;gap:22px;background:#fff;border:1px solid var(--line);border-radius:var(--radius-lg);padding:22px;box-shadow:var(--shadow-sm);margin-bottom:24px}.gdz-bookhead-cover{width:120px;flex-shrink:0;aspect-ratio:3/4;border-radius:12px;overflow:hidden;background:repeating-linear-gradient(135deg,rgba(255,255,255,.5) 0 10px,rgba(255,255,255,0) 10px 20px),linear-gradient(160deg,var(--peach-100),var(--coral-400));display:flex;flex-direction:column;justify-content:space-between;padding:12px}.gdz-bookhead-cover .cv-subj{font-family:var(--font-display);font-weight:600;font-size:14px;color:#fff;text-shadow:0 1px 2px rgba(0,0,0,.18)}.gdz-bookhead-cover .cv-num{align-self:flex-end;font-family:var(--font-display);font-weight:700;font-size:34px;color:rgba(255,255,255,.92);text-shadow:0 2px 4px rgba(0,0,0,.16)}.gdz-bookhead-meta{display:grid;grid-template-columns:1fr 1fr;gap:6px 28px;align-content:start;font-size:14px}.gdz-bookhead-meta .row{display:flex;gap:8px}.gdz-bookhead-meta .k{color:var(--ink-3);font-weight:500;white-space:nowrap}.gdz-bookhead-meta .v{color:var(--ink);font-weight:700}.gdz-bookhead-meta .v a{color:var(--coral-600)}.gdz-exsearch{display:flex;align-items:center;gap:10px;background:#fff;border:1.5px solid var(--line-2);border-radius:14px;padding:13px 18px;margin-bottom:26px;color:var(--ink-3);max-width:460px}.gdz-exsearch:focus-within{border-color:var(--coral-400);box-shadow:0 0 0 4px rgba(255,107,61,.1)}.gdz-exsearch input{border:none;outline:none;background:transparent;flex:1;font-family:var(--font-body);font-size:15px;color:var(--ink)}.gdz-toc-group{margin-bottom:26px}.gdz-toc-group h3{font-family:var(--font-body);font-weight:700;font-size:15px;color:var(--ink-3);letter-spacing:.02em;margin:0 0 12px}.gdz-num-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(64px,1fr));gap:8px}.gdz-num{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:2px;aspect-ratio:1/1;min-height:56px;background:#fff;border:1px solid var(--line);border-radius:12px;font-weight:700;font-size:16px;color:var(--ink);box-shadow:var(--shadow-sm);transition:transform .1s ease,box-shadow .12s,border-color .12s,background .12s}.gdz-num small{font-size:10.5px;font-weight:600;color:var(--ink-3)}.gdz-num:hover{transform:translateY(-2px);border-color:var(--coral-400);background:var(--peach-50);color:var(--coral-600)}.gdz-num:hover small{color:var(--coral-500)}.gdz-rail{position:relative}.gdz-rail-sticky{position:sticky;top:calc(var(--header-h) + 20px);display:flex;flex-direction:column;gap:16px}.gdz-ad{background:#fff;border:1px solid var(--line);border-radius:var(--radius-md);box-shadow:var(--shadow-sm);overflow:hidden}.gdz-ad-label{display:flex;align-items:center;justify-content:space-between;padding:7px 12px;font-size:10.5px;font-weight:700;letter-spacing:.1em;text-transform:uppercase;color:var(--ink-3);border-bottom:1px solid var(--line);background:var(--cream)}.gdz-ad-label .age{opacity:.6}.gdz-ad-slot{min-height:250px;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:8px;text-align:center;padding:24px 18px;color:var(--ink-3);background:repeating-linear-gradient(135deg,rgba(26,24,20,.018) 0 12px,rgba(26,24,20,0) 12px 24px)}.gdz-ad-slot--tall{min-height:500px}.gdz-ad-slot .ph-ic{width:40px;height:40px;border-radius:10px;background:var(--peach-50);display:grid;place-items:center;color:var(--coral-500);margin-bottom:4px}.gdz-ad-slot .ph-t{font-weight:700;font-size:13px;color:var(--ink-2);white-space:nowrap}.gdz-ad-slot .ph-id{font-family:ui-monospace,SF Mono,Menlo,monospace;font-size:11px;color:var(--ink-3);background:var(--cream-2);padding:3px 8px;border-radius:6px}.gdz-ad-slot .ph-hint{font-size:11px;color:var(--ink-3);max-width:200px;line-height:1.4}.gdz-ad-inline{margin:26px 0}.gdz-ad-inline .gdz-ad-slot{min-height:132px;padding:20px 18px}.gdz-footer{border-top:1px solid var(--line);background:var(--cream-2)}.gdz-footer-inner{max-width:var(--content-max);margin:0 auto;padding:32px 24px;display:flex;flex-wrap:wrap;gap:18px 40px;align-items:center;justify-content:space-between;font-size:13.5px;color:var(--ink-3)}.gdz-footer a:hover{color:var(--coral-500)}.gdz-footer .links{display:flex;flex-wrap:wrap;gap:18px;font-weight:600}.gdz-exnav{display:flex;align-items:center;gap:10px;margin-bottom:22px}.gdz-exnav a{display:inline-flex;align-items:center;gap:7px;padding:9px 16px;border-radius:999px;background:#fff;border:1.5px solid var(--line-2);font-weight:600;font-size:13.5px;color:var(--ink-2);transition:all .12s}.gdz-exnav a:hover{border-color:var(--peach-200);background:var(--peach-50);color:var(--coral-600)}.gdz-exnav .spacer{flex:1}.gdz-exnav .to-list{color:var(--ink-3);font-weight:600;font-size:13.5px}.gdz-exnav .to-list:hover{color:var(--coral-500)}.gdz-soltabs{display:flex;gap:6px;margin-bottom:16px;border-bottom:1px solid var(--line)}.gdz-soltab{padding:10px 18px;background:transparent;font-family:var(--font-body);font-weight:700;font-size:14px;color:var(--ink-3);cursor:pointer;border:none;border-bottom:2.5px solid transparent;margin-bottom:-1px;transition:color .12s,border-color .12s}.gdz-soltab:hover{color:var(--ink-2)}.gdz-soltab.active{color:var(--coral-600);border-bottom-color:var(--coral-500)}.gdz-solve{background:#fff;border:1px solid var(--line);border-radius:var(--radius-lg);padding:26px 28px;box-shadow:var(--shadow-sm);margin-bottom:22px}.gdz-solve-tag{display:inline-flex;align-items:center;gap:8px;font-size:12px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:var(--coral-600);margin-bottom:14px}.gdz-solve-tag .ic{width:22px;height:22px;border-radius:7px;background:var(--peach-50);display:grid;place-items:center;color:var(--coral-500)}.gdz-solve-tag.ans{color:var(--leaf-400)}.gdz-solve-tag.ans .ic{background:rgba(107,190,126,.14);color:var(--leaf-400)}.gdz-solve p{font-size:16px;line-height:1.7;color:var(--ink-2);margin:0 0 12px}.gdz-solve p:last-child{margin-bottom:0}.gdz-solve b,.gdz-solve strong{color:var(--ink);font-weight:700}.gdz-steps{display:flex;flex-direction:column;gap:16px;margin:4px 0 0;padding:0;list-style:none;counter-reset:step}.gdz-steps>li{position:relative;padding-left:42px;font-size:16px;line-height:1.65;color:var(--ink-2)}.gdz-steps>li:before{counter-increment:step;content:counter(step);position:absolute;left:0;top:-2px;width:28px;height:28px;border-radius:50%;background:var(--peach-50);color:var(--coral-600);font-weight:700;font-size:14px;display:grid;place-items:center}.gdz-formula{display:block;background:var(--cream-2);border:1px solid var(--line);border-radius:12px;padding:14px 18px;margin:10px 0;font-family:Cambria Math,Georgia,serif;font-size:18px;color:var(--ink);overflow-x:auto}.gdz-answer{background:linear-gradient(160deg,rgba(107,190,126,.1),rgba(107,190,126,.04));border:1px solid rgba(107,190,126,.3)}.gdz-figure{aspect-ratio:16/7;border-radius:12px;background:repeating-linear-gradient(135deg,rgba(26,24,20,.03) 0 12px,rgba(26,24,20,0) 12px 24px),var(--cream-2);border:1px dashed var(--line-2);display:grid;place-items:center;color:var(--ink-3);font-size:12.5px;font-weight:600;margin:10px 0}.gdz-related h2{font-family:var(--font-display);font-weight:600;letter-spacing:-.02em;font-size:20px;margin:0 0 14px}@media (max-width:960px){:root{--gap-col:24px}.gdz-shell{grid-template-columns:1fr}.gdz-rail{order:2}.gdz-rail-sticky{position:static}.gdz-ad-slot--tall{min-height:250px}}@media (max-width:720px){.gdz-header-inner{padding:0 16px;gap:12px}.gdz-logo .muted{display:none}.gdz-search{max-width:none}.gdz-header-cta .hide-sm{display:none}.gdz-shell{padding:20px 16px 64px}.gdz-bookhead{flex-direction:column;gap:16px}.gdz-bookhead-cover{width:96px}.gdz-bookhead-meta{grid-template-columns:1fr}.gdz-solve{padding:20px 18px}.gdz-exnav{flex-wrap:wrap}.gdz-exnav .spacer{display:none}}@media (max-width:560px){.gdz-search{display:none}.gdz-class-grid{grid-template-columns:repeat(auto-fill,minmax(120px,1fr))}.gdz-subj-grid{grid-template-columns:1fr}.gdz-book-grid{grid-template-columns:repeat(auto-fill,minmax(150px,1fr));gap:12px}.gdz-num-grid{grid-template-columns:repeat(auto-fill,minmax(56px,1fr))}.gdz-pagehead h1{font-size:26px}}.gdz-solution-images{display:flex;flex-direction:column;gap:12px;margin:8px 0 0}.gdz-solution-img{max-width:100%;height:auto;border-radius:8px;border:1px solid var(--border-light,#e8ecf0);background:#fff;display:block}.gdz-textbook{margin-top:28px}.gdz-textbook-lede{color:var(--ink-3);font-size:15px;margin:4px 0 16px;line-height:1.5}.gdz-textbook-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:12px}.gdz-textbook-card{display:flex;flex-direction:column;gap:6px;padding:14px 16px;background:#fff;border:1px solid var(--line);border-radius:var(--radius-md);text-decoration:none;transition:border-color .15s,box-shadow .15s,transform .15s}.gdz-textbook-card:hover{border-color:var(--coral-400);box-shadow:var(--shadow-sm);transform:translateY(-1px)}.gdz-textbook-card-title{font-weight:700;font-size:15px;color:var(--ink-1)}.gdz-textbook-card-excerpt{font-size:13px;color:var(--ink-3);line-height:1.45}.gdz-textbook-all{display:inline-block;margin-top:14px;font-weight:600;font-size:14.5px;color:var(--coral-600);text-decoration:none}.gdz-textbook-all:hover{text-decoration:underline}