.cc-book{font-family:Vazirmatn,sans-serif;color:var(--ink);background:var(--paper);line-height:1.9}.cc-book *{box-sizing:border-box}.cc-book [hidden]{display:none!important}.bk-wrap,.bk-wide{width:min(100% - 40px,1040px);margin-inline:auto}.bk-reading{width:min(100% - 40px,720px);margin-inline:auto}.cc-book a{color:var(--ink);text-underline-offset:4px}.cc-book button,.cc-book textarea{font-family:Vazirmatn,sans-serif}.bk-skip{position:fixed;z-index:20;inset-block-start:8px;inset-inline-start:8px;padding:8px 12px;border:1px solid var(--ink);background:var(--paper);transform:translateY(-150%)}.bk-skip:focus{transform:translateY(0)}.bk-header{display:flex;align-items:center;gap:10px;min-height:64px;font-size:14px}.bk-header a:first-child{font-weight:700;text-decoration:none}#progress{position:fixed;inset:0 auto auto 0;width:0;height:3px;background:var(--ink);z-index:9}.bk-mobile-nav{display:none}.bk-rail{position:fixed;inset-inline-start:max(20px,calc((100% - 1240px)/2));inset-block-start:150px;display:grid;gap:10px;width:150px;font-size:13px}.bk-rail a{color:var(--ink-soft)}.bk-cover{padding:86px 0 68px;border-block:1px solid var(--line-gold)}.bk-kicker{margin:0 0 12px;font-size:13px;font-weight:700;color:var(--ink-soft)}.cc-book h1,.cc-book h2{margin:0;color:var(--ink);font-weight:700;line-height:1.5}.cc-book h1{max-width:760px;font-size:clamp(42px,5vw,56px)}.cc-book h2{font-size:clamp(30px,3vw,38px);line-height:1.35}.cc-book p{margin:0}.bk-lead{max-width:660px;margin:20px 0 28px;font-size:20px;line-height:2}.bk-actions{display:flex;flex-wrap:wrap;align-items:center;gap:16px}.bk-actions .btn{min-height:56px}.bk-quiet{font-weight:600}.bk-download-note{margin-top:16px;color:var(--ink-soft);font-size:14px}.bk-figure{max-width:240px;margin:40px 0 0;text-align:center}.bk-figure img{max-width:100%;margin:auto}.bk-labels{display:flex;justify-content:space-between;gap:8px;margin-top:10px;color:var(--ink-soft);font-size:11px}.bk-figure figcaption{margin-top:12px;color:var(--ink-soft);font-size:13px;line-height:1.8}.bk-section{padding:68px 0;border-bottom:1px solid var(--line-gold)}.bk-section h2+p,.bk-section h2+.bk-en{margin-top:18px}.bk-section p+p{margin-top:14px}.bk-toc{margin:18px 0 0;padding:0;list-style:none}.bk-toc li{padding:11px 0;border-bottom:1px dashed var(--line-dash)}.bk-en{direction:ltr;text-align:left;padding:18px;background:var(--slip);border:1px solid var(--line-dash);border-radius:var(--r-row);line-height:1.75}.bk-check{margin:22px 0 0;padding:20px;border:1px solid var(--line-dash);border-radius:var(--r-surface);background:var(--slip)}.bk-check legend{padding-inline:6px;font-weight:700}.bk-check label{display:block;margin-top:10px;cursor:pointer}.bk-check input{margin-inline-end:8px}.bk-response{margin-top:16px!important;padding-top:14px;border-top:1px solid var(--line-gold)}#book-check-status{margin-top:16px;color:var(--ink-soft);font-size:14px}.cc-book label{display:block;margin-top:18px;font-weight:700}.cc-book textarea{display:block;width:100%;min-height:160px;margin-top:8px;padding:13px;border:1px solid var(--ink);border-radius:var(--r-control);background:var(--white);color:var(--ink);font-size:16px;line-height:1.85;resize:vertical}.cc-book textarea[readonly]{background:var(--slip);cursor:not-allowed}.bk-model{margin-top:20px;padding:18px;border:1px solid var(--ink);border-radius:var(--r-surface)}.bk-late-key{padding:68px 0;border-bottom:1px solid var(--line-gold)}.bk-nojs{margin-top:18px;padding:18px;border:1px dashed var(--line-dash)}.bk-footer{padding:42px 0 56px;font-weight:700}.bk-footer-links{display:flex;flex-wrap:wrap;gap:12px 18px;margin-top:18px}.bk-print-instruction,.bk-reference-print{display:none}.bk-write-line{min-height:2.6em;border-bottom:1px solid var(--ink-soft);padding-top:10px}.cc-book button:focus-visible,.cc-book a:focus-visible,.cc-book textarea:focus-visible,.cc-book input:focus-visible{outline:2px solid var(--ink);outline-offset:3px}
@media(max-width:1180px){.bk-rail{display:none}}@media(max-width:720px){.bk-wrap,.bk-wide,.bk-reading{width:min(100% - 32px,720px)}.bk-header{gap:7px;font-size:12px;overflow:auto;white-space:nowrap}.bk-mobile-nav{display:block;position:sticky;inset-block-start:0;z-index:8;background:var(--paper);border-block:1px solid var(--line-gold)}.bk-mobile-nav__row{display:flex;align-items:center;min-height:52px;gap:12px}.bk-mobile-nav button{min-height:44px;border:0;background:transparent;color:var(--ink);font-weight:700}.bk-mobile-nav #lbar-fill{display:block;flex:1;height:2px;background:var(--line-gold)}.bk-mobile-nav #lbar-fill::after{content:"";display:block;width:var(--book-progress,0%);height:100%;background:var(--ink)}.bk-mobile-nav #lbar-sheet{padding-bottom:14px}.bk-mobile-nav #lbar-sheet>div{display:flex;flex-wrap:wrap;gap:10px}.bk-cover{padding:50px 0}.cc-book h1{font-size:44px}.cc-book h2{font-size:33px}.bk-lead{font-size:18px}.bk-section,.bk-late-key{padding:50px 0}}@media print{@page{size:A4;margin:14mm 15mm 23mm}.cc-book{font-size:10.8pt;line-height:1.7;background:var(--white)}.bk-skip,#progress,#header,#lbar,#lrail,.bk-actions,.bk-download-note,#book-draft-note,#book-model-toggle,#book-check-status,.bk-response,#book-model,.bk-footer{display:none!important}.bk-cover{padding:0 0 10mm}.bk-section{padding:8mm 0}.bk-late-key,#book-revision[hidden]{display:block!important;padding:10mm 0;break-before:page}.cc-book h1{font-size:25pt}.cc-book h2{font-size:18pt;break-after:avoid}.bk-figure{max-width:240px;margin:6mm auto}.cc-book textarea{min-height:55mm}.bk-check{break-inside:avoid}.bk-print-instruction{display:block;margin:0 0 7mm}.bk-reference-print{display:block;padding:8mm 0;break-before:page}.bk-section#transfer{break-before:page}.bk-section#transfer>.bk-reading>label,#book-revision label{break-inside:avoid;page-break-inside:avoid}#book-revision{break-before:page}#change-reason{min-height:30mm}}
.bk-late-key .bk-en,.bk-late-key .bk-en+p{display:none!important}
@media print{#book-model,#book-model[hidden]{display:block!important}.bk-late-key .bk-en,.bk-late-key .bk-en+p{display:none!important}}

.bk-rail{inset-inline-start:auto;inset-inline-end:max(20px,calc((100% - 1240px)/2))}

.bk-rail{position:static;inset:auto;width:min(100% - 40px,1040px);margin:0 auto;padding:14px 0;display:flex;flex-wrap:wrap;align-items:center;gap:8px 16px;border-bottom:1px solid var(--line-gold)}.bk-rail a{font-size:13px}

@media(max-width:720px){.bk-rail{display:none}}

/* Paper-only workbook flow: writing spaces precede model and answer key. */
@media print{
 .cc-book .bk-reference-detail{display:none!important}
 .cc-book .bk-reference-print{break-before:auto;padding:4mm 0}
 .cc-book .bk-check{padding:4mm;margin-top:5mm}
 .cc-book .bk-check label{display:inline-flex;align-items:center;gap:2mm;margin:3mm 0 0 6mm}
 .cc-book .bk-check input{width:auto;margin:0}
 .cc-book .bk-check .bk-en{padding:3mm}
 .cc-book #book-revision,.cc-book #book-revision[hidden]{display:block!important;break-before:auto;padding:0}
 .cc-book #transfer textarea{height:42mm;min-height:42mm}
 .cc-book #transfer #change-reason{height:24mm;min-height:24mm}
 .cc-book #book-model,.cc-book #book-model[hidden]{display:block!important;break-before:page;border:0;padding:0;margin:0}
 .cc-book #late-key,.cc-book #late-key[hidden]{display:block!important;break-before:auto;padding:6mm 0}
 .cc-book #late-key h2+p{display:none}
}
/* Keep the printable response line within narrow no-JavaScript worksheets. */
.bk-nojs .bk-write-line{overflow-wrap:anywhere}