:root{--ink:#243547;--muted:#63717d;--navy:#233b54;--navy-dark:#1a2e43;--blue:#2b5e8d;--bg:#f6f5f1;--paper:#fff;--line:#e0e3e3;--pale:#edf2f6;--amber:#b97830;--amber-bg:#f5ebd9;--green:#357561;--red:#a53e38;--radius:14px;--shadow:0 12px 35px rgba(26,46,67,.1);font-family:-apple-system,BlinkMacSystemFont,'PingFang SC','Microsoft YaHei','Noto Sans SC',sans-serif;color:var(--ink);font-size:15px;line-height:1.65;font-synthesis:none}*{box-sizing:border-box}body{margin:0;background:var(--bg)}button,input,select,textarea{font:inherit}button,a,input,select,textarea{-webkit-tap-highlight-color:transparent}button,a{touch-action:manipulation}button{cursor:pointer}button:disabled{opacity:.5;cursor:wait}a{color:inherit;text-decoration:none}a:hover{text-decoration:none}button{color:inherit}::selection{background:#d6e2ec;color:#182d42}input,textarea{caret-color:var(--blue)}:focus-visible{outline:3px solid 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0;width:224px;background:var(--navy);color:#edf3f8;display:flex;flex-direction:column;padding:36px 20px 24px;z-index:30}.brand{display:flex;gap:12px;align-items:center;padding:0 11px;font-size:21px;font-weight:650;letter-spacing:.05em}.brand img{width:37px;height:37px}.brand small{display:block;letter-spacing:.11em;color:#bac9d6;font-size:10px;margin-top:1px;font-weight:400}.side-nav{display:grid;gap:7px;margin-top:48px}.side-nav a{display:flex;align-items:center;gap:13px;border-radius:9px;padding:12px 15px;color:#c5d2de;font-size:14px}.side-nav a:hover{background:#304a65;color:#fff}.side-nav a.active{background:#f5f6f5;color:var(--navy);font-weight:600}.side-nav a .icon{width:20px}.sidebar-note{margin-top:auto;padding:24px 12px 0;border-top:1px solid #41576d;color:#c0cdda;font-size:12px}.sidebar-note b{color:#f0f3f7;display:block;font-size:13px;font-weight:500;margin-bottom:5px}.topbar{height:87px;padding:0 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270px;gap:24px;align-items:start}.paper{background:#fff;border:1px solid var(--line);border-radius:12px;overflow:hidden}.paper-head{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:16px 21px;border-bottom:1px solid var(--line)}.paper-head h2{font-size:15px}.paper-head .button{min-height:32px;padding:4px 9px;font-size:11px}.image-tools{display:flex;align-items:center;gap:6px}.question-image-wrap{overflow:auto;max-height:740px;background:#fff;padding:15px;touch-action:pan-x pan-y}.question-image{width:100%;max-width:none;display:block;height:auto;transform-origin:top left}.question-text{font-family:'Songti SC','SimSun',serif;font-size:17px;line-height:2.15;white-space:pre-wrap;padding:30px;overflow-wrap:anywhere}.question-text.sans{font-family:inherit;font-size:15px;line-height:1.9}.reader-aside h3{font-size:14px;margin-bottom:12px}.reader-aside p{font-size:12px;color:var(--muted);line-height:1.9}.reader-aside .facts{margin:18px 0;border-top:1px solid 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0}.draft-preview{white-space:pre-wrap;font-size:13px;line-height:1.9;background:#f6f7f6;max-height:350px;overflow:auto;padding:20px;border-radius:8px}.toast{position:fixed;left:50%;bottom:30px;transform:translate(-50%,15px);max-width:min(500px,90vw);padding:12px 21px;background:var(--navy-dark);color:#fff;border-radius:9px;font-size:13px;box-shadow:var(--shadow);opacity:0;pointer-events:none;z-index:100;transition:opacity .2s,transform .2s}.toast.show{opacity:1;transform:translate(-50%,0)}.spinner{width:16px;height:16px;border:2px solid #ffffff60;border-top-color:currentColor;border-radius:50%;animation:spin 1s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.fade-in{animation:arrive .25s ease-out}@keyframes arrive{from{opacity:.7;transform:translateY(3px)}to{opacity:1;transform:none}}details{border-bottom:1px solid var(--line);padding:15px 0}details summary{cursor:pointer;font-size:14px;font-weight:500}details p{font-size:13px;color:var(--muted);margin-top:13px;line-height:1.9}.privacy-content{max-width:760px}.privacy-content h2{margin:30px 0 12px}.privacy-content p,.privacy-content ul{font-size:14px;line-height:1.95;color:#546675}.check-label{display:flex;gap:8px;align-items:flex-start;font-size:12px;line-height:1.8;color:var(--muted);margin:17px 0}.check-label input{margin-top:4px;accent-color:var(--navy)}.danger-zone{margin-top:24px}.danger-zone summary{color:var(--red)}.admin-editor{margin-top:25px}.admin-editor textarea{min-height:180px}.footer-line{font-size:11px;color:#75818a;margin-top:36px;display:flex;gap:18px;flex-wrap:wrap}.footer-line a:hover{color:var(--blue)}.network-strip{background:#f6e8cd;color:#835a23;text-align:center;padding:8px;font-size:12px}.narrow{max-width:800px;margin-inline:auto}.wide-button{width:100%}.hidden{display:none!important}
@media(min-width:1500px){.main{padding-top:48px}.book-cover{height:225px}.feature-lesson{min-height:270px}}
@media(max-width:1100px){.sidebar{width:196px;padding-inline:14px}.shell{padding-left:196px}.topbar{padding-inline:28px}.main{padding:30px 28px 55px}.brand{font-size:19px}.book-grid{gap:15px}.book-cover{padding:22px 20px;height:185px}.book-cover h3{font-size:27px}.cover-diagram{width:105px;right:3px}.feature-text{padding:23px}.feature-text h2{font-size:21px}.reader-split{grid-template-columns:minmax(0,1fr) 225px;gap:18px}.auth-layout{gap:32px}.two-col{gap:20px}.reader-header h1{font-size:23px}.stat-strip>div{padding:18px}}
@media(max-width:800px){.sidebar{display:none}.shell{padding:0 0 calc(72px + env(safe-area-inset-bottom))}.topbar{height:68px;padding:0 22px;padding-top:env(safe-area-inset-top)}.topbar-context{display:none}.mobile-brand{display:flex;align-items:center;gap:8px;font-size:17px;font-weight:650}.mobile-brand img{width:29px;height:29px}.topbar-tools .button{display:none}.main{padding:27px 22px 40px}.mobile-nav{display:flex;position:fixed;inset:auto 0 0;z-index:40;justify-content:space-around;padding:8px 9px calc(7px + env(safe-area-inset-bottom));background:#fff;border-top:1px solid var(--line)}.mobile-nav a{min-width:60px;display:flex;flex-direction:column;align-items:center;gap:4px;color:#63717d;font-size:10px;padding:4px 12px}.mobile-nav a.active{color:var(--navy);font-weight:600}.mobile-nav a.active .icon{stroke-width:2.2}.mobile-nav .icon{width:22px;height:22px}.book-cover{height:180px}.reader-split{grid-template-columns:1fr}.reader-aside{display:none}.auth-layout{margin-top:10px;grid-template-columns:1fr;max-width:470px;gap:25px}.auth-intro h1{font-size:27px;line-height:1.35;margin-bottom:10px}.auth-intro h1 br{display:none}.auth-intro ul{display:none}.auth-card{padding:25px}.two-col{grid-template-columns:1fr}.reader-header h1{font-size:24px}.reader-header{gap:12px}.reader-header .meta{margin-bottom:15px}.reader-actions .button .label{display:none}.toast{bottom:95px}.locate-fields{grid-template-columns:1fr 1fr}.locate-fields>.field:first-child{grid-column:1/-1}.locate-fields>.button{grid-column:1/-1}.lesson-frame{height:1200px}.reader-tabs{margin-top:3px}.reader-panel.fullscreen{padding:8px;padding-top:calc(8px + env(safe-area-inset-top))}.stat-strip{grid-template-columns:repeat(2,1fr)}.stat-strip>div{border-bottom:1px solid var(--line)}.stat-strip>div:nth-child(2){border-right:0}.stat-strip>div:nth-child(3){border-bottom:0}.stat-strip>div:last-child{border:0}}
@media(max-width:560px){h1{font-size:27px}.main{padding:25px 18px 32px}.topbar{padding-inline:18px}.page-heading{margin-bottom:22px;gap:12px}.page-heading p{font-size:12px;line-height:1.8}.page-heading>.button{font-size:12px;padding:7px 10px;min-height:37px;white-space:nowrap}.search-box{gap:9px;padding-left:12px}.search-box input{font-size:16px}.search-box .button{padding-inline:13px}.search-box>.icon{width:18px}.search-hint{font-size:11px;margin-bottom:23px}.book-grid{grid-template-columns:repeat(3,minmax(0,1fr));gap:11px}.book-cover{height:157px;padding:17px 13px}.book-cover:before{left:6px}.book-cover h3{font-size:25px;margin-top:17px}.book-cover .cover-brand{font-size:8px;letter-spacing:.03em}.book-cover .cover-sub{font-size:9px;letter-spacing:0;margin-top:6px}.cover-footer{font-size:7px;letter-spacing:0;z-index:1}.cover-diagram{width:80px;height:66px;right:0;bottom:16px;opacity:.4}.unavailable{right:6px;top:7px;font-size:8px;padding:2px 4px}.book-title h3{font-size:12px}.book-title .icon{display:none}.book-card p{font-size:10px}.book-card{padding-bottom:13px}.feature-lesson{grid-template-columns:1fr;min-height:0}.feature-text{padding:22px}.feature-text h2{font-size:20px;margin-top:10px}.feature-text p{font-size:12px;max-width:100%}.feature-text .button{min-height:39px}.feature-art{min-height:178px;max-height:178px;overflow:hidden}.feature-art svg{height:180px;width:88%;transform:translateY(-3px)}.feature-art .plot-caption{bottom:10px;left:22px;font-size:9px}.section-head{margin:25px 0 14px}.section-head h2{font-size:17px}.section-head small{font-size:11px}.filter{padding:7px 14px}.reader-header h1{font-size:22px}.reader-actions{gap:5px}.reader-actions .button{min-width:36px;min-height:36px;padding:7px}.reader-header .meta{font-size:11px;gap:7px}.breadcrumb{font-size:11px;margin-bottom:20px}.reader-tabs{gap:25px}.reader-tabs button{font-size:13px}.paper-head{padding:12px;align-items:flex-start;flex-wrap:wrap}.paper-head h2{font-size:13px}.reading-tabs .button{font-size:10px;padding-inline:8px}.question-image-wrap{padding:8px}.question-text{padding:20px;font-size:16px}.question-text.sans{font-size:14px}.q-mark{width:37px;height:42px;font-size:17px}.question-row{gap:12px;padding-block:18px}.q-info h3{font-size:14px}.q-info p{font-size:11px}.q-tags .tag{font-size:10px}.question-row .q-arrow{width:16px}.lesson-note{font-size:11px;align-items:flex-start}.lesson-note .button{font-size:11px;padding:5px 9px;min-height:32px;white-space:nowrap}.lesson-frame{height:1470px}.panel{padding:21px}.panel>h2{font-size:18px}.form-grid{grid-template-columns:1fr;gap:15px}.form-grid .field{margin-bottom:3px}.completion{font-size:11px}.completion .button{font-size:11px;padding:8px 12px}.account-link>span:not(.avatar){display:none}.stat-strip strong{font-size:22px}.admin-tabs .button{font-size:11px;padding:7px 12px;min-height:36px}.admin-toolbar{align-items:flex-start;flex-direction:column}.footer-line{font-size:10px;gap:12px;margin-top:27px}.empty{padding:35px 20px}.feature-text>.tag{font-size:10px}.notice{font-size:11px;padding:12px}.image-tools{margin-left:auto}.page-heading .inline-actions{justify-content:flex-end}.auth-intro p{font-size:13px}.auth-card h2{font-size:21px}.reader-tabs .icon{width:16px}}
@media(prefers-reduced-motion:reduce){*,*:before,*:after{animation:none!important;transition:none!important;scroll-behavior:auto!important}}
@media print{.sidebar,.topbar,.mobile-nav,.reader-actions,.reader-tabs,.reader-aside,.footer-line,.completion,.toast,.breadcrumb,.lesson-note{display:none!important}.shell{padding:0}.main{padding:0}.reader-split{display:block}.paper{border:0}.paper-head{display:none}.question-image-wrap{max-height:none;overflow:visible}.question-image{width:100%!important}.reader-header h1{font-size:20px}.question-text{font-size:14px}}
.facts dt{flex-shrink:0;white-space:nowrap}.facts dd{overflow-wrap:anywhere}.reader-header .meta>span:not(.tag){max-width:65ch}.reader-panel.fullscreen .lesson-frame{height:calc(100dvh - 65px)!important}

/* Service information pages keep the existing reading surface. */
.privacy-content p{overflow-wrap:anywhere}.privacy-content .inline-actions{align-items:center}.footer-line{color:var(--muted)}
@media print{.sidebar,.topbar,.mobile-nav,.skip-link,.toast,.privacy-content>header .button,.privacy-content>nav,.footer-line{display:none!important}.shell{display:block!important;padding:0!important}.main{padding:0!important;max-width:none}.privacy-content{max-width:none}.privacy-content h2{break-after:avoid}.privacy-content p{orphans:3;widows:3}}