.b7{--paper:#f4f1e8;--paper-deep:#e6e0cf;--ink:#1f2a28;--ink-soft:#4f5a52;--seal:#b33a2a;--seal-deep:#7a2014;--bamboo:#2f4a3f;--bamboo-bright:#3a9a4a;--gold:#d9a02a;--rule:#d6ccb0}.b7 *{box-sizing:border-box}.b7{scroll-behavior:smooth;overflow-anchor:none;margin:0;background:var(--paper);background-image:radial-gradient(ellipse at 20% 10%,rgba(179,58,42,.05),transparent 40%),radial-gradient(ellipse at 80% 90%,rgba(47,74,63,.06),transparent 45%);color:var(--ink);font-family:Noto Sans,Noto Sans SC,sans-serif;line-height:1.6}.b7:before{content:"";position:fixed;inset:0;pointer-events:none;opacity:.5;background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='120' height='120'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.04'/%3E%3C/svg%3E");z-index:1}.b7 .wrap{max-width:960px;margin:0 auto;padding:0 24px 120px}.b7 header.hero{padding:56px 24px 48px;text-align:center;border-bottom:1px solid var(--rule);overflow:hidden}.b7 .date-tag{font-size:.75rem;letter-spacing:.18em;color:var(--ink-soft);margin-bottom:28px}.b7 .seal-box{width:88px;height:88px;margin:0 auto 22px;border:3px solid var(--seal);border-radius:6px;display:flex;align-items:center;justify-content:center;color:var(--seal);font-family:"Noto Serif SC",serif;font-weight:900;font-size:1.5rem;transform:rotate(-3deg);box-shadow:0 0 0 1px rgba(179,58,42,.15);position:relative}.b7 .seal-box:after{content:"";position:absolute;inset:6px;border:1px solid var(--seal);border-radius:3px;opacity:.5}.b7 h1.cn{font-family:"Noto Serif SC",serif;font-weight:900;font-size:clamp(1.8rem,6vw,3rem);color:var(--ink);margin:0 0 6px;letter-spacing:.02em}.b7 .pinyin-line,.b7 h1.cn .red{color:var(--seal)}.b7 .pinyin-line{font-size:1rem;font-style:italic;margin-bottom:6px}.b7 .subtitle{font-size:1rem;color:var(--ink-soft)}.b7 .subtitle strong{color:var(--bamboo);font-weight:700}.b7 .brush-rule{width:140px;height:3px;margin:26px auto 0;background:linear-gradient(90deg,transparent,var(--seal) 20%,var(--seal) 80%,transparent);border-radius:2px;opacity:.8}.b7 .tts-note{max-width:640px;margin:18px auto 0;font-size:.82rem;color:var(--ink-soft);text-align:center;font-style:italic}.b7 .tts-note b{color:var(--seal);font-style:normal}.b7 .voice-picker{display:flex;align-items:center;justify-content:center;gap:8px;flex-wrap:wrap;margin-top:14px;font-size:.82rem;color:var(--ink-soft)}.b7 .voice-picker select{font-family:Noto Sans,sans-serif;font-size:.82rem;padding:5px 10px;border:1px solid var(--rule);border-radius:4px;background:var(--paper-deep);color:var(--ink);max-width:260px}.b7 .vp-status{font-weight:700}.b7 .vp-status.ok{color:var(--bamboo)}.b7 .vp-status.warn{color:var(--seal)}.b7 .back-link{display:inline-block;margin:14px 0 0 14px;font-size:.85rem;color:var(--ink-soft);text-decoration:none;border:1px solid var(--seal);border-radius:6px;padding:4px 10px}.b7 .back-link:hover{color:var(--seal);background:var(--paper-deep)}.b7 .lesson-nav{display:flex;justify-content:center;align-items:center;gap:14px;flex-wrap:wrap;padding:32px 24px 0}.b7 .prev-link{display:inline-block;font-size:.9rem;color:var(--ink-soft);text-decoration:none;border:1px solid var(--rule);border-radius:6px;padding:8px 16px;font-weight:700}.b7 .prev-link:hover{color:var(--seal-deep);border-color:var(--seal);background:var(--paper-deep)}.b7 .next-link{display:inline-block;font-size:.9rem;color:var(--seal-deep);text-decoration:none;border:1px solid var(--seal);border-radius:6px;padding:8px 16px;font-weight:700}.b7 .next-link:hover{color:var(--paper);background:var(--seal)}.b7 footer.pagefoot-note{text-align:center;padding:18px 24px 0;color:var(--ink-soft);font-size:.8rem;letter-spacing:.04em}.b7 .toc{border:1px solid var(--rule);border-radius:6px;background:var(--paper-deep);padding:18px 22px;margin:28px 0 26px}.b7 .toc-title{font-weight:700;color:var(--seal);font-size:.85rem;margin-bottom:12px}.b7 .toc-list{list-style:none;margin:0;padding:0;display:grid;gap:8px}.b7 .toc-list a{display:flex;align-items:baseline;gap:10px;text-decoration:none;color:var(--ink);padding:2px 0}.b7 .toc-list a:hover .toc-cn,.b7 .toc-list a:hover .toc-vn,.b7 .toc-num{color:var(--seal)}.b7 .toc-num{font-weight:700;min-width:1.8em;flex-shrink:0}.b7 .toc-cn{font-family:"Noto Serif SC",serif;font-weight:600;flex-shrink:0}.b7 .toc-vn{color:var(--ink-soft);font-size:.88rem}.b7 section{position:relative;padding:56px 0 8px;scroll-margin-top:20px}.b7 section+section{border-top:1px solid var(--rule)}.b7 .sec-head{display:flex;align-items:baseline;gap:16px;margin-bottom:30px}.b7 .sec-num{font-size:2.4rem;font-weight:900;color:var(--seal);line-height:1}.b7 .sec-num,.b7 .sec-title-cn{font-family:"Noto Serif SC",serif}.b7 .sec-title-cn{font-size:1.6rem;font-weight:600;color:var(--ink)}.b7 .sec-title-py{font-size:.8rem;color:var(--seal);font-style:italic;margin:1px 0 2px}.b7 .sec-title-vn{font-size:.95rem;color:var(--ink-soft);font-style:italic}.b7 .pin-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:14px;margin-bottom:28px}.b7 .pin-card{position:relative;background:#fff;border:1px solid var(--rule);border-radius:4px;padding:20px 12px 14px;text-align:center;box-shadow:0 2px 6px rgba(31,42,40,.08),0 1px 0 rgba(31,42,40,.04);transform:rotate(var(--tilt,0deg));transition:transform .15s ease,box-shadow .15s ease}.b7 .pin-card:hover{transform:rotate(0deg) translateY(-2px);box-shadow:0 8px 18px rgba(31,42,40,.12)}.b7 .pin-card:before{content:"";position:absolute;top:6px;left:50%;transform:translateX(-50%);width:11px;height:11px;border-radius:50%;background:var(--pin-color,var(--seal));box-shadow:0 1px 2px rgba(0,0,0,.35)}.b7 .pin-card .emoji{font-size:1.2rem;line-height:1;display:block;margin-top:8px}.b7 .pin-card .hz{font-family:"Noto Serif SC",serif;font-size:1.55rem;font-weight:700;color:var(--ink);display:inline-block;margin-top:2px}.b7 .pin-card .py{font-size:.8rem;color:var(--ink-soft);display:block;margin-top:4px}.b7 .pin-card .vn{font-size:.82rem;color:var(--bamboo);font-weight:600;margin-top:3px;display:block}.b7 .fc-wrap{max-width:480px;margin:0 auto}.b7 .fc-card{border:1px solid var(--rule);border-radius:14px;background:var(--paper-deep);padding:22px 18px;text-align:center;margin-bottom:14px}.b7 .fc-card .vn-hint{font-size:1.5rem;font-weight:700;color:var(--ink)}.b7 .fc-card .tap-hint{font-size:.75rem;color:var(--ink-soft);margin-top:8px}.b7 .fc-input-row{display:flex;gap:10px;margin-bottom:10px}.b7 .fc-input-row input{flex:1;padding:10px 12px;font-family:"Noto Serif SC",serif;font-size:1.15rem;border:1px solid var(--rule);border-radius:10px;background:var(--paper);color:var(--ink)}.b7 .fc-input-row input:focus{outline:2px solid var(--seal);outline-offset:1px}.b7 .fc-input-row button{padding:10px 18px;border:none;border-radius:10px;background:var(--seal);color:#fff;font-size:.95rem;font-weight:700;cursor:pointer}.b7 .fc-input-row button:hover{opacity:.85}.b7 .fc-feedback{text-align:center;font-size:.9rem;font-weight:700;min-height:1.4em;margin-bottom:8px}.b7 .fc-feedback.correct{color:var(--bamboo-bright)}.b7 .fc-feedback.wrong{color:var(--seal)}.b7 .fc-feedback .hz{font-family:"Noto Serif SC",serif}.b7 .fc-stats{display:flex;justify-content:space-between;align-items:center;font-size:.8rem;color:var(--ink-soft)}.b7 .fc-link{background:none;border:none;padding:0;font-size:.8rem;color:var(--bamboo);font-weight:700;cursor:pointer}.b7 .fc-link:hover{color:var(--seal)}.b7 .dialogue-group{margin-bottom:32px;text-align:center}.b7 .dialogue-label{display:inline-block;font-size:.75rem;letter-spacing:.12em;text-transform:uppercase;color:var(--ink-soft);font-weight:700;margin-bottom:10px;border-left:3px solid var(--seal);padding-left:10px}.b7 .sentence-stack{display:flex;flex-direction:column;gap:8px;margin:0 auto}.b7 .sentence-card{background:var(--paper-deep);border:1px solid var(--rule);border-radius:10px;padding:12px 16px;text-align:center}.b7 .sentence-card.speaker-a{border-left:4px solid var(--seal);border-radius:0 10px 10px 10px}.b7 .sentence-card.speaker-b{border-left:4px solid var(--bamboo);border-radius:0 10px 10px 10px}.b7 .sentence-tag{font-size:.72rem;color:var(--ink-soft);font-weight:700;letter-spacing:.06em;text-transform:uppercase;margin-bottom:4px}.b7 .sentence-hz{font-family:"Noto Serif SC",serif;font-size:1.35rem;font-weight:700;color:var(--ink)}.b7 .sentence-hz .hl,.b7 .sentence-py{color:var(--seal)}.b7 .sentence-py{font-size:.82rem;font-style:italic;margin-top:2px}.b7 .sentence-vn{font-size:.88rem;color:var(--ink-soft);margin-top:2px}.b7 .sentence-arrow{text-align:center;color:var(--ink-soft);font-size:1.1rem;line-height:1}.b7 .sub-head{margin-top:36px;margin-bottom:16px}.b7 .sub-head .t{font-family:"Noto Serif SC",serif;font-size:1.1rem;font-weight:700;color:var(--ink)}.b7 .sub-head .d{font-size:.82rem;color:var(--ink-soft);margin-left:10px}.b7 .compare-note{border-left:3px solid var(--bamboo);background:rgba(47,74,63,.05);padding:12px 16px;border-radius:0 8px 8px 0;font-size:.9rem;line-height:1.7;margin-bottom:14px}.b7 .compare-note b{color:var(--bamboo)}.b7 .compare-note .term{font-family:"Noto Serif SC",serif;font-weight:700;color:var(--ink);display:inline-block}.b7 .compare-note.warn{border-left-color:var(--seal);background:rgba(179,58,42,.05)}.b7 .compare-note.warn b{color:var(--seal)}.b7 .formula-banner{display:flex;align-items:center;justify-content:center;gap:14px;flex-wrap:wrap;text-align:center;max-width:640px;margin:0 auto 22px;background:linear-gradient(135deg,var(--seal) 0,var(--seal-deep) 100%);border-radius:14px;padding:18px 22px;box-shadow:0 6px 16px rgba(179,58,42,.22)}.b7 .formula-term{font-family:"Noto Serif SC",serif;font-size:1.35rem;font-weight:900;color:#fff;white-space:nowrap}.b7 .formula-term .plus{font-size:1rem;font-weight:400;opacity:.75;margin:0 2px}.b7 .formula-divider{width:1px;align-self:stretch;background:rgba(255,255,255,.3)}.b7 .formula-py{font-style:italic;font-size:.92rem;color:rgba(255,255,255,.85);white-space:nowrap}.b7 .formula-vn{font-size:.92rem;color:#fff;font-weight:600}.b7 .formula-vn .note{font-style:italic;font-weight:400;color:rgba(255,255,255,.8)}.b7 .tone-block .formula-banner{background:linear-gradient(135deg,#5d7248 0,var(--bamboo) 55%,#34412a 100%);box-shadow:0 6px 16px rgba(47,74,63,.28)}.b7 .tone-block .dialogue-label{color:var(--bamboo);border-color:var(--bamboo)}.b7 .tone-block .sentence-card{border-left-color:var(--bamboo)}.b7 .tone-block .sentence-hz .hl,.b7 .tone-block .sentence-py b{color:var(--bamboo)}.b7 .hz-story{border-left:3px solid var(--bamboo);background:rgba(47,74,63,.06);border-radius:0 6px 6px 0;padding:12px 16px;margin-bottom:14px}.b7 .hz-parts{display:flex;flex-wrap:wrap;align-items:center;gap:8px;margin-bottom:8px}.b7 .hz-parts .part{font-family:"Noto Serif SC",serif;font-weight:700;color:var(--bamboo);background:var(--paper-deep);border:1px solid var(--rule);border-radius:4px;padding:4px 10px;font-size:1rem}.b7 .hz-parts .part i{font-family:inherit;font-style:italic;font-weight:400;color:var(--ink-soft);font-size:.78rem;margin-left:4px}.b7 .hz-parts .plus{color:var(--seal);font-weight:900}.b7 .hz-story p{margin:0;font-size:.9rem;color:var(--ink-soft);line-height:1.65}.b7 .stroke-legend{border:1px solid var(--rule);background:var(--paper-deep);border-radius:6px;padding:12px 14px;margin-bottom:18px}.b7 .stroke-legend-title{font-weight:700;cursor:pointer}.b7 .stroke-legend[open] .stroke-legend-title{margin-bottom:10px}.b7 .stroke-legend-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:8px 14px}.b7 .stroke-leg-item{display:flex;gap:8px;align-items:flex-start;font-size:.88rem;cursor:pointer}.b7 .stroke-leg-item .stroke-icon{width:26px;height:26px;color:var(--seal);flex-shrink:0}.b7 .stroke-leg-item .hz{font-family:"Noto Serif SC",serif;color:var(--seal)}.b7 .stroke-leg-item .py{color:var(--ink-soft)}.b7 .stroke-leg-item .d{color:var(--ink-soft);font-size:.82rem;line-height:1.5}.b7 .stroke-seq-title{margin:12px 0 6px;font-size:.82rem;color:var(--ink-soft)}.b7 .stroke-seq{display:flex;flex-wrap:wrap;gap:8px}.b7 .stroke-seq .step{display:flex;align-items:center;gap:6px;background:var(--paper-deep);border:1px solid var(--rule);border-radius:4px;padding:6px 10px;font-size:.85rem;cursor:pointer}.b7 .stroke-seq .step .n{font-weight:900;color:var(--seal);font-family:"Noto Serif SC",serif;min-width:14px}.b7 .stroke-seq .step .stroke-icon{width:26px;height:26px;color:var(--seal);flex-shrink:0}.b7 .stroke-seq .step .vn{color:var(--ink-soft);font-size:.8rem}.b7 .prac-tabs{display:flex;gap:8px;margin:8px 0;flex-wrap:wrap}.b7 .prac-tab{font:inherit;font-size:.9rem;padding:6px 14px;cursor:pointer;background:transparent;color:var(--ink-soft);border:1px solid var(--ink-soft);border-radius:999px}.b7 .prac-tab.active{background:var(--seal);border-color:var(--seal);color:#fff}.b7 .prac-pane[hidden]{display:none}.b7 .chk-inline{width:3.4em;margin:0 4px;padding:0 2px;text-align:center;font-family:"Noto Serif SC",serif;font-size:1.1em;font-weight:700;color:var(--seal);background:transparent;border:none;border-bottom:2px solid var(--seal);border-radius:0}.b7 .chk-inline:focus{outline:none;background:var(--paper-deep)}.b7 .fc-input-row input{min-width:0;width:100%;box-sizing:border-box}.b7 .chk-item .fc-input-row{margin-top:10px}.b7 .chk-item .fc-input-row input{max-width:none}.b7 .chk-item .fc-input-row input::placeholder{font-size:.85rem}@media (max-width:480px){.b7 .chk-item{padding:12px 14px}.b7 .chk-item .fc-input-row{gap:8px}.b7 .chk-item .fc-input-row input{max-width:none;padding:8px 10px;font-size:1rem}.b7 .chk-item .fc-input-row button{padding:8px 14px;flex-shrink:0}}.b7 .make-list{max-width:640px;margin:0 auto;display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:12px;align-items:start}.b7 .make-item{background:#fff;border:1px solid var(--rule);border-radius:4px;padding:14px 18px;box-shadow:0 2px 6px rgba(31,42,40,.08)}.b7 .make-prompt{font-weight:600;color:var(--ink)}.b7 .make-prompt .num{color:var(--seal);font-weight:700;margin-right:8px}.b7 .make-prompt .vn-hint{color:var(--ink-soft);font-weight:400;margin-left:6px}.b7 .mw-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;max-width:900px;margin:0 auto 28px}@media (max-width:720px){.b7 .mw-grid{grid-template-columns:1fr}}.b7 .mw-card{--mw:var(--seal);background:#fff;border:1px solid var(--rule);border-top:5px solid var(--mw);border-radius:6px;padding:20px 20px 18px;text-align:center;box-shadow:0 4px 12px rgba(31,42,40,.1);display:flex;flex-direction:column;gap:6px}.b7 .mw-card.bam{--mw:var(--bamboo)}.b7 .mw-card.gld{--mw:var(--gold)}.b7 .mw-char{font-family:"Noto Serif SC",serif;font-size:3.6rem;font-weight:900;line-height:1.1;color:var(--mw);cursor:pointer}.b7 .mw-py{font-style:italic;color:var(--ink-soft);font-size:.95rem}.b7 .mw-tag{display:inline-block;align-self:center;margin:4px 0 2px;background:var(--mw);color:#fff;border-radius:999px;padding:3px 14px;font-size:.8rem;font-weight:700;letter-spacing:.02em}.b7 .mw-vn{font-size:1rem;color:var(--ink);line-height:1.6}.b7 .mw-ex{margin-top:auto;padding-top:12px;border-top:1px dashed var(--rule)}.b7 .mw-ex .sentence-hz{font-size:1.15rem}.b7 .mw-ex .hl{color:var(--mw)}.b7 .mw-ex .mw-ex-py{font-style:italic;color:var(--ink-soft);font-size:.85rem}.b7 .mw-ex .mw-ex-vn{color:var(--ink-soft);font-size:.88rem}.b7 .char-steps{background:#fff;border:1px solid var(--rule);border-radius:4px;padding:24px 26px;margin-bottom:20px;box-shadow:0 2px 6px rgba(31,42,40,.08),0 1px 0 rgba(31,42,40,.04)}.b7 .char-steps-title{display:flex;flex-direction:column;align-items:center;gap:6px;text-align:center;margin-bottom:14px;padding-bottom:14px;border-bottom:1px dashed var(--rule)}.b7 .char-steps-title .big{font-family:"Noto Serif SC",serif;font-size:3rem;font-weight:700;line-height:1.1;color:var(--seal)}.b7 .char-steps-title .meta{font-size:1rem;color:var(--ink-soft)}.b7 .hw-box{display:flex;flex-direction:column;align-items:center;gap:10px}.b7 .hw-target{width:150px;height:150px;background-color:var(--paper-deep);background-image:linear-gradient(var(--rule) 1px,transparent 1px),linear-gradient(90deg,var(--rule) 1px,transparent 1px),linear-gradient(var(--rule) .5px,transparent .5px),linear-gradient(90deg,var(--rule) .5px,transparent .5px);background-size:75px 75px,75px 75px,25px 25px,25px 25px;border:2px solid var(--seal);border-radius:4px}.b7 .hw-controls-row{display:flex;gap:8px}.b7 .hw-replay{font-size:.92rem;padding:7px 16px;border:1px solid var(--rule);border-radius:6px;background:var(--paper);color:var(--ink);cursor:pointer;font-family:Noto Sans,sans-serif}.b7 .hw-replay:hover{background:var(--paper-deep)}.b7 .quiz-btn{border-color:var(--seal);color:var(--seal)}.b7 .hw-quiz-status{font-size:.92rem;color:var(--bamboo);min-height:1.2em}.b7 .speakable{cursor:pointer;position:relative}.b7 .speakable:after{content:"🔊";font-size:.65rem;position:absolute;top:-6px;right:-14px;background:var(--paper);border:1px solid var(--rule);border-radius:50%;width:18px;height:18px;display:flex;align-items:center;justify-content:center;opacity:0;transition:opacity .15s,transform .15s;pointer-events:none;z-index:2}.b7 .speakable:focus-visible:after,.b7 .speakable:hover:after{opacity:1;transform:scale(1.18)}.b7 .speakable.speaking:after{opacity:1;background:var(--seal);border-color:var(--seal)}.b7 .reveal{opacity:0;transform:translateY(18px);transition:opacity .5s ease,transform .5s ease}.b7 .reveal.visible{opacity:1;transform:none}.b7 .mode-picker{display:flex;gap:6px;justify-content:center;margin:10px auto 0;flex-wrap:wrap}.b7 .mode-btn{font-size:.85rem;padding:6px 14px;border:1px solid var(--rule);border-radius:999px;background:var(--paper);cursor:pointer;font-family:Noto Sans,sans-serif}.b7 .mode-btn.active{background:var(--seal);border-color:var(--seal);font-weight:700}.b7 .mode-picker-float{position:fixed;top:50%;right:14px;transform:translateY(-50%);z-index:50;display:flex;flex-direction:column;gap:8px;padding:10px 8px;background:var(--paper);border:1px solid var(--rule);border-radius:14px;box-shadow:0 4px 14px rgba(31,42,40,.12)}.b7 .mode-picker-float .mode-btn{writing-mode:vertical-rl;text-orientation:mixed;padding:12px 6px;font-size:.78rem;white-space:nowrap}@media (max-width:720px){.b7 .mode-picker-float{right:4px;padding:4px 3px;gap:4px;border-radius:10px}.b7 .mode-picker-float .mode-btn{padding:5px 2px;font-size:.6rem;border-radius:999px}}.b7[data-mode=hanzi] .meta,.b7[data-mode=hanzi] .pinyin-line,.b7[data-mode=hanzi] .subtitle-vn,.b7[data-mode=hanzi] [class*=py],.b7[data-mode=hanzi] [class*=vn],.b7[data-mode=pinyin] .meta,.b7[data-mode=pinyin] .subtitle-vn,.b7[data-mode=pinyin] [class*=vn]{display:none!important}.b7 #luyenViet .meta,.b7 #luyenViet [class*=py],.b7 #luyenViet [class*=vn],.b7 #tuMoi .fc-wrap [class*=py],.b7 #tuMoi .fc-wrap [class*=vn]{display:revert!important}.b7 .exercise-card{border:1px solid var(--rule);background:#fff;border-radius:10px;padding:16px 18px 18px;box-shadow:0 2px 6px rgba(31,42,40,.08)}.b7 .ex-line{font-family:"Noto Serif SC",serif;font-size:1.05rem;color:var(--ink);margin-bottom:6px;line-height:1.7}.b7 .ex-line b{font-family:Noto Sans,sans-serif;color:var(--seal-deep);margin-right:4px}.b7 .ex-line .indent{display:inline-block;width:26px}.b7 .ex-reveal-btn{font-size:.8rem;color:var(--seal-deep);background:transparent;border:1px solid var(--rule);border-radius:14px;padding:5px 14px;margin-top:6px;cursor:pointer;transition:background .15s,color .15s}.b7 .ex-reveal-btn:hover{background:var(--seal);color:#fff;border-color:var(--seal)}.b7 .transcript-btn{font-size:.8rem;color:var(--seal-deep);background:transparent;border:1px solid var(--rule);border-radius:14px;padding:5px 14px;cursor:pointer;transition:background .15s,color .15s}.b7 .transcript-btn:hover{background:var(--seal);color:#fff;border-color:var(--seal)}.b7 .transcript-box{padding:14px 20px;border:1px dashed var(--rule);border-radius:10px}.b7 .transcript-box.hidden{display:none}.b7 .transcript-box p.hz{font-family:"Noto Serif SC",serif;font-size:1.05rem;line-height:1.9}.b7 .ex-answer{margin-top:12px;padding-top:12px;border-top:1px dashed var(--rule)}.b7 .ex-answer.hidden{display:none}.b7 .ex-answer .hz{font-family:"Noto Serif SC",serif;font-size:1.15rem;font-weight:600;color:var(--seal-deep)}.b7 .ex-answer .note{display:inline;font-size:.78rem;color:var(--ink-soft);font-style:italic}.b7 .ex-answer .hz+.note{display:block;margin-top:4px}.b7 .ex-answer .note.vn{display:block}.b7{background-color:#f4f1e8;background-image:radial-gradient(ellipse 60% 25% at 50% 0,rgba(255,179,92,.18),transparent 70%),url("data:image/svg+xml,%3Csvg%20xmlns%3D%22http%3A//www.w3.org/2000/svg%22%20width%3D%2260%22%20height%3D%2230%22%20viewBox%3D%220%200%2060%2030%22%20fill%3D%22none%22%20stroke%3D%22%23ffe9b8%22%20stroke-opacity%3D%22.09%22%20stroke-width%3D%221.3%22%3E%3Cpath%20d%3D%22M0%2024L15%206L30%2024L45%206L60%2024%22/%3E%3C/svg%3E");background-size:auto,60px 30px}.b7:before{opacity:.35}.b7 .wrap{position:relative;z-index:2}.b7 header.hero{background-color:#14233a;background-image:url("data:image/svg+xml,%3Csvg%20xmlns%3D%22http%3A//www.w3.org/2000/svg%22%20width%3D%2260%22%20height%3D%2230%22%20viewBox%3D%220%200%2060%2030%22%20fill%3D%22none%22%20stroke%3D%22%23ffe9b8%22%20stroke-opacity%3D%22.09%22%20stroke-width%3D%221.3%22%3E%3Cpath%20d%3D%22M0%2024L15%206L30%2024L45%206L60%2024%22/%3E%3C/svg%3E"),linear-gradient(180deg,#14233a,#5a4a7a 42%,#e88a5a 74%,#ffd08a);background-size:60px 30px,100% 100%;color:#fff;border:0;position:relative;margin-top:0;padding-top:102px;padding-bottom:300px;overflow:visible}.b7 header.hero:before{content:"";position:absolute;left:0;right:0;bottom:0;height:10px;background:repeating-linear-gradient(90deg,#d9a02a 0 20px,#2f4a3f 20px 40px);z-index:2}.b7 header.hero>*{position:relative;z-index:2}.b7 header.hero svg.art7{position:absolute;left:50%;bottom:10px;width:min(780px,98%);height:auto;transform:translateX(-50%);z-index:1;pointer-events:none;filter:drop-shadow(0 -2px 10px rgba(0,0,0,.3))}.b7 header.hero .date-tag,.b7 header.hero .pinyin-line,.b7 header.hero .subtitle,.b7 header.hero .tts-note,.b7 header.hero .voice-picker{color:#ffffff;font-weight:700;text-shadow:0 1px 3px rgba(0,0,0,.85)}.b7 header.hero h1{color:#fff;text-shadow:0 3px 0 #0e1626,0 0 22px rgba(255,190,110,.45)}.b7 header.hero .subtitle .term,.b7 header.hero .subtitle strong,.b7 header.hero .tts-note b,.b7 header.hero h1.cn .red{color:#ffd36a}.b7 header.hero .seal-box{color:#7a2014;background:#ffe9b8;border:3px solid #fff;border-radius:6px;transform:none;box-shadow:0 0 0 3px #173028,0 0 0 6px #ffd36a,0 8px 18px rgba(0,0,0,.4)}.b7 header.hero .seal-box:after{display:none}.b7 header.hero .brush-rule{background:linear-gradient(90deg,transparent,#ffd36a 20%,#ffd36a 80%,transparent);opacity:1;height:3px}.b7 header.hero .vp-status,.b7 header.hero .vp-status.ok{color:#b8ffd8}.b7 header.hero .vp-status.warn{color:#ffd36a}.b7 header.hero select{background:#fff;color:#1f2a28;border-color:#ffd36a}.b7 header.hero .mode-btn{background:#fff;color:#173028;border-color:#ffd36a}.b7 header.hero .mode-btn.active{background:#b33a2a;color:#ffffff;border-color:#fff}.b7 .toc{background:#fff;border:2px solid #2f4a3f;border-radius:8px;box-shadow:0 5px 0 #ffd36a;margin-top:28px}.b7 .sec-title-cn{display:inline-block;border-bottom:4px solid #b33a2a;padding-bottom:2px}.b7 .mode-btn{border:2px solid #2f4a3f;background:#fff;color:var(--ink);font-weight:700}.b7 .mode-btn.active{background:#2f4a3f;color:#fff;border-color:#173028}.b7 .mode-picker-float{background:#fff;border:2px solid #2f4a3f;box-shadow:0 4px 14px rgba(0,0,0,.2);opacity:.22;transition:opacity .25s ease}.b7 .mode-picker-float:focus-within,.b7 .mode-picker-float:hover{opacity:1}.b7 .mode-picker-float .mode-btn{color:var(--ink)}.b7 .mode-picker-float .mode-btn.active{color:#fff}.b7 .back-link{background:#fff;border-color:#2f4a3f;color:#173028;font-weight:700;box-shadow:0 2px 6px rgba(0,0,0,.2)}.b7 .theme-note{margin:14px auto 0;font-size:.78rem;font-weight:600;letter-spacing:.04em;color:#ffffff;text-align:center;text-shadow:0 1px 3px rgba(0,0,0,.85)}.b7 .foot-hz,.b7 .theme-hz{cursor:pointer;border-bottom:1px dotted #ffd36a;margin:0 4px 0 2px}.b7 .theme-hz{font-family:"Noto Serif SC",serif;font-size:1rem;font-weight:900;color:#fff}.b7 .foot-hz.speaking,.b7 .theme-hz.speaking{color:#ffd36a;text-shadow:0 0 10px #ffd36a}.b7 .foot-hz:after,.b7 .theme-hz:after{display:none}.b7 .speakable.speaking:after,.b7 .speakable:after,.b7 .speakable:hover:after{display:none!important}.b7 .site-foot{position:relative;z-index:2;margin-top:56px;padding:48px 24px 30px;text-align:center;background-color:#14233a;background-image:url("data:image/svg+xml,%3Csvg%20xmlns%3D%22http%3A//www.w3.org/2000/svg%22%20width%3D%2260%22%20height%3D%2230%22%20viewBox%3D%220%200%2060%2030%22%20fill%3D%22none%22%20stroke%3D%22%23ffe9b8%22%20stroke-opacity%3D%22.09%22%20stroke-width%3D%221.3%22%3E%3Cpath%20d%3D%22M0%2024L15%206L30%2024L45%206L60%2024%22/%3E%3C/svg%3E"),linear-gradient(180deg,#2f4a3f,#14231c);background-size:60px 30px,100% 100%}.b7 .site-foot:before{content:"";position:absolute;left:0;right:0;top:0;height:10px;background:repeating-linear-gradient(90deg,#d9a02a 0 20px,#2f4a3f 20px 40px)}.b7 .site-foot .lesson-nav{margin-top:0;padding:0}.b7 .site-foot .prev-link{background:#fff;color:#173028;border-color:#ffd36a}.b7 .site-foot .next-link{background:#b33a2a;color:#ffffff;border-color:#fff;font-weight:800}.b7 .site-foot .next-link:hover,.b7 .site-foot .prev-link:hover{background:#fff;color:#7a2014}.b7 .foot-motif{margin-top:22px;font-family:"Noto Serif SC",serif;font-weight:900;font-size:1.15rem;letter-spacing:.18em;color:#fff;text-shadow:0 2px 0 #173028}.b7 .site-foot footer.pagefoot-note{padding:10px 0 0;color:#ffffff;font-weight:600;text-shadow:0 1px 3px rgba(0,0,0,.85)}.b7 .site-foot{margin-top:150px}.b7 .site-foot svg.sc-foot{position:absolute;left:0;right:0;bottom:100%;width:100%;height:150px;pointer-events:none}.b7 .site-foot .foot-motif,.b7 .site-foot .lesson-nav{position:relative;z-index:1}.b7 .foot-motif{display:flex;flex-wrap:wrap;justify-content:center;gap:6px 22px}.b7 .foot-item{display:flex;flex-direction:column;align-items:center;line-height:1.25}.b7 .foot-item .foot-py,.b7 .foot-item .foot-vn{font-family:inherit;font-weight:600;font-size:.7rem;letter-spacing:.03em;color:#fff;text-shadow:0 1px 3px rgba(0,0,0,.8)}@media (max-width:760px){.b7 .site-foot svg.sc-foot{height:90px}.b7 .foot-motif{gap:6px 14px}}.b7{position:relative}.b7-top{display:flex;justify-content:space-between;align-items:center;padding:14px 14px 0;position:absolute;top:0;left:0;right:0;z-index:3}.b7 h3,.b7 p{margin-block:1em}.b7 h3{font-size:1.17em;font-weight:700}.b7 button,.b7 input,.b7 select{line-height:normal}.b7 audio{display:inline-block;vertical-align:baseline}