:root{--ink:#183b50;--muted:#617580;--teal:#007c80;--teal-soft:#e4f4f1;--coral:#d84a32;--coral-soft:#fff0e9;--yellow:#ffcf69;--paper:#fff8ea;--line:#e4e5df;--shadow:0 14px 44px #2943540a;--radius:30px}
*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font-family:"PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;font-size:18px;line-height:1.6}button,a{-webkit-tap-highlight-color:transparent}button{font:inherit;cursor:pointer}button:disabled{cursor:default}a{color:inherit}button:focus-visible,a:focus-visible,summary:focus-visible{outline:3px solid var(--teal);outline-offset:5px}button{touch-action:manipulation}.skip-link{position:absolute;top:-80px;left:16px;padding:12px;background:white;z-index:10}.skip-link:focus{top:12px}.page-shell{max-width:1200px;margin:0 auto;padding:26px 40px 18px}.site-header{display:flex;align-items:center;justify-content:space-between;margin-bottom:28px;gap:16px}.brand{font-size:23px;font-weight:800;text-decoration:none;display:flex;gap:12px;align-items:center}.brand-icon{font-size:31px}.teacher-button{color:var(--muted);background:transparent;border:1px solid #d5dcd5;border-radius:13px;padding:8px 16px;font-size:15px;min-height:44px}.teacher-button:hover{color:var(--teal);background:white}.lesson-nav{display:flex;gap:7px;justify-content:space-between;margin-bottom:23px}.nav-stop{flex:1;display:flex;gap:9px;align-items:center;justify-content:center;border:0;border-radius:14px;background:transparent;color:var(--muted);min-height:48px;padding:9px 7px;font-size:16px;white-space:nowrap}.nav-stop:hover{background:#fff}.nav-stop.active{background:var(--ink);color:white;font-weight:700}.nav-number{font-size:13px;width:22px;height:22px;display:inline-grid;place-items:center;border:1px solid currentColor;border-radius:50%;line-height:1}.nav-stop.done:not(.active){color:var(--teal)}
main{outline:none}.lesson{background:#fff;border-radius:var(--radius);box-shadow:var(--shadow);padding:42px 48px;min-height:510px;position:relative;overflow:hidden}.lesson-enter{animation:arrive .28s ease}.hero{display:grid;grid-template-columns:1.15fr 1fr;align-items:center;gap:24px;min-height:510px}.hero h1{font-size:clamp(38px,5vw,64px);line-height:1.25;letter-spacing:-1.5px;margin:15px 0 23px}.hero h1 span{display:block;color:var(--teal)}.eyebrow{display:block;font-size:15px;letter-spacing:1px;font-weight:700;color:var(--teal);margin-bottom:12px}.hero p{font-size:21px;max-width:410px;margin:0 0 28px}.hero img{width:100%;max-height:410px;object-fit:contain;mix-blend-mode:multiply}.hero .button{margin-top:0}.hero-note{font-size:14px!important;color:var(--muted);margin-top:18px!important}.button{display:inline-flex;align-items:center;justify-content:center;gap:10px;min-height:50px;padding:12px 24px;border-radius:14px;font-weight:700;border:0;background:var(--teal);color:#fff;line-height:1.4;text-decoration:none}.button:hover{background:#00666a;transform:translateY(-1px)}.button:active{transform:translateY(0)}.button.secondary{background:var(--teal-soft);color:var(--teal)}.button.secondary:hover{background:#d3ebe7}.button.ghost{color:var(--muted);background:transparent;border:1px solid var(--line)}.button:disabled{opacity:.45;transform:none}.section-head{margin-bottom:24px}.section-head h1{font-size:clamp(28px,3.2vw,40px);line-height:1.3;margin:4px 0 12px;letter-spacing:-.7px}.section-head p{color:var(--muted);margin:0;font-size:18px}.tag{color:var(--teal);font-size:14px;font-weight:700;display:block;margin-bottom:8px}.switch-row,.verb-tabs{display:flex;gap:10px;flex-wrap:wrap;margin-bottom:25px}.switch{border:1px solid var(--line);background:white;color:var(--muted);padding:9px 19px;border-radius:12px;min-height:46px}.switch.selected{background:var(--teal-soft);border-color:var(--teal);color:var(--teal);font-weight:700}.word-bank{display:flex;gap:16px;justify-content:center;flex-wrap:wrap;margin:24px 0}.word{border:0;border-radius:14px;min-width:110px;min-height:68px;font-size:32px;font-weight:800;padding:12px 24px;box-shadow:0 5px 0 #00000012;background:var(--yellow);color:var(--ink);transition:transform .15s}.word:nth-child(3n+2){background:#bce9e0}.word:nth-child(3n){background:#ffd0b8}.word:hover:not(:disabled){transform:translateY(-4px)}.word:disabled{opacity:.28;box-shadow:none}.assembly{display:flex;flex-wrap:wrap;gap:12px;align-items:center;justify-content:center;min-height:105px;border-bottom:2px dashed #d7dfd9;margin:0 0 26px;padding:12px}.assembly .word{font-size:29px;min-height:59px}.assembly-empty{color:#899791;font-size:19px}.actions{display:flex;align-items:center;justify-content:center;gap:12px;flex-wrap:wrap}.feedback{min-height:65px;text-align:center;padding:18px 12px 0;font-size:18px;font-weight:700;color:var(--teal)}.feedback.error{color:var(--coral)}.small-hint{text-align:center;font-size:14px;color:var(--muted);margin:13px 0 0}
.definition{font-size:clamp(29px,4vw,44px);line-height:1.55;font-weight:800;margin:28px 0;color:var(--ink);max-width:820px}.highlight{color:var(--coral);font-weight:800}.definition strong{color:var(--teal)}.metaphor{display:flex;align-items:baseline;gap:30px;flex-wrap:wrap;margin:0 0 32px;color:var(--muted);font-size:18px}.metaphor b{color:var(--ink);margin-right:6px}.meaning-play{border-top:1px solid var(--line);padding-top:27px;display:flex;justify-content:space-between;align-items:center;gap:25px}.meaning-play .english{font-size:clamp(32px,4vw,47px)}.meaning-play p{margin:6px 0 0;color:var(--muted)}.actor{color:var(--teal);font-weight:800}.object{color:var(--coral);font-weight:800}.english{font-family:system-ui,"Microsoft YaHei",sans-serif;line-height:1.35;letter-spacing:-.8px}.verb-layout{display:grid;grid-template-columns:1.55fr 1fr;align-items:center;gap:28px}.verb-layout img{width:100%;height:295px;object-fit:contain}.sentence{font-size:clamp(34px,4vw,52px);font-weight:500;margin:28px 0 18px;line-height:1.45}.translation{color:var(--muted);font-size:21px;margin-bottom:26px}.discovery{border-left:4px solid var(--yellow);padding:9px 0 9px 19px;color:var(--ink);font-size:19px;line-height:1.7}.discovery strong{color:var(--teal)}.verb-toggle{margin-top:25px}.compare-layout{display:grid;grid-template-columns:170px 1fr;gap:34px}.topic-list{display:flex;flex-direction:column;gap:8px}.topic-button{text-align:left;min-height:46px;border:0;border-radius:12px;padding:10px 15px;background:transparent;color:var(--muted)}.topic-button:hover{background:#f8faf8}.topic-button.selected{background:var(--teal-soft);font-weight:800;color:var(--teal)}.compare-board{position:relative;min-height:275px}.compare-label{font-size:13px;color:var(--muted);margin-bottom:6px}.compare-chinese{font-size:28px;font-weight:700;margin:0 0 21px}.compare-english{font-size:clamp(28px,3.8vw,45px);margin:0 0 24px}.compare-explain{font-size:19px;color:var(--muted);max-width:580px;margin:15px 0}.compare-art{float:right;width:160px;max-height:100px;object-fit:contain;margin:0 0 10px 20px}.compare-term{display:block;color:var(--teal);font-size:14px;font-weight:700;margin:12px 0 18px}.grammar-map{margin-top:28px;padding-top:20px;border-top:1px solid var(--line)}.grammar-map summary{cursor:pointer;color:var(--teal);font-size:16px;font-weight:700;min-height:44px}.map-list{display:grid;grid-template-columns:1fr 1fr;gap:12px 22px;padding:10px 0}.map-list p{margin:0;font-size:16px;color:var(--muted)}.map-list strong{color:var(--ink)}.map-note{font-size:15px;color:var(--muted);margin-bottom:0}
.quiz-top{display:flex;justify-content:space-between;align-items:center;gap:12px;margin-bottom:19px}.quiz-progress{display:flex;gap:7px}.quiz-dot{width:28px;height:7px;border-radius:5px;background:#e5eae6}.quiz-dot.complete{background:var(--teal)}.quiz-score{font-size:14px;color:var(--muted)}.quiz-title{font-size:22px;margin:0 0 15px}.quiz-question{font-size:clamp(31px,4vw,48px);margin:16px 0 28px;color:var(--ink)}.options{display:grid;gap:12px;grid-template-columns:1fr 1fr}.option{border:2px solid var(--line);border-radius:15px;background:white;min-height:68px;padding:16px 22px;text-align:left;color:var(--ink);font-size:22px;line-height:1.3}.option:hover{background:#fafcf9;border-color:#8cbbb2}.option.correct{background:var(--teal-soft);border-color:var(--teal);color:var(--teal)}.option.wrong{background:var(--coral-soft);border-color:var(--coral);color:var(--coral)}.option-letter{color:var(--muted);font-size:16px;margin-right:18px;font-weight:700}.quiz-response{min-height:86px;font-size:18px;padding-top:17px;color:var(--teal);font-weight:700}.quiz-response.error{color:var(--coral)}.quiz-actions{display:flex;justify-content:flex-end}.celebration{display:grid;place-items:center;text-align:center;min-height:340px}.celebration .star{font-size:66px;margin:0}.celebration h2{font-size:34px;margin:10px 0}.celebration p{max-width:620px;font-size:20px;color:var(--muted);margin:12px 0 26px}.recap-intro{font-size:20px;color:var(--muted);margin-bottom:20px}.recap-items{display:grid;gap:15px}.recap-item{border-bottom:1px solid var(--line);padding:12px 0}.recap-item summary{min-height:46px;cursor:pointer;font-size:22px;font-weight:700}.recap-item p{font-size:19px;margin:14px 0;color:var(--teal);padding-left:22px}.recap-rule{font-size:23px;margin:26px 0 0;font-weight:800}.lesson-footer{display:flex;justify-content:space-between;align-items:center;gap:18px;margin:23px 0 18px}.footer-progress{font-size:15px;color:var(--muted)}.footer-controls{display:flex;gap:10px}.bottom-note{font-size:13px;color:#7f8a81;display:flex;justify-content:space-between;gap:12px;padding-top:7px}.lesson-footer:empty{display:none}.icon-button{background:transparent;border:0;font-size:34px;line-height:1;width:48px;height:48px;color:var(--muted);border-radius:12px}.icon-button:hover{background:var(--teal-soft)}dialog{border:0;border-radius:24px;width:min(680px,calc(100% - 32px));padding:28px 34px;color:var(--ink);box-shadow:0 20px 70px #183b5040}dialog::backdrop{background:#183b5070;backdrop-filter:blur(4px)}.dialog-head{display:flex;align-items:center;justify-content:space-between;gap:20px}.dialog-head h2{font-size:26px;margin:0}.teaching-plan{padding:0;list-style:none;margin:22px 0}.teaching-plan li{padding:12px 0;border-bottom:1px solid var(--line)}.teaching-plan strong{display:block;font-size:17px}.teaching-plan span{font-size:15px;color:var(--muted)}.teacher-detail{font-size:14px;color:var(--muted)}
@keyframes arrive{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}
@media(min-width:1500px){.page-shell{max-width:1360px;padding-top:40px}.lesson{min-height:580px;padding:50px 60px}.hero{min-height:580px}.section-head h1{font-size:44px}.sentence{font-size:58px}.verb-layout img{height:360px}}
@media(max-width:900px){.page-shell{padding:22px 24px}.lesson{padding:30px}.lesson-nav{gap:4px}.nav-stop{font-size:14px;gap:5px}.nav-number{width:18px;height:18px;font-size:11px}.hero{gap:12px}.hero img{max-height:320px}.hero p{font-size:18px}.compare-layout{grid-template-columns:140px 1fr;gap:22px}.verb-layout{grid-template-columns:1.8fr 1fr;gap:15px}.verb-layout img{height:230px}.sentence{font-size:36px}.map-list{grid-template-columns:1fr}.options{grid-template-columns:1fr}}
@media(max-width:600px){body{font-size:17px}.page-shell{padding:16px 14px}.site-header{margin-bottom:18px}.brand{font-size:18px;gap:8px}.brand-icon{font-size:26px}.teacher-button{font-size:13px;padding:7px 10px}.lesson-nav{overflow-x:auto;justify-content:flex-start;padding-bottom:6px;scrollbar-width:thin;margin-bottom:14px}.nav-stop{flex:0 0 auto;font-size:14px;padding:9px 12px}.lesson{padding:26px 22px;border-radius:22px;min-height:480px}.hero{display:flex;flex-direction:column;align-items:flex-start;gap:16px;min-height:auto}.hero h1{font-size:40px;margin-top:8px}.hero p{margin-bottom:22px}.hero img{align-self:center;width:90%;height:230px;order:2}.hero-note{margin-bottom:0!important}.section-head h1{font-size:28px}.section-head p{font-size:16px}.tag{font-size:13px}.switch{padding:9px 14px;font-size:16px}.word{font-size:26px;min-width:80px;padding:12px 18px;min-height:58px}.word-bank{gap:10px;margin-top:25px}.assembly{min-height:100px}.assembly .word{min-height:50px;font-size:25px;padding:10px 15px}.assembly-empty{font-size:16px}.feedback{font-size:16px}.definition{font-size:28px;margin:20px 0}.metaphor{gap:9px;font-size:16px;flex-direction:column;margin-bottom:20px}.meaning-play{align-items:flex-start;flex-direction:column;gap:18px}.meaning-play .english{font-size:34px}.verb-layout{display:block}.verb-layout img{width:70%;height:210px;display:block;margin:20px auto}.sentence{font-size:35px}.translation{font-size:18px}.discovery{font-size:17px}.compare-layout{display:block}.topic-list{flex-direction:row;flex-wrap:wrap;gap:6px;margin-bottom:23px}.topic-button{font-size:14px;min-height:44px;padding:9px 12px}.compare-art{width:115px;max-height:85px}.compare-chinese{font-size:24px}.compare-english{font-size:30px}.compare-explain{font-size:17px}.options{grid-template-columns:1fr}.option{min-height:64px;font-size:20px;padding:13px 17px}.quiz-question{font-size:32px}.quiz-title{font-size:18px}.quiz-response{font-size:17px}.recap-item summary{font-size:20px}.recap-item p{font-size:17px;padding-left:12px}.recap-rule{font-size:21px}.lesson-footer{align-items:center;margin-top:17px;gap:8px}.footer-controls{gap:6px}.footer-controls .button{font-size:15px;padding:10px 14px;min-height:47px}.footer-progress{font-size:13px}.bottom-note{font-size:12px}.button{font-size:17px;padding:12px 19px}.celebration h2{font-size:28px}.celebration p{font-size:18px}dialog{padding:24px;max-height:85vh;overflow:auto}.dialog-head h2{font-size:23px}}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{animation:none!important;transition:none!important;scroll-behavior:auto!important}}