:root{--bg:#f7f5ed;--ink:#213f31;--muted:#778073;--accent:#ba6c43;--line:#dedfd2}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink);font-family:"PingFang SC","Microsoft YaHei",system-ui,sans-serif}button,a{-webkit-tap-highlight-color:transparent}button{font:inherit;cursor:pointer;color:inherit}button:focus-visible,a:focus-visible{outline:3px solid var(--accent);outline-offset:4px}header{max-width:1480px;margin:auto;height:88px;padding:0 48px;display:flex;align-items:center;border-bottom:1px solid var(--line);gap:25px}.brand{font-size:21px;font-weight:750;text-decoration:none;color:inherit;display:flex;align-items:center;gap:12px}.brand-icon{font-size:36px;color:#658659}.chapter{font-size:14px;color:var(--muted);margin-left:auto}.quiet{background:none;border:1px solid var(--line);border-radius:30px;padding:10px 17px;font-size:14px}main{max-width:1480px;margin:auto;padding:0 48px}.intro{display:flex;justify-content:space-between;align-items:center;margin:43px 0 36px}.eyebrow{font-size:14px;letter-spacing:.1em;font-weight:650;color:var(--accent);margin:0}h1{font-family:"Songti SC","Noto Serif CJK SC",serif;font-size:clamp(36px,4.2vw,62px);font-weight:700;line-height:1.25;margin:15px 0}h1 em{font-style:normal;color:#79895d}.subtitle{font-size:19px;color:#697665;margin:0}.intro-note{border-left:2px solid #c9cdb9;padding-left:22px;font-size:18px;line-height:1.9;color:#8b8f77}.lenses{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-bottom:24px}.lenses button{text-align:left;background:none;border:1px solid var(--line);border-radius:14px;padding:20px 24px;display:grid;grid-template-columns:42px 1fr;row-gap:7px;transition:.2s}.lenses button span{grid-row:span 2;color:#9aa38a;font-size:17px}.lenses strong{font-size:20px;letter-spacing:.01em}.lenses small{font-size:14px;color:var(--muted)}.lenses button:hover{border-color:#9caa86;background:#f0f0e3}.lenses button.selected{background:var(--ink);border-color:var(--ink);color:#fcfbef}.lenses button.selected span{color:#d6be8f}.lenses button.selected small{color:#c4cdb6}.workspace{display:grid;grid-template-columns:1fr 1.03fr;border:1px solid var(--line);border-radius:22px;overflow:hidden;background:#fffdf6;min-height:660px}.specimen{background:#eef0df;display:flex;flex-direction:column;position:relative}.scene-head{display:flex;justify-content:space-between;padding:25px 29px 0;font-size:13px;color:#6b795f}.living-dot:before{content:"";display:inline-block;width:6px;height:6px;background:#5f8753;border-radius:50%;margin:0 8px 2px 0}.plant-wrap{position:relative;flex:1;min-height:410px;display:flex;flex-direction:column;justify-content:center}.plant{width:100%;max-height:470px;overflow:visible}.organic{transform-origin:320px 390px;animation:sway 7s ease-in-out infinite}.part{transition:opacity .45s,filter .45s}.plant.focused .part{opacity:.25}.plant.focused .part.is-focus{opacity:1;filter:drop-shadow(0 0 7px #a8bf70)}.parts{display:flex;gap:6px;justify-content:center;margin-top:-9px;position:relative}.parts button{background:#ffffff66;border:1px solid #d2d7bf;border-radius:25px;padding:7px 16px;font-size:16px}.parts button.active{background:#fffdf6;border-color:#617b50;color:#35583c}.scene-caption{border-top:1px solid #d8ddc5;margin:22px 29px 0;padding:18px 0 22px;display:flex;gap:16px;align-items:center}.scene-caption>span{font-size:38px;color:#739255}.scene-caption b{font-size:20px;font-weight:650}.scene-caption p{font-size:15px;line-height:1.7;color:#738069;margin:5px 0 0}.analysis{padding:30px 34px;display:flex;flex-direction:column}.analysis-top{display:flex;align-items:center;justify-content:space-between;gap:10px}.analysis-top .eyebrow{letter-spacing:0;font-size:13px}#counter{font-size:13px;color:var(--muted)}h2{font-size:30px;line-height:1.4;letter-spacing:-.035em;margin:18px 0 22px;font-weight:700}.path-switch{display:flex;background:#f0efe6;border-radius:9px;padding:4px;gap:4px}.path-switch button{border:0;border-radius:6px;background:none;flex:1;padding:10px 8px;font-size:18px;color:#818572}.path-switch button.active{background:#fffef8;color:var(--ink);box-shadow:0 1px 4px #26302012}.path-intro{font-size:16px;line-height:1.8;color:#77806c;margin:13px 0 20px;min-height:29px}.steps{display:flex;gap:7px}.steps button{border:0;background:none;flex:1;position:relative;text-align:left;padding:14px 0;font-size:16px;color:#999b86;border-top:3px solid #e6e6d9;line-height:1.4}.steps button.active{color:var(--accent);border-color:var(--accent);font-weight:700}.steps button.done{border-color:#a4b18b;color:#6d805d}.steps small{display:block;font-size:11px;margin-bottom:7px;letter-spacing:.1em}.detail{margin:21px 0;min-height:179px;animation:enter .35s ease} .step-kicker{font-size:13px;letter-spacing:.12em;color:var(--accent);margin:0 0 9px}h3{font-size:29px;line-height:1.5;margin:0 0 10px}#step-body{font-size:21px;line-height:1.85;margin:0;color:#596a54}.subject{font-size:14px;color:#9a7150;margin-top:13px;line-height:1.6}.controls{display:flex;gap:10px;align-items:center;margin-top:auto;padding-top:12px}.controls button{border-radius:8px;min-height:47px;font-size:16px;border:1px solid var(--line)}.arrow-button{width:47px;background:none}.play-button{padding:10px 17px;background:none;color:#65755c}.next-button{margin-left:auto;background:var(--ink);color:white;border-color:var(--ink)!important;padding:10px 20px;display:flex;gap:25px}button:disabled{cursor:default;opacity:.35}.lesson{margin:24px 0 0;display:flex;gap:25px;align-items:baseline;background:#ecebdc;border-radius:12px;padding:23px 28px}.lesson span{font-size:14px;white-space:nowrap;color:var(--accent);font-weight:700}.lesson p{font-size:21px;line-height:1.7;margin:0}footer{margin:27px 0 25px;color:#969b87;font-size:12px;line-height:1.6}footer p{margin:4px 0}@keyframes sway{0%,100%{transform:rotate(-.6deg)}50%{transform:rotate(.6deg)}}@keyframes enter{from{opacity:.4;transform:translateY(5px)}to{opacity:1;transform:translateY(0)}}@media(min-width:1500px){h3{font-size:32px}#step-body{font-size:23px}.workspace{min-height:690px}}@media(max-width:1000px){header,main{padding-left:25px;padding-right:25px}.intro-note{display:none}.analysis{padding:25px}.lenses button{padding:16px;grid-template-columns:30px 1fr}.lenses strong{font-size:17px}.workspace{grid-template-columns:.9fr 1.1fr}h2{font-size:25px}h3{font-size:25px}#step-body{font-size:19px}.plant{max-height:430px}.lesson p{font-size:19px}}@media(max-width:720px){header{height:72px;padding:0 18px}.chapter{display:none}.quiet{margin-left:auto;font-size:12px}.brand{font-size:18px}main{padding:0 16px}.intro{margin:30px 2px 25px}h1{font-size:36px}.subtitle{font-size:16px;line-height:1.7}.lenses{gap:6px}.lenses button{display:block;padding:12px 9px;border-radius:10px}.lenses button span{display:block;margin-bottom:6px;font-size:12px}.lenses strong{font-size:14px;line-height:1.5;display:block}.lenses small{display:none}.workspace{display:flex;flex-direction:column;border-radius:16px}.scene-head{padding:20px 20px 0}.plant-wrap{min-height:0}.plant{max-height:310px}.scene-caption{margin:14px 20px 0;padding:14px 0}.scene-caption b{font-size:18px}.scene-caption p{font-size:14px}.analysis{padding:24px 20px}.analysis-top .eyebrow{font-size:12px}h2{margin:15px 0 19px;font-size:27px}.path-switch button{font-size:17px}.path-intro{font-size:15px}.detail{min-height:174px}h3{font-size:26px}#step-body{font-size:21px}.lesson{display:block;padding:19px 20px}.lesson span{display:block;margin-bottom:9px}.lesson p{font-size:20px}.controls .play-button{font-size:14px;padding:8px 12px}.next-button{gap:12px}footer{font-size:11px}.scene-caption>span{font-size:30px}}@media(prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}}

html{scroll-behavior:smooth;scroll-padding-top:24px}.video-lesson{margin:0 0 36px;padding:28px;background:#eeeee1;border:1px solid var(--line);border-radius:18px}.video-heading{display:flex;align-items:center;justify-content:space-between;gap:24px;margin-bottom:23px}.video-heading h2{margin:10px 0 8px;font-size:29px;letter-spacing:0}.video-heading p:not(.eyebrow){font-size:15px;color:var(--muted);margin:0;line-height:1.7}.video-download{border:1px solid #bac5ac;border-radius:8px;padding:12px 17px;color:var(--ink);text-decoration:none;font-size:15px;white-space:nowrap;background:#f9f8ef}.video-download:hover{background:#fffdf6}.video-lesson video{display:block;width:100%;aspect-ratio:16/9;background:#111a17;border-radius:10px;max-height:72vh;object-fit:contain}.video-after{display:flex;gap:20px;justify-content:space-between;align-items:center;margin-top:18px;font-size:15px;color:#6b795f}.video-after a{color:var(--ink);text-decoration:none;font-weight:650;white-space:nowrap}@media(max-width:720px){.video-lesson{padding:17px;margin-bottom:26px;border-radius:14px}.video-heading{display:block;margin-bottom:17px}.video-heading h2{font-size:24px;line-height:1.5}.video-heading p:not(.eyebrow){font-size:13px}.video-download{display:inline-block;padding:8px 12px;font-size:13px;margin-top:14px}.video-after{align-items:start;font-size:13px;gap:12px}.video-after span{max-width:60%}.video-lesson video{border-radius:6px}.video-after a{font-size:12px}}

/* Xiaoye: a character within the existing editable plant diagram. */
.plant-wrap{padding-top:61px}.mascot-bubble{position:absolute;top:15px;left:50%;transform:translateX(-50%);width:max-content;max-width:calc(100% - 44px);padding:12px 20px;background:#fffef5;border:1px solid #d8dfc2;border-radius:20px;color:#46633d;box-shadow:0 6px 19px #3b572b08;font-size:17px;line-height:1.6;text-align:center;z-index:2}.mascot-bubble:after{content:"";position:absolute;left:50%;bottom:-7px;width:12px;height:12px;background:#fffef5;border-right:1px solid #d8dfc2;border-bottom:1px solid #d8dfc2;transform:rotate(45deg)}.plant[role=button]{cursor:pointer;outline:none;border-radius:50%}.plant[role=button]:focus-visible{outline:3px dashed #789855;outline-offset:-10px}.plant .organic{animation:mascot-sway 5s ease-in-out infinite;transform-origin:320px 390px}.leaf-arm-left{transform-origin:246px 274px;animation:leaf-wave-left 5.3s ease-in-out infinite}.leaf-arm-right{transform-origin:390px 220px;animation:leaf-wave-right 6s ease-in-out infinite}.mascot-eye{transform-box:fill-box;transform-origin:center;animation:mascot-blink 5.5s infinite}.eye-right{animation-delay:.06s}.mascot-face{transform-origin:320px 265px;transition:transform .4s}.wonder-mouth{display:none}.curious-brow{opacity:0;transition:opacity .3s}.plant[data-mood=curious] .mascot-face{transform:rotate(-5deg)}.plant[data-mood=curious] .curious-brow{opacity:1}.plant[data-mood=thinking] .wonder-mouth{display:block}.plant[data-mood=thinking] .smile-mouth{display:none}.plant[data-mood=happy] .mascot-face{transform:rotate(4deg)}.plant[data-mood=happy] .cheek{opacity:.9}.plant.celebrate .organic{animation:mascot-hop .8s ease-in-out 2}.plant.celebrate .leaf-arm-right{animation:mascot-wave .6s ease-in-out 3}.plant.celebrate .leaf-arm-left{animation:leaf-wave-left .8s ease-in-out 2}.plant .roots.is-focus{animation:root-greeting 2.2s ease-in-out infinite}.mascot-invite{text-align:center;font-size:12px;letter-spacing:.02em;color:#879477;margin:-13px 0 18px}.mascot-invite span{color:#66824e}.scene-caption{margin-top:20px}
@keyframes mascot-sway{0%,100%{transform:rotate(-1.5deg)}50%{transform:rotate(1.5deg)}}@keyframes leaf-wave-left{0%,100%{transform:rotate(-3deg)}50%{transform:rotate(9deg)}}@keyframes leaf-wave-right{0%,100%{transform:rotate(4deg)}50%{transform:rotate(-9deg)}}@keyframes mascot-blink{0%,89%,96%,100%{transform:scaleY(1)}92%,94%{transform:scaleY(.08)}}@keyframes mascot-hop{0%,100%{transform:translateY(0) rotate(0)}30%{transform:translateY(-13px) rotate(-3deg)}60%{transform:translateY(-3px) rotate(3deg)}}@keyframes mascot-wave{0%,100%{transform:rotate(-2deg)}50%{transform:rotate(-25deg)}}@keyframes root-greeting{0%,100%{stroke-width:4}50%{stroke-width:5.8}}
@media(max-width:720px){.plant-wrap{padding-top:71px}.mascot-bubble{font-size:15px;padding:10px 15px;top:15px;max-width:calc(100% - 34px)}.mascot-invite{font-size:11px;margin:-3px 0 15px}.plant{max-height:330px}}
@media(prefers-reduced-motion:reduce){.mascot-eye,.leaf-arm,.plant .organic,.plant .roots.is-focus{animation:none!important}}

/* Larger plant, with clearer gestures for classroom viewing. */
.plant-wrap{min-height:510px;padding-top:78px;padding-bottom:5px}.plant{max-height:555px;overflow:visible}.mascot-bubble{font-size:18px;top:15px;max-width:calc(100% - 34px);padding:12px 18px}.mascot-invite{margin:0 0 18px}.plant .organic{animation:mascot-sway 4.2s ease-in-out infinite}.leaf-arm-left{animation:leaf-wave-left 3.9s ease-in-out infinite}.leaf-arm-right{animation:leaf-wave-right 4.5s ease-in-out infinite}.plant.celebrate .organic{animation:mascot-hop .9s ease-in-out 2}.plant.celebrate .leaf-arm-right{animation:mascot-wave .6s ease-in-out 3}
@keyframes mascot-sway{0%,100%{transform:rotate(-5deg)}50%{transform:rotate(5deg)}}
@keyframes leaf-wave-left{0%,100%{transform:rotate(-10deg)}50%{transform:rotate(20deg)}}
@keyframes leaf-wave-right{0%,100%{transform:rotate(11deg)}50%{transform:rotate(-25deg)}}
@keyframes mascot-hop{0%,100%{transform:translateY(0) rotate(0)}30%{transform:translateY(-30px) rotate(-7deg)}60%{transform:translateY(-7px) rotate(7deg)}}
@keyframes mascot-wave{0%,100%{transform:rotate(6deg)}50%{transform:rotate(-42deg)}}
@keyframes root-greeting{0%,100%{stroke-width:4}50%{stroke-width:7}}
@media(max-width:1000px) and (min-width:721px){.plant-wrap{min-height:490px;padding-top:85px}.plant{max-height:505px}.mascot-bubble{font-size:16px;max-width:calc(100% - 26px)}}
@media(max-width:720px){.plant-wrap{min-height:0;padding-top:85px;padding-bottom:8px}.plant{max-height:420px}.mascot-bubble{font-size:16px;top:16px;padding:10px 15px;max-width:calc(100% - 30px)}.mascot-invite{margin:6px 0 17px}}
@media(prefers-reduced-motion:reduce){.mascot-eye,.leaf-arm,.plant .organic,.plant .roots.is-focus{animation:none!important}}