:root{color-scheme:light;--sky:#ebf6fc;--ink:#34536c;--muted:#7b94a6;--blue:#459ed3;--line:#d9eaf2;--round:28px;font-family:ui-rounded,"SF Pro Rounded","Arial Rounded MT Bold","PingFang SC","Microsoft YaHei",sans-serif;font-synthesis:none;color:var(--ink);background:var(--sky)}*{box-sizing:border-box}body{margin:0;min-width:320px;background:radial-gradient(ellipse at 95% 4%,#dceff9 0,transparent 35%),var(--sky)}button,a{-webkit-tap-highlight-color:transparent}button{font:inherit}a{color:inherit;text-decoration:none}button{cursor:pointer}button:focus-visible,a:focus-visible{outline:3px solid #227ab4;outline-offset:5px}.site-header{max-width:1200px;margin:auto;padding:28px 40px 22px;display:flex;justify-content:space-between;align-items:center}.brand{display:flex;gap:12px;align-items:center;font-size:20px;font-weight:800;letter-spacing:1px;min-height:48px}.brand small{display:block;font-size:9px;letter-spacing:2px;margin-top:6px;color:#80a0b6;font-weight:700}.brand-icon{display:flex;width:48px;height:48px;background:#88c6e7;border-radius:16px;transform:rotate(-6deg)}.brand-icon svg{width:100%}.header-note{font-size:13px;color:#83a3b8;letter-spacing:2px}main{max-width:1200px;margin:auto;padding:16px 40px 30px}.welcome{position:relative;padding:34px 36px 36px;min-height:211px;background:#dceff9;border-radius:32px;overflow:hidden}.eyebrow{font-size:11px;letter-spacing:2.5px;font-weight:800;color:#6d9ab6;margin:0 0 13px}.welcome h1{font-size:clamp(28px,4vw,40px);letter-spacing:2px;margin:0 0 15px;line-height:1.4;font-weight:800}.welcome h1 span{color:#3694cd}.welcome p:last-of-type{font-size:15px;color:#7192a7;margin:0;line-height:1.8}.welcome-art{position:absolute;width:280px;height:180px;right:40px;top:18px;pointer-events:none}.welcome-art img{position:absolute;object-fit:contain;width:150px;height:145px;right:16px;bottom:0;transform:rotate(8deg)}.cloud{position:absolute;right:70px;top:16px;width:149px;height:82px;border-radius:50px;background:#fff;transform:rotate(-7deg)}.cloud:before,.cloud:after{content:"";position:absolute;background:white;border-radius:50%}.cloud:before{width:60px;height:60px;left:20px;top:-18px}.cloud:after{width:76px;height:76px;right:11px;top:-26px}.cloud-face{position:absolute;z-index:1;left:48px;top:30px;color:#7297b1;font-size:28px;letter-spacing:10px}.star{position:absolute;color:#edc86d;font-size:29px;right:23px;top:1px}.star.two{right:233px;top:120px;font-size:20px;color:#9bc8dd}.section-head{display:flex;align-items:center;justify-content:space-between;gap:15px;margin:32px 3px 20px}.section-head h2{font-size:20px;margin:0;letter-spacing:1px}.section-head p{margin:0;font-size:12px;color:var(--muted)}.category-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:20px}.category{background:white;border-radius:28px;padding:10px 10px 20px;border:2px solid #fff;box-shadow:0 5px 0 #dcebf3;transition:transform .18s,box-shadow .18s;position:relative}.category:active{transform:translateY(3px);box-shadow:0 2px 0 #dcebf3}.category-picture{height:188px;border-radius:20px;position:relative;display:flex;align-items:center;justify-content:center;overflow:hidden;background:var(--tint)}.blue{--tint:#e5f3fc;--accent:#609dc4}.peach{--tint:#ffede7;--accent:#c78c7a}.mint{--tint:#e8f4eb;--accent:#78a486}.yellow{--tint:#fdf3d9;--accent:#b89e57}.category-picture:before{content:"";position:absolute;width:140px;height:140px;border-radius:50%;background:#fff;opacity:.45}.category-picture img{width:100%;height:172px;position:relative;transition:transform .2s}.word-count{position:absolute;left:12px;top:12px;z-index:1;border-radius:20px;padding:5px 9px;background:#ffffffb3;font-size:10px;letter-spacing:.5px;color:var(--accent)}.category h3{font-size:20px;margin:20px 10px 4px;letter-spacing:1px}.category .english{font-size:12px;color:var(--accent);margin:0 10px;letter-spacing:.4px}.category .description{margin:15px 10px 0;color:#8a9fac;font-size:11px;line-height:1.5}.hint-strip{margin-top:30px;display:flex;align-items:center;justify-content:center;gap:14px;padding:19px;background:#f7fcff;border:1px dashed #cde2ee;border-radius:20px;color:#7693a6;font-size:13px}.hint-strip svg{width:23px;height:23px;color:#8cb8d1}.hint-strip .dot{width:3px;height:3px;border-radius:50%;background:#bbd4e3}.site-footer{max-width:1200px;margin:0 auto;padding:8px 40px 25px;text-align:center;font-size:11px;color:#8aa5b6;line-height:1.7}.offline-line{display:flex;justify-content:center;align-items:center;gap:10px;flex-wrap:wrap;margin-top:7px;font-size:10px}.offline-line button{border:0;background:transparent;color:#7397af;min-height:48px;padding:0 10px;font-size:10px}.offline-line button:hover{text-decoration:underline}.offline-line [data-state="ready"]:before{content:'✓';margin-right:5px;color:#79a695}.category-heading{display:flex;align-items:center;gap:18px;padding:10px 0 24px}.back-button{display:flex;align-items:center;justify-content:center;border:2px solid #fff;background:#fff9;width:52px;height:52px;border-radius:18px;box-shadow:0 3px 0 #d7e9f2;flex-shrink:0}.back-button svg{width:25px;height:25px}.category-heading h1{margin:0 0 6px;font-size:27px;letter-spacing:1px}.category-heading p{font-size:12px;margin:0;color:var(--muted)}.category-heading .category-total{margin-left:auto;font-size:12px;color:var(--muted);background:#ffffff8c;padding:10px 15px;border-radius:20px;white-space:nowrap}.word-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:22px}.word-card{position:relative;background:white;border:2px solid white;border-radius:27px;padding:10px 10px 17px;box-shadow:0 4px 0 #dcebf3;transition:border-color .15s,transform .15s}.word-card.playing{border-color:#81bfe2;transform:translateY(-3px)}.picture-button{display:block;border:0;padding:0;width:100%;border-radius:19px;background:var(--tint);min-height:48px}.picture-button img{display:block;width:100%;height:170px}.word-bottom{display:flex;align-items:center;justify-content:space-between;gap:5px;padding:15px 5px 0}.word-bottom h2{font-size:22px;line-height:1.2;margin:0 0 7px;color:#3b5c72;overflow-wrap:anywhere;font-weight:800;letter-spacing:.1px}.word-bottom p{font-size:13px;color:#859aaa;margin:0}.sound-button{height:48px;width:48px;flex-shrink:0;border:0;border-radius:50%;color:#67a8d0;background:#edf7fd;display:flex;align-items:center;justify-content:center}.sound-button svg{height:23px;width:23px}.playing .sound-button{color:white;background:#7abadd}.list-hint{font-size:12px;color:#91a9b8;text-align:center;margin:28px 0 0}dialog{border:0;border-radius:25px;color:var(--ink);padding:30px;max-width:450px;width:calc(100% - 36px);box-shadow:0 20px 80px #34536c30}dialog::backdrop{background:#24475e50;backdrop-filter:blur(4px)}dialog h2{font-size:23px;margin:8px 0 20px}dialog p{font-size:14px;line-height:1.9;color:#69879b}.close-dialog{position:absolute;right:8px;top:8px;width:48px;height:48px;border:0;background:transparent;color:#6a8aa0;font-size:28px}.toast{position:fixed;bottom:30px;left:50%;transform:translateX(-50%);background:#34536c;color:white;padding:13px 20px;border-radius:17px;max-width:90%;width:max-content;font-size:14px;z-index:5}.fade-in{animation:appear .25s ease-out}@keyframes appear{from{opacity:0;transform:translateY(5px)}to{opacity:1;transform:translateY(0)}}[hidden]{display:none!important}@media(hover:hover){.category:hover{transform:translateY(-5px);box-shadow:0 10px 0 #dcebf3}.category:hover img{transform:rotate(-3deg)}.sound-button:hover{background:#d9effc}}@media(min-width:1500px){main{padding-top:30px}.welcome{min-height:238px;padding-top:43px}.welcome-art{top:29px}.category-picture{height:213px}.category-picture img{height:190px}}@media(max-width:1000px){.category-grid{gap:14px}.category-picture{height:152px}.category-picture img{height:140px}.category h3{font-size:18px;margin-left:6px}.category .description{font-size:10px;margin-left:6px}.category .english{margin-left:6px}.word-grid{grid-template-columns:repeat(3,minmax(0,1fr))}}@media(max-width:700px){.site-header{padding:21px 20px 17px}.brand{font-size:17px;gap:10px}.brand small{font-size:8px;letter-spacing:1.5px}.brand-icon{width:43px;height:43px;border-radius:14px}.header-note{display:none}main{padding:8px 20px 24px}.welcome{padding:25px 22px;min-height:176px;border-radius:26px}.eyebrow{font-size:9px;letter-spacing:1.7px;margin-bottom:9px}.welcome h1{font-size:27px;letter-spacing:1px;position:relative;z-index:1}.welcome p:last-of-type{font-size:12px;max-width:185px;position:relative;z-index:1}.welcome-art{width:120px;height:140px;right:-10px;top:33px;opacity:.85}.welcome-art img{width:95px;height:85px;right:1px;bottom:-5px}.cloud{width:83px;height:50px;right:3px;top:9px;transform:rotate(-9deg)}.cloud:before{width:35px;height:35px;left:9px;top:-13px}.cloud:after{width:40px;height:40px;right:9px;top:-18px}.cloud-face{font-size:19px;letter-spacing:5px;left:22px;top:14px}.star{font-size:17px;right:23px;top:-15px}.star.two{right:100px;top:102px;font-size:14px}.section-head{margin:27px 0 16px}.section-head h2{font-size:18px}.section-head p{font-size:10px}.category-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:17px 14px}.category{padding:7px 7px 17px;border-radius:24px}.category-picture{height:145px;border-radius:18px}.category-picture img{height:137px}.category-picture:before{width:113px;height:113px}.category h3{margin-top:15px;font-size:18px}.category .description{font-size:10px;margin-top:10px}.category .english{font-size:11px}.word-count{font-size:9px;left:8px;top:8px}.hint-strip{margin-top:25px;font-size:11px;gap:10px;padding:16px 8px}.site-footer{padding:0 20px 15px;font-size:10px}.word-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:17px 13px}.word-card{padding:7px 7px 14px;border-radius:23px}.picture-button{border-radius:17px}.picture-button img{height:137px}.word-bottom{padding:12px 1px 0;gap:2px}.word-bottom h2{font-size:19px;max-width:140px}.word-bottom p{font-size:12px}.sound-button{width:48px;height:48px}.sound-button svg{width:21px;height:21px}.category-heading{gap:13px;padding:7px 0 23px}.category-heading h1{font-size:23px}.category-heading p{font-size:10px}.category-heading .category-total{font-size:10px;padding:8px 11px}.back-button{width:48px;height:48px;border-radius:16px}.offline-line{gap:0;font-size:9px}.offline-line button{font-size:9px}.list-hint{font-size:11px}}@media(max-width:360px){main{padding-left:14px;padding-right:14px}.welcome h1{font-size:24px}.word-bottom{align-items:flex-end}.word-bottom h2{font-size:16px}.sound-button{background:transparent}.category-heading .category-total{display:none}}@media(prefers-reduced-motion:reduce){*,*:before,*:after{animation:none!important;transition:none!important}}@supports(padding:max(0px)){body{padding-left:env(safe-area-inset-left);padding-right:env(safe-area-inset-right);padding-bottom:env(safe-area-inset-bottom)}}
/* Keep long English words intact, with a separate generous tap row below. */
.word-bottom{display:grid;grid-template-columns:minmax(0,1fr) 48px;gap:0 5px;padding-top:13px}.word-bottom>div{display:contents}.word-bottom h2{grid-column:1/-1;margin:0 0 3px;max-width:none;overflow-wrap:normal}.word-bottom p{grid-column:1;grid-row:2;align-self:center}.word-bottom .sound-button{grid-column:2;grid-row:2}@media(max-width:700px){.word-bottom h2{font-size:19px}.welcome h1{max-width:240px}.welcome h1 span{display:block}.welcome-art{top:55px}.welcome{min-height:209px}}@media(max-width:360px){.word-bottom h2{font-size:17px}}

.word-bottom h2{font-size:clamp(17px,1.9vw,22px);line-height:1.3;min-height:1.3em;hyphens:auto}.word-card.playing .picture-button{box-shadow:inset 0 0 0 3px #87c4e6}.list-hint{min-height:22px}@media(max-width:700px){.word-bottom h2{font-size:clamp(15px,4.7vw,19px);overflow-wrap:anywhere}.category-heading p{line-height:1.6}.category-heading>div{min-width:0}.category-heading .category-total{flex-shrink:0}}

/* Grouped online catalogue */
main{padding-top:32px;padding-bottom:52px}.home-head{display:flex;align-items:end;justify-content:space-between;gap:20px;padding:8px 3px 22px;border-bottom:2px solid #d4e8f3}.home-head .eyebrow{margin:0 0 7px}.home-head h1{font-size:clamp(30px,4vw,44px);line-height:1;margin:0;letter-spacing:2px}.home-head>p{margin:0;color:var(--muted);font-size:14px}.category-section{padding-top:26px}.category-section+.category-section{margin-top:10px}.category-section .section-head{margin:0 3px 18px}.section-head>div p{margin-top:5px}.section-head>span{font-size:12px;color:var(--muted);background:#fff8;padding:7px 11px;border-radius:16px}.category-section .category-grid{align-items:stretch}.category-section .category{min-width:0}.subcategory-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:22px}.subcategory{display:grid;grid-template-columns:minmax(128px,42%) 1fr;gap:20px;align-items:center;background:white;border:2px solid white;border-radius:28px;padding:12px;box-shadow:0 5px 0 #dcebf3;min-height:225px;transition:transform .18s,box-shadow .18s}.subcategory:active{transform:translateY(3px);box-shadow:0 2px 0 #dcebf3}.subcategory-picture{height:196px;border-radius:20px;background:var(--tint);display:flex;align-items:center;justify-content:center;overflow:hidden}.subcategory-picture img{width:100%;height:100%;object-fit:contain}.subcategory>div:last-child>span{display:inline-block;padding:5px 9px;border-radius:16px;background:var(--tint);color:var(--accent);font-size:11px}.subcategory h2{font-size:23px;margin:14px 0 5px}.subcategory p{font-size:13px;color:var(--accent);margin:0 0 16px}.subcategory small{display:block;color:var(--muted);font-size:12px;line-height:1.6}.aliases{grid-column:1/-1;display:block;color:#8aa2b1;font-size:11px;line-height:1.4;margin:-1px 0 5px}.word-bottom p{grid-row:auto}.toast{bottom:max(24px,env(safe-area-inset-bottom))}
@media(hover:hover){.subcategory:hover{transform:translateY(-5px);box-shadow:0 10px 0 #dcebf3}}
@media(max-width:1000px){.subcategory-grid{grid-template-columns:1fr}.subcategory{grid-template-columns:200px 1fr;min-height:200px}.subcategory-picture{height:176px}}
@media(max-width:700px){main{padding-top:22px;padding-bottom:38px}.home-head{padding-bottom:18px}.home-head h1{font-size:32px}.home-head>p{font-size:11px;white-space:nowrap}.category-section{padding-top:23px}.category-section+.category-section{margin-top:3px}.category-section .section-head{margin-bottom:14px}.section-head>span{font-size:10px}.subcategory{grid-template-columns:120px 1fr;gap:13px;min-height:154px;border-radius:24px;padding:8px}.subcategory-picture{height:136px;border-radius:18px}.subcategory h2{font-size:20px;margin:10px 0 4px}.subcategory p{font-size:11px;margin-bottom:8px}.subcategory small{font-size:10px}.aliases{font-size:10px}.category-heading{padding-top:0}}
@media(max-width:370px){.home-head{align-items:start;flex-direction:column;gap:8px}.subcategory{grid-template-columns:105px 1fr}.subcategory-picture{height:123px}.subcategory h2{font-size:18px}}

/* Transparent illustrations prevent stacked backgrounds and keep every card clipped. */
.category,.word-card{min-width:0;overflow:hidden}
.category-picture:before{content:none}
.category-picture img{width:100%;height:100%;padding:14px;object-fit:contain}
.picture-button{overflow:hidden}
.picture-button img{width:100%;height:170px;padding:10px;object-fit:contain}

/* Real photographs fill each frame while the rounded card clips busy edges. */
.category-picture:before{display:none}
.category-picture img,.subcategory-picture img,.picture-button img{padding:0;object-fit:cover}

/* Keep the complete outline of planets and other celestial bodies visible. */
.space-grid .picture-button{background:#03060d}
.space-grid .picture-button img{object-fit:contain;background:#03060d}

/* A single photograph fills every nature card; no mirrored or blurred extensions. */
.nature-grid .picture-button{background:#f6faf8}
.nature-grid .picture-button:before{content:none}
.nature-grid .picture-button img{object-fit:cover;object-position:center;padding:0}
.word-count{z-index:2;background:#fffffff0;box-shadow:0 2px 8px #34536c18}
@media(max-width:700px){.category-picture img{height:100%;padding:10px}.picture-button img{height:137px;padding:8px}}
.nature-grid .picture-button img{padding:0}
.word-bottom{display:grid;grid-template-columns:minmax(0,1fr) 48px;align-items:end;gap:8px;padding:13px 5px 0}
.word-bottom>div{display:block;min-width:0}
.word-bottom h2{display:block;grid-column:auto;min-height:0;margin:0 0 6px;overflow-wrap:anywhere}
.word-bottom p{display:block;grid-column:auto;grid-row:auto;margin:0}
.word-bottom .aliases{display:block;grid-column:auto;margin:-2px 0 6px;overflow-wrap:anywhere}
.word-bottom .sound-button{grid-column:2;grid-row:1;align-self:end}

/* Word challenge: playful blue UI, with the original vocabulary pictures. */
.challenge-entry{display:flex;align-items:center;gap:22px;margin-top:38px;padding:26px 30px;border:5px solid white;border-radius:32px;background:#d8f3ff;box-shadow:0 6px 0 #c5e5f2;position:relative;overflow:hidden}
.challenge-entry:after{content:"";position:absolute;right:180px;top:-55px;width:170px;height:170px;border:28px solid #fff5;border-radius:50%;pointer-events:none}
.challenge-entry-art{width:94px;flex-shrink:0;transform:rotate(-9deg)}
.challenge-entry-art svg{display:block;width:100%}
.challenge-entry-copy{flex:1;position:relative;z-index:1}
.challenge-eyebrow{font-size:11px;font-weight:800;letter-spacing:2px;color:#388dbc;margin:0 0 7px}
.challenge-entry h2{font-size:27px;margin:0 0 8px;letter-spacing:1px}
.challenge-entry-copy>p:last-child{font-size:13px;line-height:1.6;margin:0;color:#5c849c}
.challenge-primary,.challenge-secondary{display:inline-flex;align-items:center;justify-content:center;gap:12px;min-height:56px;padding:14px 27px;border:3px solid white;border-radius:23px;font-size:19px;font-weight:800;line-height:1.3;position:relative}
.challenge-primary{background:#ffcd4b;color:#725219;box-shadow:0 5px 0 #e9ac30}
.challenge-secondary{background:#e7f6ff;color:#3584b4;box-shadow:0 5px 0 #cbe4f3}
.challenge-primary:active,.challenge-secondary:active{transform:translateY(3px);box-shadow:0 2px 0 #a7ccdc}
.challenge-active{background:linear-gradient(155deg,#60cdf3 0%,#80dff0 56%,#adefe7 100%);min-height:100dvh;color:#345775;overflow-x:hidden}
.challenge-active:before{content:"A";position:fixed;left:-40px;top:8%;font-size:300px;font-weight:900;color:#ffffff15;transform:rotate(-18deg);pointer-events:none;z-index:0}
.challenge-active:after{content:"B";position:fixed;right:-30px;bottom:2%;font-size:340px;font-weight:900;color:#ffffff15;transform:rotate(16deg);pointer-events:none;z-index:0}
.challenge-active main{position:relative;z-index:1;max-width:1180px;padding-top:24px;padding-bottom:24px}
.challenge-heading{display:flex;align-items:center;gap:17px;margin:0 0 18px}
.challenge-heading .back-button{background:#ffda60;box-shadow:0 4px 0 #dbad35;border:4px solid #fff;color:#866123;width:62px;height:62px;border-radius:50%}
.challenge-heading h1{font-size:29px;line-height:1.2;margin:0 0 4px;color:#fff;letter-spacing:1px;text-shadow:0 2px 0 #368fc033}
.challenge-heading .challenge-eyebrow{color:#ebfcff;font-size:9px;margin-bottom:3px}
.challenge-heading>div>p:last-child{margin:0;font-size:12px;color:#f1fdff}
.challenge-progress-count{margin-left:auto;background:white;border:3px solid #ffffff80;border-radius:24px;padding:11px 18px;font-size:15px;font-weight:800;white-space:nowrap;color:#387fa7}
.challenge-progress-track{height:12px;background:#ffffff5e;box-shadow:inset 0 2px 3px #389cb622;border:2px solid #ffffff95;border-radius:10px;margin-bottom:20px;overflow:hidden}
.challenge-progress-track>span{display:block;height:100%;border-radius:8px;background:#ffd563;transition:width .3s}
.challenge-question{background:white;border:4px solid #fff;border-radius:28px;padding:19px 28px 21px;box-shadow:0 6px 0 #42b5d345;margin-bottom:24px}
.challenge-question-hint{display:block;color:#7f9ead;font-size:13px;margin-bottom:10px;font-weight:600}
.challenge-prompt{display:flex;align-items:center;justify-content:space-between;gap:16px;min-width:0}
.challenge-prompt>div{min-width:0}
.challenge-prompt h2{color:#345b7e;font-size:clamp(28px,4vw,45px);line-height:1.16;margin:0 0 7px;overflow-wrap:anywhere;font-weight:800}
.challenge-prompt p{color:#7396ae;font-size:20px;margin:0;line-height:1.3}
.challenge-speaker{background:#5ec7ee;color:white;display:flex;align-items:center;justify-content:center;gap:8px;border:3px solid #dcf4ff;border-radius:22px;min-width:65px;min-height:58px;padding:10px 15px;box-shadow:0 4px 0 #3fadd4;flex-shrink:0}
.challenge-speaker svg{width:28px;height:28px}
.challenge-speaker span{font-size:13px;font-weight:800}
.challenge-speaker:active{transform:translateY(2px)}
.challenge-options{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:20px;align-items:stretch}
.challenge-option{display:block;position:relative;min-width:0;aspect-ratio:1.15;background:#fff;border:8px solid #fff;border-radius:27px;padding:0;box-shadow:0 6px 0 #43aab845;transition:transform .15s,border-color .15s;overflow:hidden;color:#487b97}
.challenge-option img{display:block;width:100%;height:100%;object-fit:contain;background:#fff}
.challenge-option-number{position:absolute;left:8px;top:8px;width:27px;height:27px;display:grid;place-items:center;border-radius:50%;background:#fffef0ed;color:#59809b;font-size:13px;font-weight:800;box-shadow:0 2px 4px #23495718}
.challenge-option:not(:disabled):active{transform:translateY(3px)}
.challenge-option:disabled{cursor:default;opacity:1}
.challenge-option.is-correct{border-color:#59c98e;box-shadow:0 6px 0 #32a26c}
.challenge-option.is-wrong{border-color:#f1868b;box-shadow:0 6px 0 #d76375}
.challenge-option-mark{position:absolute;right:8px;top:8px;display:grid;place-items:center;width:32px;height:32px;border:2px solid #fff;border-radius:50%;font-size:24px;line-height:1;color:#fff;background:#40b77c;font-weight:800}
.is-wrong .challenge-option-mark{background:#e77383}
.challenge-option-label{position:absolute;bottom:0;left:0;right:0;text-align:center;padding:6px 2px;background:#ddf6e8f5;color:#2e865c;font-size:12px;font-weight:800}
.is-wrong .challenge-option-label{background:#ffeaedf5;color:#b45366}
.challenge-feedback-space{min-height:142px;display:flex;align-items:center;justify-content:center;margin-top:22px}
.challenge-feedback{position:relative;display:flex;align-items:center;gap:14px;justify-content:center;padding:6px 30px 6px 12px;border:3px solid #ffffffb5;border-radius:26px;background:#ffffffdf;box-shadow:0 5px 0 #59abbf30;max-width:100%;animation:challenge-pop .3s ease-out}
.challenge-gesture{width:116px;height:116px;object-fit:contain;flex-shrink:0;animation:challenge-gesture .7s ease-in-out}
.challenge-feedback strong{font-size:30px;letter-spacing:1px;color:#39896a}
.challenge-feedback.is-wrong strong{color:#4889b1}
.challenge-feedback p{color:#76919e;font-size:13px;line-height:1.5;margin:5px 0 0}
.challenge-confetti{position:fixed;inset:0;overflow:hidden;pointer-events:none;z-index:8}
.challenge-confetti i{position:absolute;top:-20px;left:var(--x);width:10px;height:20px;border-radius:3px;animation:challenge-confetti 1.65s var(--delay) ease-in both}
.challenge-confetti i:nth-child(3n){height:12px;border-radius:50%}
.challenge-result{max-width:800px;margin:20px auto 0;background:#fff;border:6px solid #fff;border-radius:36px;box-shadow:0 8px 0 #42b5d345;text-align:center;padding:26px 38px 34px}
.challenge-result-badge{width:108px;margin:0 auto 12px;animation:challenge-pop .4s ease-out}
.challenge-result-badge svg{display:block;width:100%}
.challenge-result h2{font-size:35px;letter-spacing:1px;color:#345b7e;margin:0 0 8px}
.challenge-result-caption{color:#7a99ab;font-size:15px;line-height:1.5;margin:0 0 22px}
.challenge-result-stats{display:grid;grid-template-columns:1fr 1fr;gap:16px;max-width:460px;margin:0 auto 25px}
.challenge-result-stats>div{display:flex;justify-content:center;align-items:center;gap:14px;background:#e4f7ed;border-radius:22px;padding:17px;color:#39946b}
.challenge-result-stats>div:last-child{color:#bc6474;background:#fff0f2}
.challenge-result-stats strong{font-size:39px;line-height:1}
.challenge-result-stats span{font-size:16px;font-weight:700}
.challenge-result-hint{color:#8ca2b1;font-size:13px;margin:0 0 13px}
.challenge-result-numbers{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:12px;max-width:500px;margin:0 auto 30px}
.challenge-result-numbers button{display:flex;align-items:center;justify-content:center;gap:7px;border:3px solid white;border-radius:17px;min-height:62px;color:#267f5b;background:#d4f2e3;box-shadow:0 4px 0 #a4dbc0}
.challenge-result-numbers button.is-wrong{color:#b55468;background:#ffe0e6;box-shadow:0 4px 0 #efbac6}
.challenge-result-numbers strong{font-size:24px}
.challenge-result-numbers span{font-size:18px}
.challenge-result-actions{display:flex;justify-content:center;gap:18px}
.challenge-review{max-width:760px;width:calc(100% - 32px);padding:30px;border:5px solid white;background:#eefaff;border-radius:30px;max-height:calc(100dvh - 40px);overflow:auto}
.challenge-review::backdrop{background:#234e7199;backdrop-filter:blur(3px)}
.challenge-review .challenge-eyebrow{margin-right:26px;margin-bottom:17px}
.challenge-review .challenge-prompt{margin-bottom:22px}
.challenge-review .challenge-prompt h2{font-size:30px}
.challenge-review .challenge-prompt p{font-size:17px;line-height:1.3}
.challenge-review-options{grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}
.challenge-review-options .challenge-option{aspect-ratio:auto}
.challenge-review-options img{height:160px}
.challenge-review-options .challenge-option-label{position:static;display:block;min-height:28px}
.challenge-review-name{font-size:13px!important;line-height:1.5!important;margin:0!important;padding:8px 5px;text-align:center;color:#5b8199!important;overflow-wrap:anywhere}
.challenge-review>.challenge-secondary{display:flex;margin:22px auto 4px}
@keyframes challenge-pop{from{opacity:0;transform:scale(.85)}to{opacity:1;transform:scale(1)}}
@keyframes challenge-gesture{0%,100%{transform:rotate(0)}40%{transform:rotate(-9deg) scale(1.09)}70%{transform:rotate(6deg)}}
@keyframes challenge-confetti{0%{opacity:0;transform:translate(0,-30px) rotate(0)}10%{opacity:1}85%{opacity:1}100%{opacity:0;transform:translate(var(--drift),100vh) rotate(var(--spin))}}
@media(min-width:701px) and (orientation:portrait){.challenge-options{grid-template-columns:repeat(2,minmax(0,1fr));max-width:800px;margin:auto}.challenge-option{aspect-ratio:1.6}.challenge-question{max-width:800px;margin-left:auto;margin-right:auto}}
@media(hover:hover){.challenge-option:not(:disabled):hover{transform:translateY(-4px)}.challenge-primary:hover{background:#ffda69}.challenge-result-numbers button:hover{filter:brightness(1.035)}}
@media(max-width:700px){
 .challenge-entry{flex-wrap:wrap;gap:12px;margin-top:28px;padding:18px;border-width:4px;border-radius:27px}
 .challenge-entry-art{width:65px}.challenge-entry h2{font-size:23px}.challenge-entry .challenge-eyebrow{font-size:9px}.challenge-entry-copy>p:last-child{font-size:11px}.challenge-entry .challenge-primary{width:100%;margin-top:4px}
 .challenge-active main{padding:18px 16px 22px}.challenge-heading{gap:11px;margin-bottom:15px}.challenge-heading .back-button{width:49px;height:49px;border-width:3px}.challenge-heading h1{font-size:23px}.challenge-heading>div>p:last-child{font-size:10px}.challenge-heading .challenge-eyebrow{font-size:8px;letter-spacing:1.2px}
 .challenge-progress-count{font-size:12px;padding:9px 11px}.challenge-progress-track{margin-bottom:15px;height:10px}.challenge-question{padding:15px 17px 17px;border-radius:24px;margin-bottom:18px}.challenge-question-hint{font-size:11px;margin-bottom:8px}.challenge-prompt h2{font-size:29px}.challenge-prompt p{font-size:17px}.challenge-speaker{min-width:52px;min-height:52px;padding:8px;border-radius:17px}.challenge-speaker span{display:none}.challenge-speaker svg{width:25px;height:25px}
 .challenge-options{grid-template-columns:repeat(2,minmax(0,1fr));gap:16px 13px}.challenge-option{border-width:6px;border-radius:22px;aspect-ratio:1.22}.challenge-option-number{width:23px;height:23px;font-size:11px;left:5px;top:5px}.challenge-option-mark{width:28px;height:28px;font-size:21px;right:5px;top:5px}.challenge-option-label{font-size:10px;padding:5px 1px}
 .challenge-feedback-space{min-height:105px;margin-top:18px}.challenge-feedback{padding:3px 14px 3px 5px;border-radius:22px;gap:4px}.challenge-gesture{width:91px;height:91px}.challenge-feedback strong{font-size:24px}.challenge-feedback p{font-size:11px}
 .challenge-result{padding:20px 15px 27px;border-radius:30px;margin-top:14px}.challenge-result-badge{width:86px;margin-bottom:9px}.challenge-result h2{font-size:29px}.challenge-result-caption{font-size:12px;margin-bottom:18px}.challenge-result-stats{gap:10px;margin-bottom:21px}.challenge-result-stats>div{padding:16px 8px;gap:10px;border-radius:18px}.challenge-result-stats strong{font-size:33px}.challenge-result-stats span{font-size:14px}.challenge-result-numbers{gap:10px 6px;margin-bottom:24px}.challenge-result-numbers button{min-height:52px;gap:3px;border-width:2px;border-radius:14px}.challenge-result-numbers strong{font-size:20px}.challenge-result-numbers span{font-size:13px}.challenge-result-actions{gap:11px}.challenge-primary,.challenge-secondary{font-size:17px;min-height:54px;padding:12px 16px;border-radius:20px}
 .challenge-review{padding:24px 14px 20px}.challenge-review-options{gap:12px}.challenge-review-options img{height:110px}.challenge-review-name{font-size:11px!important}.challenge-review .challenge-prompt h2{font-size:26px}.challenge-review .challenge-eyebrow{font-size:10px;letter-spacing:1px}
}
@media(max-height:550px) and (orientation:landscape){.challenge-active main{padding-top:12px}.challenge-heading{margin-bottom:10px}.challenge-heading .back-button{width:48px;height:48px}.challenge-heading h1{font-size:23px}.challenge-progress-track{margin-bottom:12px}.challenge-question{padding:10px 20px;margin-bottom:16px}.challenge-question-hint{margin-bottom:5px}.challenge-prompt h2{font-size:28px}.challenge-prompt p{font-size:15px}.challenge-options{grid-template-columns:repeat(4,minmax(0,1fr))}.challenge-option{aspect-ratio:1.4}.challenge-feedback-space{margin-top:14px;min-height:85px}.challenge-gesture{width:80px;height:80px}.challenge-feedback strong{font-size:23px}.challenge-result-badge{width:70px}}
@media(prefers-reduced-motion:reduce){.challenge-confetti{display:none}}

/* Challenge screens stay within the usable viewport on phones and tablets. */
body.challenge-active{height:100dvh;min-height:0;overflow:hidden;padding-top:env(safe-area-inset-top)}
.challenge-active main{height:calc(100dvh - env(safe-area-inset-top) - env(safe-area-inset-bottom));width:100%;display:flex;flex-direction:column;min-height:0;padding:clamp(10px,2vh,22px) clamp(14px,3vw,40px);overflow:hidden}
.challenge-heading{flex-shrink:0;margin-bottom:clamp(8px,1.5vh,16px)}
.challenge-heading .back-button{width:clamp(48px,7vh,62px);height:clamp(48px,7vh,62px)}
.challenge-progress-track{flex-shrink:0;height:10px;margin-bottom:clamp(10px,1.8vh,20px)}
.challenge-question{flex-shrink:0;width:100%;padding:clamp(10px,1.8vh,19px) clamp(16px,3vw,28px);margin-top:0;margin-bottom:clamp(12px,2vh,24px)}
.challenge-question-hint{margin-bottom:clamp(5px,1vh,10px)}
.challenge-prompt h2{font-size:clamp(25px,4.2vh,42px)}
.challenge-prompt p{font-size:clamp(15px,2.4vh,20px)}
.challenge-options{flex:1;min-height:0;width:100%;gap:clamp(10px,1.7vh,20px);grid-auto-rows:minmax(0,1fr)}
.challenge-option{min-height:0;height:100%;aspect-ratio:auto}
.challenge-option img{height:100%;min-height:0}
.challenge-feedback-space{flex-shrink:0;height:clamp(75px,13vh,132px);min-height:0;margin-top:clamp(10px,1.8vh,22px)}
.challenge-feedback{max-height:100%;padding:2px 18px 2px 6px;gap:8px}
.challenge-gesture{height:clamp(66px,11vh,112px);width:clamp(66px,11vh,112px)}
.challenge-feedback strong{font-size:clamp(22px,3.5vh,30px)}
.challenge-feedback p{font-size:clamp(10px,1.8vh,13px)}
.challenge-result{flex:1;min-height:0;width:100%;display:flex;flex-direction:column;align-items:center;justify-content:center;margin:0 auto;padding:clamp(12px,2.5vh,30px) clamp(14px,3vw,38px);overflow:hidden}
.challenge-result-badge{flex-shrink:0;width:clamp(46px,11vh,100px);margin-bottom:clamp(5px,1vh,12px)}
.challenge-result h2{font-size:clamp(24px,3.8vh,35px);margin-bottom:6px}
.challenge-result-caption{font-size:clamp(12px,1.9vh,15px);margin-bottom:clamp(12px,2.5vh,22px)}
.challenge-result-stats{width:100%;flex-shrink:0;margin-bottom:clamp(12px,2.5vh,25px)}
.challenge-result-stats>div{padding:clamp(10px,2vh,17px)}
.challenge-result-stats strong{font-size:clamp(28px,4vh,39px)}
.challenge-result-hint{margin-bottom:clamp(8px,1.4vh,13px)}
.challenge-result-numbers{width:100%;flex-shrink:0;margin-bottom:clamp(14px,3vh,30px);gap:clamp(7px,1.3vh,12px)}
.challenge-result-numbers button{min-height:clamp(48px,7vh,62px)}
.challenge-result-actions{flex-shrink:0}
.challenge-review{display:flex;flex-direction:column;max-height:calc(100dvh - 24px - env(safe-area-inset-top) - env(safe-area-inset-bottom));height:min(690px,calc(100dvh - 24px - env(safe-area-inset-top) - env(safe-area-inset-bottom)));overflow:hidden;padding:clamp(14px,3vh,30px);margin:auto}
.challenge-review:not([open]){display:none}
.challenge-review .challenge-eyebrow{flex-shrink:0;margin-bottom:clamp(8px,1.7vh,17px)}
.challenge-review .challenge-prompt{flex-shrink:0;margin-bottom:clamp(12px,2.5vh,22px)}
.challenge-review-options{min-height:0;flex:1}
.challenge-review-options .challenge-option{display:flex;flex-direction:column;min-height:0;height:100%;overflow:hidden}
.challenge-review-options img{height:0;min-height:0;flex:1;object-fit:contain}
.challenge-review-options .challenge-option-label,.challenge-review-name{flex-shrink:0}
.challenge-review>.challenge-secondary{flex-shrink:0;margin:clamp(12px,2vh,22px) auto 2px;min-height:48px}
@media(max-width:700px){.challenge-options{grid-template-columns:repeat(2,minmax(0,1fr))}.challenge-review-name{font-size:10px!important;padding:5px 2px}.challenge-heading h1{font-size:clamp(20px,3.4vh,23px)}}
@media(orientation:landscape){.challenge-options{grid-template-columns:repeat(4,minmax(0,1fr));max-width:none}.challenge-review-options{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-height:550px){
 .challenge-active main{padding-top:8px;padding-bottom:8px}.challenge-heading{margin-bottom:6px}.challenge-heading .back-button{width:48px;height:48px;min-height:48px}.challenge-heading h1{font-size:21px}.challenge-heading .challenge-eyebrow{display:none}.challenge-progress-count{font-size:12px;padding:8px 12px}.challenge-progress-track{height:7px;margin-bottom:7px}.challenge-question{padding:8px 16px;margin-bottom:10px;border-radius:20px}.challenge-question-hint{font-size:10px;margin-bottom:3px}.challenge-prompt h2{font-size:24px;margin-bottom:3px}.challenge-prompt p{font-size:13px}.challenge-speaker{min-height:48px;min-width:48px;padding:6px 12px}.challenge-speaker span{font-size:11px}.challenge-option{border-width:5px;border-radius:20px}.challenge-feedback-space{height:60px;margin-top:8px}.challenge-gesture{width:54px;height:54px}.challenge-feedback strong{font-size:20px}.challenge-feedback p{font-size:10px;margin-top:2px}.challenge-option-label{font-size:10px;padding:4px 1px}
 .challenge-result{padding:10px 20px;border-radius:25px}.challenge-result-badge,.challenge-result>.challenge-eyebrow{display:none}.challenge-result h2{font-size:22px;margin-bottom:3px}.challenge-result-caption{font-size:11px;margin-bottom:6px}.challenge-result-stats{gap:12px;margin-bottom:8px}.challenge-result-stats>div{padding:8px 12px}.challenge-result-stats strong{font-size:27px}.challenge-result-stats span{font-size:13px}.challenge-result-hint{font-size:11px;margin-bottom:6px}.challenge-result-numbers{gap:6px;margin-bottom:10px}.challenge-result-numbers button{min-height:48px;border-radius:12px}.challenge-result-numbers strong{font-size:18px}.challenge-result-numbers span{font-size:12px}.challenge-result-actions .challenge-primary,.challenge-result-actions .challenge-secondary{min-height:48px;font-size:15px;padding:9px 18px}
 .challenge-review{padding:12px 18px}.challenge-review .challenge-eyebrow{margin-bottom:7px}.challenge-review .challenge-prompt{margin-bottom:10px}.challenge-review .challenge-prompt h2{font-size:23px}.challenge-review-options{grid-template-columns:repeat(4,minmax(0,1fr))}.challenge-review-name{font-size:10px!important;padding:4px 1px}.challenge-review>.challenge-secondary{min-height:48px;margin-top:10px;padding:8px 20px}
}


/* Fixed native picture ratios: viewport height scales cards, never stretches them. */
.challenge-options{align-items:center;justify-items:center}
.challenge-options .challenge-option{display:flex;flex-direction:column;align-self:center;justify-self:center;width:100%;height:auto;aspect-ratio:auto;flex:none}
.challenge-option-picture{position:relative;width:100%;aspect-ratio:var(--image-ratio,1200 / 850);flex:none;overflow:hidden;background:white}
.challenge-options .challenge-option-picture img{display:block;width:100%;height:100%;min-height:0;object-fit:contain;flex:none;padding:0}
.challenge-review-options .challenge-option-label{position:absolute;display:block;min-height:0}
.challenge-review-name{width:100%;flex:none}
/* Two rows of two options on tablets, in either orientation. */
.challenge-options{grid-template-columns:repeat(2,minmax(0,1fr))}
@media(max-height:550px) and (orientation:landscape){.challenge-options{grid-template-columns:repeat(4,minmax(0,1fr))}}

/* Pack the option group with the same horizontal and vertical gap. */
.challenge-options{--option-columns:2;grid-template-columns:repeat(var(--option-columns),var(--option-track-width,minmax(0,1fr)));grid-template-rows:repeat(var(--option-rows,2),var(--option-track-height,minmax(0,1fr)));gap:clamp(10px,1.7vh,20px);align-content:center;justify-content:center;align-items:start}
.challenge-options .challenge-option{align-self:start;box-shadow:0 3px 8px #43aab830}
@media(max-height:550px) and (orientation:landscape){.challenge-options{--option-columns:4}}

.challenge-entry-art img,.challenge-result-badge img{display:block;width:100%;aspect-ratio:1;object-fit:contain}

/* Larger celebration art; the result controller caps it to the available height. */
.challenge-result-badge{width:min(280px,60vw);max-width:100%}

/* Full-screen completion celebration floats above the page without affecting layout. */
.challenge-completion-confetti{position:fixed;inset:0;width:100%;height:100%;pointer-events:none;z-index:20}
@media(prefers-reduced-motion:reduce){.challenge-completion-confetti{display:none}}

/* Vocabulary artwork uses one fixed 1200 × 850 frame on every device. */
.category-picture,.subcategory-picture,.picture-button{
  width:100%;height:auto;aspect-ratio:1200 / 850;padding:0;overflow:hidden;
}
.category-picture img,.subcategory-picture img,.picture-button img,
.nature-grid .picture-button img,.space-grid .picture-button img{
  display:block;width:100%;height:auto;aspect-ratio:1200 / 850;
  padding:0;object-fit:contain;object-position:center;
}