:root{color-scheme:light;--ink:#183f46;--muted:#44666c;--green:#347648;--paper:#fffdf4;--orange:#cd641b;--blue:#247b9d;--line:#cadcc8;--shadow:0 10px 30px #244b4524;font-family:"Microsoft YaHei","PingFang SC",sans-serif}
*{box-sizing:border-box}body{margin:0;background:#e9f4ef;color:var(--ink)}button,input{font:inherit}button,a,input{ -webkit-tap-highlight-color:transparent}button{cursor:pointer;color:inherit;background:#fffef8;border:1px solid #b8cdba;border-radius:9px;min-height:44px;padding:9px 14px;font-weight:700;transition:background .16s,transform .16s}button:hover:not(:disabled){background:#e9f3dd}button:active:not(:disabled){transform:translateY(1px)}button:disabled{opacity:.48;cursor:not-allowed}button:focus-visible,a:focus-visible,input:focus-visible,svg[tabindex]:focus-visible{outline:3px solid #176a9a;outline-offset:3px}::selection{background:#c8e6cc}input{caret-color:var(--green)}[hidden]{display:none!important}svg{overflow:visible}button svg,.topbar svg{width:21px;height:21px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round;flex-shrink:0}.icon-library{position:absolute;width:0;height:0;overflow:hidden}.topbar{display:flex;align-items:center;gap:18px;padding:10px 22px;background:#fbfff9;min-height:66px;position:relative;z-index:5;border-bottom:1px solid #ceded1}.back-link{color:#28636a;text-decoration:none;font-size:15px;white-space:nowrap}.small-title{font-size:20px;font-weight:800;white-space:nowrap}.topbar nav{display:flex;gap:5px;justify-content:flex-end;margin-left:auto;flex-wrap:wrap}.topbar button{display:flex;gap:5px;align-items:center;min-height:38px;font-size:14px;padding:7px 9px;border-color:transparent;background:transparent}.topbar button[aria-pressed=true]{background:#e3efd6;border-color:#b4cfa7}.topbar button[data-action=sound][aria-pressed=true]{border-color:transparent;background:transparent}main{max-width:2200px;margin:auto}.welcome{position:relative;display:grid;grid-template-columns:minmax(0,1.6fr) minmax(360px,.8fr);gap:35px;min-height:calc(100svh - 67px);padding:40px max(30px,5vw);background:#b6deee url('../assets/lesson24/canyon.png') center/cover}.intro-scene{position:relative;min-height:640px;isolation:isolate}.intro-scene h1{margin:36px 0 12px;font-size:clamp(48px,5.4vw,90px);font-weight:900;letter-spacing:.015em;color:#246e49;text-shadow:0 3px 0 #ffffff,2px 0 0 #fff,-2px 0 0 #fff,0 7px 18px #f8ffff;line-height:1.16}.intro-scene h1 span{font-size:.64em;margin:0 .1em;color:#c67122}.intro-copy{font-size:clamp(19px,1.6vw,27px);font-weight:700;max-width:26em;line-height:1.65;text-shadow:0 2px 8px #fff;background:#f5fffaad;display:inline-block;padding:8px 12px;border-radius:8px}.intro-island{position:absolute;background:url('../assets/lesson24/island.png') center top/100% 100% no-repeat;width:42%;height:310px;top:42%;z-index:-1}.island-left{left:-8%}.island-right{right:-2%;transform:scaleX(-1)}.intro-bridge{position:absolute;top:54%;left:24%;width:47%;height:26px;background:repeating-linear-gradient(90deg,#bc8146 0,#ddac69 3px,#efc37f 23px,#a96d33 25px);border:3px solid #80582f;transform:rotate(-6deg);box-shadow:0 7px 12px #183d3b26;z-index:-1}.explorer{background-image:url('../assets/lesson24/explorers.png');background-size:200% 100%;background-repeat:no-repeat;aspect-ratio:1/1;pointer-events:none}.boy{background-position:left center}.girl{background-position:right center}.intro-boy,.intro-girl{position:absolute;width:25%;max-width:190px;top:29%}.intro-boy{left:5%}.intro-girl{right:1%;transform:scaleX(-1)}.scene-caption{position:absolute;left:0;bottom:8%;font-size:17px;background:#fcfff1e8;border-radius:10px;padding:13px 18px;box-shadow:var(--shadow);max-width:95%}.rules-panel{align-self:center;background:#fffef5f5;border:1px solid #fff;padding:30px 32px;border-radius:24px;box-shadow:0 18px 50px #244d4940;max-width:500px;width:100%}.rules-panel h2{font-size:28px;margin:0 0 24px}.rules-panel fieldset{border:0;padding:0;margin:0 0 22px}.rules-panel legend{font-size:16px;font-weight:700;margin-bottom:10px}.choices{display:flex;gap:8px}.choices label{flex:1;position:relative}.choices input{position:absolute;opacity:0;width:1px;height:1px}.choices span{display:flex;min-height:48px;justify-content:center;align-items:center;border:1px solid #b2c7ab;background:#f4f7e9;border-radius:10px;cursor:pointer;font-size:16px;font-weight:700;padding:8px 4px;white-space:nowrap}.choices input:checked+span{background:#3e794d;color:#fff;border-color:#3e794d;box-shadow:0 3px 8px #34582d24}.choices input:focus-visible+span{outline:3px solid #25799e;outline-offset:3px}.start-button{display:flex;align-items:center;justify-content:center;gap:24px;width:100%;font-size:22px;background:#d97727;border-color:#b95e19;color:white;min-height:62px;margin-top:28px;box-shadow:0 5px 12px #98430f2b}.start-button:hover:not(:disabled){background:#bd5d17}.text-button{background:none;border:0;text-decoration:underline;text-underline-offset:4px;display:block;margin:14px auto 0;font-size:14px;font-weight:400;color:#3e6263}.resume{display:block;width:100%;margin-top:12px}.game{padding:18px 20px 8px;background:#f0f8ee;min-height:calc(100svh - 67px)}.players{display:grid;grid-template-columns:1fr 1fr;gap:20px;max-width:1920px;margin:auto}.players.solo{grid-template-columns:minmax(0,1050px);justify-content:center}.player{background:#fffcf0;border-radius:18px;overflow:hidden;box-shadow:0 5px 20px #31535715;min-width:0;border:2px solid #d7ad79;--team:#b75b15;--team-pale:#fff0d5}.player.blue{border-color:#78b7ce;--team:#176a92;--team-pale:#e2f3fa}.player-header{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:13px 18px;background:var(--team-pale);border-bottom:1px solid #dfdccb}.team-name{font-size:22px;font-weight:800;color:var(--team)}.level-count{font-size:14px;display:block;font-weight:400;margin-top:2px}.progress{display:flex;gap:5px;flex-wrap:wrap;max-width:230px}.progress span{display:grid;place-items:center;width:23px;height:23px;border:1px solid #b5b99f;border-radius:50%;color:#4a614d;background:#fffff1;font-size:12px;font-weight:700}.progress .completed{background:#407d4a;color:#fff;border-color:#407d4a}.progress .current{background:#f6cc69;border-color:#b88823;color:#604215}.clock{display:flex;align-items:center;gap:5px;font-size:19px;font-variant-numeric:tabular-nums}.clock svg{width:19px;height:19px;fill:none;stroke:currentColor;stroke-width:1.7}.world{display:block;width:100%;aspect-ratio:600/374;background:#b5dded url('../assets/lesson24/canyon.png') center/cover;overflow:hidden;touch-action:none;user-select:none}.world text{font-family:inherit;paint-order:stroke;stroke:#fffdf5;stroke-width:3px;stroke-linejoin:round;fill:#314e53;font-weight:700}.world .island-word{font-size:16px}.world .point-label{font-size:16px}.world .ruler{cursor:grab;touch-action:none}.world .ruler:active{cursor:grabbing}.world .ruler-number{font-size:12px;fill:#2a493c;stroke:none;font-weight:500}.world .ruler-unit{font-size:12px;fill:#345147;stroke:none;font-weight:700}.world .rotation-handle{cursor:crosshair}.world .ruler-help{font-size:11px;fill:#345e52;stroke:none}.world .annotation-path{fill:none;stroke:#d03f46;stroke-width:3.5;stroke-linecap:round;stroke-linejoin:round;pointer-events:none}.world.pen-mode{cursor:crosshair}.world .magnifier{pointer-events:none}.world .magnifier-border{fill:none;stroke:#225d5f;stroke-width:3}.tools-row{display:flex;align-items:center;gap:6px;justify-content:flex-end;padding:8px 14px 0;background:#fcfcf4}.tools-row .ruler-type{font-size:13px;color:#486259;margin-right:auto}.tools-row button{min-width:43px;min-height:36px;padding:5px 10px;font-size:14px}.tools-row .rotate-button{font-size:21px;line-height:1}.answer-area{padding:12px 18px 15px;background:#fcfcf4}.answer-row{display:flex;gap:9px;align-items:center;justify-content:center;min-height:59px;flex-wrap:wrap;font-size:20px}.answer-row label{display:flex;gap:6px;align-items:center}.answer-input{width:85px;height:52px;background:#fffef7;border:2px solid #a5ba91;border-radius:9px;text-align:center;color:#203e33;font-size:26px;line-height:1;font-weight:800;appearance:none;box-shadow:inset 0 2px 5px #4b614810}.answer-input.active{border-color:var(--team);background:var(--team-pale)}.answer-input::placeholder{color:#71877d;font-size:23px}.input-unit{font-size:18px;font-weight:700}.keypad-and-submit{display:grid;grid-template-columns:minmax(0,1fr) 100px 145px;gap:8px;align-items:stretch;margin-top:12px}.keypad{display:grid;grid-template-columns:repeat(5,1fr);gap:6px}.keypad button{font-size:23px;min-height:44px;padding:4px;border-color:#c4d4aa;background:#f0f5df}.keypad button:hover:not(:disabled){background:#e3edc2}.edit-keys{display:grid;grid-template-rows:1fr 1fr;gap:6px}.edit-keys button{display:flex;align-items:center;justify-content:center;gap:4px;padding:4px 7px;font-size:15px}.bridge-button{display:flex;align-items:center;justify-content:center;gap:10px;background:#4f853e;color:white;border-color:#3e7534;font-size:23px;border-radius:13px}.bridge-button:hover:not(:disabled){background:#3c702d}.blue .bridge-button{background:#287fab;border-color:#1c648c}.blue .bridge-button:hover:not(:disabled){background:#216e93}.feedback{min-height:44px;margin:11px 0 0;text-align:center;font-size:16px;line-height:1.5;color:#435e4b}.feedback.error{color:#a53c24;font-weight:700}.feedback.success{color:#28713b;font-weight:700}.game-hint{text-align:center;color:#486957;font-size:14px;line-height:1.6;margin:15px 0 4px}.player-done .answer-area{background:#edf6e5}.player-done .answer-row{font-size:25px;color:#357443;font-weight:800}.player-done .keypad-and-submit{display:none}.player-done .feedback{font-size:18px}.solid-button{background:#417d49;border-color:#417d49;color:#fff}.solid-button:hover:not(:disabled){background:#34683c}dialog{border:0;border-radius:22px;background:#fffef7;color:var(--ink);padding:34px;max-width:630px;width:calc(100% - 32px);box-shadow:0 24px 80px #163c3555}dialog::backdrop{background:#143c4148}dialog h2{font-size:29px;margin:0 0 16px}dialog p{font-size:17px;line-height:1.65}.close-dialog{position:absolute;right:12px;top:10px;min-width:40px;min-height:40px;padding:0;border:0;background:transparent;font-size:29px;font-weight:400;color:#45675f}.help-dialog ol{padding-left:25px;margin:20px 0;font-size:18px;line-height:1.75}.help-dialog li{margin-bottom:12px}.help-detail{font-size:14px!important;color:#4c6a61}.help-dialog .solid-button{display:block;margin:25px auto 0;min-width:220px}.finish-dialog{text-align:center}.finish-dialog .explorer{height:150px;width:150px;margin:-15px auto 5px}.finish-dialog h2{color:#377947;font-size:32px}.finish-dialog p{margin:10px 0}.finish-time strong{font-size:30px;font-variant-numeric:tabular-nums;color:#c3651d}.finish-actions{display:flex;justify-content:center;gap:10px;margin-top:25px}.finish-actions button{min-height:48px;font-size:17px;flex:1}.toast{position:fixed;bottom:24px;left:50%;transform:translate(-50%,20px);opacity:0;pointer-events:none;z-index:20;background:#244e43;color:white;padding:13px 20px;border-radius:12px;font-size:16px;box-shadow:var(--shadow);transition:opacity .2s,transform .2s;max-width:calc(100% - 32px)}.toast.visible{opacity:1;transform:translate(-50%,0)}
@media(min-width:1700px){.world{aspect-ratio:600/350}.answer-area{padding:18px 24px}.keypad button{min-height:51px}.answer-row{font-size:25px}.answer-input{width:98px;height:58px}.feedback{font-size:19px}.tools-row button{font-size:17px}.game-hint{font-size:17px}}
@media(max-width:1150px){.small-title{display:none}.topbar{padding:8px 12px;gap:8px}.topbar nav{gap:0}.topbar button{font-size:12px;padding:7px}.welcome{gap:20px;padding:25px}.intro-scene{min-height:570px}.rules-panel{padding:25px}.intro-scene h1{font-size:54px}.intro-boy,.intro-girl{top:33%;width:30%}.keypad-and-submit{grid-template-columns:minmax(0,1fr) 76px 100px;gap:6px}.bridge-button{font-size:18px;gap:4px;flex-direction:column}.answer-area{padding:10px 12px}.answer-row{font-size:18px;gap:6px}.answer-input{width:67px}.input-unit{font-size:16px}.team-name{font-size:19px}.player-header{padding:10px 12px;gap:7px}.progress{gap:3px;max-width:128px}.progress span{width:19px;height:19px;font-size:10px}.clock{font-size:16px}.players{gap:12px}.game{padding:12px}.keypad button{font-size:21px}}
@media(max-width:760px){.topbar{flex-wrap:wrap;padding:7px 10px;gap:3px}.small-title{display:block;margin-left:auto;font-size:18px}.topbar nav{width:100%;justify-content:space-between;gap:0}.topbar button{font-size:11px;padding:6px 5px;min-height:41px;flex-direction:column;gap:2px}.topbar button svg{width:17px;height:17px}.welcome{grid-template-columns:1fr;padding:20px;gap:0;background-position:35% center}.intro-scene{min-height:335px}.intro-scene h1{font-size:48px;margin-top:5px}.intro-copy{font-size:16px;margin:0;padding:6px}.intro-island{top:40%;height:185px}.intro-bridge{top:61%;height:18px}.intro-boy,.intro-girl{top:29%;max-width:115px}.scene-caption{display:none}.rules-panel{margin:0 auto 15px;max-width:530px;padding:24px}.rules-panel h2{font-size:24px;margin-bottom:20px}.rules-panel fieldset{margin-bottom:18px}.players{grid-template-columns:1fr;gap:20px}.game{padding:10px 8px}.world{aspect-ratio:600/374}.player-header{padding:12px}.progress{max-width:220px;gap:5px}.progress span{width:22px;height:22px;font-size:11px}.team-name{font-size:21px}.clock{font-size:18px}.answer-area{padding:12px}.keypad-and-submit{grid-template-columns:minmax(0,1fr) 72px 96px;gap:6px}.answer-row{gap:7px;font-size:20px}.answer-input{height:49px;width:78px}.bridge-button{font-size:19px}.keypad button{min-height:46px}.feedback{min-height:47px;font-size:15px}.tools-row button{min-height:42px}.game-hint{padding:0 12px}.finish-dialog h2{font-size:25px}.finish-actions{gap:6px}.finish-actions button{padding:8px;font-size:15px}dialog{padding:29px 24px}.help-dialog ol{font-size:16px}.help-dialog p{font-size:15px}}
@media(prefers-reduced-motion:reduce){button,.toast{transition:none}}

/* Keep the atlas feet on the same grass baseline at each layout size. */
.intro-island{top:calc(55% - 97px)}
.intro-boy,.intro-girl{width:clamp(110px,14vw,190px);top:calc(55% - clamp(93px,11.83vw,160.6px));max-width:none}
.intro-bridge{top:calc(55% - 8px);left:27%;width:40%;transform:none}
@media(max-width:760px){
 .intro-island{top:calc(70% - 58px)}
 .intro-boy,.intro-girl{width:115px;top:calc(70% - 97px)}
 .intro-bridge{top:calc(70% - 6px)}
 .keypad-and-submit{grid-template-columns:1fr 1fr}
 .keypad{grid-column:1/-1}
 .edit-keys{display:flex;gap:6px}
 .edit-keys button{flex:1;min-height:47px}
 .bridge-button{flex-direction:row;min-height:47px}
}

.world .ruler-number{font-size:14px}
.world .ruler-unit{font-size:14px}
@media(max-width:760px){
 .world .ruler-number{font-size:21px;transform:translateY(5px)}
 .world .ruler-unit{font-size:20px;transform:translateY(7px)}
 .world .ruler-body{transform:scaleY(1.2)}
 .world .point-label{font-size:21px}
 .world .magnifier>text{font-size:20px}
}