/* System fonts keep the app usable without a font service or extra downloads. */
:root{font-family:'Be Vietnam Pro',system-ui,sans-serif;color:#233e36;background:#f7f5ec;--green:#215d50;--orange:#ed9b35;--cream:#fffdf6}*{box-sizing:border-box}body{margin:0}button,input,select{font:inherit}button,a,input,select{touch-action:manipulation}button{cursor:pointer}button:disabled{opacity:.55;cursor:default}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible{outline:3px solid #c97a17;outline-offset:3px}a{color:var(--green)}header{max-width:1150px;margin:auto;display:flex;align-items:center;justify-content:space-between;gap:12px;padding:22px 28px}.brand{display:flex;align-items:center;gap:12px;font-weight:800}.brand small{display:block;font-weight:400;color:#63776d;margin-top:4px}.logo{background:#dce8d9;padding:12px;border-radius:18px;font-size:26px}header select{max-width:240px;background:var(--cream);border:1px solid #d3ddce;border-radius:20px;padding:12px}main{max-width:1100px;margin:auto;padding:20px 28px 115px}.eyebrow{font-size:12px;font-weight:700;letter-spacing:.12em;text-transform:uppercase;color:#6c7d6d}h1{font-size:clamp(26px,4vw,42px);letter-spacing:-.045em;margin:8px 0 14px}h2{font-size:23px;letter-spacing:-.025em}h3{margin:8px 0 12px}p{line-height:1.7}.muted,small{color:#63756c}.small{font-size:13px}.row{display:flex;gap:10px;align-items:center;flex-wrap:wrap}.between{justify-content:space-between}.btn{border:1px solid #d7dfd1;background:var(--cream);color:var(--green);padding:13px 18px;border-radius:14px;font-weight:600;text-decoration:none;display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:46px}.primary{background:var(--green);color:#fff;border-color:var(--green)}.warm{background:var(--orange);color:#2f311c;border:0}.ghost{background:transparent;border-color:transparent}.full{width:100%}.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,230px),1fr));gap:16px}.card{background:var(--cream);border:1px solid #e1e5d6;border-radius:24px;padding:24px}.tag{display:inline-block;border-radius:99px;padding:7px 11px;background:#e8efdf;color:#365846;font-size:12px}.section{margin-top:30px}.hero{display:grid;grid-template-columns:1.15fr 1fr;gap:25px;align-items:center}.hero-text{padding:20px 0}.hero p{max-width:450px}.map{position:relative;min-height:420px;background:linear-gradient(160deg,#dbe9cd,#eef1cf 55%,#c4e3da);border-radius:100px 100px 35px 35px;overflow:hidden;border:7px solid #fffdf6;padding:22px 20px;box-shadow:0 16px 50px #31564212}.map:before{content:'🌲　🌳　🌿　⛰️';position:absolute;bottom:20px;left:25px;font-size:36px;opacity:.55}.path{position:absolute;left:45%;top:45px;width:55px;height:300px;border:14px solid #f8e7b9;border-radius:50%;transform:rotate(15deg)}.node{position:relative;display:flex;align-items:center;gap:12px;margin:12px auto;width:210px;background:#fffcf1ed;border:1px solid #ffffff;border-radius:18px;padding:12px;box-shadow:0 5px 0 #568f6720;text-align:left}.node:nth-of-type(even){transform:translateX(22px)}.node:nth-of-type(odd){transform:translateX(-18px)}.node .circle{background:#d6e6c4;border-radius:50%;width:40px;height:40px;display:grid;place-items:center;flex-shrink:0}.node.active{border:2px solid #dc992f}.node.active .circle{background:#f7be5a}.fox{font-size:52px;line-height:1.4}.topic{display:flex;align-items:center;gap:15px;width:100%;text-align:left;transition:transform .15s}.topic:hover{transform:translateY(-3px)}.topic-icon{font-size:30px}.topic small{display:block;margin-top:7px;font-weight:400}.tabs{display:flex;gap:8px;overflow:auto;padding-bottom:6px;margin:15px 0}.tabs button{white-space:nowrap}.tabs .selected{background:var(--green);color:white}.bottom{position:fixed;bottom:0;left:50%;transform:translateX(-50%);width:min(100%,650px);display:flex;justify-content:space-around;padding:10px 8px max(12px,env(safe-area-inset-bottom));background:#fffdf6f5;border:1px solid #dce2d4;border-radius:24px 24px 0 0;backdrop-filter:blur(15px);z-index:5}.bottom button{border:0;background:none;color:#65796d;display:grid;gap:4px;justify-items:center;font-size:11px;padding:7px 10px;border-radius:12px}.bottom button span{font-size:21px}.bottom .active{color:#194f3e;background:#e5eddc}.lesson{max-width:720px;margin:auto}.word{font-size:38px;font-weight:700;margin:12px 0}.read{font-size:18px;color:#647b62}.progress{height:7px;background:#e3e8d8;border-radius:20px;margin:20px 0;overflow:hidden}.progress>span{display:block;height:100%;background:#76a37b}.answer{width:100%;justify-content:flex-start;margin-top:10px;padding:19px}.success{background:#e2edda;padding:15px;border-radius:14px}.incorrect{background:#fff0d9;padding:15px;border-radius:14px}.caption{text-align:center;min-height:200px;display:flex;flex-direction:column;align-items:center;justify-content:center;background:linear-gradient(130deg,#e7eed8,#d2e5da);border-radius:22px;padding:20px}.caption strong{font-size:25px}.wordrow{display:flex;gap:12px;align-items:center;padding:18px 0;border-bottom:1px solid #e5e8dd}.wordrow strong{font-size:19px}.wordrow .info{flex:1}.wordrow .info p{margin:5px 0}input,select{border:1px solid #cbd8c7;background:var(--cream);color:#233e36;border-radius:12px;padding:13px;width:100%}label{display:grid;gap:8px;margin:15px 0}textarea{width:100%;min-height:120px;border:1px solid #cbd8c7;border-radius:12px;padding:12px;font:inherit}.notice{border-left:3px solid #b7caa6;padding:4px 15px;color:#63756c;font-size:13px}.draw{background:#fffdf6;border:1px solid #bfcdb7;width:100%;max-width:320px;aspect-ratio:1;touch-action:none;border-radius:20px;background-image:linear-gradient(90deg,transparent 49.7%,#e4e5db 50%,transparent 50.3%),linear-gradient(transparent 49.7%,#e4e5db 50%,transparent 50.3%)}#toast{position:fixed;bottom:100px;left:50%;transform:translateX(-50%);max-width:90%;padding:13px 20px;background:#203f34;color:white;border-radius:14px;z-index:10;display:none}.sources a{display:block;margin:15px 0}audio{width:100%;margin:15px 0}.stat{font-size:32px;font-weight:700}.empty{text-align:center;padding:35px}.check{display:flex;align-items:center;gap:10px}.check input{width:auto}.source{font-size:12px}.nextbox{padding:20px;background:#edf0df;border-radius:18px}details{margin:14px 0}summary{cursor:pointer;padding:10px 0}footer{text-align:center;font-size:12px;color:#748375;margin:30px 0}#file{display:none}@media(max-width:700px){header{padding:18px 16px}.brand small{font-size:10px}.brand{font-size:13px}.logo{padding:8px;font-size:22px}header select{width:150px;padding:10px;font-size:11px}main{padding:12px 18px 105px}.hero{grid-template-columns:1fr}.hero-text{padding:5px 0}.hero h1{font-size:32px}.map{min-height:380px;border-radius:60px 60px 26px 26px}.node{margin:9px auto}.card{padding:20px}.bottom button{padding:7px 8px}.word{font-size:32px}.row .btn{flex-grow:1}}