:root{color-scheme:light;font-family:system-ui,-apple-system,"Segoe UI","Noto Sans TC",Arial,sans-serif;color:#1e3152;background:#f5f7fc;--blue:#225bd5;--pale:#eaf1ff;--text:#253b60;--muted:#697c99}*{box-sizing:border-box}body{margin:0}.shell{width:min(830px,100%);margin:0 auto;padding:26px 18px 40px}h1,h2,h3,p{margin-top:0}button,input,select{font:inherit}button:focus-visible,input:focus-visible,select:focus-visible{outline:3px solid #f5ad31;outline-offset:2px}button{cursor:pointer}button:disabled{cursor:not-allowed;opacity:.5}.hero{background:linear-gradient(125deg,#2158c9,#427ded);color:#fff;border-radius:26px;padding:25px 26px;display:flex;justify-content:space-between;align-items:center;gap:12px;box-shadow:0 10px 28px #2054bc19}.overline{font-size:11px;letter-spacing:2px;font-weight:800;color:#d8e7ff;margin-bottom:9px}.hero h1{font-size:26px;line-height:1.35;margin:0 0 6px;max-width:535px}.sub{font-size:13px;margin:0;color:#dfebff}.hero-counter{flex:0 0 auto;text-align:center;background:#ffffff24;padding:13px 18px;border-radius:17px}.hero-counter strong{display:block;font-size:32px}.hero-counter span{font-size:11px}.tabs{display:grid;grid-template-columns:repeat(3,1fr);gap:5px;background:#e8edf8;padding:5px;border-radius:15px;margin:20px 0 23px}.tab{border:0;background:transparent;color:#59749e;padding:12px 4px;font-weight:750;border-radius:11px}.tab.active{background:#fff;color:#225bd5;box-shadow:0 3px 9px #344b7320}.hidden{display:none!important}.heading-row{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-bottom:13px}.heading-row h2{margin:4px 0;font-size:23px}.eyebrow{font-size:11px;font-weight:850;letter-spacing:1.7px;color:#6382b5;margin:0}.small-muted{color:var(--muted);font-size:13px}.progress-track{height:9px;background:#dde7f8;border-radius:99px;overflow:hidden;margin:11px 0 18px}.progress-track>span{display:block;background:#588bea;height:100%;width:0%;transition:width .2s}.toolbar{display:flex;gap:10px;margin-bottom:17px}.toolbar input,.toolbar select,.quiz-options select,.quiz-card input{border:1px solid #d0daeb;border-radius:12px;padding:12px 14px;background:white;color:var(--text);min-width:0}.toolbar input{width:47%}.toolbar select{flex:1}.word-card,.quiz-card,.review-block{background:#fff;border-radius:24px;box-shadow:0 5px 24px #1839700c;padding:23px;text-align:center}.illustration{height:182px;border-radius:20px;background:linear-gradient(135deg,#edf5ff,#f7f9ff);display:grid;place-items:center;font-size:85px;margin-bottom:15px}.word-number{font-weight:800;color:#8196b4;letter-spacing:1.5px;font-size:12px}.word-card h3{font-size:42px;color:#1c345b;margin:7px 0 0;overflow-wrap:anywhere}.meaning{font-size:17px;color:#627a9a;margin:3px 0 22px}.button-group{display:flex;gap:10px;justify-content:center;flex-wrap:wrap}.btn{border:0;padding:12px 17px;border-radius:12px;font-size:14px;font-weight:750;min-height:44px}.btn-primary{background:var(--blue);color:#fff}.btn-soft{background:var(--pale);color:#2556b5}.btn-outline{background:white;border:1px solid #cbd8ef;color:#2556b5}.actions{display:flex;gap:10px;margin-top:16px}.actions>.btn{flex:1}.notice{color:#ba5735;font-size:13px;min-height:19px;margin:14px 0 0}.score{background:#e7efff;color:#275ccd;padding:11px 16px;font-weight:850;border-radius:12px}.quiz-options{display:flex;align-items:center;gap:10px;margin-bottom:15px}.quiz-options label{white-space:nowrap;font-size:13px;color:var(--muted)}.quiz-options select{flex:1;max-width:310px}.quiz-card{padding:29px 23px}.headphone{font-size:58px}.quiz-card h3{font-size:22px;margin:8px 0}.quiz-tip,.footnote{color:#8290a4;font-size:13px;line-height:1.7}.listen{margin:13px 0 10px}.answer-label{display:block;margin:17px 0 8px;font-size:13px;color:var(--muted)}.quiz-card input{display:block;width:min(400px,100%);margin:0 auto 17px;text-align:center;font-size:23px;letter-spacing:1px}.feedback{min-height:28px;margin-top:15px;font-weight:750;line-height:1.6}.feedback.good{color:#168251}.feedback.bad{color:#b45435}.stats{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin-bottom:15px}.stat{background:#fff;border-radius:17px;padding:18px 10px;text-align:center;box-shadow:0 4px 18px #1839700c}.stat strong{display:block;color:#2c61d7;font-size:29px}.stat span{font-size:12px;color:#7485a0}.review-block{text-align:left;margin-bottom:15px}.review-block h3{font-size:18px;margin:2px 0 8px}.review-head{display:flex;justify-content:space-between;align-items:center;gap:10px}.btn-small{min-height:36px;padding:8px 10px}.wrong-list{display:flex;flex-wrap:wrap;gap:9px;margin-top:15px}.wrong-word{border:1px solid #e6cfcb;background:#fff6f3;color:#a94b35;border-radius:10px;padding:9px 12px;font-weight:700}.empty{font-size:14px;color:#8190a9}.offline-meter{font-size:13px;color:#416baa;margin-top:12px;font-weight:800}.offline-progress{max-width:480px}.offline-progress>span{background:#23a47c}footer{text-align:center;margin:25px 6px 0;font-size:12px;color:#8393ac;line-height:1.8}.visually-hidden{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}@media(max-width:540px){.shell{padding:12px 12px 30px}.hero{padding:19px 17px;border-radius:20px}.hero h1{font-size:20px}.sub{font-size:11px}.hero-counter{padding:11px 9px}.hero-counter strong{font-size:26px}.tab{font-size:12px;padding:11px 2px}.illustration{height:154px;font-size:74px}.word-card h3{font-size:36px}.word-card,.quiz-card,.review-block{padding:19px 15px}.toolbar{flex-direction:column}.toolbar input,.toolbar select{width:100%}.actions{flex-wrap:wrap}.actions>.btn{flex:1 1 28%;padding:10px 5px;font-size:12px}.stats{gap:6px}.stat strong{font-size:25px}.review-head{align-items:flex-start}.review-head .btn{font-size:11px}}

/* V3：觸控大字母鍵盤；維持 V2 的學習與複習樣式 */
.keyboard-shell{width:min(620px,100%);margin:0 auto 20px;padding:13px 10px 14px;background:#f0f5ff;border:1px solid #dce6f8;border-radius:18px}
.keyboard-hint{font-size:12px;color:#697c99;margin:0 0 11px;line-height:1.5}
.letter-keyboard{display:grid;gap:7px}.letter-row{display:flex;justify-content:center;gap:5px}
.letter-key{flex:1 1 0;min-width:0;min-height:52px;border:1px solid #d3def0;border-bottom:3px solid #c3d0e8;background:white;border-radius:10px;color:#254b93;font-weight:800;font-size:clamp(14px,2.6vw,22px);padding:3px 0;touch-action:manipulation;user-select:none}
.letter-key:active:not(:disabled){background:#cfe0ff;transform:translateY(1px);border-bottom-width:1px}
.keyboard-tools{display:flex;justify-content:center;gap:10px;margin-top:12px}
.key-tool{min-width:105px;min-height:44px;padding:9px 17px;background:#d9e5fa;border:0;border-radius:10px;color:#2453a5;font-weight:800;touch-action:manipulation}
.keyboard-shell button:disabled{opacity:.45}
#answer{margin-bottom:10px;letter-spacing:2px;font-weight:650;text-transform:uppercase}
@media(max-width:540px){.keyboard-shell{padding:11px 5px}.letter-row{gap:3px}.letter-key{min-height:49px;border-radius:7px;font-size:15px}.keyboard-hint{font-size:11px}.quiz-card{padding:18px 9px}}