:root{--bg:#f7f6ef;--paper:#fffefa;--ink:#223c33;--muted:#718076;--green:#245c48;--light:#e7eee5;--line:#e1e5da;--orange:#f1ad63;--red:#a63f36;--radius:20px;font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",sans-serif;color:var(--ink);background:var(--bg);font-synthesis:none}
*{box-sizing:border-box}body{margin:0}button,input,select,textarea{font:inherit}button,a,input,textarea,select{-webkit-tap-highlight-color:transparent}button{cursor:pointer}button:disabled{opacity:.55;cursor:wait}a{color:var(--green)}button:focus-visible,a:focus-visible,input:focus-visible,textarea:focus-visible,select:focus-visible{outline:3px solid var(--orange);outline-offset:3px}h1,h2,h3,p{margin:0}h1{font-size:30px;line-height:1.35;letter-spacing:-1px}h2{font-size:21px;line-height:1.5}h3{font-size:18px;line-height:1.5}p{line-height:1.8}small,.small{font-size:13px}.muted{color:var(--muted)}.eyebrow{font-size:12px;letter-spacing:2px;font-weight:700}.row{display:flex;align-items:center;gap:12px}.between{justify-content:space-between}.wrap{flex-wrap:wrap}.stack{display:flex;flex-direction:column;gap:18px}.gap-sm{gap:8px}.boot{min-height:90vh;display:grid;align-content:center;justify-items:center;gap:20px}.brand-mark{width:42px;height:42px;display:grid;place-items:center;font:700 27px Georgia,serif;background:var(--green);color:var(--paper);border-radius:13px}.brand{display:flex;align-items:center;gap:11px}.brand strong{display:block;font-size:17px}.brand small{color:var(--muted);font-size:11px;letter-spacing:1px}.topbar{max-width:1056px;margin:auto;padding:24px 28px;display:flex;align-items:center;justify-content:space-between}.top-actions{display:flex;align-items:center;gap:12px}.avatar{width:32px;height:32px;border-radius:50%;background:#eadac0;display:grid;place-items:center;font-size:13px;font-weight:700}.shell{max-width:1000px;margin:0 auto;padding:14px 28px 115px;min-height:80vh}.nav{position:fixed;z-index:10;bottom:0;left:0;right:0;background:rgba(255,254,250,.98);border-top:1px solid var(--line);padding:10px 15px calc(10px + env(safe-area-inset-bottom));display:flex;justify-content:center;gap:35px}.nav 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9px;font-size:12px;background:var(--light);color:var(--green)}.pill.math{background:#e9eee1;color:#59714b}.pill.english{background:#e3edf1;color:#426c83}.pill.chinese{background:#f3e7dd;color:#925b43}.section-heading{margin:28px 0 16px}.hero{margin-top:22px;background:var(--green);color:#fffcf0;border-radius:25px;padding:34px 38px;display:flex;align-items:center;justify-content:space-between;gap:26px;position:relative;overflow:hidden}.hero h2{font-size:29px;font-weight:650;margin:10px 0}.hero p{max-width:400px;color:#d7e2d5;font-size:15px}.hero .btn{margin-top:24px}.hero-art{width:185px;flex:0 0 auto;transform:rotate(-6deg)}.intro{display:flex;align-items:flex-end;justify-content:space-between;gap:12px}.intro h1{margin-bottom:8px}.intro .date{font-size:13px;color:var(--muted)}.stats{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-top:18px}.stat{padding:19px 20px;background:var(--paper);border:1px solid var(--line);border-radius:16px}.stat strong{font:600 29px 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var(--line);border-radius:24px}.login-box h2{margin:0 0 8px}.login-box .form{margin-top:25px}.login-footer{margin-top:20px;line-height:1.8;font-size:12px;color:var(--muted)}.mobile-only{display:none}.footer{text-align:center;color:var(--muted);font-size:12px;margin-top:30px}.footer a{color:inherit}.filter-bar{margin:12px 0 24px}.history-entry{border-bottom:1px solid var(--line);padding:17px 0}.history-entry:last-child{border:0}.history-entry p{font-size:14px;white-space:pre-wrap;word-break:break-word}.toast{position:fixed;z-index:100;bottom:115px;left:50%;transform:translateX(-50%);background:#213d31;color:white;padding:13px 20px;border-radius:13px;box-shadow:0 5px 25px #203b3020;max-width:90vw;line-height:1.7;font-size:14px}.hidden{display:none!important}.button-row{display:flex;gap:12px;flex-wrap:wrap}.button-row .btn{flex:1}.overview-cols{display:grid;grid-template-columns:1.5fr 1fr;gap:25px}.overview-cols .section-heading{margin-top:25px}@keyframes 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@media(max-width:700px){h1{font-size:26px}.topbar{padding:19px 20px}.brand strong{font-size:16px}.top-actions{gap:6px}.top-actions .username{display:none}.shell{padding:10px 20px 115px}.intro{align-items:flex-start}.intro .date{display:none}.hero{padding:26px 24px;gap:12px}.hero h2{font-size:25px;max-width:200px}.hero p{max-width:220px;font-size:14px}.hero-art{width:104px;position:absolute;right:16px;top:24px;opacity:.95}.hero .eyebrow{font-size:11px}.hero .btn{margin-top:22px}.hero p{max-width:210px}.stats{gap:8px;margin-top:14px}.stat{padding:16px 12px}.stat strong{font-size:26px}.stat span{font-size:12px}.nav{gap:12px}.nav button{flex:1;max-width:90px;min-width:56px}.panel{padding:20px}.page-head{margin-bottom:20px}.page-head p{font-size:14px}.item-card{padding:15px;gap:12px}.item-title{font-size:15px}.item-card .thumb{width:49px;height:62px}.settings-grid{grid-template-columns:1fr}.settings-grid .wide{grid-column:auto}.login-wrap{display:block;padding:30px 24px}.login-intro h1{font-size:31px;max-width:270px;margin:23px 0 12px}.login-intro p{font-size:14px}.login-art{display:none}.login-box{padding:25px;margin-top:26px}.login-footer{text-align:center}.choices.reason{gap:6px}.choices.reason .choice{font-size:12px}.upload-area{padding:28px 15px}.btn{padding:12px 16px}.overview-cols{display:block}.step{font-size:12px}.lesson-title{font-size:22px}.mobile-only{display:block}}