:root{
  --bg:#f5f2ea;--surface:#fffef9;--ink:#20251f;--muted:#72776f;--line:#dedfd7;
  --green:#2f7456;--green-soft:#e4efe7;--bad:#9b463e;--bad-soft:#f6e6e3;--shadow:0 14px 35px rgba(47,61,48,.08);
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;color:var(--ink);background:var(--bg);
}
*{box-sizing:border-box}body{margin:0;background:var(--bg);min-height:100vh}button,select{font:inherit}.boot{padding:30vh 0;text-align:center;font-weight:800}
.app-shell{max-width:560px;margin:0 auto;min-height:100vh;padding-bottom:92px}.topbar{display:flex;justify-content:space-between;align-items:center;padding:18px 18px 12px;position:sticky;top:0;background:rgba(245,242,234,.94);backdrop-filter:blur(16px);z-index:10}.brand{font-weight:900;font-size:21px;letter-spacing:.02em}.subbrand{font-size:12px;color:var(--muted);margin-top:2px}.streak{font-weight:800;background:var(--surface);border:1px solid var(--line);border-radius:99px;padding:8px 12px}
main{padding:6px 16px 24px}.hero-card,.card,.stats-card{background:var(--surface);border:1px solid var(--line);border-radius:24px;box-shadow:var(--shadow)}.hero-card{padding:25px 22px;margin-bottom:14px;background:linear-gradient(145deg,#fffef9 20%,#e7efe8)}.hero-card h1,.page-title h1,.lesson-card h1,.exercise h1,.finish h1{font-size:29px;line-height:1.15;margin:8px 0 18px}.eyebrow{font-size:12px;letter-spacing:.12em;text-transform:uppercase;font-weight:800;color:var(--green)}.today-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:8px;margin-top:25px}.today-grid div,.stats-card div{display:flex;flex-direction:column;gap:3px}.today-grid b,.stats-card b{font-size:22px}.today-grid span,.stats-card span{font-size:11px;color:var(--muted)}
.card{padding:19px;margin:12px 0}.card h2{margin:7px 0 10px;font-size:20px}.card p,.page-title p,.finish p,.mini-note{font-size:14px;line-height:1.65;color:var(--muted)}.baseline{display:flex;gap:15px;align-items:center}.baseline>div{flex:1}.pill{display:inline-flex;padding:5px 8px;border-radius:99px;background:var(--green-soft);color:var(--green);font-size:11px;font-weight:800}.accent{border-color:#b8d0bf}.focus{padding:22px}.section-head{display:flex;justify-content:space-between;gap:12px;align-items:flex-start}.section-head h2{margin:4px 0}.time{font-size:12px;color:var(--muted);white-space:nowrap;background:#f2f1eb;border-radius:99px;padding:6px 9px}.mini-note{padding:6px 5px 15px}
.btn{border:0;border-radius:15px;padding:13px 17px;font-weight:800;cursor:pointer;min-height:46px}.btn.primary{background:var(--green);color:white}.btn.secondary{background:var(--green-soft);color:var(--green)}.btn.ghost{background:#f2f1eb;color:var(--ink)}.btn:disabled{opacity:.5}.button-row{display:flex;gap:8px;flex-wrap:wrap}
.tabs{position:fixed;left:50%;bottom:0;transform:translateX(-50%);width:min(560px,100%);display:grid;grid-template-columns:repeat(4,1fr);padding:8px 8px calc(8px + env(safe-area-inset-bottom));background:rgba(255,254,249,.96);border-top:1px solid var(--line);backdrop-filter:blur(18px);z-index:20}.tab{background:none;border:0;color:var(--muted);padding:7px;display:flex;flex-direction:column;gap:2px;align-items:center;font-size:11px}.tab span{font-size:16px;font-weight:800}.tab.active{color:var(--green);font-weight:800}
.page-title{padding:16px 5px 12px}.page-title h1{margin-bottom:8px}.path{display:flex;flex-direction:column;gap:12px}.path-node{display:flex;text-align:left;gap:14px;width:100%;border:1px solid var(--line);background:var(--surface);border-radius:20px;padding:15px;box-shadow:var(--shadow)}.path-node.done{border-color:#b8d0bf}.path-node.locked{opacity:.48}.node-mark{width:46px;height:46px;display:grid;place-items:center;border-radius:50%;background:var(--green-soft);color:var(--green);font-weight:900;flex:none}.node-copy{display:flex;flex-direction:column;gap:3px}.node-copy span,.node-copy small{font-size:11px;color:var(--muted)}.node-copy strong{font-size:16px}.review-row,.metric-row{display:flex;justify-content:space-between;align-items:center;padding:12px 0;border-bottom:1px solid var(--line);gap:10px}.review-row div{display:flex;flex-direction:column;gap:3px}.review-row small,.review-row>span{font-size:11px;color:var(--muted)}.empty{padding:20px 0;color:var(--muted);font-size:14px}.stats-card{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;padding:20px;margin-bottom:12px}
.lesson-shell{max-width:560px;margin:0 auto;min-height:100vh;padding:14px 16px 40px}.lesson-progress{display:flex;align-items:center;gap:12px;margin:5px 0 25px}.lesson-progress>button{border:0;background:none;font-size:28px;color:var(--muted);padding:0 4px}.lesson-progress>span{font-size:12px;color:var(--muted);min-width:35px;text-align:right}.bar{height:8px;background:#dedfd7;border-radius:99px;overflow:hidden;flex:1}.bar i{display:block;height:100%;background:var(--green);border-radius:inherit;transition:width .2s}.lesson-card,.exercise{background:var(--surface);border:1px solid var(--line);border-radius:25px;padding:25px 20px;box-shadow:var(--shadow)}.lesson-card p{font-size:17px;line-height:1.9;white-space:normal}.lesson-card .btn{width:100%;margin-top:22px}.takeaway{padding:14px;border-radius:15px;background:var(--green-soft);color:#315d49;font-weight:700;line-height:1.6;margin-top:20px}.exercise h1{font-size:24px;margin-top:12px}.options{display:flex;flex-direction:column;gap:10px;margin-top:25px}.options.two{display:grid;grid-template-columns:1fr 1fr}.option{display:flex;gap:12px;align-items:center;text-align:left;border:1px solid var(--line);background:white;border-radius:15px;padding:14px 15px;min-height:54px;font-weight:700}.option span{width:28px;height:28px;display:grid;place-items:center;background:#f0f1eb;border-radius:9px;font-size:12px}.match-list{display:flex;flex-direction:column;gap:10px;margin:22px 0}.match-list label{display:grid;grid-template-columns:105px 1fr;gap:10px;align-items:center}.match-list span{font-weight:800}.match-list select{width:100%;padding:13px;border-radius:12px;border:1px solid var(--line);background:white}
.feedback{position:fixed;left:0;right:0;bottom:0;z-index:100;padding:18px max(18px,calc((100vw - 560px)/2 + 18px)) calc(18px + env(safe-area-inset-bottom));border-top:1px solid var(--line);box-shadow:0 -15px 40px rgba(0,0,0,.08)}.feedback.ok{background:#e4efe7}.feedback.bad{background:var(--bad-soft)}.feedback strong{font-size:19px}.feedback p{margin:7px 0;color:#525c53;line-height:1.5}.feedback span{display:block;font-weight:900;color:var(--green);margin-bottom:8px}.feedback .btn{width:100%}.feedback.bad .btn{background:var(--bad)}
.finish{max-width:520px;margin:0 auto;min-height:100vh;padding:22vh 22px 40px;text-align:center}.finish-mark{width:86px;height:86px;margin:0 auto 20px;border-radius:50%;display:grid;place-items:center;background:var(--green-soft);color:var(--green);font-weight:900;font-size:30px}.finish-xp{font-weight:900;font-size:22px;color:var(--green);margin:20px}.finish .btn{width:100%;max-width:320px}.metric-row b{font-size:13px}.metric-row:last-child,.review-row:last-child{border-bottom:0}
@media(max-width:380px){.today-grid{gap:4px}.today-grid b{font-size:18px}.stats-card{grid-template-columns:repeat(2,1fr)}.baseline{display:block}.baseline .btn{margin-top:10px;width:100%}}