:root{--ink:#23382f;--green:#2e624c;--muted:#758078;--line:#e2e7df;--paper:#fafbf7;--lime:#deedb5}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font-family:-apple-system,BlinkMacSystemFont,'PingFang SC','Microsoft YaHei',sans-serif;font-size:15px;line-height:1.8}button,a,input,textarea{font:inherit}button{cursor:pointer}button:focus-visible,a:focus-visible,input:focus-visible,textarea:focus-visible{outline:3px solid #a5bc65;outline-offset:3px}header{height:86px;border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;padding:0 5vw;background:#fff}.brand{display:flex;align-items:center;gap:13px;color:var(--ink);text-decoration:none;font-weight:700;font-size:20px}.brand small{font-size:12px;color:var(--muted);font-weight:400;margin-left:12px}.logo{background:var(--green);color:#fff;border-radius:12px;width:39px;height:39px;text-align:center;line-height:39px}button{border:1px solid var(--line);border-radius:9px;background:white;padding:9px 17px;color:var(--ink)}.layout{max-width:1420px;margin:auto;display:grid;grid-template-columns:270px 1fr}aside{padding:42px 28px;border-right:1px solid var(--line)}.eyebrow{font-size:12px;letter-spacing:2px;color:var(--green);font-weight:650}h2{font-size:23px;line-height:1.6;font-weight:550;margin:16px 0 25px}h1{font-size:33px;line-height:1.45;letter-spacing:-.7px;font-weight:600;margin:14px 0}.progress{font-size:14px;margin-bottom:32px}progress{display:block;width:100%;height:7px;accent-color:var(--green);margin:12px 0}.progress small{font-size:11px;color:var(--muted)}nav{display:grid;gap:7px}nav button{border:0;text-align:left;background:transparent}nav button.active{background:#e9efdf;color:var(--green);font-weight:600}nav span{float:right;font-size:12px}.aside-note{font-size:13px;color:var(--muted);margin:65px 0 30px}.text-btn{background:none;border:0;padding:0;font-size:12px;color:var(--green)}main{min-width:0;padding:40px 50px}.hero{display:flex;justify-content:space-between;gap:25px;padding:28px 32px;background:#edf1e4;border-radius:16px;margin-bottom:30px}.hero p{margin:10px 0 0;color:#667662;font-size:14px}.hero-mark{font-size:68px;font-family:Georgia,serif;font-style:italic;color:#9baf7f;align-self:center}.pill{display:inline-block;padding:3px 10px;background:#fff9;border-radius:20px;font-size:11px;margin-right:7px}.section-head{display:flex;align-items:center;gap:12px;margin:27px 0 13px;font-size:17px;font-weight:600}.num{color:var(--green);font-size:12px;border:1px solid #d5dec9;border-radius:50%;width:27px;height:27px;line-height:25px;text-align:center}.section-head small{font-weight:400;font-size:11px;color:var(--muted);margin-left:auto}.card{background:#fff;border:1px solid var(--line);border-radius:13px;padding:24px 28px}.core{font-size:18px;font-weight:500;margin:0 0 15px}.muted{color:var(--muted);font-size:14px}.case{border-left:3px solid #a4bc6c;background:#f1f4ea;padding:21px 25px;border-radius:0 10px 10px 0}.options{display:grid;gap:10px;margin:20px 0}.option{display:flex;align-items:center;gap:12px;padding:13px 17px;border:1px solid var(--line);border-radius:9px;cursor:pointer}.option:has(input:checked){border-color:var(--green);background:#eff5e8}input{accent-color:var(--green)}.primary{background:var(--green);color:white;border-color:var(--green)}button:disabled{opacity:.5;cursor:default}textarea{display:block;width:100%;resize:vertical;min-height:84px;border:1px solid var(--line);border-radius:9px;padding:13px;background:#fdfefb;margin:10px 0 16px;color:var(--ink)}.feedback{padding:15px 18px;background:#eff4e7;border-radius:9px;margin-top:16px}.knowledge{background:var(--ink);color:#f5f8ed;border-radius:13px;padding:22px 28px;margin-top:27px}.knowledge small{color:#c4d69e;letter-spacing:2px}.knowledge p{margin:10px 0 0}.next{display:flex;justify-content:space-between;align-items:center;gap:20px;margin:26px 0}.week{margin:27px 0}.week h2{font-size:17px;margin:0 0 13px}.row{display:flex;gap:15px;align-items:center;background:#fff;border:1px solid var(--line);padding:14px 18px;margin-top:7px;border-radius:9px;width:100%;text-align:left}.row b{font-size:12px;color:var(--green);min-width:51px}.row small{margin-left:auto;white-space:nowrap;color:var(--muted)}footer{border-top:1px solid var(--line);padding-top:23px;margin-top:45px;font-size:11px;color:var(--muted)}footer span{float:right}#toast{position:fixed;bottom:28px;left:50%;transform:translateX(-50%);background:var(--ink);color:white;border-radius:9px;padding:10px 20px;display:none}.note{white-space:pre-wrap}.empty{padding:45px;text-align:center;border:1px dashed #cbd5c4;border-radius:12px;color:var(--muted)}@media(max-width:850px){.layout{grid-template-columns:210px 1fr}aside{padding:30px 18px}main{padding:30px 25px}.hero{padding:23px}.hero-mark{display:none}h1{font-size:27px}.brand small{display:none}}@media(max-width:600px){header{height:70px;padding:0 20px}.layout{display:block}aside{border-right:0;border-bottom:1px solid var(--line);padding:18px 20px}aside h2,aside>.eyebrow,.aside-note{display:none}.progress{margin:0 0 12px}.progress small{display:none}nav{display:flex;gap:4px}nav button{font-size:13px;padding:9px}nav span{display:none}aside>.text-btn{margin-top:10px}main{padding:25px 18px}.hero{padding:22px}h1{font-size:25px}.card{padding:20px}.section-head{font-size:16px}.row{font-size:13px;padding:12px}.next{align-items:flex-start;flex-direction:column}footer span{display:none}.brand{font-size:18px}}
/* Mobile-first reading and discussion layout */
body{font-size:16px;padding-bottom:calc(85px + env(safe-area-inset-bottom));overflow-wrap:anywhere}header{height:68px;padding:0 18px;position:sticky;top:0;z-index:5;background:#fafbf7f5;backdrop-filter:blur(12px)}header button{min-height:44px;font-size:13px;padding:8px 12px}.brand{font-size:18px}.brand small{display:none}.layout{display:block;max-width:1120px}aside{padding:16px 20px 0;border:0}aside>.eyebrow,aside h2,.aside-note{display:none}.progress{margin:0}.progress small{display:block;font-size:11px}progress{height:5px;margin:7px 0}nav{position:fixed;z-index:20;bottom:0;left:0;right:0;display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:0;background:#fffffff5;border-top:1px solid var(--line);padding:9px 8px calc(9px + env(safe-area-inset-bottom));backdrop-filter:blur(12px)}nav button{min-height:48px;font-size:12px;text-align:center;padding:8px 2px;border-radius:10px;white-space:nowrap}nav span{display:none}aside>.text-btn{display:block;margin-top:8px;min-height:35px;font-size:12px}main{padding:22px 18px 0;min-width:0}.hero{padding:23px 20px;margin-bottom:24px}.hero-mark{display:none}h1{font-size:26px;line-height:1.5}.hero p{font-size:13px}.eyebrow{font-size:11px}.pill{font-size:11px}.card{padding:21px 18px}.core{font-size:18px;line-height:1.85}.section-head{font-size:16px;margin-top:26px}.section-head small{font-size:11px;white-space:nowrap}.case{padding:20px;font-size:16px}.option{min-height:56px;padding:14px 12px}.option input{width:19px;height:19px;flex-shrink:0}textarea{font-size:16px;min-height:100px}button{min-height:44px}.primary{width:100%}.next{display:flex;flex-direction:column;align-items:stretch}.knowledge{padding:22px}.row{font-size:14px;gap:10px;min-height:62px}.row small{font-size:11px}.row b{min-width:44px;font-size:11px}footer{margin-top:32px;padding:20px 0;font-size:10px}footer span{display:none}#toast{bottom:calc(90px + env(safe-area-inset-bottom));max-width:90vw;width:max-content;font-size:13px;z-index:30}.ask-ai{margin-top:18px;width:100%;border-color:#cbdcbc;background:#eef4e6;color:var(--green);font-size:13px;text-align:left;padding:14px}.suggestions{display:flex;gap:8px;overflow-x:auto;margin:20px 0;padding-bottom:5px}.suggestions button{flex-shrink:0;font-size:12px;border-radius:22px;background:#edf2e6}.bubble{white-space:pre-wrap;padding:16px 18px;margin:14px 0;border-radius:15px;background:white;border:1px solid var(--line)}.bubble.user{background:#e9f1df;margin-left:28px}.bubble small{display:block;font-size:11px;color:var(--muted);margin-bottom:7px}.chat-error{color:#9c3e24;background:#fff1e8;padding:13px;border-radius:9px}.report-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:9px;margin:22px 0}.metric{background:#edf1e4;border-radius:12px;padding:16px 10px;text-align:center}.metric strong{display:block;font-size:26px;font-weight:550}.metric span{font-size:11px;color:var(--muted)}.evidence{font-size:13px;padding:14px 0;border-bottom:1px solid var(--line)}#messages:empty:after{content:'从一个问题开始。讨论记录会按课程分别保存。';display:block;padding:30px 15px;text-align:center;color:var(--muted);font-size:14px}#chat-form{margin-top:24px;padding-top:18px;border-top:1px solid var(--line)}[hidden]{display:none!important}
@media(min-width:760px){body{padding-bottom:0}header{padding:0 5vw;height:80px}.brand small{display:inline}aside{padding:36px 22px;border-right:1px solid var(--line)}aside>.eyebrow,aside h2,.aside-note{display:block}.layout{display:grid;grid-template-columns:230px minmax(0,1fr)}nav{position:static;display:grid;grid-template-columns:1fr;background:none;border:0;padding:24px 0;backdrop-filter:none;gap:6px}nav button{text-align:left;font-size:14px;padding:10px 13px}.progress small{font-size:11px}.aside-note{margin:30px 0}main{padding:36px 34px}h1{font-size:31px}.hero{padding:28px}.hero-mark{display:block;font-size:56px}.primary{width:auto;min-width:150px}.next{flex-direction:row;align-items:center}.card{padding:25px}.suggestions{flex-wrap:wrap}.report-grid{gap:15px}#toast{bottom:28px}footer span{display:block}.brand{font-size:20px}}
/* Vertical learning path: state follows existing lesson IDs and saved progress. */
.path-intro{display:flex;gap:14px;align-items:center;background:#eaf2dc;border:1px solid #d7e4bd;border-radius:18px;padding:18px;margin:24px 0}.path-intro b{font-size:16px}.path-intro p{margin:3px 0 0;font-size:12px;color:#546c48}.path-spark{font-size:36px;color:#5a8038}.path-unit{margin:18px 0;border:1px solid var(--line);border-radius:18px;background:#fff;overflow:hidden}.path-unit summary{list-style:none;display:flex;align-items:center;gap:12px;padding:18px;cursor:pointer;background:#f1f5e9}.path-unit summary::-webkit-details-marker{display:none}.unit-index{font-size:25px;font-weight:750;color:#839d5f}.path-unit summary b,.path-unit summary small{display:block}.path-unit summary small{font-size:11px;color:#637955}.path-unit summary b{font-size:18px}.unit-state{margin-left:auto;font-size:12px;white-space:nowrap;color:#637955}.level-path{position:relative;padding:22px 18px 30px;max-width:470px;margin:auto}.level-path:before{content:'';position:absolute;left:55px;top:50px;bottom:70px;width:5px;border-radius:5px;background:repeating-linear-gradient(to bottom,#dce6d0 0 9px,transparent 9px 16px)}.level-stop{position:relative;display:flex;align-items:center;gap:20px;min-height:132px}.level-stop:nth-child(even){padding-left:20px}.level-node{flex:0 0 72px;height:72px;border-radius:50%;border:4px solid white;background:#e9f0dc;box-shadow:0 5px 0 #c7d5b0,0 0 0 2px #e7ecdf;color:#486737;font-size:27px;font-weight:750;padding:0;position:relative}.level-node:hover:not(:disabled){transform:translateY(-2px)}.passed .level-node{background:#57843e;color:white;box-shadow:0 5px 0 #3f632c,0 0 0 2px #caddbc}.recommended .level-node{background:#dced9e;color:#365321;box-shadow:0 5px 0 #aac762,0 0 0 5px #e8f2ce}.level-caption{flex:1;min-width:0}.level-caption small{display:block;font-size:11px;color:#708265}.level-caption b{display:block;font-size:15px;line-height:1.6;margin:2px 0 4px}.level-caption>span{display:block;font-size:11px;color:#6b7f5c}.recommended .level-caption>span{color:#466c2b;font-weight:700}.pending .level-node{opacity:1;background:#edf0ea;color:#a5afa1;box-shadow:0 5px 0 #dce1d7,0 0 0 2px #edf0e9}.pending .level-caption{color:#7a8574}.pending .level-caption>span{color:#8c9587}@media(min-width:760px){.level-path{max-width:480px;padding-top:30px}.level-stop{min-height:145px}.level-caption b{font-size:16px}.path-unit summary{padding:20px 24px}}