@charset "UTF-8";
:root{--paper:#f7f8f2;--card:#fff;--ink:#1e332d;--muted:#69786e;--green:#245e4f;--line:#e0e6dc;--lime:#d9ed9c;--pale:#edf4eb;--orange:#a46626;--red:#a34335;--shadow:0 8px 32px #253e2e08;--radius:20px}
*{box-sizing:border-box}body{margin:0;color:var(--ink);background:var(--paper);font:15px/1.7 -apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",sans-serif}button,input,textarea,select{font:inherit}button,a,input,select,textarea{-webkit-tap-highlight-color:transparent}button,.button{cursor:pointer}a{color:var(--green);text-decoration:none}button{color:inherit}button:disabled{cursor:not-allowed;opacity:.48}button:focus-visible,a:focus-visible,summary:focus-visible,input:focus-visible,textarea:focus-visible,select:focus-visible{outline:3px solid #8ca845;outline-offset:3px}button{border:0;background:none}h1,h2,h3,p{margin-top:0}h1{font-size:clamp(25px,3.1vw,39px);line-height:1.38;letter-spacing:-.8px;font-weight:750;margin-bottom:14px}h2{font-size:22px;line-height:1.45;margin-bottom:12px}h3{font-size:17px;margin-bottom:8px;line-height:1.5}p{margin-bottom:15px}.muted{color:var(--muted)}.small{font-size:13px}.eyebrow{font-size:12px;font-weight:700;letter-spacing:1.6px;color:var(--green);margin-bottom:12px}.tag{display:inline-flex;padding:4px 10px;border-radius:7px;font-size:11px;font-weight:600;white-space:nowrap;background:var(--pale);color:var(--green)}.tag.fill{background:#f4eddf;color:#876431}.tag.preview{background:#eaf0fa;color:#536791}
#sidebar{position:fixed;left:0;top:0;bottom:0;width:252px;background:#fcfcf8;border-right:1px solid var(--line);padding:30px 20px 18px;display:flex;flex-direction:column;z-index:30;overflow-y:auto}.brand{display:flex;gap:12px;align-items:center;margin:0 4px 26px}.brand-mark{height:40px;width:40px;border-radius:12px;background:var(--green);color:var(--lime);display:grid;place-items:center;font-size:23px;font-weight:700}.brand strong{display:block;font-size:17px;letter-spacing:-.5px}.brand small{font-size:10px;letter-spacing:2px;color:var(--muted)}.nav-item{display:flex;gap:11px;align-items:center;width:100%;padding:11px 13px;border-radius:11px;margin:3px 0;font-size:14px;color:#627268;text-align:left}.nav-item.active{background:var(--green);color:white;font-weight:600}.nav-icon{width:20px;text-align:center;font-size:18px}.nav-count{font-size:11px;margin-left:auto}.side-caption{color:#8a948a;font-size:11px;letter-spacing:1.4px;margin:28px 13px 10px}.side-chapter{margin:5px 0}.side-chapter summary{font-size:12px;cursor:pointer;padding:7px 10px;list-style:none;border-radius:8px}.side-chapter[open] summary{background:#eef2e8}.side-chapter summary::before{content:'›';display:inline-block;margin-right:8px}.side-chapter[open] summary::before{transform:rotate(90deg)}.side-lesson{font-size:12px;display:flex;gap:9px;padding:7px 8px 7px 25px;color:var(--muted);line-height:1.5}.side-lesson.current{color:var(--green);font-weight:700}.side-tip{margin-top:auto;padding:28px 12px 0;color:#7f8a7f;font-size:11px}.side-tip b{color:var(--green)}.shell{margin-left:252px}.topbar{height:82px;display:flex;align-items:center;justify-content:space-between;gap:12px;padding:0 48px;border-bottom:1px solid var(--line);background:#fafbf6}.top-label{font-size:12px;color:var(--muted)}.top-actions{display:flex;gap:20px;align-items:center}.course-pill{font-size:11px;color:var(--muted);white-space:nowrap}.course-pill b{margin-left:7px;background:#e8eee0;padding:6px 10px;border-radius:6px;color:var(--green)}.small-btn{padding:7px 13px;border:1px solid var(--line);border-radius:8px;font-size:12px;background:#fff}.mobile-menu{display:none}.icon-btn{font-size:22px;line-height:1;padding:10px;border-radius:10px}.icon-btn:hover{background:var(--pale)}#main{max-width:1250px;margin:0 auto;padding:40px 48px 56px;min-height:calc(100vh - 160px);outline:none}.footer{padding:20px 40px;text-align:center;border-top:1px solid var(--line);font-size:11px;color:#849084}.text-btn{color:var(--green);padding:4px;text-decoration:underline;text-underline-offset:3px}
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.demo{background:#f6f8f0;border:1px solid #dce6cf;border-radius:15px;padding:23px;margin-top:22px}.demo h3{font-size:17px}.demo label{font-size:12px;margin:15px 0 9px}.demo input[type=range]{display:block;width:100%;accent-color:var(--green);margin:14px 0;height:22px}.demo-intro{font-size:12px;color:var(--muted)}.demo-result{background:white;border:1px solid var(--line);padding:16px;border-radius:12px;font-size:13px;margin:18px 0 8px}.demo-result p:last-child{margin-bottom:0}.demo-result strong{color:var(--green)}.meter-row{display:grid;grid-template-columns:80px 1fr 50px;gap:12px;align-items:center;font-size:11px;margin:13px 0}.meter-track{height:14px;background:#e5eadf;border-radius:4px;overflow:hidden}.meter-track span{height:100%;display:block;background:#92b398;transition:width .2s}.meter-track.sample span{background:#b8ca73}.demo .chips{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:12px}.pair-table{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin:15px 0}.pair-col{background:#fff;border:1px solid var(--line);border-radius:10px;padding:13px;font-size:12px}.pair-col span{display:block;border-top:1px solid var(--line);margin-top:8px;padding-top:7px}.number-pair{display:grid;grid-template-columns:repeat(2,1fr);gap:10px;margin:15px 0}.number-pair>div{padding:16px;background:white;border-radius:10px;border:1px solid var(--line);font-size:12px}.number-pair strong{display:block;font-size:22px;color:var(--green)}.demo-svg{width:100%;height:auto;display:block;max-height:210px;margin:10px auto}.demo svg text{font:13px -apple-system,"PingFang SC",sans-serif;fill:var(--ink)}.demo-caption{font-size:11px;color:var(--muted);margin:8px 0 0}.chips{display:flex;gap:8px;flex-wrap:wrap}.filter-row{display:flex;gap:15px;align-items:center;justify-content:space-between;margin:22px 0}.method-grid{display:grid;grid-template-columns:1fr 1fr;gap:15px}.method-card{padding:24px;background:#fff;border:1px solid var(--line);border-radius:15px}.method-card .tag{margin-bottom:12px}.method-card p{font-size:12px;color:var(--muted)}.method-name{font-size:18px!important;font-weight:600;color:var(--green)!important}.method-card .limit{font-size:11px;padding:10px 12px;background:#f8f3e8;border-radius:7px;color:#84694b}.method-card>a{font-size:12px;font-weight:600}.empty{padding:55px 30px;text-align:center;border:1px dashed #c8d5bf;border-radius:18px;background:#fcfdf8;margin-top:28px}.empty-icon{font-size:35px;color:#8ba477;margin-bottom:15px}.empty p{font-size:13px;color:var(--muted);max-width:450px;margin:0 auto 20px}.list-card{padding:23px;border:1px solid var(--line);border-radius:15px;background:white;margin:15px 0}.list-card h3{margin:10px 0}.list-card p{font-size:13px;color:var(--muted)}.list-card a{font-size:12px;font-weight:600}.note-preview{white-space:pre-wrap;overflow-wrap:anywhere;font-size:14px;border-left:3px solid #cbd9ad;padding-left:15px;margin:14px 0;max-height:160px;overflow:auto}.review-question{padding:10px 13px;background:#faf2e9;border-radius:9px;margin:8px 0;font-size:12px;color:#8d5a36}.lab-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px}.lab-grid>.study-card{padding:24px}.lab-grid .demo{margin:0;border:0;padding:0;background:none}.lab-grid>.study-card:first-child{grid-column:span 2}.storage-warning{padding:13px 30px;background:#faecd5;color:#8a5426;font-size:12px}.toast{position:fixed;bottom:25px;left:calc(50% + 120px);transform:translateX(-50%);padding:12px 22px;background:#233e30;color:white;border-radius:11px;box-shadow:0 8px 25px #0002;font-size:13px;z-index:100;opacity:0;pointer-events:none;transition:opacity .15s;max-width:80vw}.toast.show{opacity:1}dialog{border:1px solid var(--line);border-radius:21px;width:min(600px,calc(100% - 32px));padding:28px 30px;color:var(--ink);box-shadow:0 20px 100px #17322233;max-height:88vh;overflow-y:auto;background:#fff}dialog::backdrop{background:#152d2366;backdrop-filter:blur(3px)}.dialog-top{display:flex;justify-content:space-between;gap:12px;align-items:center;margin-bottom:15px}.dialog-top h2{font-size:23px;margin:0}dialog p{font-size:13px}dialog hr{border:0;border-top:1px solid var(--line);margin:24px 0}.backup-actions{display:flex;gap:12px;flex-wrap:wrap;align-items:center}.backup-actions label{margin:0}.danger-btn{color:var(--red);font-size:12px;padding:8px 0;text-decoration:underline}.skip{position:fixed;top:-80px;left:10px;padding:10px;background:white;z-index:100}.skip:focus{top:10px}.no-results{padding:25px;color:var(--muted)}
@media(min-width:1450px){#main{padding-top:45px}.hero{padding:40px 44px}.map-grid{gap:18px}}
@media(max-width:1100px){#sidebar{width:224px;padding:25px 14px}.shell{margin-left:224px}.topbar{padding:0 28px}#main{padding:32px 28px 45px}.hero{grid-template-columns:1fr 160px;padding:28px}.hero h1{font-size:29px}.orbit{width:145px;height:145px}.map-grid{grid-template-columns:repeat(2,1fr)}.stat{padding:16px;gap:12px}.stats{gap:10px}.stat strong{font-size:23px}.lesson-head h1{font-size:25px}.study-card{padding:25px}.toast{left:calc(50% + 100px)}}
@media(max-width:760px){#sidebar{transform:translateX(-100%);width:270px;box-shadow:10px 0 50px #17322222;transition:transform .2s}#sidebar.open{transform:translateX(0)}.shell{margin-left:0}.topbar{height:65px;padding:0 16px;gap:8px}.mobile-menu{display:block}.top-label{display:none}.top-actions{gap:12px;margin-left:auto}.small-btn{padding:7px 10px;font-size:11px}.course-pill{font-size:10px}#main{padding:24px 18px 35px}.hero{grid-template-columns:1fr;padding:26px 24px;border-radius:18px;gap:0}.hero h1{font-size:28px;max-width:310px}.hero p{font-size:12px}.hero-art{display:none}.hero .primary{padding:10px 18px}.hero-bottom{font-size:10px!important}.stats{gap:8px;margin:15px 0 29px}.stat{display:block;padding:13px 11px;border-radius:12px}.stat strong{font-size:24px}.stat span{font-size:11px}.stat small{font-size:9px}.section-head p{max-width:145px;text-align:right;font-size:10px}.section-head h2{font-size:19px}.path-title{margin-top:23px;gap:8px}.path-title span{font-size:9px}.path-title b{font-size:13px}.map-grid{grid-template-columns:1fr;gap:11px}.chapter-card{padding:20px}.card-top{margin-bottom:12px}.chapter-card h3{font-size:17px}.chapter-card p{font-size:12px;margin-bottom:12px}.home-shortcuts{grid-template-columns:1fr;gap:10px}.footer{padding:18px;font-size:10px}.lesson-meta{gap:8px;flex-wrap:wrap;font-size:10px}.lesson-head h1{font-size:25px;letter-spacing:-.4px}.lesson-tools{gap:2px}.lesson-tools .icon-btn{font-size:18px;padding:9px}.stepper{gap:3px;margin:17px 0 22px}.step-tab{padding:11px 0;font-size:10px;gap:5px;justify-content:center}.step-tab span{width:19px;height:19px;font-size:9px}.study-card{padding:22px 19px;border-radius:15px}.study-card h2{font-size:21px}.case-text{font-size:19px}.choice{padding:13px;font-size:13px;gap:10px}.idea-list li{font-size:14px}.step-navigation .primary,.step-navigation .secondary{padding:10px 15px;font-size:12px}.step-navigation small{display:none}.demo{padding:17px}.demo h3{font-size:16px}.demo .chips button{font-size:11px;padding:7px 10px}.meter-row{grid-template-columns:63px 1fr 43px;gap:8px}.method-grid,.lab-grid{grid-template-columns:1fr}.lab-grid>.study-card:first-child{grid-column:auto}.filter-row{align-items:flex-start;flex-direction:column;gap:12px}.chips{gap:6px}.chips button{font-size:11px;padding:7px 11px}.lesson-meta select{font-size:11px}.source-box{overflow-wrap:anywhere}.number-pair>div{padding:12px}.number-pair strong{font-size:19px}dialog{padding:22px}.dialog-top h2{font-size:21px}.toast{left:50%;width:max-content;max-width:90vw;font-size:12px}.status-options{gap:6px}.status-options button{font-size:11px;padding:8px 10px}.storage-warning{padding:12px 18px}.mini-flow{gap:7px}.mini-flow b{padding:8px 10px;font-size:11px}}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{transition:none!important;scroll-behavior:auto!important}}