:root{--ink: #1e1b16;--muted: #655f57;--paper: #fbf7ef;--panel: #fffdf7;--line: #ded2bf;--clay: #b2573f;--moss: #326b55;--blue: #235f83;--gold: #b78322;--rose: #8f3f5b;--shadow: 0 18px 50px rgba(55, 43, 26, .13)}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;color:var(--ink);background:radial-gradient(circle at top left,rgba(178,87,63,.13),transparent 34rem),radial-gradient(circle at 80% 10%,rgba(35,95,131,.12),transparent 32rem),linear-gradient(135deg,#fbf7ef,#f2ecdf 48%,#edf3ef);font-family:Microsoft YaHei,Noto Sans SC,PingFang SC,sans-serif;line-height:1.68}.grain{position:fixed;inset:0;pointer-events:none;opacity:.08;background-image:linear-gradient(90deg,#000 1px,transparent 1px),linear-gradient(#000 1px,transparent 1px);background-size:23px 23px;mix-blend-mode:multiply}header.hero{min-height:88vh;padding:6vw 6vw 3rem;display:grid;align-items:end;border-bottom:1px solid var(--line);position:relative}.hero-inner{max-width:1180px;width:100%;margin:0 auto;display:grid;grid-template-columns:minmax(0,1.1fr) minmax(280px,.55fr);gap:clamp(1.5rem,4vw,4rem);align-items:end}.eyebrow{display:inline-flex;gap:.55rem;flex-wrap:wrap;color:var(--moss);font-size:.86rem;font-weight:700;letter-spacing:0;text-transform:uppercase}h1{margin:1rem 0 1.1rem;font-family:Georgia,Times New Roman,Microsoft YaHei,serif;font-size:clamp(2.2rem,6.6vw,5.8rem);line-height:.98;letter-spacing:0;max-width:980px}.subtitle{max-width:760px;font-size:clamp(1rem,2vw,1.28rem);color:#3f3a33}.player-panel{background:#fffdf7c7;border:1px solid var(--line);padding:1rem;box-shadow:var(--shadow);backdrop-filter:blur(12px)}audio{width:100%;margin-top:.7rem}.meta-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:.65rem;margin-top:1rem}.metric{border-top:3px solid var(--gold);padding-top:.55rem;min-width:0}.metric b{display:block;font-size:1.05rem}.metric span{color:var(--muted);font-size:.82rem}main{max-width:1180px;margin:0 auto;padding:3rem 6vw 5rem}section{margin:0 0 4rem}.section-head{display:flex;align-items:end;justify-content:space-between;gap:1rem;border-bottom:1px solid var(--line);padding-bottom:.8rem;margin-bottom:1.2rem}h2{margin:0;font-family:Georgia,Times New Roman,Microsoft YaHei,serif;font-size:clamp(1.7rem,3vw,2.65rem);letter-spacing:0}.section-note{color:var(--muted);max-width:520px;font-size:.95rem}.takeaway{display:grid;grid-template-columns:minmax(0,.85fr) minmax(260px,.45fr);gap:1rem;align-items:stretch}.takeaway .lead{background:var(--panel);border-left:8px solid var(--clay);padding:clamp(1.2rem,3vw,2rem);box-shadow:var(--shadow);font-size:1.08rem}.takeaway aside{background:#183c47;color:#f8f0df;padding:1.2rem;display:flex;flex-direction:column;justify-content:space-between}.takeaway aside b{font-size:2.3rem;font-family:Georgia,serif}.chapter-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:.9rem}.chapter-card,.idea-card,.term{background:#fffdf7e0;border:1px solid var(--line);padding:1rem;min-width:0;box-shadow:0 10px 24px #3e301c12}.chapter-card{position:relative;overflow:hidden}.chapter-card:before{content:"";position:absolute;inset:0 0 auto;height:5px;background:linear-gradient(90deg,var(--clay),var(--gold),var(--moss),var(--blue))}.chapter-card h3,.idea-card h3,.term h3{margin:.65rem 0 .45rem;line-height:1.25;font-size:1.05rem}.chapter-card p,.idea-card p,.term p{margin:0;color:#48423b;font-size:.93rem}.chapter-time{min-height:2.1rem}.timestamp{appearance:none;border:1px solid rgba(30,27,22,.18);background:#f8ead0;color:#573218;font:inherit;font-size:.82rem;font-weight:700;padding:.35rem .52rem;cursor:pointer;border-radius:0;transition:transform .16s ease,background .16s ease,border-color .16s ease}.timestamp:hover,.timestamp:focus-visible{transform:translateY(-1px);background:#ffe0a3;border-color:var(--gold);outline:none}.timestamp.tiny{padding:.2rem .42rem;font-size:.78rem}#learning-map{width:min(1540px,calc(100vw - 2rem));margin-left:50%;transform:translate(-50%)}.learning-map{display:grid;grid-template-columns:330px minmax(680px,1fr) 320px;gap:1.25rem;align-items:start;min-height:760px}.map-rail,.map-detail,.toolbox{background:#fffdf7e6;border:1px solid var(--line);box-shadow:0 12px 30px #3e301c14;min-width:0}.map-rail,.toolbox{position:sticky;top:1rem;max-height:calc(100vh - 2rem);overflow:auto}.map-rail-head{padding:1rem;border-bottom:1px solid var(--line);background:#f6f0e5}.map-rail-head h3,.toolbox h3{margin:0;font-size:1.05rem;line-height:1.25}.map-rail-head p,.toolbox p{color:var(--muted);font-size:.86rem;margin:.35rem 0 0}.map-filter-tags{display:flex;flex-wrap:wrap;gap:.35rem;margin-top:.8rem}.map-filter-tags span,.node-tags span,.level-pill{border:1px solid #cbd8e9;background:#f7fbff;color:#244b70;padding:.22rem .45rem;font-size:.75rem;line-height:1.2;white-space:nowrap}.map-node{width:100%;text-align:left;display:grid;grid-template-columns:4.6rem minmax(0,1fr);gap:.55rem;border:0;border-bottom:1px solid var(--line);background:transparent;color:var(--ink);padding:.85rem .75rem;cursor:pointer;font:inherit}.map-node:hover,.map-node.is-active{background:#eef5ff;box-shadow:inset 4px 0 #2367d1}.map-node-time{color:#0d62d7;font-family:Consolas,Courier New,monospace;font-size:.78rem;font-weight:800;padding-top:.12rem}.map-node-title{display:block;font-weight:800;line-height:1.25;margin-bottom:.22rem}.map-node-range{color:var(--muted);font-size:.8rem}.node-tags{display:flex;flex-wrap:wrap;gap:.28rem;margin-top:.46rem}.node-tags span:first-child{background:#142033;color:#fff;border-color:#142033}.map-detail{padding:clamp(1.2rem,2.2vw,2rem)}.detail-kicker{color:var(--blue);font-size:.86rem;font-weight:800}.detail-title-row{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:1rem;align-items:start;margin:.25rem 0 .65rem}.detail-title-row h3{font-family:Georgia,Times New Roman,Microsoft YaHei,serif;font-size:clamp(1.65rem,2.8vw,2.55rem);line-height:1.08;margin:0;letter-spacing:0}.detail-summary{font-size:1.05rem;color:#3e4757;margin:0 0 1rem}.detail-stats{display:flex;flex-wrap:wrap;gap:.5rem;margin-bottom:1.1rem}.detail-stats span{background:#eef2f6;color:#405069;padding:.35rem .58rem;font-size:.82rem}.explain-grid{display:grid;grid-template-columns:1fr 1fr;gap:.8rem;margin-bottom:1rem}.explain-card{border:1px solid var(--line);padding:.9rem;background:#f7fafc}.explain-card.warm{background:#fff8ea;border-color:#e3bd72}.explain-card h4,.detail-block h4{margin:0 0 .45rem;font-size:1rem}.explain-card p,.detail-block p{margin:0;color:#3c4658;font-size:.94rem}.detail-block{border:1px solid var(--line);padding:.95rem;margin-bottom:.85rem;background:#ffffff8c}.level-list{display:grid;gap:.38rem;margin-top:.3rem}.timeline-clues{list-style:none;margin:.4rem 0 0;padding:0;display:grid;gap:.35rem}.timeline-clues li{display:grid;grid-template-columns:auto minmax(0,1fr);gap:.7rem;align-items:start;padding:.42rem 0;border-bottom:1px solid rgba(222,210,191,.7)}.learning-questions{margin:.4rem 0 0;color:#2f3d50}.takeaway-strip{background:#1d3c49;color:#fff7e8;padding:1rem;margin-top:1rem;font-weight:700}.toolbox{padding:1rem}.toolbox-tabs{display:flex;flex-wrap:wrap;gap:.38rem;margin:.9rem 0 1rem}.toolbox-tab{border:1px solid #cfd9e7;background:#fff;color:#1e2c3f;padding:.42rem .62rem;font:inherit;font-size:.84rem;cursor:pointer}.toolbox-tab.is-active{background:#142033;border-color:#142033;color:#fff}.tool-card{border:1px solid var(--line);background:#fffdf7;padding:.85rem;margin-bottom:.65rem}.tool-card h4{margin:0 0 .38rem;font-size:.95rem;line-height:1.25}.tool-card p{margin:0;color:#42506a;font-size:.88rem}.detail-conclusion{background:#142033;color:#fff8ea;border-left:7px solid var(--gold);padding:1rem 1.1rem;margin:1rem 0;font-size:1.02rem;box-shadow:0 14px 30px #14203324}.detail-conclusion b{display:block;color:#ffd88a;margin-bottom:.35rem;font-size:.9rem}.recall-grid{display:grid;grid-template-columns:1fr 1fr;gap:.85rem;margin:1rem 0}.recall-card{border:1px solid var(--line);background:#ffffffa8;padding:.95rem;min-width:0}.recall-card h4{margin:0 0 .55rem;font-size:1rem}.recall-card ol,.recall-card ul{margin:0;padding-left:1.15rem;color:#354256;font-size:.94rem}.recall-card li+li{margin-top:.36rem}.mind-map{border:1px solid #d9c6a2;background:linear-gradient(135deg,#fff8ea,#f7fbff);padding:1rem;margin:1rem 0}.mind-map h4{margin:0 0 .8rem;font-size:1rem}.mind-map-body{display:grid;grid-template-columns:minmax(170px,.7fr) minmax(0,1.3fr);gap:.8rem;align-items:stretch}.mind-core{display:flex;align-items:center;justify-content:center;text-align:center;min-height:128px;background:#1d3c49;color:#fff8ea;padding:1rem;font-weight:900;line-height:1.25}.mind-branches{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:.55rem}.mind-branch{border:1px solid rgba(35,95,131,.28);background:#ffffffbf;color:#26384d;padding:.65rem;font-size:.9rem;font-weight:700}.detail-stats{margin-bottom:.6rem}.idea-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:1rem}.idea-card:nth-child(2n){border-top:6px solid var(--moss)}.idea-card:nth-child(odd){border-top:6px solid var(--blue)}.idea-card:nth-child(3n){border-top-color:var(--rose)}.idea-tag{display:inline-block;color:#fff;background:var(--ink);padding:.2rem .48rem;font-size:.76rem;font-weight:700}.chip-row{display:flex;flex-wrap:wrap;gap:.45rem;margin-top:.8rem}.best-list{list-style:none;padding:0;margin:0;display:grid;gap:.7rem}.best-list li{display:grid;grid-template-columns:auto minmax(0,1fr);gap:.8rem;align-items:start;padding:.85rem;background:#ffffff94;border-bottom:1px solid var(--line)}.term-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:.8rem}.caveats{background:#f2e7d5;border:1px solid var(--line);padding:1rem 1.2rem}.transcript-tools{display:flex;gap:.7rem;flex-wrap:wrap;margin-bottom:.8rem}.filter{flex:1 1 260px;border:1px solid var(--line);padding:.7rem .8rem;background:var(--panel);color:var(--ink);font:inherit}.transcript-block{background:#ffffffa6;border:1px solid var(--line);border-radius:8px;margin-bottom:.6rem;overflow:hidden;box-shadow:0 2px 8px #0f172a03}.transcript-block summary{cursor:pointer;padding:.9rem 1.25rem;display:flex;align-items:center;justify-content:space-between;gap:1.5rem;font-weight:700;color:var(--clay);transition:background .15s ease}.transcript-block summary:hover{background:#f8fafc}.transcript-block p{margin:0;padding:.8rem 1.25rem 1.1rem;color:#4a4238;font-size:.95rem;line-height:1.7;border-top:1px dashed rgba(203,213,225,.6)}.tool-btn{appearance:none;background:#f1f5f9;color:#4a4238;border:1px solid #cbd5e1;padding:.6rem 1rem;font:inherit;font-size:.88rem;font-weight:600;cursor:pointer;border-radius:6px;transition:all .15s ease}.tool-btn:hover{background:#e2e8f0;color:var(--ink)}.tool-btn.primary{background:var(--ink);color:#fff;border-color:var(--ink)}.tool-btn.primary:hover{background:#1e293b}.timestamp.play-btn{appearance:none;border:1px solid rgba(79,70,229,.15);background:#e0e7ff;color:#3730a3;font:inherit;font-size:.84rem;font-weight:700;padding:.4rem .6rem;cursor:pointer;border-radius:6px;transition:all .16s ease}.timestamp.play-btn:hover{background:#c7d2fe;border-color:var(--clay);outline:none}.transcript-block-title{flex:1 1 auto;font-size:.98rem;color:var(--ink)}footer{margin-top:4rem;padding-top:1.2rem;border-top:1px solid var(--line);color:var(--muted);font-size:.86rem;word-break:break-word}@media(max-width:980px){.hero-inner,.takeaway{grid-template-columns:1fr}#learning-map{width:auto;margin-left:0;transform:none}.learning-map{grid-template-columns:1fr}.map-rail,.toolbox{position:static;max-height:none}.chapter-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.idea-grid,.term-grid{grid-template-columns:1fr 1fr}header.hero{min-height:auto}}@media(max-width:640px){main,header.hero{padding-left:1rem;padding-right:1rem}.chapter-grid,.idea-grid,.term-grid,.meta-grid,.explain-grid,.recall-grid,.mind-map-body,.mind-branches{grid-template-columns:1fr}.map-node{grid-template-columns:4rem minmax(0,1fr)}.detail-title-row{grid-template-columns:1fr}.section-head{display:block}.best-list li{grid-template-columns:1fr}h1{font-size:clamp(2rem,13vw,3.7rem)}}