:root{
  --bg:#f8fafc;
  --card:#ffffff;
  --ink:#0f172a;
  --ink-2:#475569;
  --ink-3:#64748b;
  --line:#e2e8f0;
  --line-soft:#eef2f7;
  --navy:#1e3a5f;
  --blue:#2563eb;
  --blue-soft:#eff6ff;
  --blue-line:#dbeafe;
  --serif:'Noto Serif SC','Source Han Serif SC','Songti SC','STSong','SimSun',serif;
  --sans:-apple-system,BlinkMacSystemFont,'PingFang SC','Microsoft YaHei','Noto Sans SC',sans-serif;
}
*{box-sizing:border-box;margin:0;padding:0}
html{-webkit-text-size-adjust:100%}
body{background:var(--bg);color:var(--ink);font-family:var(--sans);font-size:15px;line-height:1.7}
a{color:inherit;text-decoration:none}
a:hover{color:var(--blue)}
img{display:block;max-width:100%}
.wrap{max-width:1200px;margin:0 auto;padding:0 28px}
.icon{width:1em;height:1em;vertical-align:-0.15em;flex:none}

/* ===== Search hero ===== */
.hero{background:#fff;border-bottom:1px solid var(--line);padding:72px 0 64px;position:relative;overflow:hidden}
.hero-dna{position:absolute;right:-28px;top:50%;transform:translateY(-50%);color:#dbeafe;opacity:.55;pointer-events:none;width:230px}
.hero-dna svg{width:100%;height:auto}
.hero .lead{font-family:var(--serif);font-size:34px;font-weight:700;line-height:1.35;letter-spacing:.01em;color:var(--ink);margin-bottom:14px}
.hero .lead em{font-style:normal;color:var(--blue)}
.hero .sub{font-size:15.5px;color:var(--ink-2);max-width:620px;margin-bottom:30px}
.search-box{display:flex;align-items:stretch;max-width:760px;background:#fff;border:1px solid #cbd5e1;border-radius:8px;overflow:hidden;box-shadow:0 1px 3px rgba(15,23,42,.06),0 6px 24px rgba(15,23,42,.06)}
.search-box:focus-within{border-color:var(--blue);box-shadow:0 0 0 4px rgba(37,99,235,.10)}
.search-box .scope{display:flex;align-items:center;gap:6px;padding:0 14px;border-right:1px solid var(--line);color:var(--ink-2);font-size:14px;background:#fbfcfe}
.search-box select{border:0;outline:none;background:transparent;font-family:var(--sans);font-size:14px;color:var(--ink-2);cursor:pointer}
.search-box input{flex:1;border:0;outline:none;padding:15px 18px;font-family:var(--sans);font-size:15.5px;color:var(--ink);min-width:0}
.search-box input::placeholder{color:#94a3b8}
.search-box button{display:flex;align-items:center;gap:8px;border:0;background:var(--navy);color:#fff;font-family:var(--sans);font-size:15px;font-weight:500;padding:0 26px;cursor:pointer;transition:background .15s}
.search-box button:hover{background:var(--blue)}
.search-box button .icon{font-size:18px}
.search-note{margin-top:16px;font-size:13px;color:var(--ink-3)}
.search-note b{color:var(--navy);font-weight:600}
.quick{display:flex;flex-wrap:wrap;gap:10px;margin-top:22px}
.quick a{display:inline-flex;align-items:center;gap:7px;font-size:13.5px;color:var(--ink-2);background:#fff;border:1px solid var(--line);border-radius:20px;padding:7px 15px;transition:all .15s}
.quick a .icon{font-size:16px;color:var(--blue)}
.quick a:hover{border-color:var(--blue);color:var(--blue)}

/* ===== Section 通用 ===== */
.sec{padding:52px 0}
.sec-head{display:flex;align-items:baseline;justify-content:space-between;margin-bottom:26px}
.sec-head h2{font-family:var(--serif);font-size:23px;font-weight:700;letter-spacing:.01em;color:var(--ink)}
.sec-head .more{display:inline-flex;align-items:center;gap:5px;font-size:13.5px;color:var(--blue)}
.sec-head .more .icon{font-size:14px}
.sec-head .more:hover{text-decoration:underline}

/* ===== Tools grid ===== */
.sec-tools{background:var(--bg)}
.tools-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:20px}
.tool-cat{background:var(--card);border:1px solid var(--line);border-radius:8px;padding:22px 20px 18px;transition:border-color .15s,box-shadow .15s}
.tool-cat:hover{border-color:var(--blue-line);box-shadow:0 12px 30px rgba(15,23,42,.10);transform:translateY(-3px)}
.tool-cat .cat-head{display:flex;align-items:center;gap:12px;margin-bottom:4px}
.cat-icon{width:44px;height:44px;border-radius:10px;background:var(--blue-soft);border:1px solid var(--blue-line);display:flex;align-items:center;justify-content:center;flex:none;font-size:22px;color:var(--navy)}
.tool-cat .cat-head h3{font-family:var(--serif);font-size:17px;font-weight:700;color:var(--ink)}
.tool-cat .cnt{font-size:12.5px;color:var(--ink-3);margin:0 0 14px 34px}
.tool-cat ul{list-style:none;display:grid;grid-template-columns:1fr 1fr;gap:1px 14px}
.tool-cat li{font-size:13px;line-height:2.2;border-bottom:1px dashed var(--line-soft)}
.tool-cat li a{color:var(--ink-2)}
.tool-cat li a:hover{color:var(--blue)}

/* ===== Workflow ===== */
.sec-flow{background:#fff}
.flow{display:flex;align-items:stretch;gap:0}
.flow-step{flex:1;background:var(--card);border:1px solid var(--line);border-radius:8px;padding:24px 20px;position:relative}
.flow-step .step-top{display:flex;align-items:center;gap:8px;margin-bottom:10px}
.flow-icon{width:40px;height:40px;border-radius:10px;background:var(--blue-soft);border:1px solid var(--blue-line);display:flex;align-items:center;justify-content:center;flex:none;font-size:20px;color:var(--blue)}
.flow-step .step-top .idx{font-size:12px;font-weight:700;color:var(--blue);letter-spacing:.06em}
.flow-step h3{font-family:var(--serif);font-size:18px;font-weight:700;margin-bottom:8px;color:var(--ink)}
.flow-step .desc{font-size:13px;color:var(--ink-3);line-height:1.65;margin-bottom:14px;min-height:42px}
.flow-step .tools{display:flex;flex-wrap:wrap;gap:6px}
.flow-step .tools a{font-size:12px;color:var(--blue);background:var(--blue-soft);border:1px solid var(--blue-line);border-radius:6px;padding:3px 9px}
.flow-step .tools a:hover{background:var(--blue-line)}
.flow-arrow{display:flex;align-items:center;justify-content:center;color:var(--ink-3);flex:none;width:36px}
.flow-arrow .icon{font-size:18px}

/* ===== Stats (深蓝横幅) ===== */
.stats{background:var(--navy);color:#fff}
.stats-inner{display:grid;grid-template-columns:repeat(3,1fr)}
.stat{padding:38px 20px;text-align:center;position:relative}
.stat + .stat::before{content:"";position:absolute;left:0;top:22%;bottom:22%;width:1px;background:rgba(255,255,255,.18)}
.stat .num{font-family:var(--serif);font-size:42px;font-weight:700;line-height:1.05;color:#fff}
.stat .num small{font-size:18px;font-weight:600;color:#93c5fd;margin-left:3px}
.stat .lbl{font-size:13.5px;color:rgba(255,255,255,.78);margin-top:8px;letter-spacing:.02em}

/* ===== Research (Nature editorial) ===== */
.sec-research{background:#fff}
.research{display:grid;grid-template-columns:5fr 7fr;gap:36px}
.lead-story{border-bottom:1px solid var(--line);padding-bottom:24px}
.lead-story .thumb{display:block;margin-bottom:18px;aspect-ratio:16/9;overflow:hidden;border-radius:8px;background:#eef2f7}
.lead-story .thumb img{width:100%;height:100%;object-fit:cover;transition:transform .4s}
.lead-story .thumb:hover img{transform:scale(1.03)}
.lead-story .kicker{display:inline-block;font-size:12px;color:var(--blue);font-weight:600;letter-spacing:.05em;margin-bottom:8px}
.lead-story h3{font-family:var(--serif);font-size:23px;font-weight:700;line-height:1.45;margin-bottom:12px}
.lead-story h3 a:hover{color:var(--blue)}
.lead-story .sum{font-size:14px;color:var(--ink-2);line-height:1.75;margin-bottom:12px}
.meta{font-size:12.5px;color:var(--ink-3)}
.article-list{list-style:none}
.article-list > li{display:flex;gap:16px;padding:18px 0;border-bottom:1px solid var(--line-soft)}
.article-list > li:first-child{padding-top:0}
.article-list .thumb{flex:0 0 132px;aspect-ratio:16/10;overflow:hidden;border-radius:8px;background:#eef2f7}
.article-list .thumb img{width:100%;height:100%;object-fit:cover}
.article-list .body{flex:1;min-width:0}
.article-list h4{font-family:var(--serif);font-size:16px;font-weight:600;line-height:1.5;margin-bottom:5px}
.article-list h4 a:hover{color:var(--blue)}
.article-list .sum{font-size:13px;color:var(--ink-2);line-height:1.7;margin-bottom:7px;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.article-list .meta{font-size:12px}

/* ===== Tutorials ===== */
.sec-tut{background:var(--bg)}
.tut-grid{display:grid;grid-template-columns:1fr 1fr;gap:0 44px}
.tut-grid .article-list > li{flex-direction:column;gap:7px;padding:20px 0}
.tut-grid .article-list .thumb{display:none}
.tut-grid .article-list h4{font-size:15.5px}
.tut-grid .article-list .sum{font-size:13px;-webkit-line-clamp:2}