/* AI for Excel blog — shares the landing palette; no JavaScript required. */
:root{
  color-scheme:light;
  --green:#3a6b52; --green-strong:#2b5540; --green-soft:#eef4f0;
  --ink:#1b2a22; --muted:#5c6b63; --line:#e2e8e4;
  --bg:#f7f9f7; --card:#ffffff; --amber:#c8891f; --radius:14px;
  --font:'Segoe UI','PingFang SC','Microsoft YaHei',system-ui,sans-serif;
}
*{box-sizing:border-box;margin:0;padding:0;}
body{font-family:var(--font);color:var(--ink);background:var(--bg);line-height:1.65;font-size:16px;}
a{color:inherit;text-decoration:none;}
img{max-width:100%;height:auto;}
.wrap{max-width:1080px;margin:0 auto;padding:0 22px;}

/* header */
.bh{position:sticky;top:0;z-index:20;background:rgba(247,249,247,.9);backdrop-filter:blur(8px);border-bottom:1px solid var(--line);}
.nav{display:flex;align-items:center;gap:18px;height:60px;}
.brand{display:flex;align-items:center;gap:9px;font-weight:800;font-size:17px;}
.brand .mk{width:26px;height:26px;border-radius:7px;background:var(--green);color:#fff;display:grid;place-items:center;font-size:13px;font-weight:800;}
.nav .sp{flex:1;}
.nav .links{display:flex;gap:16px;}
.nav .links a{color:var(--muted);font-size:14px;}
.nav .links a:hover,.nav .links a.on{color:var(--green);}
.langs{position:relative;font-size:13px;color:var(--ink);white-space:nowrap;}
.langs summary{list-style:none;display:inline-flex;align-items:center;justify-content:space-between;gap:10px;min-width:118px;height:38px;padding:0 12px;border:1px solid var(--line);border-radius:10px;background:#fff;cursor:pointer;user-select:none;}
.langs summary::-webkit-details-marker{display:none;}
.langs summary::marker{content:"";}
.langs summary::after{content:"";width:7px;height:7px;border-right:2px solid var(--muted);border-bottom:2px solid var(--muted);transform:rotate(45deg) translateY(-2px);}
.langs[open] summary{border-color:#c8d8ce;box-shadow:0 8px 22px rgba(43,85,64,.10);}
.langs:not([open]) .lang-options{display:none;}
.langs[open] .lang-options{display:flex;}
.lang-options{position:absolute;right:0;top:calc(100% + 6px);z-index:30;flex-direction:column;min-width:150px;padding:6px;background:#fff;border:1px solid var(--line);border-radius:10px;box-shadow:0 16px 34px rgba(43,85,64,.14);}
.lang-options a,.lang-options .cur{display:block;padding:8px 10px;border-radius:7px;color:var(--muted);}
.lang-options a:hover{background:var(--green-soft);color:var(--green-strong);}
.lang-options .cur{background:var(--green-soft);color:var(--green-strong);font-weight:700;}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;padding:9px 18px;border-radius:10px;font-weight:600;font-size:14px;background:var(--green);color:#fff;transition:.15s;}
.btn:hover{background:var(--green-strong);}
.btn.ghost{background:#fff;color:var(--ink);border:1px solid var(--line);}
.btn.ghost:hover{border-color:var(--green);color:var(--green);}

/* blog index hero */
.blog-hero{padding:52px 0 26px;max-width:640px;}
.blog-hero h1{font-size:38px;letter-spacing:-.5px;line-height:1.15;margin-bottom:12px;}
.blog-hero p{color:var(--muted);font-size:16px;}
.chips{display:flex;gap:8px;flex-wrap:wrap;margin-top:18px;}
.chip{display:inline-block;font-size:12.5px;font-weight:600;color:var(--green-strong);background:var(--green-soft);border:1px solid #d7e4dc;padding:5px 12px;border-radius:99px;}
.chip:hover{border-color:var(--green);}

/* card grid */
.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;padding:16px 0 56px;}
.card{display:flex;flex-direction:column;background:var(--card);border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;transition:.15s;}
.card:hover{border-color:var(--green);transform:translateY(-3px);box-shadow:0 12px 28px rgba(43,85,64,.10);}
.card .cover{display:grid;place-items:center;height:110px;background:linear-gradient(135deg,var(--green-soft),#dcebe2);}
.card .cover i{font-style:normal;font-weight:800;font-size:15px;color:var(--green-strong);background:rgba(255,255,255,.75);border:1px solid #d7e4dc;padding:6px 14px;border-radius:99px;}
.card.cat-excel-formulas .cover{background:linear-gradient(135deg,#eef4f0,#dbeadf);}
.card.cat-data-cleaning .cover{background:linear-gradient(135deg,#eef4f0,#e5ecdc);}
.card.cat-csv-processing .cover{background:linear-gradient(135deg,#eff3ee,#dde9e6);}
.card.cat-excel-automation .cover{background:linear-gradient(135deg,#edf3ef,#d9e7df);}
.card.cat-vba-and-macros .cover{background:linear-gradient(135deg,#f0f4ef,#e2e9da);}
.card.cat-ai-for-excel .cover{background:linear-gradient(135deg,#eaf2ed,#d5e6dc);}
.card .body{display:flex;flex-direction:column;gap:8px;padding:16px;}
.card .meta{font-size:12px;color:var(--muted);}
.card strong{font-size:16px;line-height:1.35;color:var(--ink);}
.card .desc{font-size:13.5px;color:var(--muted);}

/* breadcrumbs */
.crumbs{padding:20px 0 0;font-size:13px;color:var(--muted);}
.crumbs a{color:var(--muted);}
.crumbs a:hover{color:var(--green);}

/* article */
.article-wrap{max-width:820px;}
.post-head{padding:26px 0 6px;}
.post-head .chip{margin-bottom:14px;}
.post-head h1{font-size:34px;line-height:1.2;letter-spacing:-.5px;margin:10px 0 14px;}
.post-head .standfirst{font-size:17px;color:var(--muted);margin-bottom:14px;}
.post-head .byline{font-size:13px;color:#8a978f;border-bottom:1px solid var(--line);padding-bottom:18px;}

.toc{margin:22px 0;background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:16px 20px;}
.toc strong{display:block;font-size:13px;text-transform:uppercase;letter-spacing:.4px;color:var(--green-strong);margin-bottom:8px;}
.toc ol{list-style:none;counter-reset:toc;}
.toc li{counter-increment:toc;font-size:14px;margin:5px 0;}
.toc li::before{content:counter(toc) ". ";color:var(--green);font-weight:700;}
.toc a:hover{color:var(--green);}

.prose{font-size:16px;}
.prose h2{font-size:24px;letter-spacing:-.3px;margin:36px 0 12px;scroll-margin-top:76px;}
.prose h3{font-size:18px;margin:26px 0 8px;scroll-margin-top:76px;}
.prose p{margin:12px 0;}
.prose ul,.prose ol{margin:12px 0 12px 24px;}
.prose li{margin:6px 0;}
.prose strong{color:var(--ink);}
.prose a{color:var(--green-strong);text-decoration:underline;text-decoration-color:#bcd3c6;text-underline-offset:3px;}
.prose a:hover{color:var(--green);}
.prose blockquote{border-left:3px solid var(--green);background:var(--green-soft);padding:10px 16px;border-radius:0 10px 10px 0;margin:16px 0;color:#2c4a3c;}
.prose code{font-family:Consolas,ui-monospace,'SF Mono',monospace;font-size:14px;background:#eef1ee;border:1px solid #e0e6e1;border-radius:6px;padding:1px 6px;color:#1f5a3e;}
.prose pre{background:#132a1f;color:#dcefe4;border-radius:12px;padding:16px 18px;overflow-x:auto;margin:16px 0;}
.prose pre code{background:none;border:none;color:inherit;padding:0;font-size:13.5px;line-height:1.6;}
.prose table{width:100%;border-collapse:collapse;margin:16px 0;font-size:14.5px;}
.prose th,.prose td{border:1px solid var(--line);padding:8px 12px;text-align:left;vertical-align:top;}
.prose th{background:var(--green-soft);color:var(--green-strong);}
.prose hr{border:none;border-top:1px solid var(--line);margin:28px 0;}

/* CTA box */
.cta-box{display:flex;align-items:center;gap:20px;justify-content:space-between;background:var(--green-soft);border:1px solid #d7e4dc;border-radius:var(--radius);padding:20px 22px;margin:30px 0;flex-wrap:wrap;}
.cta-box strong{display:block;font-size:16px;color:var(--green-strong);margin-bottom:4px;}
.cta-box p{font-size:13.5px;color:#41544a;max-width:440px;}
.cta-actions{display:flex;gap:10px;flex-wrap:wrap;}

/* related */
.related{padding:10px 0 56px;}
.related h2{font-size:22px;margin-bottom:16px;}

/* footer */
.bf{border-top:1px solid var(--line);background:rgba(255,255,255,.6);color:var(--muted);font-size:13.5px;}
.bf-in{display:grid;grid-template-columns:1.4fr 2fr;gap:28px;padding:38px 0 22px;}
.bf-in p{margin-top:10px;max-width:300px;}
.bf-in .endorse{font-size:12.5px;color:#8a978f;}
.bf .cols{display:grid;grid-template-columns:repeat(3,1fr);gap:20px;}
.bf h4{font-size:13.5px;color:var(--ink);margin-bottom:10px;}
.bf .cols a{display:block;margin-bottom:8px;color:var(--muted);}
.bf .cols a:hover{color:var(--green);}
.bf-bottom{border-top:1px solid var(--line);padding:14px 22px;font-size:12.5px;color:#8a978f;}

@media(max-width:900px){.grid{grid-template-columns:repeat(2,1fr);}}
@media(max-width:820px){.bf-in{grid-template-columns:1fr;}}
@media(max-width:600px){
  .grid{grid-template-columns:1fr;}
  .nav .links{display:none;}
  .langs summary{min-width:108px;height:36px;padding:0 10px;}
  .lang-options{right:0;min-width:138px;}
  .blog-hero h1{font-size:30px;}
  .post-head h1{font-size:26px;}
  .prose h2{font-size:21px;}
  .prose{font-size:15px;}
  .cta-box{flex-direction:column;align-items:flex-start;}
}