:root{
  --ink:#1a2332; --muted:#5b6b82; --line:#e3e9f2; --bg:#f7f9fc;
  --brand:#2456c8; --brand-dark:#1a41a0; --ok:#0e7a3d; --warn:#b3261e;
  --card:#ffffff; --radius:14px;
}
*{box-sizing:border-box}
html,body{margin:0;padding:0}
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  color:var(--ink); background:var(--bg); line-height:1.6;}
a{color:var(--brand); text-decoration:none}
a:hover{text-decoration:underline}
.wrap{max-width:1060px; margin:0 auto; padding:0 20px}
header.site{background:#fff; border-bottom:1px solid var(--line); position:sticky; top:0; z-index:10}
header.site .wrap{display:flex; align-items:center; gap:14px; height:60px}
.logo{font-weight:800; font-size:20px; color:var(--ink)}
.logo span{color:var(--brand)}
.badge{margin-left:auto; font-size:12.5px; color:var(--ok); background:#e8f6ee; border:1px solid #bfe6cf;
  padding:3px 10px; border-radius:999px; white-space:nowrap}
nav.main{display:flex; gap:16px; font-size:14.5px}
nav.main a{color:var(--muted)}
.hero{padding:48px 0 8px; text-align:center}
.hero h1{font-size:34px; margin:0 0 10px; letter-spacing:.5px}
.hero p{color:var(--muted); font-size:16.5px; margin:0 auto; max-width:640px}
.hero .lock{color:var(--ok); font-weight:600}
.grid{display:grid; grid-template-columns:repeat(auto-fill,minmax(300px,1fr)); gap:18px; padding:30px 0 10px}
.card{background:var(--card); border:1px solid var(--line); border-radius:var(--radius); padding:22px;
  transition:box-shadow .15s ease, transform .15s ease; display:block; color:var(--ink)}
.card:hover{box-shadow:0 8px 24px rgba(26,35,50,.08); transform:translateY(-2px); text-decoration:none}
.card h3{margin:0 0 6px; font-size:18px}
.card p{margin:0; color:var(--muted); font-size:14.5px}
.card .tag{display:inline-block; font-size:12px; color:var(--brand); background:#e9effe;
  border-radius:6px; padding:1px 8px; margin-bottom:10px}
section.why{padding:26px 0 6px}
section.why h2{font-size:22px; margin:0 0 8px}
section.why p{color:var(--muted); max-width:760px}
.ad-slot{margin:28px 0; border:1.5px dashed #c8d4e6; border-radius:var(--radius); color:#93a5c0;
  text-align:center; padding:26px 10px; font-size:13.5px; background:#fff}
footer.site{border-top:1px solid var(--line); margin-top:44px; padding:22px 0 34px; color:var(--muted); font-size:13.5px; background:#fff}
footer.site .wrap{display:flex; gap:18px; flex-wrap:wrap}
/* tool pages */
main.tool{padding:30px 0 10px}
main.tool h1{font-size:27px; margin:0 0 6px}
main.tool .sub{color:var(--muted); margin:0 0 22px}
.panel{background:#fff; border:1px solid var(--line); border-radius:var(--radius); padding:22px}
.drop{border:2px dashed #b9c9e4; border-radius:var(--radius); padding:34px 16px; text-align:center;
  color:var(--muted); cursor:pointer; background:#fbfcfe}
.drop:hover,.drop.over{border-color:var(--brand); color:var(--brand); background:#f2f6ff}
.drop strong{display:block; font-size:16.5px; color:var(--ink); margin-bottom:4px}
.btn{display:inline-block; background:var(--brand); color:#fff; border:none; border-radius:10px;
  padding:10px 22px; font-size:15px; cursor:pointer; font-weight:600}
.btn:hover{background:var(--brand-dark)}
.btn:disabled{background:#a9bcdf; cursor:not-allowed}
.btn.ghost{background:#fff; color:var(--brand); border:1px solid var(--brand)}
.btn.small{padding:5px 12px; font-size:13.5px; border-radius:8px}
.row{display:flex; gap:12px; flex-wrap:wrap; align-items:center}
.field{display:flex; flex-direction:column; gap:5px; font-size:13.5px; color:var(--muted)}
.field input,.field select,.field textarea{font-size:15px; padding:8px 10px; border:1px solid var(--line);
  border-radius:9px; color:var(--ink); background:#fff}
.field textarea{width:100%; min-height:150px; resize:vertical}
.list{margin:16px 0; display:flex; flex-direction:column; gap:8px}
.item{display:flex; align-items:center; gap:10px; background:#fbfcfe; border:1px solid var(--line);
  border-radius:10px; padding:9px 12px; font-size:14.5px}
.item .name{flex:1; overflow:hidden; text-overflow:ellipsis; white-space:nowrap}
.item .size{color:var(--muted); font-size:13px}
.item button{border:1px solid var(--line); background:#fff; border-radius:7px; padding:3px 9px; cursor:pointer; font-size:13px}
.item button:hover{border-color:var(--brand); color:var(--brand)}
.status{margin-top:14px; font-size:14.5px; min-height:22px}
.status.ok{color:var(--ok)}
.status.err{color:var(--warn)}
.kv{display:grid; grid-template-columns:repeat(auto-fill,minmax(150px,1fr)); gap:12px; margin-top:14px}
.kv .box{background:#fbfcfe; border:1px solid var(--line); border-radius:10px; padding:12px; text-align:center}
.kv .box b{display:block; font-size:22px; color:var(--ink)}
.kv .box span{font-size:13px; color:var(--muted)}
.thumb{width:52px; height:52px; object-fit:cover; border-radius:8px; border:1px solid var(--line)}
.note{font-size:13px; color:var(--muted); margin-top:10px}
.progress{height:8px; background:#edf1f8; border-radius:99px; overflow:hidden; margin-top:12px; display:none}
.progress i{display:block; height:100%; width:0; background:var(--brand); transition:width .2s}
article.doc{background:#fff; border:1px solid var(--line); border-radius:var(--radius); padding:28px; margin-top:26px}
article.doc h2{margin-top:0}
@media (max-width:640px){ .hero h1{font-size:27px} nav.main{display:none} }
.lang-switch{font-size:13.5px; color:var(--muted); border:1px solid var(--line); border-radius:8px; padding:3px 10px; white-space:nowrap}
.lang-switch:hover{color:var(--brand); border-color:var(--brand); text-decoration:none}
.badge + .lang-switch{margin-left:0}
@media (max-width:640px){ .badge{display:none} .lang-switch{margin-left:auto} }