:root{
  --bg:#ffffff; --ink:#1a1a1a; --muted:#6b7280; --line:#e5e7eb;
  --brand:#4f46e5; --brand-dark:#4338ca; --dark:#0f172a; --dark2:#1e293b;
  --soft:#eef2ff; --radius:14px; --code-bg:#0f172a;
}
*{box-sizing:border-box;margin:0;padding:0}
body{font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;color:var(--ink);background:var(--bg);line-height:1.75;-webkit-font-smoothing:antialiased}
.wrap{max-width:1080px;margin:0 auto;padding:0 20px}
a{color:var(--brand);text-decoration:none}
a:hover{text-decoration:underline}
code{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;background:var(--soft);color:var(--brand-dark);padding:2px 7px;border-radius:6px;font-size:.92em}

/* nav */
.nav{position:sticky;top:0;background:var(--dark);z-index:50}
.nav-inner{display:flex;align-items:center;justify-content:space-between;height:60px}
.logo{font-weight:800;font-size:20px;color:#fff}
.logo span{color:#818cf8}
.menu{display:flex;gap:20px}
.menu a{color:#94a3b8;font-size:15px}
.menu a.active,.menu a:hover{color:#fff;text-decoration:none}

/* hero */
.hero{background:linear-gradient(135deg,#0f172a 0%,#1e1b4b 70%,#312e81 100%);padding:64px 0 56px;text-align:center;color:#fff}
.hero-kicker{display:inline-block;font-size:13px;color:#c7d2fe;background:rgba(99,102,241,.18);border:1px solid rgba(99,102,241,.4);border-radius:999px;padding:4px 14px;margin-bottom:16px;font-weight:600}
.hero h1{font-size:38px;line-height:1.3;margin-bottom:12px}
.hero h1 .hl{color:#818cf8}
.hero-sub{color:#94a3b8;font-size:16.5px;max-width:620px;margin:0 auto}
.terminal{display:inline-block;margin-top:22px;background:#020617;border:1px solid #334155;border-radius:10px;padding:12px 22px;font-family:ui-monospace,Menlo,Consolas,monospace;font-size:14px;color:#a5b4fc;text-align:left}
.terminal .p{color:#34d399}

/* tool grid */
.section{padding:52px 0 8px}
.section-title{font-size:25px;margin-bottom:6px}
.section-desc{color:var(--muted);margin-bottom:26px}
.grid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}
.tool-card{border:1px solid var(--line);border-radius:var(--radius);padding:24px 20px;color:var(--ink);transition:.2s;display:block;background:#fff}
.tool-card:hover{box-shadow:0 12px 30px rgba(79,70,229,.14);text-decoration:none;transform:translateY(-2px);border-color:#c7d2fe}
.tool-card .icon{font-size:30px;display:block;margin-bottom:10px}
.tool-card h3{font-size:16px;margin-bottom:6px}
.tool-card p{font-size:13px;color:var(--muted);line-height:1.6}

/* tool page */
.tool-page{max-width:860px;margin:0 auto;padding:44px 20px 20px}
.tool-page h1{font-size:30px;margin-bottom:8px}
.tool-page .lede{color:var(--muted);margin-bottom:26px}
.panel{border:1px solid var(--line);border-radius:var(--radius);padding:28px;background:#fff;margin-bottom:20px}
.row{display:flex;gap:14px;flex-wrap:wrap;align-items:center;margin:16px 0}
.row label{font-size:14px;color:#374151;min-width:90px}
input[type=text],input[type=number],select,textarea{border:1px solid var(--line);border-radius:8px;padding:10px 12px;font-size:14.5px;font-family:inherit;width:100%}
textarea{min-height:130px;resize:vertical;font-family:ui-monospace,Menlo,Consolas,monospace;font-size:13.5px}
textarea.tall{min-height:200px}
.btn{display:inline-block;padding:11px 26px;border-radius:999px;font-weight:600;font-size:15px;border:1px solid transparent;cursor:pointer;transition:.2s;background:var(--brand);color:#fff}
.btn:hover{background:var(--brand-dark);text-decoration:none}
.btn-ghost{background:#fff;color:var(--ink);border-color:var(--line)}
.btn-ghost:hover{border-color:var(--brand);color:var(--brand-dark)}
.btn:disabled{opacity:.5;cursor:not-allowed}
.output{font-family:ui-monospace,Menlo,Consolas,monospace;background:var(--code-bg);color:#e2e8f0;border-radius:10px;padding:16px;word-break:break-all;font-size:13.5px;margin-top:12px;white-space:pre-wrap;max-height:420px;overflow:auto}
.output:empty{display:none}
.kv{display:flex;justify-content:space-between;gap:12px;padding:9px 0;border-bottom:1px solid #1e293b;font-size:13.5px}
.kv:last-child{border-bottom:none}
.kv .k{color:#94a3b8;flex-shrink:0}
.kv .v{color:#e2e8f0;text-align:right;word-break:break-all}
.hint{font-size:13px;color:var(--muted);margin-top:10px}
.error{color:#dc2626;font-size:14px;margin-top:10px}
.success{color:#15803d;font-size:14px;margin-top:10px}
.checkbox-row{display:flex;gap:16px;flex-wrap:wrap;font-size:14.5px;color:#374151}
.checkbox-row label{display:flex;align-items:center;gap:6px;cursor:pointer;min-width:0}
mark{background:#fde68a;color:#92400e;border-radius:3px;padding:0 2px}

/* howto + faq */
.howto h2,.faq h2{font-size:21px;margin:34px 0 12px}
.howto ol,.howto ul{margin-left:22px;color:#374151}
.howto li{margin-bottom:8px}
.faq details{border:1px solid var(--line);border-radius:12px;padding:14px 18px;margin-bottom:10px;background:#f8fafc}
.faq summary{font-weight:600;cursor:pointer}
.faq p{margin-top:8px;color:#4b5563;font-size:14.5px}

/* cheatsheet tables */
.article{max-width:800px;margin:0 auto;padding:44px 20px 20px}
.article h1{font-size:30px;line-height:1.4;margin-bottom:10px}
.article .meta{color:var(--muted);font-size:14px;margin-bottom:24px}
.article h2{font-size:22px;margin:32px 0 12px}
.article p{margin-bottom:14px;color:#374151}
.article table{width:100%;border-collapse:collapse;margin:16px 0;font-size:14px}
.article th,.article td{border:1px solid var(--line);padding:9px 12px;text-align:left}
.article th{background:var(--soft)}
.article td code{white-space:nowrap}
.back{display:inline-block;margin-bottom:8px;font-size:14px}

/* ads */
.ad-slot{margin:24px auto;text-align:center;min-height:90px;display:flex;align-items:center;justify-content:center;background:#fafafa;border:1px dashed var(--line);border-radius:8px;color:#cbd5e1;font-size:12px;max-width:970px}
.ad-slot.filled{background:none;border:none;min-height:0}

/* footer */
.footer{margin-top:60px;background:var(--dark);padding:34px 0;color:#94a3b8}
.footer p{font-size:13px;margin-bottom:6px}
.footer a{color:#a5b4fc}
.copyright{text-align:center;margin-top:14px}

@media(max-width:900px){.grid{grid-template-columns:1fr 1fr}}
@media(max-width:520px){.grid{grid-template-columns:1fr}.hero h1{font-size:28px}}