:root{--primary:#2f6fed;--primary-dark:#1f54c4;--bg:#f4f6fb;--card:#fff;--text:#1f2330;--muted:#7a8194;--border:#e5e8f0;--ok:#17a36a;--warn:#e07a00;--shadow:0 4px 16px rgba(31,84,196,.08)}
*{box-sizing:border-box}html,body{margin:0;padding:0}body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;background:var(--bg);color:var(--text);font-size:15px;line-height:1.6}
a{color:var(--primary);text-decoration:none}a:hover{text-decoration:underline}.container{max-width:960px;margin:0 auto;padding:16px}
.hero{background:linear-gradient(135deg,var(--primary),var(--primary-dark));color:#fff;border-radius:16px;padding:28px 22px;margin-bottom:18px;box-shadow:var(--shadow)}
.hero h1{font-size:24px;margin:0 0 8px}.hero .sub{margin:0;opacity:.95;font-size:14px}
.cat-card{background:var(--card);border-radius:14px;padding:16px 18px;margin-bottom:14px;box-shadow:var(--shadow);cursor:pointer;transition:transform .15s}
.cat-card:hover{transform:translateY(-2px)}.cat-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:10px}
.cat-head h2{font-size:17px;margin:0}.badge{background:var(--primary);color:#fff;border-radius:20px;padding:2px 10px;font-size:12px}
.tool-list{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(150px,1fr));gap:8px}
.tool-list a{display:block;padding:9px 12px;background:var(--bg);border-radius:9px;font-size:14px;color:var(--text)}
.tool-list a:hover{background:#e8efff;color:var(--primary);text-decoration:none}
.page-head{display:flex;align-items:center;gap:12px;margin-bottom:14px;flex-wrap:wrap}.page-head h2{font-size:19px;margin:0}.back{color:var(--primary);font-size:14px}
.desc{color:var(--muted);font-size:13px;margin:4px 0 14px}
.tool-row{background:var(--card);border-radius:12px;padding:14px 16px;margin-bottom:12px;box-shadow:var(--shadow);display:flex;align-items:center;justify-content:space-between;gap:12px}
.tool-row h3{font-size:15px;margin:0 0 4px}.tool-row .desc{margin:0;font-size:12px}
.calc-form{background:var(--card);border-radius:14px;padding:18px;box-shadow:var(--shadow)}
.field{display:flex;flex-direction:column;gap:6px;margin-bottom:14px}
.field label{font-size:14px;font-weight:600;color:var(--text)}.field input{width:100%;padding:11px 12px;border:1px solid var(--border);border-radius:9px;font-size:15px;background:#fbfcfe;outline:none;transition:border .15s}
.field input:focus{border-color:var(--primary)}
.btn{display:inline-block;background:var(--primary);color:#fff;border:none;border-radius:9px;padding:12px 18px;font-size:15px;font-weight:600;cursor:pointer;text-align:center}
.btn:hover{background:var(--primary-dark)}.btn.small{padding:8px 14px;font-size:13px}
.result{margin-top:16px;background:#eef6ff;border-left:4px solid var(--primary);border-radius:9px;padding:14px 16px}
.result p{margin:6px 0;font-size:14px}.result p:first-child{font-weight:700;color:var(--primary-dark)}
@media(min-width:720px){.hero{padding:40px}.hero h1{font-size:30px}.tool-list{grid-template-columns:repeat(3,1fr)}}