*{margin:0;padding:0;box-sizing:border-box}
:root{--primary:#165DFF;--primary-dark:#0E42D2;--bg:#F5F7FA;--card-bg:#fff;--text-main:#1D2129;--text-secondary:#4E5969;--text-tertiary:#86909C;--border:#E5E6EB;--shadow-sm:0 2px 8px rgba(0,0,0,.04);--shadow-md:0 8px 24px rgba(0,0,0,.08);--radius:12px;--transition:all .3s cubic-bezier(.4,0,.2,1)}
body{font-family:'Inter',-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,sans-serif;background:var(--bg);color:var(--text-main);line-height:1.6}
.container{max-width:1200px;margin:0 auto;padding:0 24px}
.navbar{background:#fff;box-shadow:var(--shadow-sm);position:sticky;top:0;z-index:100}
.nav-inner{height:64px;display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap}
.logo{font-size:20px;font-weight:700;color:var(--primary);text-decoration:none}
.nav-links{display:flex;gap:24px;flex-wrap:wrap}
.nav-links a{color:var(--text-secondary);text-decoration:none;font-size:14px;transition:var(--transition)}
.nav-links a:hover,.nav-links a.active{color:var(--primary)}
.page-hero{padding:48px 0 32px;text-align:center}
.page-hero h1{font-size:36px;margin-bottom:12px}
.page-hero p{font-size:16px;color:var(--text-secondary);max-width:680px;margin:0 auto}
.category-tabs{display:flex;flex-wrap:wrap;gap:12px;justify-content:center;margin-bottom:32px}
.tab-item{padding:8px 20px;background:#fff;border:1px solid var(--border);border-radius:20px;font-size:14px;color:var(--text-secondary);cursor:pointer;transition:var(--transition);text-decoration:none}
.tab-item.active,.tab-item:hover{background:var(--primary);color:#fff;border-color:var(--primary)}
.tools-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:24px;padding-bottom:64px}
.tool-card{background:var(--card-bg);border-radius:var(--radius);padding:28px 24px;box-shadow:var(--shadow-sm);text-decoration:none;color:inherit;transition:var(--transition);border:1px solid transparent;display:flex;flex-direction:column;height:100%}
.tool-card:hover{transform:translateY(-6px);box-shadow:var(--shadow-md);border-color:rgba(22,93,255,.2)}
.tool-icon{width:48px;height:48px;border-radius:12px;background:linear-gradient(135deg,#165DFF,#4080FF);display:flex;align-items:center;justify-content:center;color:#fff;font-size:22px;margin-bottom:16px}
.tool-card h3{font-size:18px;margin-bottom:8px;line-height:1.4}
.tool-card p{font-size:14px;color:var(--text-secondary);flex:1;margin-bottom:16px}
.tool-card .card-tag{font-size:12px;color:var(--text-tertiary)}
.tool-detail-wrap{padding:32px 0 64px}
.tool-main-card{background:#fff;border-radius:var(--radius);padding:32px;box-shadow:var(--shadow-sm);margin-bottom:32px}
.tool-main-card h1{font-size:28px;margin-bottom:8px}
.tool-subtitle{color:var(--text-secondary);margin-bottom:24px}
.calculator-form{display:grid;grid-template-columns:repeat(2,1fr);gap:20px;margin-bottom:24px}
.form-group label{display:block;font-size:14px;color:var(--text-secondary);margin-bottom:6px;font-weight:500}
.form-group input,.form-group select{width:100%;padding:12px 14px;border:1px solid var(--border);border-radius:8px;font-size:15px;transition:var(--transition);background:#fff}
.form-group input:focus,.form-group select:focus{outline:none;border-color:var(--primary);box-shadow:0 0 0 3px rgba(22,93,255,.1)}
.calc-btn{grid-column:1/-1;padding:14px;background:var(--primary);color:#fff;border:none;border-radius:8px;font-size:16px;font-weight:600;cursor:pointer;transition:var(--transition)}
.calc-btn:hover{background:var(--primary-dark)}
.result-section{background:#F7F8FA;border-radius:8px;padding:24px;margin-top:24px}
.result-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:20px;text-align:center}
.result-item .value{font-size:24px;font-weight:700;color:var(--primary);margin-bottom:4px;word-break:break-all}
.result-item .label{font-size:13px;color:var(--text-secondary)}
.content-section{background:#fff;border-radius:var(--radius);padding:36px;box-shadow:var(--shadow-sm);margin-bottom:24px}
.content-section h2{font-size:24px;margin-bottom:16px;padding-bottom:12px;border-bottom:1px solid var(--border)}
.content-section h3{font-size:20px;margin:24px 0 12px}
.content-section p{margin-bottom:14px;color:var(--text-secondary);line-height:1.8}
.content-section ul,.content-section ol{margin:12px 0 16px 24px;color:var(--text-secondary);line-height:1.8}
.content-section li{margin-bottom:8px}
.content-section a{color:var(--primary);text-decoration:none}
.content-section a:hover{text-decoration:underline}
.footer{background:#1D2129;color:#C9CDD4;padding:48px 0 24px;margin-top:48px}
.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:32px;margin-bottom:32px}
.footer-col h4{color:#fff;margin-bottom:16px;font-size:16px}
.footer-col a{display:block;color:#C9CDD4;text-decoration:none;margin-bottom:10px;font-size:14px;transition:var(--transition)}
.footer-col a:hover{color:#fff}
.footer-col p{font-size:14px;line-height:1.7}
.footer-bottom{border-top:1px solid #2E343B;padding-top:24px;text-align:center;font-size:13px;color:#86909C}
.breadcrumb{font-size:14px;color:var(--text-tertiary);margin-bottom:20px}
.breadcrumb a{color:var(--text-secondary);text-decoration:none}
.breadcrumb a:hover{color:var(--primary)}
@media(max-width:768px){
.calculator-form{grid-template-columns:1fr}
.result-grid{grid-template-columns:1fr 1fr;gap:16px}
.footer-grid{grid-template-columns:1fr 1fr}
.page-hero h1{font-size:28px}
.content-section,.tool-main-card{padding:24px}
.nav-inner{height:auto;padding:12px 0;gap:12px}
}
@media(max-width:480px){.result-grid,.footer-grid{grid-template-columns:1fr}}