:root{--bg:#0f172a;--surface:#1e293b;--surface2:#334155;--primary:#6366f1;--primary-hover:#818cf8;--accent:#06b6d4;--text:#f1f5f9;--text-muted:#94a3b8;--border:#334155;--success:#22c55e;--warning:#f59e0b;--danger:#ef4444;--radius:12px;--shadow:0 4px 24px rgba(0,0,0,.3);--max-w:960px}*{margin:0;padding:0;box-sizing:border-box}html{scroll-behavior:smooth}body{font-family:'Segoe UI',system-ui,-apple-system,sans-serif;background:var(--bg);color:var(--text);line-height:1.6;min-height:100vh}a{color:var(--primary-hover);text-decoration:none}a:hover{text-decoration:underline}.container{max-width:var(--max-w);margin:0 auto;padding:0 20px}header{background:var(--surface);border-bottom:1px solid var(--border);position:sticky;top:0;z-index:100;backdrop-filter:blur(10px)}.header-inner{display:flex;align-items:center;justify-content:space-between;height:60px}.logo{font-size:1.4rem;font-weight:800;color:var(--text);display:flex;align-items:center;gap:8px}.logo span{color:var(--primary)}.header-right{display:flex;align-items:center;gap:16px}.lang-dropdown{position:relative}.lang-btn{background:var(--surface2);border:1px solid var(--border);color:var(--text);padding:6px 14px;border-radius:8px;cursor:pointer;font-size:.9rem}.lang-btn:hover{border-color:var(--primary)}.lang-menu{position:absolute;right:0;top:100%;margin-top:4px;background:var(--surface);border:1px solid var(--border);border-radius:8px;min-width:140px;box-shadow:var(--shadow);display:none;z-index:200}.lang-menu.show{display:block}.lang-menu a{display:block;padding:10px 16px;color:var(--text);cursor:pointer;font-size:.9rem}.lang-menu a:hover{background:var(--surface2)}.lang-menu a.active,.lang-menu .lang-current{color:var(--primary);font-weight:600;background:var(--surface2)}main{padding:40px 0}.page-title{font-size:2rem;font-weight:800;margin-bottom:8px}.page-desc{color:var(--text-muted);font-size:1.05rem;margin-bottom:32px}.tool-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:16px}.tool-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:24px;transition:transform .2s,border-color .2s}.tool-card:hover{transform:translateY(-3px);border-color:var(--primary);text-decoration:none}.tool-icon{font-size:2rem;margin-bottom:12px}.tool-card h3{font-size:1.1rem;font-weight:700;margin-bottom:6px;color:var(--text)}.tool-card p{font-size:.85rem;color:var(--text-muted)}.tool-box{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:32px;margin-bottom:32px}.form-group{margin-bottom:20px}.form-group label{display:block;margin-bottom:6px;font-weight:600;font-size:.95rem}.form-group input,.form-group select,.form-group textarea{width:100%;background:var(--bg);border:1px solid var(--border);color:var(--text);padding:12px 16px;border-radius:8px;font-size:1rem}.form-group input:focus,.form-group select:focus{outline:none;border-color:var(--primary)}.btn{display:inline-block;background:var(--primary);color:#fff;border:none;padding:12px 32px;border-radius:8px;font-size:1rem;font-weight:600;cursor:pointer;transition:background .2s}.btn:hover{background:var(--primary-hover)}.btn-secondary{background:var(--surface2)}.result{background:var(--bg);border:1px solid var(--border);border-radius:8px;padding:20px;margin-top:20px;min-height:60px}.result-value{font-size:2.5rem;font-weight:800;color:var(--accent)}.result-label{color:var(--text-muted);font-size:.9rem}.info-section{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:28px;margin-bottom:24px}.info-section h2{font-size:1.3rem;margin-bottom:12px}.info-section p,.info-section li{color:var(--text-muted);margin-bottom:8px}.info-section ul{margin-left:20px}.faq-item{border-bottom:1px solid var(--border);padding:16px 0}.faq-item:last-child{border:none}.faq-item h3{font-size:1rem;margin-bottom:6px;color:var(--text)}.faq-item p{color:var(--text-muted);font-size:.9rem}.back-link{display:inline-flex;align-items:center;gap:6px;color:var(--text-muted);margin-bottom:24px;font-size:.9rem}.back-link:hover{color:var(--primary-hover)}.ad-slot{background:var(--surface2);border:1px dashed var(--border);border-radius:8px;min-height:90px;display:flex;align-items:center;justify-content:center;color:var(--text-muted);font-size:.85rem;margin:24px 0}footer{background:var(--surface);border-top:1px solid var(--border);padding:32px 0;margin-top:60px}.footer-inner{display:flex;flex-wrap:wrap;justify-content:space-between;gap:20px}.footer-section h4{font-size:.95rem;margin-bottom:8px}.footer-section a{display:block;color:var(--text-muted);font-size:.85rem;margin-bottom:4px}.footer-bottom{text-align:center;color:var(--text-muted);font-size:.8rem;margin-top:24px;padding-top:16px;border-top:1px solid var(--border)}@media(max-width:640px){.page-title{font-size:1.5rem}.tool-grid{grid-template-columns:1fr}.tool-box{padding:20px}.result-value{font-size:1.8rem}}.tool-content{margin-top:48px;padding-top:32px;border-top:1px solid var(--border)}.tool-content .content-block{margin-bottom:36px}.tool-content h2{font-size:1.35rem;margin-bottom:14px;color:var(--text)}.tool-content h3{font-size:1.1rem;margin-bottom:8px;color:var(--text)}.tool-content h4{font-size:1rem;margin-bottom:6px;color:var(--text)}.tool-content p{color:var(--text-muted);line-height:1.75;margin-bottom:12px;font-size:.95rem}.tool-content ul,.tool-content ol{color:var(--text-muted);line-height:1.75;margin-bottom:12px;padding-left:24px;font-size:.95rem}.tool-content li{margin-bottom:6px}.ref-table{width:100%;border-collapse:collapse;margin:16px 0;font-size:.9rem}.ref-table th{background:var(--surface);color:var(--text);font-weight:600;text-align:left;padding:10px 14px;border-bottom:2px solid var(--border)}.ref-table td{padding:10px 14px;border-bottom:1px solid var(--border);color:var(--text-muted)}.ref-table tr:hover td{background:var(--surface)}.ad-slot.in-content{min-height:120px;margin:32px 0;clear:both}.tool-content .faq-item h4{cursor:default;font-size:.95rem}.tool-content code{background:var(--surface2);padding:2px 6px;border-radius:4px;font-size:.9rem;color:var(--text)}.tool-content .formula-box{background:var(--surface2);border-left:3px solid var(--primary);padding:16px 20px;margin:16px 0;border-radius:4px;font-size:.95rem}@media(max-width:640px){.tool-content h2{font-size:1.15rem}.tool-content p{font-size:.9rem}.ref-table{font-size:.85rem}}