:root{--bg-light:#f8f9fa;--text-main:#111827;--text-muted:#6b7280;--border-color:#e5e7eb;--accent-blue:#0284c7}*{box-sizing:border-box}body{margin:0;font-family:Roboto,-apple-system,BlinkMacSystemFont,Segoe UI,Helvetica,Arial,sans-serif;background-color:var(--bg-light);color:var(--text-main);min-height:100vh}#loading-overlay{position:fixed;inset:0;background:#fff;z-index:9999;opacity:1;visibility:visible;transition:opacity .5s ease,visibility .5s ease}#loading-overlay.loaded{opacity:0;visibility:hidden}#app-container,.app-inner{width:100%;min-height:100vh;display:flex}.sidebar{width:260px;flex-shrink:0;background:#fff;border-right:1px solid var(--border-color);padding:24px 20px 0;display:flex;flex-direction:column;position:sticky;top:0;height:100vh}.logo-brand{display:flex;align-items:center;text-decoration:none;color:inherit;margin-bottom:24px}.logo-img{height:36px;width:auto;display:block;-o-object-fit:contain;object-fit:contain}.nav-list{flex-direction:column}.nav-btn,.nav-list{display:flex;width:100%}.nav-btn{align-items:center;gap:12px;padding:12px 16px;margin-bottom:8px;background:transparent;color:var(--text-muted);font-size:14px;font-weight:500;text-decoration:none;border-radius:0;transition:background-color .15s,color .15s}.nav-btn.active,.nav-btn:hover{background:#f3f4f6;color:var(--text-main)}.menu-img-container,.nav-list .nav-btn i{display:none}.main-content{flex:1;padding:40px;overflow-y:auto}.premium-free-page{max-width:720px}.premium-free-page h1{margin:0 0 12px;font-size:28px;font-weight:800;letter-spacing:-.5px}.premium-free-page .page-intro{margin:0 0 32px;font-size:16px;line-height:1.7;color:#374151}.free-method{margin-bottom:36px}.free-method h2{margin:0 0 12px;font-size:20px;font-weight:700;letter-spacing:-.3px}.premium-free-page p,.premium-free-page ul{margin:0 0 14px;font-size:15px;line-height:1.7;color:#374151}.premium-free-page ul{padding-left:20px}.premium-free-page li{margin-bottom:8px}.premium-free-page a{color:var(--accent-blue);font-weight:600;text-decoration:none}.premium-free-page a:hover{text-decoration:underline}.page-footer-note{margin-top:8px;font-size:14px;color:var(--text-muted)}@media (max-width:1024px){.app-inner{flex-direction:column}.sidebar{width:100%;height:auto;position:static;border-right:none;border-bottom:1px solid var(--border-color)}.nav-list{flex-direction:row;overflow-x:auto;gap:8px}.nav-btn{white-space:nowrap;width:auto;margin-bottom:0}.main-content{padding:24px 16px}.nav-list{gap:18px}.nav-list .nav-btn{position:relative}.nav-list .nav-btn:not(:last-child):after{content:"|";position:absolute;right:-12px;top:50%;transform:translateY(-50%);color:#9ca3af;font-weight:400;pointer-events:none;line-height:1}}