/* ============================================================
   site-chrome.css —— 顶栏 / 页脚 / 移动端 Tab 栏 / 回顶按钮 的
   唯一样式来源。首页（index.html）与全部工具页（css/common.css
   通过 @import 引入）共用此文件，改一处即全站生效。
   ============================================================ */

/* ===== 桌面顶栏 ===== */
.nav-top{position:fixed;top:0;left:0;right:0;z-index:1000;display:flex;align-items:center;justify-content:space-between;height:68px;padding:0 28px;background:rgba(255,255,255,0.75);backdrop-filter:blur(24px) saturate(180%);-webkit-backdrop-filter:blur(24px) saturate(180%);border-bottom:1px solid rgba(15,23,42,0.06)}
.nav-logo{display:flex;align-items:center;gap:10px;flex-shrink:0;cursor:pointer;transition:transform .2s}
.nav-logo:hover{transform:scale(1.02)}
.nav-logo img{height:36px;width:auto}
.nav-logo-text{display:flex;flex-direction:column;line-height:1.15}
.nav-logo-name{font-size:17px;font-weight:800;background:linear-gradient(135deg,var(--primary),var(--secondary));-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text;letter-spacing:-0.02em}
.nav-logo-sub{font-size:11px;color:var(--text-muted);font-weight:500}
.nav-search{flex:1;max-width:520px;margin:0 28px;position:relative}
.nav-search input{width:100%;height:42px;padding-left:44px;padding-right:16px;border-radius:12px;background:var(--bg-hover);border:1.5px solid transparent;font-size:14px;transition:all .25s;outline:none;color:var(--text)}
.nav-search input:focus{background:var(--card-bg);border-color:var(--primary);box-shadow:0 0 0 4px rgba(255,107,53,0.1)}
.nav-search-icon{position:absolute;left:14px;top:50%;transform:translateY(-50%);width:18px;height:18px;color:var(--text-muted);pointer-events:none}
.nav-actions{display:flex;align-items:center;gap:6px;flex-shrink:0}
.nav-actions .nav-icon-btn{height:38px;border-radius:10px;display:inline-flex;align-items:center;justify-content:center;gap:6px;padding:0 12px;white-space:nowrap;transition:all .2s;color:var(--text-muted);background:none;border:none;cursor:pointer}
.nav-actions .nav-icon-btn:hover{background:var(--bg-hover);color:var(--primary)}
.nav-actions .nav-icon-btn svg{width:19px;height:19px}
.nav-btn-label{font-size:13px;font-weight:600;line-height:1}
.nav-lang-slot{display:inline-flex;align-items:center;margin-left:4px}
.nav-lang-slot .lang-switcher select{min-width:84px}

/* ===== 移动顶栏 ===== */
.nav-mobile{display:none;position:fixed;top:0;left:0;right:0;z-index:1000;align-items:center;justify-content:space-between;height:54px;padding:0 14px;background:rgba(255,255,255,0.8);backdrop-filter:blur(20px) saturate(180%);-webkit-backdrop-filter:blur(20px) saturate(180%);border-bottom:1px solid rgba(15,23,42,0.06)}
.nav-mobile-logo{display:flex;align-items:center;gap:8px;cursor:pointer}
.nav-mobile-logo img{height:30px;width:auto}
.nav-mobile-logo span{font-size:15px;font-weight:800;background:linear-gradient(135deg,var(--primary),var(--secondary));-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}
.nav-mobile-actions{display:flex;align-items:center;gap:2px}
.nav-mobile-actions .nav-icon-btn{height:34px;min-width:34px;border-radius:9px;display:flex;align-items:center;justify-content:center;gap:5px;padding:0 8px;background:none;border:none;cursor:pointer;color:var(--text-muted)}
.nav-mobile-actions .nav-icon-btn svg{width:18px;height:18px;flex-shrink:0}
.nav-mobile-actions .nav-btn-label{display:none;font-size:12px;font-weight:600;line-height:1;white-space:nowrap}
@media(min-width:480px){.nav-mobile-actions .nav-btn-label{display:inline}}

/* 语言切换器复用 .nav-icon-btn 类，需解除其固定宽高，否则下拉文字被截断 */
.nav-actions .nav-icon-btn.lang-switcher,
.nav-mobile-actions .nav-icon-btn.lang-switcher{width:auto;height:auto;min-width:72px;padding:0 10px;flex-shrink:0;}
.nav-actions .nav-icon-btn.lang-switcher select,
.nav-mobile-actions .nav-icon-btn.lang-switcher select{min-width:72px;max-width:140px;}

/* 固定顶栏占位：统一由 body 顶部内边距撑开，避免遮挡内容 */
body{padding-top:54px}
@media(min-width:768px){body{padding-top:68px}}
html.embedded body{padding-top:0 !important;}

/* ===== 页脚（深色三栏）===== */
.footer{margin-top:56px;background:linear-gradient(180deg,#1A1A2E 0%,#141425 100%);color:#fff;position:relative;overflow:hidden}
.footer::before{content:'';position:absolute;top:0;left:0;right:0;height:1px;background:linear-gradient(90deg,transparent,rgba(255,107,53,0.4),rgba(124,58,237,0.4),transparent)}
@media(min-width:768px){.footer{margin-top:72px}}
.footer-inner{max-width:1152px;margin:0 auto;padding:48px 16px 28px;position:relative}
@media(min-width:768px){.footer-inner{padding:64px 32px 36px}}
.footer-grid{display:grid;grid-template-columns:1fr;gap:32px}
@media(min-width:768px){.footer-grid{grid-template-columns:1.5fr 1fr 1fr 1fr;gap:40px}}
.footer-brand{display:flex;align-items:center;gap:10px;margin-bottom:14px}
.footer-brand img{height:30px;width:auto;filter:brightness(1.5) drop-shadow(0 1px 1px rgba(0,0,0,.25))}
.footer-brand span{font-size:18px;font-weight:800;background:linear-gradient(135deg,#fff,#c4b5fd);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}
.footer-desc{font-size:13px;color:#94a3b8;line-height:1.7;max-width:280px}
.footer h2{font-size:13px;font-weight:700;margin-bottom:16px;color:#e2e8f0;letter-spacing:.02em}
.footer ul{list-style:none}
.footer li{margin-bottom:10px}
.footer a{font-size:13px;color:#94a3b8;transition:all .25s;display:inline-block;text-decoration:none}
.footer a:hover{color:var(--primary);transform:translateX(2px)}
.footer-copy{margin-top:40px;padding-top:24px;border-top:1px solid rgba(255,255,255,0.06);text-align:center;font-size:12px;color:#6b7280;line-height:1.8}
.desktop-only-block{display:block}
@media(max-width:767px){.desktop-only-block{display:none}}

/* ===== 移动端底部 Tab 栏 ===== */
.tab-bar{display:flex;position:fixed;bottom:0;left:0;right:0;z-index:1000;background:rgba(255,255,255,0.92);backdrop-filter:blur(20px);-webkit-backdrop-filter:blur(20px);border-top:1px solid rgba(15,23,42,0.06);box-shadow:0 -4px 20px rgba(0,0,0,0.04)}
@media(min-width:768px){.tab-bar{display:none}}
.tab-bar-inner{display:flex;align-items:center;justify-content:space-around;width:100%;height:58px;padding-bottom:env(safe-area-inset-bottom)}
.tab-bar-btn{display:flex;flex-direction:column;align-items:center;gap:2px;color:var(--text-muted);background:none;border:none;cursor:pointer;padding:4px 12px;min-height:44px;transition:all .25s;border-radius:10px;position:relative;flex:1}
.tab-bar-btn svg{width:20px;height:20px}
.tab-bar-btn span{font-size:10px;font-weight:600}
.tab-bar-spacer{height:58px}
@media(min-width:768px){.tab-bar-spacer{display:none}}

/* ===== 回顶按钮 ===== */
.jump-top{position:fixed;bottom:80px;right:16px;width:44px;height:44px;border-radius:12px;background:linear-gradient(135deg,var(--primary),var(--secondary));color:#fff;box-shadow:0 8px 20px rgba(255,107,53,0.3);display:flex;align-items:center;justify-content:center;opacity:0;pointer-events:none;transition:all .3s;z-index:900;border:none;cursor:pointer}
.jump-top.show{opacity:1;pointer-events:auto}
@media(min-width:768px){.jump-top{bottom:32px;right:28px;width:46px;height:46px}}
.jump-top:hover{transform:translateY(-2px)}
.jump-top svg{width:20px;height:20px}

/* ===== 深色模式适配（兼容 body.dark 与 [data-theme="dark"]）===== */
body.dark .nav-top,body.dark .nav-mobile,[data-theme="dark"] .nav-top,[data-theme="dark"] .nav-mobile{background:rgba(26,26,46,0.8);border-bottom-color:rgba(255,255,255,0.06)}
body.dark .nav-search input,[data-theme="dark"] .nav-search input{background:var(--card-bg);color:var(--text)}
body.dark .nav-actions .nav-icon-btn:hover,[data-theme="dark"] .nav-actions .nav-icon-btn:hover{background:var(--bg-hover)}
body.dark .footer,[data-theme="dark"] .footer{background:linear-gradient(180deg,#0a0a15 0%,#080812 100%)}
body.dark .tab-bar,[data-theme="dark"] .tab-bar{background:rgba(26,26,46,0.92);border-top-color:rgba(255,255,255,0.06)}