Reduce navigation flash with instant theme background and view transitions.

Co-authored-by: Cursor <cursoragent@cursor.com>

static/css/tech.css

@@ -1,8 +1,25 @@
 /* Copyright (c) 2025-2026 马建军. All rights reserved. 专有软件，详见 LICENSE.zh-CN.txt */
 /* 科技感增强层 — 与 base.html 变量配合 */
 
+@view-transition {
+    navigation: auto;
+}
+
+::view-transition-old(app-main),
+::view-transition-new(app-main) {
+    animation-duration: .18s;
+}
+
+::view-transition-old(app-tech-bg),
+::view-transition-new(app-tech-bg),
+::view-transition-old(site-header),
+::view-transition-new(site-header) {
+    animation: none;
+}
+
 .tech-bg{
     position:fixed;inset:0;z-index:0;pointer-events:none;overflow:hidden;
+    view-transition-name:app-tech-bg;
 }
 .tech-grid{
     position:absolute;inset:0;
@@ -59,6 +76,7 @@
     border-bottom:1px solid var(--border-header);
     background:transparent;
     backdrop-filter:none;
+    view-transition-name:site-header;
 }
 .site-header::after{
     content:"";display:block;height:1px;margin-top:-1px;

static/js/nav.js

@@ -41,10 +41,29 @@
         backdrop.addEventListener('click', closeNav);
     }
 
-    nav.querySelectorAll('a').forEach(function (link) {
+    function prefetchNav(href) {
+        if (!href || href.indexOf(window.location.origin) !== 0) return;
+        if (href === window.location.href) return;
+        var links = document.head.querySelectorAll('link[rel="prefetch"]');
+        for (var i = 0; i < links.length; i++) {
+            if (links[i].href === href) return;
+        }
+        var link = document.createElement('link');
+        link.rel = 'prefetch';
+        link.href = href;
+        document.head.appendChild(link);
+    }
+
+    nav.querySelectorAll('a[href]').forEach(function (link) {
         link.addEventListener('click', function () {
             if (isMobileNav()) closeNav();
         });
+        link.addEventListener('mouseenter', function () {
+            prefetchNav(link.href);
+        });
+        link.addEventListener('touchstart', function () {
+            prefetchNav(link.href);
+        }, { passive: true });
     });
 
     window.addEventListener('resize', function () {

static/js/theme.js

@@ -19,10 +19,14 @@
             theme = 'dark';
         }
         document.documentElement.setAttribute('data-theme', theme);
+        document.documentElement.style.colorScheme = theme;
+        document.documentElement.style.background = theme === 'light' ? '#e8eef8' : '#050508';
         try {
             localStorage.setItem(KEY, theme);
         } catch (e) { /* ignore */ }
         updateButtons(theme);
+        var meta = document.getElementById('meta-theme-color');
+        if (meta) meta.setAttribute('content', theme === 'light' ? '#e8eef8' : '#050508');
     }
 
     var saved = null;

static/sw.js

@@ -2,7 +2,7 @@
  * 专有软件 — 未经授权禁止复制、传播、转售。
  * 详见 LICENSE.zh-CN.txt
  */
-var CACHE_VERSION = 'qihuo-v3';
+var CACHE_VERSION = 'qihuo-v4';
 var STATIC_CACHE = CACHE_VERSION + '-static';
 var STATIC_ASSETS = [
     '/static/css/tech.css',