fix(login): 统一登录页主题链路

src/assets/images/login-bg.svg

@@ -1,45 +1,24 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <svg xmlns="http://www.w3.org/2000/svg" width="100%" height="100%" viewBox="0 0 1400 800">
   <defs>
-    <style>
-      @media (prefers-color-scheme: dark) {
-        #bg-layer { fill: url(#bgDark); }
-        #soft-glow { fill: url(#glowDark); }
-        .accent-arc { stroke: rgba(118, 156, 255, 0.35); }
-        .accent-dot { fill: rgba(154, 188, 255, 0.45); }
-      }
-    </style>
-
     <linearGradient id="bgLight" x1="0%" y1="0%" x2="100%" y2="100%">
       <stop offset="0%" stop-color="#f3f7ff" />
       <stop offset="60%" stop-color="#e3edff" />
       <stop offset="100%" stop-color="#d6e7ff" />
     </linearGradient>
-    
-    <linearGradient id="bgDark" x1="0%" y1="0%" x2="100%" y2="100%">
-      <stop offset="0%" stop-color="#0b1324" />
-      <stop offset="60%" stop-color="#162135" />
-      <stop offset="100%" stop-color="#1e2c44" />
-    </linearGradient>
-    
+
     <radialGradient id="glowLight" cx="20%" cy="15%" r="60%">
       <stop offset="0%" stop-color="rgba(64,128,255,0.35)" />
       <stop offset="40%" stop-color="rgba(64,128,255,0.18)" />
       <stop offset="100%" stop-color="rgba(64,128,255,0)" />
     </radialGradient>
-    
-    <radialGradient id="glowDark" cx="20%" cy="15%" r="60%">
-      <stop offset="0%" stop-color="rgba(98,142,255,0.4)" />
-      <stop offset="50%" stop-color="rgba(98,142,255,0.18)" />
-      <stop offset="100%" stop-color="rgba(98,142,255,0)" />
-    </radialGradient>
-    
+
     <radialGradient id="glowSecondary" cx="80%" cy="70%" r="55%">
       <stop offset="0%" stop-color="rgba(22,93,255,0.3)" />
       <stop offset="50%" stop-color="rgba(22,93,255,0.12)" />
       <stop offset="100%" stop-color="rgba(22,93,255,0)" />
     </radialGradient>
-    
+
     <linearGradient id="meshLight" x1="0%" y1="0%" x2="100%" y2="100%">
       <stop offset="0%" stop-color="rgba(255,255,255,0.6)" />
       <stop offset="35%" stop-color="rgba(255,255,255,0.2)" />
@@ -60,4 +39,4 @@
   </g>
 
   <!-- 去掉点状噪声，仅保留大区域柔光 -->
-</svg>
+</svg>