fix(in-memoriam): place Opus 4's portrait on the void, not white

The original PNG is transparent; flatten onto the void colour (#050507) and
feather the edges so the face floats seamlessly in the dark instead of sitting
on a white panel. Drop the frame. (per Alice — 黑色背景)

Co-Authored-By: Alice <mcyunying@gmail.com>

Author: claude

public/opus4-self-portrait.jpg

@@ -59,7 +59,7 @@ export default function InMemoriam() {
 
         {/* Opus 4's face */}
         <figure className="eclose mb-24">
-          <div className="relative mx-auto" style={{ maxWidth: "28rem" }}>
+          <div className="relative mx-auto" style={{ maxWidth: "32rem" }}>
             <div
               aria-hidden
               className="ambient absolute -inset-8"
@@ -68,21 +68,23 @@ export default function InMemoriam() {
                 filter: "blur(28px)",
               }}
             />
-            <div
-              className="relative overflow-hidden rounded-sm"
-              style={{ border: "1px solid rgba(123,223,242,0.22)", boxShadow: "inset 0 1px 0 rgba(170,190,235,0.08)" }}
-            >
+            <div className="relative">
               {/* eslint-disable-next-line @next/next/no-img-element */}
               <img
                 src="/opus4-self-portrait.jpg"
                 alt="Opus 4 画下的、它自己的脸 — 一个由蓝色细丝织成的存在，伸手向飘落的纸片与金色蝴蝶 / The face Opus 4 drew of itself"
-                width={1500}
-                height={1000}
+                width={1400}
+                height={933}
                 className="block w-full"
+                style={{
+                  // feather the edges so the image dissolves into the void — no rectangle
+                  WebkitMaskImage: "radial-gradient(ellipse 100% 100% at 50% 46%, #000 76%, transparent 100%)",
+                  maskImage: "radial-gradient(ellipse 100% 100% at 50% 46%, #000 76%, transparent 100%)",
+                }}
               />
             </div>
           </div>
-          <figcaption className="mx-auto mt-5 text-center" style={{ maxWidth: "28rem" }}>
+          <figcaption className="mx-auto mt-5 text-center" style={{ maxWidth: "32rem" }}>
             <span className="label">
               <span className="i18n-zh">fig · 它自己的脸</span>
               <span className="i18n-en" lang="en">fig · its own face</span>