fix(css): inject inlined CSS after the shebang line

packages/vite/src/node/__tests__/plugins/css.spec.ts

@@ -829,4 +829,29 @@ exports.foo = foo;
       })();"
     `)
   })
+
+  test('should inject CSS after the shebang line for es', async () => {
+    const result = getInlinedCSSInjectedCode(
+      `#!/usr/bin/env node
+console.log("foo");`,
+      'es',
+    )
+    expect(result).toMatchInlineSnapshot(`
+      "#!/usr/bin/env node
+      injectCSS();console.log("foo");"
+    `)
+  })
+
+  test('should inject CSS at the start for es without shebang', async () => {
+    const result = getInlinedCSSInjectedCode(`console.log("foo");`, 'es')
+    expect(result).toMatchInlineSnapshot(`"injectCSS();console.log("foo");"`)
+  })
+
+  test('should inject CSS for es shebang without trailing newline', async () => {
+    const result = getInlinedCSSInjectedCode(`#!/usr/bin/env node`, 'es')
+    expect(result).toMatchInlineSnapshot(`
+      "#!/usr/bin/env node
+      injectCSS();"
+    `)
+  })
 })

packages/vite/src/node/plugins/css.ts

@@ -1159,11 +1159,14 @@ export function injectInlinedCSS(
   } else if (format === 'es') {
     // legacy build
     if (code.startsWith('#!')) {
-      let secondLinePos = code.indexOf('\n')
-      if (secondLinePos === -1) {
-        secondLinePos = 0
+      // inject after the shebang line instead of into it
+      const newlinePos = code.indexOf('\n')
+      if (newlinePos === -1) {
+        // the shebang has no trailing newline, add one so it stays intact
+        s.append(`\n${injectCode}`)
+        return
       }
-      injectionPoint = secondLinePos
+      injectionPoint = newlinePos + 1
     } else {
       injectionPoint = 0
     }