diff --git a/src/MprIcons.php b/src/MprIcons.php
index 0804a14..f8771ef 100644
--- a/src/MprIcons.php
+++ b/src/MprIcons.php
@@ -404,15 +404,31 @@ class MprIcons
                 if (!file_exists($cssFile)) {
                     continue;
                 }
-                // Read first 50KB — font-face is always near the top
+                // Minified theme.css can be 200KB+; font-face may be at ~85KB
+                // Read in 100KB chunks, scan up to 200KB
                 $handle = fopen($cssFile, 'r');
                 if ($handle) {
-                    $chunk = fread($handle, 51200);
+                    $hasMaterial = false;
+                    $hasFA = false;
+                    $bytesRead = 0;
+                    while (!feof($handle) && $bytesRead < 204800) {
+                        $chunk = fread($handle, 102400);
+                        $bytesRead += strlen($chunk);
+                        if (!$hasMaterial && stripos($chunk, 'Material Icons') !== false) {
+                            $hasMaterial = true;
+                        }
+                        if (!$hasFA && stripos($chunk, 'FontAwesome') !== false) {
+                            $hasFA = true;
+                        }
+                        if ($hasMaterial || $hasFA) {
+                            break;
+                        }
+                    }
                     fclose($handle);
-                    if (stripos($chunk, 'Material Icons') !== false) {
+                    if ($hasMaterial) {
                         return self::MATERIAL;
                     }
-                    if (stripos($chunk, 'FontAwesome') !== false) {
+                    if ($hasFA) {
                         return self::FA;
                     }
                 }
@@ -481,9 +497,18 @@ class MprIcons
                 }
                 $handle = fopen($cssFile, 'r');
                 if ($handle) {
-                    $chunk = fread($handle, 51200);
+                    $found = false;
+                    $bytesRead = 0;
+                    while (!feof($handle) && $bytesRead < 204800) {
+                        $chunk = fread($handle, 102400);
+                        $bytesRead += strlen($chunk);
+                        if (stripos($chunk, $needle) !== false) {
+                            $found = true;
+                            break;
+                        }
+                    }
                     fclose($handle);
-                    if (stripos($chunk, $needle) !== false) {
+                    if ($found) {
                         return true;
                     }
                 }