3 files changed, 67 insertions, 48 deletions
diff --git a/phpBB/adm/style/acp_styles.html b/phpBB/adm/style/acp_styles.html
index 38bec5a1e4..cfa804090f 100644
--- a/phpBB/adm/style/acp_styles.html
+++ b/phpBB/adm/style/acp_styles.html
@@ -146,7 +146,9 @@
 		{styles_list.EXTRA}
 		<td class="{$ROW_CLASS} mark" width="20">
 			<!-- IF styles_list.STYLE_ID -->
-				<input class="checkbox" type="checkbox" name="ids[]" value="{styles_list.STYLE_ID}" />
+				{% if styles_list.STYLE_NAME !== 'prosilver' %}
+					<input class="checkbox" type="checkbox" name="ids[]" value="{styles_list.STYLE_ID}" />
+				{% endif %}
 			<!-- ELSE -->
 				<!-- IF styles_list.COMMENT != '' -->
 					&nbsp;
diff --git a/phpBB/includes/acp/acp_styles.php b/phpBB/includes/acp/acp_styles.php
index 5029510839..87c8d88f52 100644
--- a/phpBB/includes/acp/acp_styles.php
+++ b/phpBB/includes/acp/acp_styles.php
@@ -259,6 +259,19 @@ class acp_styles
 		// Get list of styles to uninstall
 		$ids = $this->request_vars('id', 0, true);
 
+		// Don't remove prosilver, you can still deactivate it.
+		$sql = 'SELECT style_id
+			FROM ' . STYLES_TABLE . "
+			WHERE style_name = '" . $this->db->sql_escape('prosilver') . "'";
+		$result = $this->db->sql_query($sql);
+		$prosilver_id = (int) $this->db->sql_fetchfield('style_id');
+		$this->db->sql_freeresult($result);
+
+		if ($prosilver_id && in_array($prosilver_id, $ids))
+		{
+			trigger_error($this->user->lang('UNINSTALL_PROSILVER') . adm_back_link($this->u_action), E_USER_WARNING);
+		}
+
 		// Check if confirmation box was submitted
 		if (confirm_box(true))
 		{
@@ -998,11 +1011,14 @@ class acp_styles
 				'L_ACTION'	=> $this->user->lang['EXPORT']
 			); */
 
-			// Uninstall
-			$actions[] = array(
-				'U_ACTION'	=> $this->u_action . '&amp;action=uninstall&amp;hash=' . generate_link_hash('uninstall') . '&amp;id=' . $style['style_id'],
-				'L_ACTION'	=> $this->user->lang['STYLE_UNINSTALL']
-			);
+			if ($style['style_name'] !== 'prosilver')
+			{
+				// Uninstall
+				$actions[] = array(
+					'U_ACTION'	=> $this->u_action . '&amp;action=uninstall&amp;hash=' . generate_link_hash('uninstall') . '&amp;id=' . $style['style_id'],
+					'L_ACTION'	=> $this->user->lang['STYLE_UNINSTALL']
+				);
+			}
 
 			// Preview
 			$actions[] = array(
diff --git a/phpBB/language/en/acp/styles.php b/phpBB/language/en/acp/styles.php
index ab85d9d2f5..44be3c11cd 100644
--- a/phpBB/language/en/acp/styles.php
+++ b/phpBB/language/en/acp/styles.php
@@ -21,7 +21,7 @@ if (!defined('IN_PHPBB'))
 
 if (empty($lang) || !is_array($lang))
 {
-	$lang = array();
+	$lang = [];
 }
 
 // DEVELOPERS PLEASE NOTE
@@ -36,55 +36,56 @@ if (empty($lang) || !is_array($lang))
 // equally where a string contains only two placeholders which are used to wrap text
 // in a url you again do not need to specify an order e.g., 'Click %sHERE%s' is fine
 
-$lang = array_merge($lang, array(
-	'ACP_STYLES_EXPLAIN'	=> 'Here you can manage the available styles on your board. You may alter existing styles, delete, deactivate, reactivate, install new ones. You can also see what a style will look like using the preview function. Also listed is the total user count for each style, note that overriding user styles will not be reflected here.',
+$lang = array_merge($lang, [
+	'ACP_STYLES_EXPLAIN'						=> 'Here you can manage the styles available on your board.<br>Please note you cannot uninstall the “<strong>prosilver</strong>” style as it is phpBB’s default and primary parent style.',
 
-	'CANNOT_BE_INSTALLED'			=> 'Cannot be installed',
-	'CONFIRM_UNINSTALL_STYLES'		=> 'Are you sure you wish to uninstall selected styles?',
-	'COPYRIGHT'						=> 'Copyright',
+	'CANNOT_BE_INSTALLED'						=> 'Cannot be installed',
+	'CONFIRM_UNINSTALL_STYLES'					=> 'Are you sure you wish to uninstall selected styles?',
+	'COPYRIGHT'									=> 'Copyright',
 
-	'DEACTIVATE_DEFAULT'		=> 'You cannot deactivate the default style.',
-	'DELETE_FROM_FS'			=> 'Delete from filesystem',
-	'DELETE_STYLE_FILES_FAILED'	=> 'Error deleting files for style "%s".',
-	'DELETE_STYLE_FILES_SUCCESS'	=> 'Files for style "%s" have been deleted.',
-	'DETAILS'					=> 'Details',
+	'DEACTIVATE_DEFAULT'						=> 'You cannot deactivate the default style.',
+	'DELETE_FROM_FS'							=> 'Delete from filesystem',
+	'DELETE_STYLE_FILES_FAILED'					=> 'Error deleting files for style "%s".',
+	'DELETE_STYLE_FILES_SUCCESS'				=> 'Files for style "%s" have been deleted.',
+	'DETAILS'									=> 'Details',
 
-	'INHERITING_FROM'			=> 'Inherits from',
-	'INSTALL_STYLE'				=> 'Install style',
-	'INSTALL_STYLES'			=> 'Install styles',
-	'INSTALL_STYLES_EXPLAIN'	=> 'Here you can install new styles.<br />If you cannot find a specific style in list below, check to make sure style is already installed. If it is not installed, check if it was uploaded correctly.',
-	'INVALID_STYLE_ID'			=> 'Invalid style ID.',
+	'INHERITING_FROM'							=> 'Inherits from',
+	'INSTALL_STYLE'								=> 'Install style',
+	'INSTALL_STYLES'							=> 'Install styles',
+	'INSTALL_STYLES_EXPLAIN'					=> 'Here you can install new styles.<br>If you cannot find a specific style in list below, check to make sure style is already installed. If it is not installed, check if it was uploaded correctly.',
+	'INVALID_STYLE_ID'							=> 'Invalid style ID.',
 
-	'NO_MATCHING_STYLES_FOUND'	=> 'No styles match your query.',
-	'NO_UNINSTALLED_STYLE'		=> 'No uninstalled styles detected.',
+	'NO_MATCHING_STYLES_FOUND'					=> 'No styles match your query.',
+	'NO_UNINSTALLED_STYLE'						=> 'No uninstalled styles detected.',
 
-	'PURGED_CACHE'				=> 'Cache was purged.',
+	'PURGED_CACHE'								=> 'Cache was purged.',
 
-	'REQUIRES_STYLE'			=> 'This style requires the style "%s" to be installed.',
+	'REQUIRES_STYLE'							=> 'This style requires the style "%s" to be installed.',
 
-	'STYLE_ACTIVATE'			=> 'Activate',
-	'STYLE_ACTIVE'				=> 'Active',
-	'STYLE_DEACTIVATE'			=> 'Deactivate',
-	'STYLE_DEFAULT'				=> 'Make default style',
-	'STYLE_DEFAULT_CHANGE_INACTIVE'	=> 'You must activate style before making it default style.',
-	'STYLE_ERR_INVALID_PARENT'	=> 'Invalid parent style.',
-	'STYLE_ERR_NAME_EXIST'		=> 'A style with that name already exists.',
-	'STYLE_ERR_STYLE_NAME'		=> 'You must supply a name for this style.',
-	'STYLE_INSTALLED'			=> 'Style "%s" has been installed.',
+	'STYLE_ACTIVATE'							=> 'Activate',
+	'STYLE_ACTIVE'								=> 'Active',
+	'STYLE_DEACTIVATE'							=> 'Deactivate',
+	'STYLE_DEFAULT'								=> 'Make default style',
+	'STYLE_DEFAULT_CHANGE_INACTIVE'				=> 'You must activate style before making it default style.',
+	'STYLE_ERR_INVALID_PARENT'					=> 'Invalid parent style.',
+	'STYLE_ERR_NAME_EXIST'						=> 'A style with that name already exists.',
+	'STYLE_ERR_STYLE_NAME'						=> 'You must supply a name for this style.',
+	'STYLE_INSTALLED'							=> 'Style "%s" has been installed.',
 	'STYLE_INSTALLED_RETURN_INSTALLED_STYLES'	=> 'Return to installed styles list',
 	'STYLE_INSTALLED_RETURN_UNINSTALLED_STYLES'	=> 'Install more styles',
-	'STYLE_NAME'				=> 'Style name',
-	'STYLE_NAME_RESERVED'		=> 'Style "%s" can not be installed, because the name is reserved.',
-	'STYLE_NOT_INSTALLED'		=> 'Style "%s" was not installed.',
-	'STYLE_PATH'				=> 'Style path',
-	'STYLE_UNINSTALL'			=> 'Uninstall',
-	'STYLE_UNINSTALL_DEPENDENT'	=> 'Style "%s" cannot be uninstalled because it has one or more child styles.',
-	'STYLE_UNINSTALLED'			=> 'Style "%s" uninstalled successfully.',
-	'STYLE_PHPBB_VERSION'		=> 'phpBB Version',
-	'STYLE_USED_BY'				=> 'Used by (including robots)',
-	'STYLE_VERSION'				=> 'Style version',
+	'STYLE_NAME'								=> 'Style name',
+	'STYLE_NAME_RESERVED'						=> 'Style "%s" can not be installed, because the name is reserved.',
+	'STYLE_NOT_INSTALLED'						=> 'Style "%s" was not installed.',
+	'STYLE_PATH'								=> 'Style path',
+	'STYLE_UNINSTALL'							=> 'Uninstall',
+	'STYLE_UNINSTALL_DEPENDENT'					=> 'Style "%s" cannot be uninstalled because it has one or more child styles.',
+	'STYLE_UNINSTALLED'							=> 'Style "%s" uninstalled successfully.',
+	'STYLE_PHPBB_VERSION'						=> 'phpBB Version',
+	'STYLE_USED_BY'								=> 'Used by (including robots)',
+	'STYLE_VERSION'								=> 'Style version',
 
-	'UNINSTALL_DEFAULT'		=> 'You cannot uninstall the default style.',
+	'UNINSTALL_PROSILVER'						=> 'You cannot uninstall the style “prosilver”.',
+	'UNINSTALL_DEFAULT'							=> 'You cannot uninstall the default style.',
 
-	'BROWSE_STYLES_DATABASE'	=> 'Browse styles database',
-));
+	'BROWSE_STYLES_DATABASE'					=> 'Browse styles database',
+]);