better colorblindness support prompt

Author: wxiaoguang

options/locale/locale_en-US.ini

@@ -763,6 +763,8 @@ manage_themes = Select default theme
 manage_openid = Manage OpenID Addresses
 email_desc = Your primary email address will be used for notifications, password recovery and, provided that it is not hidden, web-based Git operations.
 theme_desc = This will be your default theme across the site.
+theme_colorblindness_help = Colorblindness Theme Support
+theme_colorblindness_prompt = Gitea just gets some themes with basic colorblindness support, which only have a few colors defined. The work is still in progress. More improvements could be done by defining more colors in the theme CSS files.
 primary = Primary
 activated = Activated
 requires_activation = Requires activation

templates/user/settings/appearance.tmpl

@@ -1,30 +1,31 @@
-{{template "user/settings/layout_head" (dict "ctxData" . "pageClass" "user settings sshkeys")}}
+{{template "user/settings/layout_head" (dict "ctxData" . "pageClass" "user settings")}}
 	<div class="user-setting-content">
 
 		<!-- Theme -->
 		<h4 class="ui top attached header">
 			{{ctx.Locale.Tr "settings.manage_themes"}}
 		</h4>
 		<div class="ui attached segment">
-			<div class="ui email list">
-				<div class="item">
+			<form class="ui form" action="{{.Link}}/theme" method="post">
+				{{.CsrfTokenHtml}}
+				<div class="field">
 					{{ctx.Locale.Tr "settings.theme_desc"}}
+					<a class="muted" target="_blank" href="https://github.com/go-gitea/gitea/blob/main/web_src/css/themes/" data-tooltip-content="{{ctx.Locale.Tr "settings.theme_colorblindness_prompt"}}">
+						{{svg "octicon-question"}} {{ctx.Locale.Tr "settings.theme_colorblindness_help"}}
+					</a>
 				</div>
-				<form class="ui form" action="{{.Link}}/theme" method="post">
-					{{.CsrfTokenHtml}}
-					<div class="field">
-						<label for="ui">{{ctx.Locale.Tr "settings.ui"}}</label>
-						<select name="theme" class="ui dropdown">
-							{{range $theme := .AllThemes}}
-							<option value="{{$theme}}" {{Iif (eq $.SignedUser.Theme $theme) "selected"}}>{{$theme}}</option>
-							{{end}}
-						</select>
-					</div>
-					<div class="field">
-						<button class="ui primary button">{{ctx.Locale.Tr "settings.update_theme"}}</button>
-					</div>
-				</form>
-			</div>
+				<div class="field">
+					<label>{{ctx.Locale.Tr "settings.ui"}}</label>
+					<select name="theme" class="ui dropdown">
+						{{range $theme := .AllThemes}}
+						<option value="{{$theme}}" {{Iif (eq $.SignedUser.Theme $theme) "selected"}}>{{$theme}}</option>
+						{{end}}
+					</select>
+				</div>
+				<div class="field">
+					<button class="ui primary button">{{ctx.Locale.Tr "settings.update_theme"}}</button>
+				</div>
+			</form>
 		</div>
 
 		<!-- Language -->