Style tweaks: reorganize in submenus, add a few

Try to limit the nb of items per menu page to 5 or 6 by
splitting related ones into sub-menus, so we get more
room below to see how they affect the content.
Adds "No indentation on first/following paragraphs" and
"Paragraphs margins and paddings", and Links underlining.

frontend/ui/data/css_tweaks.lua

@@ -34,6 +34,7 @@ local CssTweaks = {
                 title = _("Ignore vertical margins"),
                 priority = 2,
                 css = [[* { margin-top: 0 !important; margin-bottom: 0 !important; }]],
+                separator = true,
             },
             {
                 id = "padding_horizontal_all_0";
@@ -49,6 +50,8 @@ local CssTweaks = {
             },
             separator = true,
         },
+        {
+            title = _("Page breaks and blank pages"),
             {
                 id = "titles_page-break-before_avoid ";
                 title = _("Avoid blank page on chapter start"),
@@ -125,6 +128,7 @@ h1 + h6, h2 + h6, h3 + h6, h4 + h6, h5 + h6 { page-break-before: avoid !importan
                 },
             },
         },
+    },
     {
         title = _("Text"),
         {
@@ -204,6 +208,7 @@ You may also want to enable, in the top menu → Gear → Navigation →, Invert
                 title = _("Document direction LTR"),
                 css = [[body { direction: ltr !important; }]],
             },
+            separator = true,
         },
         {
             title = _("Widows and orphans"),
@@ -279,16 +284,20 @@ h1, h2, h3, h4, h5, h6 { hyphens: none !important; }
             separator = true,
         },
         {
-            id = "sub_sup_smaller";
-            title = _("Smaller sub- and superscript"),
-            description = _("Prevent sub- and superscript from affecting line-height."),
-            priority = 5, -- so we can override "font_size_all_inherit"
-            -- https://friendsofepub.github.io/eBookTricks/
-            -- https://github.com/koreader/koreader/issues/3923#issuecomment-386510294
-            css = [[
-sup { font-size: 50% !important; vertical-align: super !important; }
-sub { font-size: 50% !important; vertical-align: sub !important; }
-            ]],
+            title = _("Fonts and line heights"),
+            {
+                id = "font_family_all_inherit";
+                title = _("Ignore publisher font families"),
+                description = _("Disable font-family specified in embedded styles."),
+                -- we have to use this trick, font-family handling by crengine is a bit complex
+                css = [[* { font-family: "NoSuchFont" !important; }]],
+            },
+            {
+                id = "font_size_all_inherit";
+                title = _("Ignore publisher font sizes"),
+                description = _("Disable font-size specified in embedded styles."),
+                css = [[* { font-size: inherit !important; }]],
+                separator = true,
             },
             {
                 id = "lineheight_all_inherit";
@@ -305,17 +314,17 @@ sub { font-size: 50% !important; vertical-align: sub !important; }
                 separator = true,
             },
             {
-            id = "font_size_all_inherit";
-            title = _("Ignore publisher font sizes"),
-            description = _("Disable font-size specified in embedded styles."),
-            css = [[* { font-size: inherit !important; }]],
+                id = "sub_sup_smaller";
+                title = _("Smaller sub- and superscript"),
+                description = _("Prevent sub- and superscript from affecting line-height."),
+                priority = 5, -- so we can override "font_size_all_inherit"
+                -- https://friendsofepub.github.io/eBookTricks/
+                -- https://github.com/koreader/koreader/issues/3923#issuecomment-386510294
+                css = [[
+sup { font-size: 50% !important; vertical-align: super !important; }
+sub { font-size: 50% !important; vertical-align: sub !important; }
+                ]],
             },
-        {
-            id = "font_family_all_inherit";
-            title = _("Ignore publisher font families"),
-            description = _("Disable font-family specified in embedded styles."),
-            -- we have to use this trick, font-family handling by crengine is a bit complex
-            css = [[* { font-family: "NoSuchFont" !important; }]],
         },
     },
     {
@@ -337,11 +346,14 @@ p {
             ]],
             separator = true,
         },
+        {
+            title = _("Paragraph first-line indentation"),
             {
                 id = "paragraph_no_indent";
                 title = _("No indentation on first paragraph line"),
                 description = _("Do not indent the first line of paragraphs."),
                 css = [[p { text-indent: 0 !important; }]],
+                separator = true,
             },
             {
                 id = "paragraph_indent";
@@ -351,25 +363,67 @@ p {
 p { text-indent: 1.2em !important; }
 body, h1, h2, h3, h4, h5, h6, div, li, td, th { text-indent: 0 !important; }
                 ]],
-            separator = true,
             },
+            {
+                id = "paragraph_first_no_indent";
+                title = _("No indentation on first paragraph"),
+                description = _("Do not indent the first line of the first paragraph of its container. This might be needed to correctly display drop caps, while still having indentation on following paragraphs."),
+                priority = 2, -- so it can override 'paragraph_indent'
+                css = [[p:first-child { text-indent: 0 !important; }]],
+            },
+            {
+                id = "paragraph_following_no_indent";
+                title = _("No indentation on following paragraphs"),
+                description = _("Do not indent the first line of following paragraphs, but leave the first paragraph of its container untouched."),
+                priority = 2, -- so it can override 'paragraph_indent'
+                css = [[p + p { text-indent: 0 !important; }]],
+            },
+        },
+        {
+            title = _("Spacing between paragraphs"),
             {
                 id = "paragraph_whitespace";
                 title = _("Spacing between paragraphs"),
                 description = _("Add a line of whitespace between paragraphs."),
+                priority = 5, -- Override "Ignore margins and paddings" below
                 css = [[p + p { margin-top: 1em !important; }]],
             },
             {
                 id = "paragraph_whitespace_half";
                 title = _("Spacing between paragraphs (half)"),
                 description = _("Add half a line of whitespace between paragraphs."),
+                priority = 5,
                 css = [[p + p { margin-top: .5em !important; }]],
             },
             {
                 id = "paragraph_no_whitespace";
                 title = _("No spacing between paragraphs"),
                 description = _("No whitespace between paragraphs is the default, but it may be overridden by publisher styles. This will re-enable it for paragraphs and list items."),
+                priority = 5,
                 css = [[p, li { margin-top: 0 !important; margin-bottom: 0 !important; }]],
+                separator = true,
+            },
+            {
+                id = "paragraph_no_vertical_padding";
+                title = _("Ignore vertical paragraph padding"),
+                priority = 3, -- Override "Pages > Ignore margin and padding"
+                css = [[p, li { padding-top: 0 !important; padding-bottom: 0 !important; }]],
+            },
+        },
+        {
+            title = _("Horizontal paragraph margins"),
+            {
+                id = "paragraph_no_horizontal_margin";
+                title = _("Ignore horizontal paragraph margins"),
+                priority = 3, -- Override "Pages > Ignore margin and padding"
+                css = [[p, li { margin-left: 0 !important; margin-right: 0 !important; }]],
+            },
+            {
+                id = "paragraph_no_horizontal_padding";
+                title = _("Ignore horizontal paragraph padding"),
+                priority = 3,
+                css = [[p, li { padding-left: 0 !important; padding-right: 0 !important; }]],
+            },
         },
     },
     {
@@ -391,6 +445,7 @@ body, h1, h2, h3, h4, h5, h6, div, li, td, th { text-indent: 0 !important; }
             title = _("Center small tables"),
             description = _("Horizontally center tables that do not use the full page width."),
             css = [[table { margin-left: auto !important; margin-right: auto !important; }]],
+            priority = 3, -- Override "Pages > Ignore margin and padding"
             separator = true,
         },
         {
@@ -438,6 +493,18 @@ table, tcaption, tr, th, td { border: black solid 1px; border-collapse: collapse
             id = "a_not_bold";
             title = _("Links never bold"),
             css = [[a { font-weight: normal !important; }]],
+            separator = true,
+        },
+        {
+            id = "a_underline";
+            title = _("Links always underlined"),
+            css = [[a[href] { text-decoration: underline !important; }]],
+            -- Have it apply only on real links with a href=, not on anchors
+        },
+        {
+            id = "a_not_underline";
+            title = _("Links never underlined"),
+            css = [[a { text-decoration: none !important; }]],
         },
     },
     {