Constant STYLE 

const STYLE: &str = "
<style>
body                { margin: 0; }
pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padding: 0.4em; }

.lifetime           { color: #DFAF8F; font-style: italic; }
.label              { color: #DFAF8F; font-style: italic; }
.comment            { color: #7F9F7F; }
.documentation      { color: #629755; }
.intra_doc_link     { font-style: italic; }
.injected           { opacity: 0.65 ; }
.struct, .enum      { color: #7CB8BB; }
.enum_variant       { color: #BDE0F3; }
.string_literal     { color: #CC9393; }
.field              { color: #94BFF3; }
.function           { color: #93E0E3; }
.parameter          { color: #94BFF3; }
.text               { color: #DCDCCC; }
.type               { color: #7CB8BB; }
.builtin_type       { color: #8CD0D3; }
.type_param         { color: #DFAF8F; }
.attribute          { color: #94BFF3; }
.numeric_literal    { color: #BFEBBF; }
.bool_literal       { color: #BFE6EB; }
.macro              { color: #94BFF3; }
.proc_macro         { color: #94BFF3; text-decoration: underline; }
.derive             { color: #94BFF3; font-style: italic; }
.module             { color: #AFD8AF; }
.value_param        { color: #DCDCCC; }
.variable           { color: #DCDCCC; }
.format_specifier   { color: #CC696B; }
.mutable            { text-decoration: underline; }
.escape_sequence    { color: #94BFF3; }
.keyword            { color: #F0DFAF; font-weight: bold; }
.control            { font-style: italic; }
.reference          { font-style: italic; font-weight: bold; }
.const              { font-weight: bolder; }
.unsafe             { color: #BC8383; }
.deprecated         { text-decoration: line-through; }

.invalid_escape_sequence { color: #FC5555; text-decoration: wavy underline; }
.unresolved_reference    { color: #FC5555; text-decoration: wavy underline; }
</style>
";