I don’t understand something about the Body global style? _html/css_WEB-ITnose

Some parts of the CSS style of the mobile web page are not very clear.

body {
font: 16px/2 'Helvetica Neue', Helvetica, STHeiti, 'Hiragino Sans GB', sans-serif;
color: #ccc;
-webkit-text -size-adjust: 100%;
text-size-adjust: 100%;
text-transform: none;
speak: none;
-webkit-font- smoothing: antialiased;
-moz-osx-font-smoothing: grayscale;
background: #f2f2f2;
}

Problem:
text-transform : none;The default value is also none. It doesn’t seem like there’s much meaning in writing it here? ? ? Why still write? ? ?

“speak: none;” cancels the pronunciation. What is its specific function? ? ? Why do you need to write this style attribute? ? ?

Reply to the discussion (solution)

Does anyone know what these two attributes are? ? ?

It is normal to write these on the mobile terminal.

It is estimated that there is a default assignment in the outer layer,,,, and it has been restored here. . . .

It is estimated that the outer layer has a default assignment,,,, which has been restored here. . . .

1 should be.

I checked speak online: The speak property defines whether text should be rendered aurally and if so, how. It should be in the experimental stage, and it is basically useless.

Characteristics
Possible values ​​
none
Suppresses aural rendering so that the element requires no time to speak. Note, however, that descendants may override this value and cause the element to be spoke. To ensure descendants do not override, use the display property. Note also the difference between an element whose volume property has a value of silent and an element whose speak property has the value none. If the volume property is silent, although no sound is generated , rendering the text takes up as much time as if the text were being spoken, including any pauses before and after the element. The resulting silence can be used in language teaching applications, for example, where the pause that is generated allows pupils sufficient time to speak out loud a word or phrase.
normal
Uses language-dependent pronunciation rules for rendering an element and its children.
spell-out
Spells the text one letter at a time (useful for acronyms and abbreviations).
inherit
Use the same computed value as the parent element for this property.
Default value
normal

Applies to
All elements

Inherited
Yes