css cut everything out of body code example

Example 1: css all caps

.uppercase {
  text-transform: uppercase;
}

#example {
  text-transform: none;	/* No capitalization, the text renders as it is (default) */
  text-transform: capitalize;	/* Transforms the first character of each word to uppercase */
  text-transform: uppercase;	/* Transforms all characters to uppercase */
  text-transform: lowercase;	/* Transforms all characters to lowercase */
  text-transform: initial;	/* Sets this property to its default value */
  text-transform: inherit;	/* Inherits this property from its parent element */
}

Example 2: css make background visible in text

.transparency{
    background-color: rgba(255, 255, 0, 0.3); /* <-- this line is modified */
    display: block;
    margin: 0 auto;
    width: 300px;
    height: 500px;
}
.content{
    color: #000;
    text-align: center;
}
img{
    /* Set rules to fill background */
    min-height: 100%;
    min-width: 1920px;
    /* Set up proportionate scaling */
    width: 100%;
    height: auto;
    /* Set up positioning */
    position: fixed;
    top: 0;
    left: 0;  
    z-index:-1; /* <-- this line is added */
}