Nice.css

body{
    background-color: #d8ebe4;
    margin: 0;/*To get rid of default CSS*/
    text-align: center;/*Does not work for elements which have width specified*/
    color: #40514E;
}
h1{
    margin-top: 0;
    width: 30%;
    margin: 0 auto 0 auto;/*top - right - bottom - left*//*Centre Allign*/
    font-family: 'Redressed', cursive, sans-serif;/*1st -> 2nd  -> .....*/
    color: #66BFBF;
}
hr{
    border: dotted #f1e789 6px;
    border-bottom: none;
    width: 10%;
    margin: 50px auto;
}
.End{
    width: 40%;
    margin: 10px auto 60px;
}
h3{
    font-family: Verdana, Geneva, Tahoma, sans-serif;
}
h2{
    font-family: Verdana, Geneva, Tahoma, sans-serif;/*Serif is default*/
    color: #66BFBF;
}
p{
    font-family: Verdana, Geneva, Tahoma, sans-serif;/*Serif is default*/
    line-height: 2;
}
/*Try not to use float - clear=> anti - float*/
.QP{
    font-size: 5rem;/*wrt Body*//*16px = 1em = 100%*/
    margin: 0 auto 0 auto;
    color: #66BFBF;
}
.R{
    padding-bottom: 0;
}
.RF{
    color: coral;
    font-size: 1.5rem;
    font-weight: normal;
    font-weight: 800;
}
.Guitar{
    margin-top: 30px;
}
.Code{
    margin: 0;
}
.intro{
    width: 60%;
    margin: 25px auto 25px auto;
}
.RE{
    font-size: 2rem;
    color: coral;
}
.RR{
padding-top: 100px;
}
.P{
position: relative;
left: 125px;
bottom: 25px;
}
.Q{
position: absolute;
left: 475px;
top: 250px;/*Distance from top margin*/
}
.Yeah{
    background-color: #fbff0a;
    padding: 20px;
    border: solid;
    border-width: 10px;
    width: 200px;
    height: 200px;
}
/*Content -> Padding -> Border -> Margin(Not part of the box)*/
.NO{
    background-color: rgb(221, 42, 57);
    width: 200px;
    height: 200px;
    border-width: 20px;
    border: solid;
    margin-left: 260px;
}
.OP{
    background-color: rgb(20, 231, 221);
    width: 200px;
    height: 200px;
    border-width: 10px;
    border: solid;
    margin-left: 465px;
}
.Noice{
    text-decoration: underline;
    background-color: sandybrown;
    width: 100px;
    display: inline-block
}
.TT{
    display: none;/*No Space*/
}
.PP{
    visibility: hidden;/*Space remains*/
}
.AA{
    width: 100px;
    height: 100px;
    background-color: red;
    display: inline-block;
}
.BB{
    width: 100px;
    height: 100px;
    background-color: greenyellow;
    display: inline-block;
}/*HTML elements have static position by default*/
/*top - left and other features => Does not affect the other elements*/
/*Child - Parent => Nested*/
/*Relative Position => Relative to HTML element - Absolute position => Relative to Page - Out of flow*/
.CC{
    width: 100px;
    height: 100px;
    background-color: purple;
    display: inline-block;
    /*margin-left: 200px;*/
}
/*Inline => Cannot change width - Block => Can change width*/
.YY{
    border-radius: 100%;
    margin-bottom: 30px;
}
a{
    color: #11868a;
    margin: 10px 10px;
    text-decoration: none;/*Underline by default for anchor tags*/

}
a:hover{
    color: #EAF6F6;
}
.footer{
    background-color: #66BFBF;
    padding: 10px 0 5px;
    font-family: Verdana, Geneva, Tahoma, sans-serif;/*Serif is default*/
    margin-top: 20px;
}
.Copy{
    font-size: 0.75em;
    color: #EAF6F6;
}
.btn {
    background: #3DDAF6;
    background-image: -webkit-linear-gradient(top, #3DDAF6, #891ED0);
    background-image: -moz-linear-gradient(top, #3DDAF6, #891ED0);
    background-image: -ms-linear-gradient(top, #3DDAF6, #891ED0);
    background-image: -o-linear-gradient(top, #3DDAF6, #891ED0);
    background-image: -webkit-gradient(to bottom, #3DDAF6, #891ED0);
    -webkit-border-radius: 8px;
    -moz-border-radius: 8px;
    border-radius: 8px;
    height: 27px;
    line-height: 27px;
    color: #FFFFFF;
    font-family: Verdana;
    width: 150px;
    font-size: 20px;
    font-weight: 100;
    padding: 10px;
    -webkit-box-shadow: 1px 1px 20px 0 #000000;
    -moz-box-shadow: 1px 1px 20px 0 #000000;
    box-shadow: 1px 1px 20px 0 #000000;
    text-shadow: 1px 1px 20px #000000;
    border: solid #337FED 1px;
    text-decoration: none;
    display: inline-block;
    cursor: pointer;
    text-align: center;
 }
 
 .btn:hover {
    border: solid #6633ED 1px;
    background: #3DF643;
    background-image: -webkit-linear-gradient(top, #3DF643, #3DA8F6);
    background-image: -moz-linear-gradient(top, #3DF643, #3DA8F6);
    background-image: -ms-linear-gradient(top, #3DF643, #3DA8F6);
    background-image: -o-linear-gradient(top, #3DF643, #3DA8F6);
    background-image: -webkit-gradient(to bottom, #3DF643, #3DA8F6);
    -webkit-border-radius: 20px;
    -moz-border-radius: 20px;
    border-radius: 20px;
    text-decoration: none;
 }