$espacestd:8px;
$stdfontsize:12px;

@mixin reset-margins
{    
    margin: 0;
    margin-block-start: 0;
    margin-block-end: 0;
}

body
{
    padding:0px;
    @include reset-margins;
    font-size:$stdfontsize;
}

nav#menu-haut
{
    background-color:#ccc;
    //exemple avec interpolation;
    width:calc(100% - #{$espacestd * 2});
    ul
    {
        list-style:none;
        margin:0;
        padding:$espacestd;
        li
        {
            margin-bottom:$espacestd;
            &.current
            {
                background-color:#eee;
            }
        }
    }
}

h1,h2,h3,h4,h5,h6
{
    @include reset-margins;
}

@for $i from 0 through 5 {
    h#{$i+1} {
        font-size:$stdfontsize*2 - $i*2px;
    }
}

@for $i from 0 through 100 {
    .c#{$i}pourcent {
       width: #{$i} + '%';
    }
}