Sass tips

sass-tips.scss

// Placeholder
%btn {
    padding: 10px;
    color: #fff;
    cursor: pointer;
    border: none;
    shadow: none;
    font-size: 14px;
    width: 150px;
    margin: 5px 0;
    text-align: center;
    display: block;
    text-decoration: none;
}

// Mixin
@mixin btn-background($btn-background) {
    @extend %btn;
    background-color: $btn-background;
    &:hover {
        background-color: lighten($btn-background, 10%);
    }
}

// Usage
.btn-alert {
    @include btn-background(green);
}

.btn-warning {
    @include btn-background(red);
}

.btn-success {
    @include btn-background(blue);
}