h2(class="heading-2 c-white trailer--nano") SVG & full CSS Button Animation
p(class="teasing-1 c-white trailer") Design by #[a(href="https://twitter.com/alexaneminga") @alexaneminga] & thanks #[a(href="https://twitter.com/sreucherand") @sreucherand] for the help !

a(href="#project").btn.btn--svg.js-animated-button
  span.btn--svg__label Hover me !
  svg(width="190" x="0px" y="0px" viewBox="0 0 60 60" enable-background="new 0 0 60 60").btn--svg__circle
    circle(fill="#FFFFFF" cx="30" cy="30" r="28.7").js-discover-circle
  svg(x="0px" y="0px" preserveaspectratio="none" viewBox="2 29.3 56.9 13.4" enable-background="new 2 29.3 56.9 13.4" width="190").btn--svg__border
    g(id="Calque_2").btn--svg__border--left.js-discover-left-border
      path(fill="none" stroke="#FFF" stroke-width="0.5" stroke-miterlimit="1" d="M30.4,41.9H9c0,0-6.2-0.3-6.2-5.9S9,30.1,9,30.1h21.4")
    g(id="Calque_3").btn--svg__border--right.js-discover-right-border
      path(fill="none" stroke="#FFF" stroke-width="0.5" stroke-miterlimit="1" d="M30.4,41.9h21.5c0,0,6.1-0.4,6.1-5.9s-6-5.9-6-5.9H30.4")

body {
    background: black;
    text-align: center;
    padding: 50px;
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    -ms-box-sizing: border-box;
    box-sizing: border-box;
}

.btn {
    font-size: 1em;
    line-height: 1em;
    letter-spacing: 0.04em;
    display: inline-block;

    &--svg {
        position: relative;
        height: 42px;
        width: 190px;
        overflow: hidden;
        border-radius: 21px;

        &:hover {
            .btn--svg__circle {
                circle {
                    -webkit-transform: scale(0);
                    -moz-transform: scale(0);
                    -ms-transform: scale(0);
                    transform: scale(0);
                }
            }

            .btn--svg__label {
                color: #fff;
            }

            .btn--svg__border--left,
            .btn--svg__border--right {
                path {
                    stroke-dasharray: 61.8204345703125 61.8204345703125;
                    stroke-dashoffset: 0;
                    -webkit-transition-delay: 0.25s;
                    -webkit-transition-duration: 0.5s;
                    -webkit-transition-timing-function: ease-in-out;
                    -webkit-transition-property: stroke-dashoffset;
                    -moz-transition-delay: 0.25s;
                    -moz-transition-duration: 0.5s;
                    -moz-transition-timing-function: ease-in-out;
                    -moz-transition-property: stroke-dashoffset;
                    -ms-transition-delay: 0.25s;
                    -ms-transition-duration: 0.5s;
                    -ms-transition-timing-function: ease-in-out;
                    -ms-transition-property: stroke-dashoffset;
                    transition-delay: 0.25s;
                    transition-duration: 0.5s;
                    transition-timing-function: ease-in-out;
                    transition-property: stroke-dashoffset;
                }
            }
        }

        &__label {
            -webkit-font-smoothing: antialiased;
            font-family: sans-serif;
            font-weight: bold;
            text-align:center;
            color: black;
            z-index: 3;
            width: 100%;
            -webkit-transition: color 0.5s ease-in-out;
            -moz-transition: color 0.5s ease-in-out;
            -ms-transition: color 0.5s ease-in-out;
            transition: color 0.5s ease-in-out;
        }

        &__circle {
            circle {
                -webkit-transition: transform 0.5s ease-in-out;
                -webkit-transform: scale(1.1);
                -webkit-transform-origin: 50% 50%;
                -moz-transition: transform 0.5s ease-in-out;
                -moz-transform: scale(1.1);
                -moz-transform-origin: 50% 50%;
                -ms-transition: transform 0.5s ease-in-out;
                -ms-transform: scale(1.1);
                -ms-transform-origin: 50% 50%;
                transition: transform 0.5s ease-in-out;
                transform: scale(1.1);
                transform-origin: 50% 50%;
            }
        }

        &__border {

            &--left,
            &--right {
                path {
                    stroke-dasharray: 61.8204345703125 61.8204345703125;
                    -webkit-transition-duration: 0s;
                    -webkit-transition-timing-function: ease-in-out;
                    -webkit-transition-property: stroke-dashoffset;
                    -webkit-transition-delay: 0.5s;
                    -moz-transition-duration: 0s;
                    -moz-transition-timing-function: ease-in-out;
                    -moz-transition-property: stroke-dashoffset;
                    -moz-transition-delay: 0.5s;
                    -ms-transition-duration: 0s;
                    -ms-transition-timing-function: ease-in-out;
                    -ms-transition-property: stroke-dashoffset;
                    -ms-transition-delay: 0.5s;
                    transition-duration: 0s;
                    transition-timing-function: ease-in-out;
                    transition-property: stroke-dashoffset;
                    transition-delay: 0.5s;
                }
            }

            &--left {
                path {
                    stroke-dashoffset: -61.8204345703125;
                }
            }

            &--right {
                path {
                    stroke-dashoffset: 61.8204345703125;
                }
            }
        }

        svg,
        &__label {
            position: absolute;
            top: 50%;
            left: 50%;
            -webkit-transform: translate(-50%, -50%);
            -webkit-transform-origin: 50% 50%;
            -moz-transform: translate(-50%, -50%);
            -moz-transform-origin: 50% 50%;
            -ms-transform: translate(-50%, -50%);
            -ms-transform-origin: 50% 50%;
            transform: translate(-50%, -50%);
            transform-origin: 50% 50%;
        }
    }
}

// Utils
.c-white {
    color: white;
}

.trailer {
    margin-bottom: 40px;
    
    &--nano {
        margin-bottom: 10px;
    }
}

a {
    position: relative;
    text-decoration: none;
    color: red;
    
    &:after {
        content: '';
        height: 1px;
        bottom: -4px;
        position: absolute;
        left: 5%;
        right: 95%;
        background: red;
        transition: right 0.25s ease-in-out;
    }
    
    &:hover:after {
        right: 5%;
    }
}

.teasing-1,
.heading-2 {
    font-family: sans-serif;
    letter-spacing: 0.04em;
    -webkit-font-smoothing: antialiased;
}

.teasing-1 {
    font-size: 14px;
    line-height: 14px;
}

.heading-2 {
    font-weight: bold;
    font-size: 20px;
    line-height: 20px;
    text-transform: uppercase;
}