html, body {
    height: 100%;
}

#app {
    height: 100%;
    display: -webkit-flex;
    display: flex;
    flex-direction: column;
}

.index {
    flex: 1 1 auto;
}

.action-btn {
    transition: all .3s ease-in-out;
    -webkit-transition: all .3s ease-in-out;
    background-image: linear-gradient(90deg, #4373f9, #3a97ff);
    background-size: 0 100%;
    background-repeat: no-repeat;
}

.float-left {
    float: left;
}

.clear-float {
    clear: both;
}