body {
    color: #333;
    font-family: 'Open Sans', sans-serif;
    margin: 0;
    padding: 0;
}

main {
    margin: 40px;
}

h1 {
    font-size: 30px;
    margin-bottom: 40px;
}

.button_container {
    border: 1px solid #ddd;
    margin: 0 10px 10px 0;
    padding: 20px;
    width: 300px;
    height: 300px;
    float: left;
    overflow: hidden;
    box-sizing: border-box;
    display: flex;
    justify-content: center;
    align-items: center;
}

a#btn_spotify {
    color: #1db954;
    font-size: 4rem;
    text-decoration: none;
    display: block;
    position: relative;
}

a#btn_spotify i {
    position: absolute;
    transform: translate(-50%, -50%);
    transition: transform 1s ease;
}

a#btn_spotify i:hover {
    color: #3ea161;
    transform: translate(calc(-50% - 30px), -50%);
}

a#btn_spotify .spotify-label {
    position: absolute;
    top: 50%;
    left: calc(50% + 10px);
    transform: translateY(-50%) translateX(40px);
    font-size: 1.5rem;
    font-weight: 600;
    color: #1db954;
    opacity: 0;
    transition: transform 1s ease;
}

a#btn_spotify i:hover + .spotify-label {
    opacity: 1;
    transform: translateY(-50%) translateX(0);
    color: #3ea161;
}

a#btn_amazon {
    background: #232f3e;
    color: white;
    font-size: 3rem;
    display: block;
    position: relative;
    width: 80px;
    height: 80px;
    border-radius: 50px;
}

a#btn_amazon i {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

a#btn_amazon:hover {
    background: #364557;
    color: #FF9800;
    transform: rotate(360deg);
    transition: transform 1s;
}

a#btn_twitter {
    background: #56cdf1;
    color: white;
    font-size: 1rem;
    display: block;
    position: relative;
    padding: 15px 45px 15px 20px;
    border-radius: 5px;
    text-decoration: none;
    font-family: 'Arial', sans-serif;
    font-weight: 600;
    transition: scale 0.5s;
}

a#btn_twitter i {
    position: absolute;
    left: 65%;
    font-size: 1.2rem;
}

a#btn_twitter:hover {
    background: #4bb7d8;
    scale: 1.1;
    transition: scale 0.5s;
}

a#btn_apple {
    background: #ffffff;
    color: #505c65;
    font-size: 3rem;
    display: block;
    position: relative;
    width: 80px;
    height: 80px;
    border-radius: 50px;
    box-shadow: 0 0 8px #696b6d;
    transition: background 1s, color 0.5s, scale 0.5s;
}

a#btn_apple i {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

a#btn_apple:hover{
    color: rgb(255, 255, 255);
    background: linear-gradient(135deg, 
    #ff867a, 
    #ffb3e2, 
    #d97cff, 
    #8d8cff, 
    #51d1ff
    );
    scale: 1.1;
    transition: scale 0.5s;
}

a#btn_lyft {
    color: #ff00bf;
    font-size: 2rem;
    text-decoration: none;
    font-family: 'Ubuntu';
    position: relative;
    padding: 8px 25px;
    border-radius: 5px;
    transition: color 0.5s;
    overflow: hidden;
}

a#btn_lyft::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 0;
    height: 100%;
    background: #ff00bf;
    border-radius: 5px;
    transition: width 0.5s ease;
    z-index: -1;
}

a#btn_lyft:hover::before {
    width: 100%;
}

a#btn_lyft:hover {
    color: white;
}

a#btn_insta {
    color: white;
    background: linear-gradient(135deg,
    #ffdc80, #f77737, #e1306c, #c13584, #833ab4
    );
    padding: 8px 2px;
    border-radius: 17px;
    display: block;
    position: relative;
    transition: scale 0.5s;
}

a#btn_insta i {
    font-size: 3rem;
}

a#btn_insta:hover {
    border: 2px solid #ff0080;
    animation: borderPulse 2s ease-in-out infinite;
    scale: 1.1;
    transition: scale 0.5s;
}

/* source : https://stackoverflow.com/questions/8752835/with-css3-can-i-create-keyframes-that-make-border-pulse-in-and-out */

@keyframes borderPulse {
    0% {
        border-color: #ff0080;
        box-shadow: 0 0 5px #ff0080;
    }
    33% {
        border-color: #ff8c00;
        box-shadow: 0 0 10px #ff8c00;
    }
    66% {
        border-color: #40e0d0;
        box-shadow: 0 0 10px #40e0d0;
    }
    100% {
        border-color: #ff0080;
        box-shadow: 0 0 5px #ff0080;
    }
}

a#btn_npr {
    font-size: 2rem;
    text-decoration: none;
    font-family: 'Ubuntu';
}

.npr-content {
    display: flex;
    color: #000000;
}

.npr-n {
    padding: 2px 0;
    transition: all 0.5s ease;
}

.npr-p {
    padding: 2px 0;
    transition: all 0.5s ease;
}

.npr-r {
    padding: 2px 0;
    transition: all 0.5s ease;
}

a#btn_npr:hover .npr-n {
    background: #ee3b25;
    color: white;
    padding: 2px 10px;
}

a#btn_npr:hover .npr-p {
    background: #000000;
    color: white;
    padding: 2px 10px;
}

a#btn_npr:hover .npr-r {
    background: #4066b1;
    color: white;
    padding: 2px 10px;
}

a#btn_facebook {
    color: #1877f2;
    font-size: 4rem;
    display: block;
    position: relative;
    width: 80px;
    height: 80px;
    border-radius: 50px;
}

a#btn_facebook .fb-label {
    text-decoration: none;
    font-size: 20px;
    position: absolute;
    top: 60%;
    left: 60%;
    opacity: 0;
    transition: opacity 0.5s, text-shadow 0.5s;
}

a#btn_facebook i {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    transition: text-shadow 0.5s, transform 1s;
}

a#btn_facebook:hover i {
    transform: translate(calc(-50% - 30px), -50%);
    text-shadow:  0 0 2px #1877f2;
}

a#btn_facebook:hover .fb-label {
    opacity: 1;
    left: 50%;
    text-shadow:  0 0 1px #1877f2;
}

a#btn_newyorker {
    position: relative;
    display: block;
    padding: 30px 30px 10px 30px;
}

a#btn_newyorker img {
    width: 100%;
    position: relative;
}

a#btn_newyorker::before {
    content: '';
    position: absolute;
    width: 0px;
    height: 3px;
    left: 50%;
    bottom: 5px;
    background-color: #000000;
    transform: translateX(-50%);
    transition: width ease-in-out 0.4s;
    z-index: 10;
}

a#btn_newyorker:hover::before {
    width: calc(100% - 60px);
}

a#btn_tesla {
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 30px 30px 10px 30px;
}

a#btn_tesla #tesla_black {
    width: 50%;
    position: relative;
    transition: opacity 0.5s ease;
}

a#btn_tesla #tesla_red {
    width: 50%;
    opacity: 0;
    position: absolute;
    top: 70%;
    left: 50%;
    transform: translate(-50%, -50%);
    transition: opacity 0.5s ease;
}

a#btn_tesla:hover #tesla_black {
    opacity: 0;
}

a#btn_tesla:hover #tesla_red {
    opacity: 1;
}