html, body {
    width: 100%;
    margin: 0;
}

html {
    height: 100%;
}

body {
    min-height: 100%;
    padding: 20px;
    box-sizing: border-box;
}

p {
    word-break: break-all;
}

@media (max-width: 500px) {
    h1 {
        margin-top: 80px;
    }
}

.flex {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

.block {
    display: block;
    position: relative;
}

.url {
    font-size: 18px;
    text-align: center;
    padding: 10px 10px 10px 5px;
    position: relative;
    width: 300px;
    border: none;
    border-bottom: 2px solid #bfbfbf;
}

input:focus {
    outline: none;
}

.bar {
    content: '';
    height: 2px;
    width: 100%;
    bottom: 0;
    position: absolute;
    background: #00bfb3;
    transition: 0.2s ease transform;
    -moz-transition: 0.2s ease transform;
    -webkit-transition: 0.2s ease transform;
    transform: scaleX(0);
}

.url:focus ~ .bar {
    transform: scaleX(1);
}

.btn {
    line-height: 38px;
    background-color: #00bfb3;
    color: #fff;
    white-space: nowrap;
    text-align: center;
    font-size: 14px;
    border: none;
    border-radius: 2px;
    cursor: pointer;
    padding: 5px;
    width: 160px;
    margin: 30px 0;
}

.panel-group .desc {
    position: relative;
    text-align: center;
}

#accordion {
    display: flex; 
    flex-direction: column;
    justify-content: center;
    text-align: center;
}

.tips {
    font-size: 18px;
    font-weight: bold;
    color: #c4a622;
    width: 200px;
    background-color: #fff;
    border: none;
    border-bottom: 2px solid #bfbfbf;
}

.font {
    color: rgb(83, 126, 14);
    font-weight: bold;
}

.back {
    color: black;
}

.back:visited {
    color: black;
}

.back:hover {
    color: red;
}