body {
    /*background-color: #f1f1f1;*/
    background-image: radial-gradient(rgba(68, 68, 68, 0.5) 1px, transparent 0);
    background-size: 50px 50px; /* 点阵间距 */
    font-family: cursive;
}

header h1 {
    font-size: 5rem;
    text-shadow: 3px 3px #000;
}

p{
    background-color: #ffffff;
    font-family: Cambria, "Cambria Math", stixgeneral, "Times New Roman", Times, serif;
    font-size: 19px;
}


header h4 {
    font-size: 1.3rem;
    text-shadow: 1px 1px #000;
}

header .btn-lg {
    font-size: 1rem;
    margin: 0 15px;
    background-color: crimson;
}

header .btn-lg:hover {
    background-color: darkred;
}

header .btn-lg:focus {
    background-color: darkred;
}

h2 {
    margin: 10px;
    font-size: 1.8rem;
    font-weight: bold;
}

h3 {
    margin: 10px;
    font-size: 1.3rem;
    font-weight: bold;
}

p {
    padding-left: 15px;
}

#selection-box {
    padding: 20px;
    text-align: center;
}

input[type="file"] {
    display: none;
}

.custom-file-upload {
    width: 80%;
    height: 160px;
    line-height: 160px;
    display: inline-block;
    background-color: #f5f8fa;
    border-color: rgb(145, 145, 125);
    border-radius: 6px;
    border-style: dashed;
    border-width: 3px;
    text-align: center;
    font-size: 1.5rem;
    font-weight: normal;
}

.custom_form {
    background-color: #ffffff;
    margin: auto;
    max-width: 80%;
    text-align: left;
}

#download_btn {
    font-size: 1.05rem;
    font-weight: bold;
    background-color: #fafafa;
}

#process_vid_btn {
    font-size: 1.05rem;
    font-weight: bold;
    background-color: #fafafa;
}

#img1 {
    max-width: 80%;
    max-height: 1000px;
    margin: 5px;
}

#processed_video {
    max-width: 80%;
    max-height: 1000px;
    margin: 5px;
}

#gallery-box {
/*    background-color: #333333;*/
    padding: 20px;
    text-align: center;
}

#gallery-box h2 {
    color: #fff;
    text-shadow: 3px 3px #000;
}

#gallery-box .container {
    column-count: 4;
    column-gap: 2rem;
}

.card {
    display: inline-block;
    width: 100%;
    margin-bottom: 1rem;
    break-inside: avoid;
    background: white;
    border: 1px solid #ccc;
    border-radius: 8px;
    overflow: hidden;
}
.card video,
.card img {
    width: 100%;
    height: auto;
    display: block;
}

footer {
    background-color: #333333;
}

.form-check b{
    width: 120px;
    max-width: 120px;
    display: inline-block;
}

.form-check-label {
    width: 105px;
    max-width: 105px;
    display: inline-block;
}

#img_preview{
    width: 100px;
    height: 100px;
    max-width: 100px;
    max-height: 100px;
    display: inline-block;
    margin-right: 50px;
}

#original_video{
    width: 100px;
    height: 100px;
    max-width: 100px;
    max-height: 100px;
    display: none;
    margin-right: 50px;
}