body {
    font-family: Verdana, Ariel;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    min-height: 100vh; /* viewport units */
    background-color: rgb(20, 20, 20); 
    background-size: cover;
    background-position-x: center;
    background-attachment: fixed;
}

main 
{
    margin: 0;
    flex-grow: 1;
    /*min-height: calc(100vh - 96px);*/
    width: 100%;
    text-align: center;
    background-color: transparent;
}

footer 
{
    /*position: fixed;*/
    /*bottom: 0;*/
}

.headbar {
    /*position: fixed;*/
    position: sticky;
    margin: 0px;
    /*left: 0px;*/ 
    top: 0px; 
    width: 100%; 
    height: 50px; 
    z-index: 999;    
    background-color: rgb(16, 16, 16); /*Match this to rightmost pixel color.*/
    /*border-bottom: 2px solid rgb(60, 160, 255);*/
    border-bottom: 2px solid rgb(48, 104, 144);
    /*border-bottom: 2px solid rgb(60, 160, 255, 0.6);*/
}

.footbar {
    /*text-align: center;*/
    width: 100%; 
    height: 128px; 
    /*z-index: 999;*/
    background-color: rgb(16, 16, 16);
    /*border-top: 2px solid rgb(60, 160, 255);*/
    border-top: 2px solid rgb(48, 104, 144);
}

.content {
    width: 100%;
    text-align: center;
    background-color: transparent;
}

.card_holder {
    text-align: center;
    background-color: transparent;
    padding-left: 10px;
    padding-right: 10px;
    min-height: 720px;
}

.card {
    /*box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2);  this adds the "card" effect */
    /*box-shadow: 8px 8px 32px 16px rgba(68, 168, 255, 0.2); */
    padding: 16px;
    text-align: center;
    background-color: rgba(32, 32, 32, .7);
    width: 25%;
    margin: 10px;
    display: inline-table; /* The best of responsiveness. */
    vertical-align: top; /* Make the tops align. */
    border-radius: 16px;
}

.vid_thumbnail{
    /*box-shadow: 8px 8px 32px 16px rgba(68, 168, 255, 0.2); */
    box-shadow: 0px 0px 32px 12px rgba(68, 168, 255, 0.4);        
    width: 320px; 
    border-radius: 16px;
    object-fit: contain;
    /*border: 2px solid rgb(56, 72, 88);*/
    border: 2px solid rgb(128, 144, 160);
}

/* To get consistency on Edge and Firefox. */ 
.hr_line {
    height: 2px;
    color: rgb(60, 160, 255);
    background-color: rgb(60, 160, 255);
    border: none;
}


.buttongroup {
    float: right;
    margin-top: 6px;
    margin-right: 12px;
}

@media (max-width: 640px) {
    .buttongroup {
        visibility: hidden;
    }
}

.menubutton {
    float: right;
    text-align: center;
    cursor: pointer;
}

.curtain {
    height: 0%;
    width: 100%;
    position: fixed;
    z-index: 1;
    top: 46px;
    left: 0;
    background-color: rgb(16,8,8);
    background-color: rgba(16,8,8, 0.9);
    overflow-y: hidden;
    transition: 0.5s;
}

.curtain-content {
    position: relative;
    top: 25%;
    width: 100%;
    text-align: center;
    margin-top: 30px;
}

.curtain a {
    padding: 8px;
    text-decoration: none;
    font-size: 18px;
    color: rgb(92, 176, 240);
    display: block;
    transition: 0.3s;
}

.curtain a:hover, .curtain a:focus {
    color: #f1f1f1;
}

.curtain .closebtn {
    position: absolute;
    top: 20px;
    right: 45px;
    font-size: 60px;
}


@media screen and (max-height: 450px) {
    .curtain {overflow-y: auto;}
    .curtain a {font-size: 20px}
    .curtain .closebtn {
    font-size: 40px;
    top: 15px;
    right: 35px;
  }
}

.gradient-button {
    margin-top: 96px;
    margin-bottom: 96px;                
    width: 128px;
    height: 128px;
    background-image: linear-gradient(to bottom, rgb(144, 192, 255), rgb(40, 80, 192));
    opacity: 0.5;
    color: white; /* Text color */
    border: 0px;
    padding: 10px 20px; 
    border-radius: 16px;
}            

.gradient-button:hover {
  background-image: linear-gradient(to bottom, rgb(224, 240, 255), rgb(64, 128, 255));
}

/*Button is pressed.*/
.gradient-button:active {
  background-image: linear-gradient(to bottom, rgb(60, 160, 255), white);
}
​