:root {
  --reader-progressbar-height: 0.3em;
}


#reader-frame {
    display: flex;
    flex-direction: column;
}

#reader-content-frame {
    flex: 1;
    position: relative;
    overflow: hidden;
}

#reader-pages {
    position: absolute;
    flex-direction: row;
    left: 0px;
    right: 0px;
    transition: all 1.5s ease;
}

#reader-pages > img {
    display: inline-block;
    opacity: 0;
    transition: all 1s cubic-bezier(.9,.03,.69,.22); /* ease-in quartic */
    flex-shrink: 0;
}

#focus-overlay, #focus-overlay * {
    transition: all 1.5s ease;
}

#focus-overlay, #nav-controls {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    
    display: grid;
    
    grid-template-areas: 
        "left top right"
        "left center right"
        "left bottom right";
}

#focus-overlay {
    grid-template-columns: 50% auto 50%;
    grid-template-rows: 50% auto 50%;
}

#nav-controls {
    grid-template-columns: 33% 0 1fr;
    grid-template-rows: auto;
}

#nav-controls > div {
    cursor: pointer;
}

.top {
    grid-area: top;
}

.left {
    grid-area: left;
}

.right {
    grid-area: right;
}

.top {
    grid-area: top;
}

.bottom {
    grid-area: bottom;
}

#focus-overlay > *:not(.center) {
    background-color: rgba(0, 0, 0, 0.85);
}

#focus-overlay > .center {
    box-shadow: inset 0px 0px 5px 5px rgba(0, 0, 0, 0.85);
}

#help-menu{
    font-size: 120%;
    display: flex;
    flex-direction: column;
    color: white;
    background-color: rgba(0,0,0,0.8)
    border: 0.1em solid black;
    height: 100%;
    justify-content: end;
    box-sizing: border-box;
    align-items: end;
}

#help-menu > #help-controls {
    padding: 0 1em 1em 0;
    background-color: rgba(0,0,0,0.5);
    z-index: 1;
    opacity: 0;
    transition: all 1.7s cubic-bezier(.76,.05,.86,.06);
    border: white solid;
    border-width: 1px 0 0 1px;
    border-radius: 0.3em 0 0 0;
    transform: translate(0, calc(100% - 2em));
}

#help-menu > #help-controls:hover {
    opacity: 1;
    transition: all 0.3s linear;
    transform: translate(0, 0);
}

#help-menu > #help-controls > div {
    margin-top: 1em;
    text-align: end;
}

.key {
    display: inline;
    margin: 0 0.5em;
    border: 1px white solid;
    padding: 0 0.1em;
    border-radius: 0.2em;
}

#reader-progress-container {
    background-color: dimgray;
}

#reader-progress-bar{
    height: var(--reader-progressbar-height);
    background-color: whitesmoke;
    width: 0%;
    transition: all 0.5s ease-in-out;
}