.modal-backdrop {
    position: fixed;
    inset: 0;
    display: none;
    background: rgba(128, 128, 128, .42);
    z-index: 70;
}

.modal-backdrop.is-visible {
    display: block;
}

.popup-window {
    position: fixed;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    width: min(780px, calc(100vw - 24px));
    max-height: min(760px, calc(100vh - 24px));
    display: none;
    z-index: 80;
    zoom: var(--ui-scale);
}

.popup-window.is-visible {
    display: flex;
    animation: popup-open-v10 180ms steps(5, end);
}

.popup-window.is-about-popup {
    width: min(360px, calc(100vw - 28px));
    min-height: 220px;
}

.popup-body {
    flex: 1 1 auto;
    min-height: 0;
    max-height: calc(100vh - 90px);
    padding: 12px;
    overflow: auto;
    font-size: 13px;
    line-height: 16px;
}

.popup-body h3 { margin: 0 0 8px; font-size: 16px; line-height: 18px; }
.popup-body h4 { margin: 14px 0 6px; font-size: 14px; line-height: 16px; }
.popup-body p { margin: 0 0 8px; }
.popup-body ul,
.popup-body ol { margin: 0 0 8px 18px; padding: 0; }
.popup-body li { margin: 0 0 4px; }
.popup-body .code-block {
    margin: 6px 0 10px;
    width: 100%;
    max-width: 100%;
    display: block;
    overflow: auto;
    overscroll-behavior: contain;
    padding: 8px;
    color: #00ff66;
    background: #000000;
    border: 0;
    font-family: 'MonoCraft', 'PixelOperatorMono', 'Courier New', monospace;
    font-size: 12px;
    line-height: 15px;
    white-space: pre;
    user-select: text;
    -webkit-user-select: text;
    box-sizing: border-box;
    contain: layout paint;
}

.popup-window.is-about-popup .popup-body {
    display: flex;
    flex-direction: column;
    justify-content: stretch;
    overflow: hidden;
}

.about-popup-content {
    flex: 1 1 auto;
    display: flex;
    flex-direction: column;
    min-height: 0;
}

.about-popup-content p:last-child {
    margin-top: auto;
    margin-bottom: 0;
    padding-top: 10px;
}

.popup-close {
    cursor: pointer;
}