styles.css

@property --percent {
    syntax: '<number>';
    inherits: true;
    /* stylelint-disable-next-line -- not yet supported in FireFox. */
    initial-value: 0;
}

.fc-chart-pie .chart-area .chart-image {
    width: auto;
}

.fc-progress-pie {
    --color: purple;
    --percent: 0;
    --size: 150px;
    --border: 20px;
    --bgcolor: #f0f0f0;

    width: var(--size);
    aspect-ratio: 1;
    position: relative;
    display: inline-grid;
    margin: 5px;
    place-content: center;
    font-size: 1.5rem;
    font-weight: bold;
}
.fc-progress-pie:before,
.fc-progress-pie:after {
    content: "";
    position: absolute;
    border-radius: 50%;
}
.fc-progress-pie:before {
    inset: 0;
    background:
        radial-gradient(farthest-side, var(--color) 98%, #0000) top/var(--border) var(--border) no-repeat,
        conic-gradient(var(--color) calc(var(--percent) * 1%), #0000 0);
    -webkit-mask: radial-gradient(farthest-side, #0000 calc(99% - var(--border)), #000 calc(100% - var(--border)));
    mask: radial-gradient(farthest-side, #0000 calc(99% - var(--border)), #000 calc(100% - var(--border)));
    background-color: var(--bgcolor);
    background-size: 0 0, auto;

}
.fc-progress-pie:after {
    inset: calc(50% - var(--border) / 2);
    background: var(--color);
    transform: rotate(calc(var(--percent) * 3.6deg)) translateY(calc(50% - var(--size) / 2));
    content: none;
}
.fc-progress-pie.animate {
    animation: fc-progress-pie-percent 1s .5s both;
}

@keyframes fc-progress-pie-percent {
    from {
        --percent: 0;
    }
}

kbd {
    padding: 0.1rem 0.4rem;
    background-color: #eee;
    border: 1px solid #b4b4b4;
    border-radius: 0.25rem;
    font-family: SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
    box-shadow: 0 1px 1px rgba(0, 0, 0, 0.2), 0 2px 0 0 rgba(255, 255, 255, 0.7) inset;
    color: #333;
    white-space: nowrap;
    display: inline-block;
}