.mathcourse-artplayer {
    display: block;
    width: 100%;
    aspect-ratio: 16 / 9;
    min-height: 0;
    height: auto;
    background: #000;
    border-radius: 10px;
    overflow: hidden;
    position: relative;
}

.mathcourse-artplayer .art-video-player {
    display: block;
    width: 100%;
    height: 100%;
    min-width: 0;
    min-height: 0;
}

.mathcourse-artplayer video {
    display: block;
    width: 100%;
    height: 100%;
    object-fit: contain;
}

/* 进度条与控制按钮拉开距离，避免拖动时误触右侧按钮。 */
.mathcourse-artplayer .art-bottom {
    padding-bottom: 3px;
}

.mathcourse-artplayer .art-progress {
    height: 4px;
    margin-bottom: 10px;
}

.mathcourse-artplayer .art-control-bar {
    min-height: 48px;
    padding-bottom: 2px;
}

/* 倍速按钮使用自定义直接显示的 1.0x / 1.25x 等文字。 */
.mathcourse-artplayer .art-control-mathcourse-speed {
    white-space: nowrap;
    min-width: 48px;
}

.mathcourse-artplayer .mathcourse-speed-menu {
    position: absolute;
    right: 12px;
    bottom: 62px;
    z-index: 10050;
    display: flex;
    flex-direction: column;
    gap: 4px;
    min-width: 72px;
    padding: 6px;
    border-radius: 8px;
    background: rgba(20, 24, 30, .96);
    box-shadow: 0 6px 24px rgba(0,0,0,.35);
}

.mathcourse-artplayer .mathcourse-speed-menu[hidden] {
    display: none;
}

.mathcourse-artplayer .mathcourse-speed-option {
    border: 0;
    border-radius: 6px;
    padding: 7px 10px;
    background: transparent;
    color: #fff;
    font-size: 13px;
    line-height: 1.2;
    text-align: center;
    cursor: pointer;
}

.mathcourse-artplayer .mathcourse-speed-option:hover,
.mathcourse-artplayer .mathcourse-speed-option.is-active {
    background: rgba(255,255,255,.14);
}

/* 浏览器真正进入 fullscreen 后，反色必须跟随 video 一起保留。 */
.mathcourse-artplayer.mathcourse-inverted video,
.mathcourse-artplayer:fullscreen video,
.mathcourse-artplayer:-webkit-full-screen video,
.mathcourse-artplayer.art-fullscreen video {
    filter: brightness(.9) invert(1) hue-rotate(180deg) !important;
}

@media (min-width: 1051px) {
    .mathcourse-artplayer {
        width: 100% !important;
        max-width: none !important;
        min-width: 0 !important;
        min-height: 0 !important;
        aspect-ratio: 16 / 9 !important;
        height: auto !important;
    }

    .mathcourse-artplayer .art-video-player {
        width: 100% !important;
        max-width: none !important;
        height: 100% !important;
        min-width: 0 !important;
        min-height: 0 !important;
    }

    .mathcourse-artplayer .art-control-bar {
        min-height: 50px;
    }
}

@media (max-width: 767px) {
    .mathcourse-artplayer {
        min-height: 0;
        border-radius: 8px;
    }

    .mathcourse-artplayer .art-progress {
        margin-bottom: 8px;
    }

    .mathcourse-artplayer .art-control-bar {
        min-height: 42px;
    }
}