.equalizer-btn {
    position: relative;
    width: 50px;
    height: 50px;
    border: none;
    border-radius: 5px;
    background-color: #1e1e1e;
    cursor: pointer;
}

.equalizer-btn .bar {
    position: absolute;
    width: 10px;
    height: 18px;
    bottom: 2px;
    transform: translateX(-50%);
    background-color: #fff;
    animation: equalizer 1s ease-in-out infinite;
    animation-duration: calc(0.2s + var(--delay));
    animation-delay: calc(-0.2s - var(--delay));
    animation-direction: alternate;
    transform-origin: bottom center;
}

.equalizer-btn .bar:nth-child(1) {
    --delay: 0.2s;
    left: 10px;
}

.equalizer-btn .bar:nth-child(2) {
    --delay: 0.4s;
    left: 50%;
}

.equalizer-btn .bar:nth-child(3) {
    --delay: 0.6s;
    right: 0;
}

@keyframes equalizer {
    0% {
        transform: translateX(-50%) scaleY(1);
    }

    25% {
        transform: translateX(-50%) scaleY(1.3);
    }

    50% {
        transform: translateX(-50%) scaleY(1.5);
    }

    75% {
        transform: translateX(-50%) scaleY(1.3);
    }

    100% {
        transform: translateX(-50%) scaleY(1);
    }
}

.play-button {
    display: inline-block;
    position: relative;
    width: 50px;
    height: 50px;
    border: none;
    border-radius: 5px;
    background-color: #1e1e1e;
    cursor: pointer;
}

.play-button::before {
    content: "";
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 0;
    height: 0;
    border-top: 14px solid transparent;
    border-bottom: 14px solid transparent;
    border-left: 22px solid #fff;
}

.stop-button {
    display: inline-flex;
    justify-content: center;
    align-items: center;
    position: relative;
    width: 50px;
    height: 50px;
    border: none;
    border-radius: 5px;
    background-color: #1e1e1e;
    cursor: pointer;
}

.stop-button::before {
    content: "";
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 18px;
    height: 18px;
    background-color: #fff;
}