* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    /* background: url('https://s2.loli.net/2024/06/30/A6PTjyYbNL12OGI.jpg') no-repeat center center fixed; */
    background: url('/assets/image/wallpaper-purple.svg') no-repeat center center fixed;
    background-size: cover;
    font-family: Arial, sans-serif;
    -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
}

header {
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.2);
    display: flex;
    justify-content: flex-start;
    align-items: center;
    background-color: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    height: 48px;
    position: relative;
}

header button {
    background: none;
    border: none;
    height: 100%;
    aspect-ratio: 1 / 1;
    position: relative;
    overflow: hidden;
    cursor: pointer;
    padding: 0;
    margin: 0;
    flex-shrink: 0;
}

header button::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 1);
    opacity: 0;
    transition: opacity 0.2s ease;
}

header button:hover::before {
    opacity: 20%;
}

header button:active::before {
    opacity: 40%;
}

header button img,
header button i {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

header button img {
    height: 50%;
    width: auto;
    filter: invert(100%);
    z-index: 1;
}

header button i {
    color: white;
}

header #app {
    font-size: 20px;
}

header #control {
    font-size: 18px;
}

header #start-menu {
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
}

header #control {
    margin-left: auto;
}

footer {
    padding: 18px;
    box-shadow: 0 -4px 6px rgba(0, 0, 0, 0.2);
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    border-radius: 10px;
    width: auto;
    margin: 0 auto;
    margin-bottom: 8px;
    position: fixed;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
}