html, body {
    margin: 0;
    padding: 0;
    height: 100%;
    overflow: hidden;
}

body {
    display: flex;
    justify-content: center;
    align-items: center;
    background: #eee;
    font-family: 'Sigmar', cursive;
}

#gameContainer {
    padding-top: 40px;
    width: 100%;
    height: 100%;
    background: linear-gradient(to right, #FFDC02, #19AE47, #0C87D1);
    background-size: 300% 300%;
    animation: gradientShift 8s ease infinite;
    box-sizing: border-box;
    text-align: center;
    position: relative;
}

#gameCanvas {
    background: #333;
    display: block;
    margin: 10px auto 0 auto;
    cursor: none;
    border: 5px solid black;
    border-radius: 5px;
}

#mainMenuOverlay {
    position: absolute;
    top: 0; left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(to right, #FFDC02, #19AE47, #0C87D1);
    background-size: 300% 300%;
    animation: gradientShift 8s ease infinite;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    cursor: pointer;
}

#mainMenuTitle {
    font-size: 80px;
    color: #012169;
    margin-bottom: 20px;
    user-select: none;
}

#menuLogo {
    width: 300px;
    height: auto;
    margin-bottom: 20px;
    filter: drop-shadow(5px 5px 10px rgba(0, 0, 0, 0.75));
}

#playGameText {
    font-size: 40px;
    color: #db3c24;
    user-select: none;
    margin-top: 10px;
}

#guideText {
    font-size: 40px;
    color: #a22c1a;
    user-select: none;
    margin-top: 10px;
}

#guideOverlay {
    position: absolute;
    top: 0; left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.8);
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 999;
    cursor: pointer;
}

#guideTitle {
    font-size: 60px;
    color: #fff;
    user-select: none;
    margin-bottom: 20px;
}

#guideContent {
    font-size: 24px;
    color: #fff;
    max-width: 600px;
    text-align: center;
    margin-bottom: 30px;
}

#guideGoBack {
    position: absolute;
    bottom: 10px;
    left: 10px;
    font-size: 32px;
    color: #fff;
    user-select: none;
    cursor: pointer;
}

#startOverlay {
    position: absolute;
    top: 0; left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.8);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 999;
    cursor: pointer;
}

#startTitle {
    font-size: 80px;
    color: #fff;
    user-select: none;
    margin-bottom: 20px;
}

#startGoBack {
    position: absolute;
    bottom: 10px;
    left: 10px;
    font-size: 32px;
    color: #fff;
    user-select: none;
    cursor: pointer;
}

#countdownOverlay {
    position: absolute;
    top: 0; left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.8);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 999;
}

#countdownNumber {
    font-size: 120px;
    color: #fff;
    user-select: none;
}

#gameOverOverlay {
    position: absolute;
    top: 0; left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    transform: translateY(100%);
    transition: transform 0.7s ease;
    z-index: 999;
    cursor: pointer;
}

#gameOverOverlay.show {
    transform: translateY(0);
}

#gameOverTitle {
    font-size: 80px;
    color: #fff;
    margin-bottom: 20px;
    user-select: none;
}

#gameOverSub {
    font-size: 32px;
    color: #fff;
    user-select: none;
}

#finalScoreWrapper {
    margin-top: 15px;
    font-size: 24px;
    color: #fff;
    text-align: center;
}

#gameOverGoBack {
    position: absolute;
    bottom: 10px;
    left: 10px;
    font-size: 32px;
    color: #fff;
    user-select: none;
    cursor: pointer;
}

#leaderboardOverlay {
    position: absolute;
    top: 0; left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.8);
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 999;
    cursor: pointer;
}

#leaderboardTitle {
    font-size: 60px;
    color: #fff;
    margin-bottom: 20px;
    user-select: none;
}

#leaderboardTable {
    background: #fff;
    border-collapse: collapse;
    width: 400px;
    max-width: 90%;
    margin: 0 auto 20px auto;
}

#leaderboardTable th,
#leaderboardTable td {
    padding: 8px 12px;
    border: 1px solid #ccc;
    text-align: center;
}

#leaderboardGoBack {
    position: absolute;
    bottom: 10px;
    left: 10px;
    font-size: 32px;
    color: #fff;
    user-select: none;
    cursor: pointer;
}

#scoreSaveWrapper {
    margin: 15px 0;
}

#playerNameInput {
    font-size: 18px;
    padding: 6px;
    width: 200px;
}

#saveScoreBtn {
    display: inline-block;
    margin-left: 10px;
    font-size: 20px;
    color: gold;
    cursor: pointer;
    user-select: none;
}

@keyframes gradientShift {
    0%   { background-position: 0% 50%; }
    50%  { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}