:root {
    --bg-color: #1a1a1a;
    --primary-text-color: #ffffff;
    --secondary-text-color: #cccccc;
    --border-color: #444;
    --panel-bg-color: #2c2c2c;
    --button-bg-color: #3d3d3d;
    --button-hover-bg-color: #555555;
    --font-family: 'Helvetica Neue', Arial, sans-serif;
    --app-height: 100vh; /* Fallback */
}

html, body {
    height: var(--app-height);
    margin: 0;
    background-color: var(--bg-color);
    color: var(--primary-text-color);
    font-family: var(--font-family);
    overflow: hidden;
}

.game-container {
    display: flex;
    flex-direction: column;
    height: 100%;
    width: 100%;
    max-width: 400px;
    margin: 0 auto;
    padding: 4px;
    box-sizing: border-box;
    gap: 4px;
}

.top-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 8px;
    background-color: var(--panel-bg-color);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    flex-shrink: 0;
    font-size: 0.8rem;
    height: 24px;
    box-sizing: border-box;
}

.top-bar > span {
    color: var(--secondary-text-color);
}

#score {
    font-weight: bold;
    color: #4dff4d;
    margin-left: 4px;
}

.next-container {
    display: flex;
    align-items: center;
    gap: 4px;
    color: var(--secondary-text-color);
}

#next-block-canvas {
    background-color: #000;
    border-radius: 3px;
    width: 20px;
    height: 20px;
}

.game-main {
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-grow: 1;
    min-height: 0;
}

#game-board {
    border: 2px solid var(--border-color);
    background-color: #000;
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
}

.bottom-bar {
    flex-shrink: 0;
}

.controls {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 4px;
}

.controls button {
    padding: 4px;
    font-size: 1.2rem;
    font-weight: bold;
    cursor: pointer;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    background-color: var(--button-bg-color);
    color: var(--primary-text-color);
    transition: background-color 0.3s, transform 0.1s;
    user-select: none;
    line-height: 1;
}

.controls button:hover {
    background-color: var(--button-hover-bg-color);
}

.controls button:active {
    transform: scale(0.95);
}

.game-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.75);
    color: white;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
}

.game-overlay h2 {
    font-size: 2em;
    margin: 0 0 15px 0;
}

.final-score-text {
    font-size: 1.5em;
    color: #4dff4d; /* Bright green */
    margin: 0 0 20px 0;
    font-weight: bold;
}

#game-clear-screen h2 {
    color: #4dff4d;
}

#start-screen h1 {
    font-size: 2.5em;
    margin: 0 0 20px 0;
}

.game-overlay button {
    padding: 10px 20px;
    font-size: 1em;
    cursor: pointer;
    border: none;
    border-radius: 5px;
    background-color: var(--button-bg-color);
    color: var(--primary-text-color);
    transition: background-color 0.3s;
}

.game-overlay button:hover {
    background-color: var(--button-hover-bg-color);
}

@media (min-width: 768px) {
    .game-container {
        max-width: 600px;
        padding: 8px;
        gap: 8px;
    }

    .top-bar {
        font-size: 1.2rem;
        height: 40px;
        padding: 0 12px;
    }

    #next-block-canvas {
        width: 40px;
        height: 40px;
    }

    .controls button {
        font-size: 1.5rem;
        padding: 8px;
    }

    .game-overlay h2 {
        font-size: 3em;
    }

    .final-score-text {
        font-size: 2em;
    }

    #start-screen h1 {
        font-size: 3.5em;
    }

    .game-overlay button {
        padding: 15px 30px;
        font-size: 1.2em;
    }
}