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

body {
    font-family: Arial, sans-serif;
    background: linear-gradient(135deg, #1e3c72, #2a5298);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

.game-container {
    background-color: rgba(255, 255, 255, 0.9);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.2);
    text-align: center;
}

.score-board {
    margin-bottom: 1rem;
}

.score-board h1 {
    color: #2a5298;
    margin-bottom: 1rem;
}

.power-ups {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin: 1rem 0;
}

.power-up {
    background: rgba(42, 82, 152, 0.1);
    padding: 0.5rem;
    border-radius: 8px;
    cursor: pointer;
    transition: transform 0.2s;
}

.power-up:hover {
    transform: scale(1.1);
}

.power-up-count {
    display: block;
    font-size: 0.8rem;
    color: #2a5298;
}

.difficulty-selector {
    margin: 1rem 0;
}

.difficulty-btn {
    background-color: #2a5298;
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    margin: 0 0.5rem;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s;
}

.difficulty-btn:hover {
    background-color: #1e3c72;
}

.difficulty-btn.active {
    background-color: #1e3c72;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.2);
}

#game-area {
    width: 600px;
    height: 400px;
    background-color: rgba(255, 255, 255, 0.8);
    border: 2px solid #2a5298;
    border-radius: 10px;
    position: relative;
    overflow: hidden;
    margin: 1rem 0;
}

.bubble {
    position: absolute;
    border-radius: 50%;
    background: radial-gradient(circle at 30% 30%, #ffffff, #2a5298);
    cursor: pointer;
    transition: transform 0.1s;
}

.bubble:hover {
    transform: scale(1.1);
}

.bubble.power-up {
    animation: pulse 1s infinite;
}

.bubble.frozen {
    background: radial-gradient(circle at 30% 30%, #ffffff, #00bfff);
    animation: none;
}

.bubble.speed {
    background: radial-gradient(circle at 30% 30%, #ffffff, #ff4500);
}

@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.1); }
    100% { transform: scale(1); }
}

#start-button {
    background-color: #2a5298;
    color: white;
    border: none;
    padding: 1rem 2rem;
    font-size: 1.2rem;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s;
}

#start-button:hover {
    background-color: #1e3c72;
}

#score, #time, #level {
    font-weight: bold;
    color: #2a5298;
}