:root {
    --bg-color: #0a0e17;
    --accent-color: #00f2ff;
    --text-color: #ffffff;
    --bubble-glow: rgba(0, 242, 255, 0.6);
}

body, html {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    background-color: var(--bg-color);
    font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    color: var(--text-color);
    user-select: none;
    -webkit-tap-highlight-color: transparent;
}

#game-container {
    position: relative;
    width: 100vw;
    height: 100vh;
    background: radial-gradient(circle at center, #1a2a4a 0%, #0a0e17 100%);
}

#ui {
    position: absolute;
    top: 20px;
    left: 0;
    right: 0;
    display: flex;
    justify-content: space-between;
    padding: 0 30px;
    pointer-events: none;
    z-index: 10;
}

#score-board, #timer-board {
    font-size: 24px;
    font-weight: bold;
    text-shadow: 0 0 10px var(--accent-color);
}

.screen {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: rgba(10, 14, 23, 0.8);
    z-index: 20;
    text-align: center;
}

#start-screen, #game-over-screen {
    transition: opacity 0.3s ease;
}

.hidden {
    display: none !important;
    opacity: 0;
}

h1 {
    font-size: 4rem;
    margin-bottom: 10px;
    color: var(--accent-color);
    text-shadow: 0 0 20px var(--accent-color);
    animation: float 3s ease-in-out infinite;
}

p {
    font-size: 1.2rem;
    margin-bottom: 30px;
    opacity: 0.8;
}

button {
    padding: 15px 40px;
    font-size: 1.5rem;
    background: transparent;
    color: var(--accent-color);
    border: 2px solid var(--accent-color);
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.2s;
    box-shadow: 0 0 15px var(--bubble-glow);
    text-transform: uppercase;
    letter-spacing: 2px;
}

button:hover {
    background: var(--accent-color);
    color: var(--bg-color);
    box-shadow: 0 0 30px var(--accent-color);
}

.bubble {
    position: absolute;
    border-radius: 50%;
    cursor: pointer;
    background: radial-gradient(circle at 30% 30%, rgba(255, 255, 255, 0.4) 0%, rgba(0, 242, 255, 0.3) 40%, rgba(0, 242, 255, 0.1) 100%);
    box-shadow: inset 0 0 20px rgba(255, 255, 255, 0.5), 0 0 15px var(--bubble-glow);
    border: 1px solid rgba(255, 255, 255, 0.3);
    animation: rise linear forwards;
}

@keyframes rise {
    from { transform: translateY(110vh) scale(1); }
    to { transform: translateY(-20vh) scale(1.1); }
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-20px); }
}

.pop-effect {
    position: absolute;
    pointer-events: none;
    border-radius: 50%;
    border: 2px solid var(--accent-color);
    animation: pop 0.3s ease-out forwards;
}

@keyframes pop {
    0% { transform: scale(0.5); opacity: 1; }
    100% { transform: scale(2); opacity: 0; }
}