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

body {
    font-family: 'Noto Sans JP', sans-serif;
    background: linear-gradient(180deg, #87CEEB 0%, #F0E68C 100%);
    min-height: 100vh;
    overflow: hidden;
}

.game-container {
    position: relative;
    width: 100vw;
    height: 100vh;
}

.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    padding: 1rem;
    z-index: 1000;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.header h1 {
    font-size: 1.5rem;
    color: #2C5F2D;
    font-weight: 600;
}

.stats {
    display: flex;
    gap: 2rem;
    font-weight: 600;
    color: #2C5F2D;
}

.game-screen {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    background: rgba(255, 255, 255, 0.95);
    z-index: 500;
}

.instructions {
    text-align: center;
    background: white;
    padding: 2rem;
    border-radius: 20px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    max-width: 400px;
}

.instructions p {
    margin-bottom: 1rem;
    color: #2C5F2D;
    font-size: 1.1rem;
}

.start-btn, .restart-btn {
    background: #4CAF50;
    color: white;
    border: none;
    padding: 1rem 2rem;
    font-size: 1.1rem;
    border-radius: 50px;
    cursor: pointer;
    font-family: inherit;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(76, 175, 80, 0.3);
}

.start-btn:hover, .restart-btn:hover {
    background: #45a049;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(76, 175, 80, 0.4);
}

.beach {
    position: absolute;
    top: 80px;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(180deg, transparent 0%, #F4A460 100%);
    cursor: crosshair;
}

.shell {
    position: absolute;
    font-size: 2rem;
    cursor: pointer;
    user-select: none;
    animation: pulse 2s infinite alternate;
    transition: all 0.3s ease;
    z-index: 10;
}

.shell:hover {
    transform: scale(1.2);
    filter: brightness(1.2);
}

.shell.non-shell:hover {
    transform: scale(1.2);
    filter: brightness(1.2) hue-rotate(20deg);
}

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

@keyframes collect {
    0% {
        transform: scale(1);
        opacity: 1;
    }
    50% {
        transform: scale(1.5) rotate(180deg);
        opacity: 0.7;
    }
    100% {
        transform: scale(0) rotate(360deg);
        opacity: 0;
    }
}

.shell.collected {
    animation: collect 0.5s ease-out forwards;
    pointer-events: none;
}

.game-over {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    background: rgba(255, 255, 255, 0.95);
    z-index: 600;
}

.game-over.show {
    display: flex;
}

.game-over h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: #2C5F2D;
}

.game-over p {
    font-size: 1.5rem;
    margin-bottom: 2rem;
    color: #666;
}

.hidden {
    display: none !important;
}

/* Mobile responsiveness */
@media (max-width: 768px) {
    .header h1 {
        font-size: 1.2rem;
    }
    
    .stats {
        gap: 1rem;
        font-size: 0.9rem;
    }
    
    .shell {
        font-size: 1.8rem;
    }
    
    .instructions {
        padding: 1.5rem;
        margin: 0 1rem;
    }
    
    .game-over h2 {
        font-size: 2rem;
    }
    
    .game-over p {
        font-size: 1.2rem;
    }
}

/* Wave animation at the bottom */
.beach::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 100px;
    background: url("data:image/svg+xml,%3Csvg width='100' height='20' viewBox='0 0 100 20' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M21.184 20c.357-.13.72-.264 1.088-.402l1.768-.661C33.64 15.347 39.647 14 50 14c10.271 0 15.362 1.335 24.629 4.928l1.660.643c.364.14.725.277 1.075.41C85.966 21.86 93.333 23 100 23v-3H0v.019c2.875.29 5.813.513 8.815.669z' fill='%23ffffff' fill-opacity='0.4'/%3E%3C/svg%3E") repeat-x;
    animation: wave 3s linear infinite;
}

@keyframes wave {
    0% { background-position: 0 0; }
    100% { background-position: 100px 0; }
}