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

body {
    font-family: Arial, sans-serif;
    background: linear-gradient(135deg, #4facfe, #00f2fe);
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

.container {
    text-align: center;
    background: white;
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 8px 20px rgba(0,0,0,0.2);
}

h1 {
    margin-bottom: 20px;
}

.coin {
    width: 150px;
    height: 150px;
    position: relative;
    margin: 20px auto;
    transform-style: preserve-3d;
}

.coin.flip-heads {
    animation: flipHeads 2s forwards;
}

.coin.flip-tails {
    animation: flipTails 2s forwards;
}

.side {
    position: absolute;
    width: 100%;
    height: 100%;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 3rem;
    font-weight: bold;
    color: white;
    backface-visibility: hidden;
}

.heads {
    background: gold;
}

.tails {
    background: silver;
    transform: rotateY(180deg);
}

button {
    padding: 12px 24px;
    font-size: 1rem;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    background: #4facfe;
    color: white;
    transition: 0.3s;
}

button:hover {
    background: #2196f3;
}

#result {
    margin-top: 20px;
    font-size: 1.2rem;
    font-weight: bold;
}

@keyframes flipHeads {
    from {
        transform: rotateY(0deg);
    }
    to {
        transform: rotateY(1800deg);
    }
}

@keyframes flipTails {
    from {
        transform: rotateY(0deg);
    }
    to {
        transform: rotateY(1980deg);
    }
}