body {
    text-align: center;
    background-color: #011F3F; 
    font-family: 'Poppins', sans-serif;
    color: #FEF2BF;
    margin: 0;
    padding-top: 1rem;
}

h1 {
    font-size: 3rem;
    margin-bottom: 0.5rem;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
}

h2 {
    font-size: 1.5rem;
    font-weight: 400;
    margin-top: 0;
    margin-bottom: 1rem;
}

.btn-container {
    display: flex;
    justify-content: center;
    flex-wrap: wrap; 
}

.btn {
    height: 180px;
    width: 180px;
    border-radius: 20%;
    border: 8px solid #444;
    margin: 2rem 1rem;
    box-shadow: 5px 5px 10px rgba(0, 0, 0, 0.4);
    transition: all 0.1s ease-in-out;
    font-size: 0; 
}

.btn:hover {
    cursor: pointer;
    filter: brightness(1.1);
}

.btn:active {
    transform: scale(0.97);
    box-shadow: inset 2px 2px 8px rgba(0, 0, 0, 0.6);
}

.red {
    background-color: #c72c41;
}

.purple {
    background-color: #8E44AD;
}

.orange {
    background-color: #ee9f27;
}

.blue {
    background-color: #2D82B5;
}

.gameflash {
    background-color: white;
    box-shadow: 0 0 20px white;
    border-color: white;
}

.usercorrectflash {
    background-color: #63F282;
    box-shadow: 0 0 20px #63F282;
    border-color: #63F282;
}

.userwrongflash {
    background-color: #E74C3C;
    box-shadow: 0 0 20px #E74C3C;
    border-color: #E74C3C;
    animation: shake 0.5s;
}

body.game-over {
    background-color: #5E0B15; 
    transition: background-color 0.5s ease;
}

@keyframes shake {
  10%, 90% { transform: translateX(-5px); }
  20%, 80% { transform: translateX(5px); }
  30%, 50%, 70% { transform: translateX(-3px); }
  40%, 60% { transform: translateX(3px); }
}