body, html {
    height: 100%;
    margin: 0;
    font-family: 'Arial', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    background: linear-gradient(to right, #ff7e5f, #feb47b);
}

.container {
    text-align: center;
    background: rgba(255, 255, 255, 0.2);
    padding: 20px;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    backdrop-filter: blur(10px);
    animation: fadeIn 1s ease-in-out;
    max-width: 90%;
    margin: 20px;
}

h1 {
    color: #fff;
    font-size: 2.5rem;
    margin-bottom: 20px;
    animation: bounce 1s infinite;
}

.mode-buttons {
    margin-bottom: 20px;
}

.mode-button {
    padding: 10px 20px;
    margin: 5px;
    font-size: 1.2rem;
    color: #fff;
    background: #76c7c0;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: background 0.3s, transform 0.3s;
}

.mode-button:hover {
    background: #63b2ab;
    transform: scale(1.05);
}

.board {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
    margin-bottom: 20px;
    width: 100%;
}

.cell {
    width: 100%;
    padding-bottom: 100%; /* Aspect ratio 1:1 */
    background: rgba(255, 255, 255, 0.3);
    border-radius: 15px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 3rem;
    color: #fff;
    cursor: pointer;
    transition: background 0.3s, transform 0.3s;
    animation: slideIn 0.6s ease-in-out;
}

.cell:hover {
    background: rgba(255, 255, 255, 0.5);
    transform: scale(1.05);
}

#reset {
    padding: 10px 20px;
    font-size: 1.2rem;
    color: #feb47b;
    background: #fff;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: background 0.3s, transform 0.3s;
}

#reset:hover {
    background: #fdd6a7;
    transform: scale(1.05);
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}

@keyframes slideIn {
    from { transform: translateY(20px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

@keyframes popIn {
    0% { transform: scale(0.5); }
    100% { transform: scale(1); }
}

/* Media Queries for Responsiveness */
@media (min-width: 600px) {
    h1 {
        font-size: 3rem;
    }

    .board {
        gap: 15px;
    }

    .cell {
        font-size: 3rem;
    }

    #reset {
        font-size: 1.5rem;
    }
}

@media (min-width: 768px) {
    .container {
        max-width: 600px;
    }

    h1 {
        font-size: 3.5rem;
    }

    .board {
        gap: 20px;
    }

    .cell {
        font-size: 3.5rem;
    }

    #reset {
        font-size: 1.7rem;
    }
}