/* The :root selector is where we can store colors as 'variables' to reuse them easily */
:root {
    --primary-red: #FF5A5F;
    --primary-blue: #4A90E2;
    --primary-yellow: #FFCA28; /* A warm, bright yellow */
    --primary-green: #7ED321;
    --background-color: #F0F8FF; /* AliceBlue, a nice light sky blue */
    --text-color: #333333;
    --white: #FFFFFF;
}

body {
    font-family: 'Nunito', sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    margin: 0;
    padding: 0;
    text-align: center;
}

header {
    background-color: var(--primary-blue);
    color: var(--white);
    padding: 40px 20px;
    border-bottom: 8px solid #3A70B2;
    border-radius: 0 0 40px 40px;
    margin-bottom: 40px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.15);
}

header h1 {
    font-size: 3rem;
    margin: 0;
    text-shadow: 3px 3px 0px rgba(0,0,0,0.2);
}

header p {
    font-size: 1.5rem;
    margin-top: 10px;
    font-weight: 700;
}

main {
    padding: 20px;
    max-width: 1200px;
    margin: 0 auto;
}

main h2 {
    font-size: 2.5rem;
    color: var(--primary-red);
    margin-bottom: 30px;
}

.game-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    padding: 10px;
}

.game-card {
    background-color: var(--white);
    border-radius: 30px;
    padding: 30px 20px;
    box-shadow: 0 8px 0px rgba(0,0,0,0.1);
    transition: transform 0.2s, box-shadow 0.2s;
    border: 5px solid transparent;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.game-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 18px 0px rgba(0,0,0,0.1);
}

.math-theme { border-color: var(--primary-red); }
.balloon-theme { border-color: #9B51E0; } /* Purple theme for balloons */
.code-theme { border-color: var(--primary-blue); }
.word-theme { border-color: var(--primary-yellow); }
.science-theme { border-color: var(--primary-green); }

.card-icon {
    font-size: 5rem;
    margin-bottom: 15px;
}

.game-card h3 {
    font-size: 2rem;
    margin: 0 0 10px 0;
}

.game-card p {
    font-size: 1.2rem;
    line-height: 1.5;
    flex-grow: 1;
}

.play-btn {
    background-color: var(--primary-green);
    color: var(--white);
    border: none;
    padding: 15px 30px;
    font-size: 1.5rem;
    font-weight: 900;
    font-family: 'Nunito', sans-serif;
    border-radius: 50px;
    cursor: pointer;
    box-shadow: 0 6px 0px #5B9E17;
    margin-top: 20px;
    transition: all 0.1s;
    width: 100%;
}

.play-btn:active {
    transform: translateY(6px);
    box-shadow: 0 0px 0px #5B9E17;
}

footer {
    margin-top: 60px;
    padding: 30px;
    background-color: #E6F2FF;
    color: #666;
    font-size: 1.2rem;
    font-weight: 700;
    border-radius: 40px 40px 0 0;
}

@media (max-width: 600px) {
    header h1 { font-size: 2.2rem; }
    header p { font-size: 1.2rem; }
    main h2 { font-size: 2rem; }
    .game-grid { gap: 20px; }
    .game-card { padding: 20px 15px; }
}