:root {
    --primary-color: #2c3e50;
    --accent-color: #3498db;
    --accent-hover: #2980b9;
    --bg-color: #f8f9fa;
    --card-bg: #ffffff;
    --text-color: #333;
    --light-text: #7f8c8d;
    --shadow-sm: 0 2px 5px rgba(0,0,0,0.05);
    --shadow-md: 0 5px 15px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 25px rgba(0,0,0,0.15);
    --font-heading: 'Poppins', sans-serif;
    --font-body: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    --gradient-hero: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

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

body {
    font-family: var(--font-body);
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

/* Hero Section */
.hero {
    background: var(--gradient-hero);
    color: white;
    padding: 60px 20px;
    text-align: center;
    border-radius: 0 0 50px 50px;
    margin-bottom: 40px;
}

.hero h1 {
    font-family: var(--font-heading);
    font-size: 2.5rem;
    margin-bottom: 10px;
    font-weight: 700;
}

.hero p {
    font-size: 1.2rem;
    opacity: 0.9;
    max-width: 600px;
    margin: 0 auto;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Grid Layout */
.quiz-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    padding-bottom: 60px;
}

/* Card Styles */
.card {
    background: var(--card-bg);
    border-radius: 15px;
    box-shadow: var(--shadow-sm);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.card-image {
    height: 160px;
    background: linear-gradient(45deg, #f0f2f5, #e1e4e8);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 4rem;
}

.card-image.blue { background: linear-gradient(135deg, #a1c4fd 0%, #c2e9fb 100%); color: #fff; }
.card-image.purple { background: linear-gradient(135deg, #e0c3fc 0%, #8ec5fc 100%); color: #fff; }
.card-image.orange { background: linear-gradient(135deg, #f6d365 0%, #fda085 100%); color: #fff; }
.card-image.green { background: linear-gradient(135deg, #84fab0 0%, #8fd3f4 100%); color: #fff; }

.card-content {
    padding: 20px;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.card-title {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    margin-bottom: 10px;
    color: var(--primary-color);
}

.card-desc {
    font-size: 0.9rem;
    color: var(--light-text);
    margin-bottom: 20px;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 10px 20px;
    background-color: var(--accent-color);
    color: white;
    text-decoration: none;
    border-radius: 25px;
    text-align: center;
    font-weight: 600;
    transition: background-color 0.2s;
    border: none;
    width: 100%;
}

.btn:hover {
    background-color: var(--accent-hover);
}

/* Footer */
footer {
    text-align: center;
    padding: 20px;
    color: var(--light-text);
    font-size: 0.9rem;
    border-top: 1px solid #eee;
    margin-top: auto;
}

@media (max-width: 600px) {
    .hero {
        padding: 40px 20px;
        border-radius: 0 0 30px 30px;
    }
    .hero h1 {
        font-size: 2rem;
    }
}