/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

/* Container */
.container {
    max-width: 900px;
    margin: 0 auto;
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    overflow: hidden;
}

/* Header */
header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 40px 30px;
    text-align: center;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    animation: fadeInDown 0.8s ease-out;
}

.subtitle {
    font-size: 1.1rem;
    opacity: 0.9;
    animation: fadeInUp 0.8s ease-out;
}

/* Main Content */
main {
    padding: 30px;
}

/* Cards */
.card {
    background: #f8f9fa;
    border-radius: 15px;
    padding: 25px;
    margin-bottom: 20px;
    border-left: 4px solid #667eea;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(102, 126, 234, 0.2);
}

.card h2 {
    color: #667eea;
    margin-bottom: 15px;
    font-size: 1.8rem;
}

.card p {
    color: #555;
    margin-bottom: 10px;
}

.card ul {
    list-style: none;
    padding-left: 0;
}

.card ul li {
    padding: 10px 0;
    padding-left: 30px;
    position: relative;
    color: #555;
}

.card ul li:before {
    content: "✓";
    position: absolute;
    left: 0;
    color: #667eea;
    font-weight: bold;
    font-size: 1.2rem;
}

/* Interactive Card */
.interactive {
    text-align: center;
    background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
}

/* Button */
.btn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 15px 40px;
    font-size: 1.1rem;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
    margin: 20px 0;
    font-weight: 600;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 7px 20px rgba(102, 126, 234, 0.6);
}

.btn:active {
    transform: translateY(0);
}

/* Info Grid */
.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
    margin-top: 15px;
}

.info-item {
    padding: 15px;
    background: white;
    border-radius: 10px;
    text-align: center;
    border: 2px solid #e9ecef;
}

.info-item strong {
    display: block;
    color: #667eea;
    margin-bottom: 5px;
    font-size: 0.9rem;
}

/* Message */
#message {
    margin-top: 20px;
    padding: 20px;
    background: white;
    border-radius: 10px;
    color: #667eea;
    font-weight: 600;
    font-size: 1.2rem;
    animation: fadeIn 0.5s ease-out;
}

.hidden {
    display: none;
}

/* Footer */
footer {
    background: #f8f9fa;
    padding: 30px;
    text-align: center;
    color: #666;
    border-top: 1px solid #e9ecef;
}

footer p {
    line-height: 1.8;
}

/* Animations */
@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

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

/* Responsive Design */
@media (max-width: 768px) {
    header h1 {
        font-size: 2rem;
    }

    .card {
        padding: 20px;
    }

    .card h2 {
        font-size: 1.5rem;
    }

    .info-grid {
        grid-template-columns: 1fr;
    }

    main {
        padding: 20px;
    }
}

@media (max-width: 480px) {
    body {
        padding: 10px;
    }

    header {
        padding: 30px 20px;
    }

    header h1 {
        font-size: 1.8rem;
    }

    .btn {
        padding: 12px 30px;
        font-size: 1rem;
    }
}