:root {
    --primary-color: #2e7d32;
    --primary-light: #4caf50;
    --primary-dark: #1b5e20;
    --bg-color: #f1f8e9;
    --card-bg: #ffffff;
    --text-color: #333333;
    --text-light: #666666;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 10px 15px rgba(0, 0, 0, 0.15);
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

header {
    background: linear-gradient(135deg, var(--primary-dark), var(--primary-color));
    color: white;
    padding: 3rem 1rem;
    text-align: center;
    margin-bottom: 2rem;
    box-shadow: var(--shadow);
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    font-weight: 700;
}

header p {
    font-size: 1.1rem;
    opacity: 0.9;
}

main {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem 3rem 1rem;
}

.grid-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 2rem;
}

.card {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 2rem;
    text-align: center;
    box-shadow: var(--shadow);
    transition: var(--transition);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: space-between;
    height: 100%;
}

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

.card-icon {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    background: #e8f5e9;
    width: 80px;
    height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: var(--transition);
}

.card:hover .card-icon {
    background: var(--primary-color);
    color: white;
}

.card h2 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
    color: var(--primary-dark);
}

.card p {
    font-size: 0.9rem;
    color: var(--text-light);
    margin-bottom: 1.5rem;
}

.btn-join {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    background-color: var(--primary-color);
    color: white;
    text-decoration: none;
    padding: 0.75rem 1.5rem;
    border-radius: 25px;
    font-weight: 600;
    transition: var(--transition);
    width: 100%;
}

.btn-join:hover {
    background-color: var(--primary-dark);
    transform: scale(1.02);
}

footer {
    text-align: center;
    padding: 2rem;
    background-color: var(--primary-dark);
    color: white;
    margin-top: auto;
}

footer p {
    opacity: 0.8;
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
}

.sponsor {
    margin-top: 0.5rem;
    font-size: 0.85rem;
}

.sponsor a {
    color: #a5d6a7;
    text-decoration: none;
    font-weight: 600;
    transition: color 0.3s;
}

.sponsor a:hover {
    color: white;
    text-decoration: underline;
}

/* Responsive adjustments */
@media (max-width: 600px) {
    header h1 {
        font-size: 2rem;
    }

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

/* Detail Page Styles */
.detail-main {
    max-width: 800px;
}

.back-link {
    position: absolute;
    left: 20px;
    top: 30px;
    color: white;
    text-decoration: none;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: opacity 0.3s;
}

.back-link:hover {
    opacity: 0.8;
}

.detail-card {
    background: white;
    border-radius: 12px;
    padding: 3rem;
    box-shadow: var(--shadow);
    text-align: left;
}

.detail-icon {
    font-size: 4rem;
    color: var(--primary-color);
    text-align: center;
    margin-bottom: 2rem;
    background: #e8f5e9;
    width: 120px;
    height: 120px;
    line-height: 120px;
    border-radius: 50%;
    margin-left: auto;
    margin-right: auto;
}

.detail-title {
    font-size: 2rem;
    text-align: center;
    color: var(--primary-dark);
    margin-bottom: 3rem;
    border-bottom: 2px solid #eee;
    padding-bottom: 1rem;
}

.detail-section {
    margin-bottom: 2.5rem;
}

.detail-section h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.4rem;
}

.rules-list {
    list-style: none;
}

.rules-list li {
    margin-bottom: 0.8rem;
    padding-left: 1.5rem;
    position: relative;
    color: var(--text-color);
}

.rules-list li i {
    position: absolute;
    left: 0;
    top: 5px;
    color: var(--primary-light);
    font-size: 0.9em;
}

.action-area {
    text-align: center;
    margin-top: 3rem;
}

.btn-large {
    font-size: 1.2rem;
    padding: 1rem 3rem;
    border-radius: 50px;
}

@media (max-width: 768px) {
    .back-link span {
        display: none;
    }

    .detail-card {
        padding: 1.5rem;
    }

    .detail-title {
        font-size: 1.5rem;
    }
}