:root {
    --primary-color: #4a90e2;
    --secondary-color: #f5a623;
    --background-color: #f8f9fa;
    --card-background: #ffffff;
    --text-color: #333333;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --glow-color: rgba(74, 144, 226, 0.5);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
}

header {
    background-color: var(--primary-color);
    color: white;
    text-align: center;
    padding: 2rem 1rem;
    background-image: linear-gradient(45deg, var(--primary-color), var(--secondary-color));
}

header h1 {
    margin: 0;
    font-size: 2.5rem;
    font-weight: 700;
    text-shadow: 1px 1px 3px var(--shadow-color);
}

#login-btn {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background-color: var(--secondary-color);
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

#login-btn:hover {
    background-color: #e0930f;
}

.modal {
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0,0,0,0.5);
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-content {
    background-color: var(--card-background);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 8px 16px var(--shadow-color);
    width: 90%;
    max-width: 400px;
    position: relative;
    animation: modal-fade-in 0.3s;
}

@keyframes modal-fade-in {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.close-btn {
    color: #aaa;
    position: absolute;
    top: 1rem;
    right: 1rem;
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
}

.close-btn:hover,
.close-btn:focus {
    color: #333;
}

#login-form h2 {
    margin-top: 0;
}

#login-form input {
    width: 100%;
    padding: 0.75rem;
    margin-bottom: 1rem;
    border: 1px solid #ddd;
    border-radius: 8px;
    box-sizing: border-box;
}

#login-form button {
    width: 100%;
    padding: 0.75rem;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

#login-form button:hover {
    background-color: #3a7bc8;
}

main {
    padding: 2rem 1rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

site-card {
    background-color: var(--card-background);
    border-radius: 12px;
    box-shadow: 0 8px 16px var(--shadow-color);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

site-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 24px var(--shadow-color), 0 0 15px var(--glow-color);
}

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