body {
    font-family: 'Inter', sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f0f2f5; /* Light gray background, common in dev tools/spaces */
    color: #333;
    line-height: 1.6;
}

header {
    background-color: #ffffff;
    padding: 20px 40px;
    text-align: center;
    border-bottom: 1px solid #e0e0e0;
    margin-bottom: 30px;
}

header h1 {
    margin: 0 0 10px 0;
    color: #1a1a1a;
    font-weight: 700;
}

header p {
    margin-bottom: 20px;
    color: #555;
}

.filter-container input[type="text"] {
    padding: 10px 15px;
    width: 100%;
    max-width: 400px;
    border: 1px solid #ccc;
    border-radius: 25px; /* Rounded search bar */
    box-sizing: border-box;
    font-size: 16px;
    transition: border-color 0.3s;
}

.filter-container input[type="text"]:focus {
    border-color: #007bff; /* Highlight on focus */
    outline: none;
}

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

.category-section {
    margin-bottom: 40px;
}

.category-title {
    font-size: 1.8em;
    font-weight: 600;
    color: #2c3e50; /* Darker blue for titles */
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid #3498db; /* Accent color */
}

.newsletter-grid-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); /* Responsive grid */
    gap: 25px;
}

.newsletter-card {
    background-color: #ffffff;
    border: 1px solid #e0e0e0;
    border-radius: 8px; /* Rounded corners for cards */
    padding: 20px;
    box-shadow: 0 4px 8px rgba(0,0,0,0.05); /* Subtle shadow */
    transition: transform 0.2s ease-in-out, box-shadow 0.2s ease-in-out;
    display: flex;
    flex-direction: column;
    justify-content: space-between; /* Pushes link to bottom */
}

.newsletter-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 12px rgba(0,0,0,0.1);
}

.newsletter-card h3 {
    font-size: 1.3em;
    margin-top: 0;
    margin-bottom: 10px;
    color: #333;
    font-weight: 600;
}

.newsletter-card p {
    font-size: 0.95em;
    color: #555;
    flex-grow: 1; /* Allows paragraph to take available space */
    margin-bottom: 15px;
}

.newsletter-card a {
    display: inline-block;
    background-color: #007bff; /* Primary button color */
    color: white;
    padding: 10px 15px;
    text-decoration: none;
    border-radius: 5px;
    text-align: center;
    font-weight: 500;
    transition: background-color 0.2s;
    margin-top: auto; /* Pushes link to the bottom */
}

.newsletter-card a:hover {
    background-color: #0056b3; /* Darker on hover */
}

footer {
    text-align: center;
    padding: 20px;
    margin-top: 40px;
    background-color: #343a40; /* Dark footer */
    color: #f8f9fa;
    font-size: 0.9em;
}

footer a {
    color: #6cb2eb; /* Lighter blue for links in dark footer */
    text-decoration: none;
}

footer a:hover {
    text-decoration: underline;
}