body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f4f7f6;
    color: #333;
    line-height: 1.6;
    margin: 0;
    padding: 20px;
    display: flex;
    justify-content: center;
    align-items: flex-start; /* Align to top */
    min-height: 100vh;
}

.container {
    background-color: #fff;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    width: 95%;
    max-width: 800px;
    text-align: center;
}

h1 {
    color: #2c3e50;
    margin-bottom: 30px;
    font-size: 2.5em;
}

h2 {
    color: #34495e;
    border-bottom: 2px solid #e0e0e0;
    padding-bottom: 10px;
    margin-bottom: 20px;
    text-align: left;
    font-size: 1.8em;
}

.section {
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 1px solid #eee;
}

.section:last-child {
    border-bottom: none;
    margin-bottom: 0;
}

.input-group {
    margin-bottom: 20px;
    text-align: left;
}

.input-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: bold;
    color: #555;
}

.input-group input[type="number"] {
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 5px;
    width: 80px;
    margin-right: 10px;
    font-size: 1em;
}

.number-selector {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 10px;
}

.number-selector button {
    padding: 8px 12px;
    border: 1px solid #aaa;
    border-radius: 5px;
    background-color: #f0f0f0;
    cursor: pointer;
    font-size: 0.95em;
    transition: background-color 0.2s ease, border-color 0.2s ease;
    min-width: 35px; /* Ensure consistent button width */
    text-align: center;
    box-sizing: border-box; /* Include padding and border in the element's total width and height */
}

.number-selector button.selected {
    background-color: #4CAF50; /* Green */
    color: white;
    border-color: #4CAF50;
}

.number-selector button.excluded {
    background-color: #f44336; /* Red */
    color: white;
    border-color: #f44336;
}

.selected-numbers {
    margin-top: 10px;
    font-size: 0.9em;
    color: #777;
    display: flex;
    flex-wrap: wrap;
    gap: 5px;
}

.selected-numbers span {
    background-color: #e0f7fa;
    padding: 3px 8px;
    border-radius: 3px;
    border: 1px solid #b2ebf2;
}

button#generate-btn {
    background-color: #007bff;
    color: white;
    padding: 15px 25px;
    border: none;
    border-radius: 8px;
    font-size: 1.2em;
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.2s ease;
    margin-top: 20px;
}

button#generate-btn:hover {
    background-color: #0056b3;
    transform: translateY(-2px);
}

.results-section {
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid #eee;
}

#results-textarea {
    width: 100%;
    padding: 15px;
    border: 1px solid #ccc;
    border-radius: 8px;
    font-size: 1em;
    box-sizing: border-box;
    background-color: #f8f9fa;
    color: #333;
    resize: vertical; /* Allow vertical resizing */
}