body {
    font-family: 'Segoe UI', Arial, sans-serif;
    background: linear-gradient(135deg, #e0e7ff, #c3dafe);
    margin: 0;
    padding: 20px;
    color: #333;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background: #fff;
    border-radius: 15px;
    padding: 30px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.title {
    text-align: center;
    color: #1e40af;
    font-size: 2.5em;
    margin-bottom: 20px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.input-section {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    justify-content: center;
    margin-bottom: 30px;
}

.input-section label {
    font-size: 1.2em;
    color: #1e40af;
    align-self: center;
}

.input-section input, .input-section select {
    padding: 12px;
    font-size: 1em;
    border: 2px solid #93c5fd;
    border-radius: 8px;
    transition: border-color 0.3s;
}

.input-section input:focus, .input-section select:focus {
    outline: none;
    border-color: #1e40af;
}

.button-group {
    display: flex;
    gap: 10px;
}

button {
    padding: 12px 20px;
    font-size: 1em;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: transform 0.2s, background 0.3s;
}

button:hover {
    transform: translateY(-2px);
}

#calculate {
    background: #1e40af;
    color: #fff;
}

#reset {
    background: #ef4444;
    color: #fff;
}

#download {
    background: #10b981;
    color: #fff;
}

.output-section {
    margin-top: 30px;
}

.output-section h2 {
    text-align: center;
    color: #1e40af;
    font-size: 1.8em;
    margin-bottom: 20px;
}

.category-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
}

.category-card {
    background: #f8fafc;
    border-radius: 10px;
    padding: 20px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05);
    transition: transform 0.3s;
}

.category-card:hover {
    transform: translateY(-5px);
}

.category-card h3 {
    margin: 0 0 10px;
    color: #1e40af;
    font-size: 1.2em;
}

.category-card p {
    margin: 0;
    font-size: 1.1em;
    color: #4b5563;
}

.subcategory {
    margin-top: 10px;
    padding-left: 10px;
    border-left: 3px solid #93c5fd;
}

.subcategory p {
    font-size: 0.95em;
    margin: 5px 0;
}

@media (max-width: 768px) {
    .container {
        padding: 15px;
    }

    .title {
        font-size: 2em;
    }

    .input-section {
        flex-direction: column;
        align-items: stretch;
    }

    .input-section input, .input-section select {
        width: 100%;
    }

    .button-group {
        flex-direction: column;
    }

    button {
        width: 100%;
    }

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