body {
    font-family: 'Segoe UI', Arial, sans-serif;
    margin: 0;
    padding: 40px 20px;
    max-width: 800px;
    margin: 0 auto;
    background-color: #f0f2f5;
    color: #1a1a1a;
}

h2 {
    color: #1a73e8;
    text-align: center;
    margin-bottom: 30px;
    font-size: 28px;
    font-weight: 600;
}

form {
    background-color: white;
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    margin-bottom: 20px;
}

.input-group {
    margin: 15px 0;
    padding: 10px;
    border-radius: 8px;
    background-color: #f8f9fa;
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 10px;
    align-items: center;
}

.input-group.date-group {
    grid-template-columns: repeat(3, 1fr);
    margin-top: 10px;
}

.date-field {
    display: flex;
    flex-direction: column;
    gap: 0;
}

.input-group label {
    display: block;
    color: #444;
    font-weight: 500;
    font-size: 14px;
    margin-bottom: 5px;
}

select, input {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid #ddd;
    border-radius: 6px;
    font-size: 14px;
    transition: all 0.3s ease;
    box-sizing: border-box;
}

select:focus, input:focus {
    outline: none;
    border-color: #1a73e8;
    box-shadow: 0 0 0 2px rgba(26,115,232,0.2);
}

input[type="submit"] {
    background-color: #1a73e8;
    color: white;
    padding: 12px 24px;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 16px;
    margin-top: 20px;
    transition: all 0.3s ease;
    width: 100%;
    font-weight: 500;
}

input[type="submit"]:hover {
    background-color: #1557b0;
    box-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

input[type="submit"]:disabled {
    background-color: #ccc;
    cursor: not-allowed;
}

.result {
    margin-top: 20px;
    padding: 25px;
    border-radius: 12px;
    background-color: white;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.result p {
    margin: 10px 0;
    line-height: 1.5;
}

.result strong {
    color: #1a73e8;
}

.error {
    color: #e74c3c;
    padding: 10px;
    border-left: 4px solid #e74c3c;
    background-color: #fde9e8;
    margin: 10px 0;
}

.optional {
    color: #7f8c8d;
    font-size: 0.9em;
    font-style: italic;
}

.invalid-combination {
    color: #999;
    pointer-events: none;
    background-color: #f0f0f0;
}

.debug-info {
    background: #f0f0f0;
    padding: 10px;
    margin: 5px;
    border: 1px solid #ccc;
    border-radius: 4px;
    font-family: monospace;
    font-size: 12px;
}

.conversion-details {
    background-color: #e8f6ff;
    padding: 15px;
    border-radius: 4px;
    margin-top: 15px;
}

.calculation-formula {
    font-family: monospace;
    color: #666;
    padding: 5px;
    background-color: #f8f9fa;
    border-radius: 3px;
}