:root {
    --primary-color: #4a90e2;
    --secondary-color: #f5f7fa;
    --text-color: #333;
    --border-color: #dce1e6;
    --success-color: #4caf50;
    --error-color: #f44336;
    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

body {
    font-family: var(--font-family);
    background-color: var(--secondary-color);
    color: var(--text-color);
    margin: 0;
    padding: 2rem;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    line-height: 1.6;
}

.container {
    width: 100%;
    max-width: 800px;
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    overflow: hidden;
}

header {
    background: var(--primary-color);
    color: #fff;
    padding: 1.5rem 2rem;
    text-align: center;
}

header h1 {
    margin: 0;
    font-size: 1.8rem;
}

header p {
    margin: 0.5rem 0 0;
    opacity: 0.9;
}

main {
    padding: 2rem;
}

.wizard-step {
    display: none;
}

.wizard-step.active {
    display: block;
}

h2 {
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: 0.5rem;
    margin-top: 0;
    margin-bottom: 1.5rem;
    color: var(--primary-color);
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.form-group small {
    display: block;
    color: #777;
    margin-top: -0.25rem;
    margin-bottom: 0.5rem;
    font-size: 0.85rem;
}

input[type="text"],
select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    box-sizing: border-box;
    font-size: 1rem;
    transition: border-color 0.2s;
}

input[type="text"]:focus,
select:focus {
    outline: none;
    border-color: var(--primary-color);
}

.bone-mapping-grid, .expression-mapping-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1rem;
}

.bone-mapping-item, .expression-mapping-item {
    display: flex;
    flex-direction: column;
}

.bone-mapping-item label, .expression-mapping-item label {
    font-size: 0.9rem;
    font-weight: 500;
}

.required-field::after {
    content: ' *';
    color: var(--error-color);
    font-weight: bold;
}

.button-group {
    display: flex;
    justify-content: space-between;
    margin-top: 2rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border-color);
}

button {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 4px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s;
}

button:active {
    transform: translateY(1px);
}

.btn-primary {
    background-color: var(--primary-color);
    color: #fff;
}

.btn-primary:hover {
    background-color: #3a80d2;
}

.btn-secondary {
    background-color: #e0e0e0;
    color: var(--text-color);
}

.btn-secondary:hover {
    background-color: #d0d0d0;
}

.btn-success {
    background-color: var(--success-color);
    color: #fff;
}

.btn-success:hover {
    background-color: #388e3c;
}

button:disabled {
    background-color: #ccc;
    cursor: not-allowed;
}

#file-upload-section {
    text-align: center;
}

#file-upload-label {
    display: inline-block;
    padding: 1rem 2rem;
    background: var(--primary-color);
    color: #fff;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1.1rem;
}

#file-upload-label:hover {
    background-color: #3a80d2;
}

#file-upload {
    display: none;
}

#file-name {
    margin-top: 1rem;
    font-style: italic;
    color: #555;
}

#status-log {
    margin-top: 1.5rem;
    padding: 1rem;
    background: #f0f0f0;
    border-radius: 4px;
    font-family: 'Courier New', Courier, monospace;
    font-size: 0.9rem;
    white-space: pre-wrap;
    word-wrap: break-word;
    max-height: 200px;
    overflow-y: auto;
}