:root {
    --bg-color: #1e1e1e;
    --card-bg-color: #2a2a2a;
    --text-color: #e0e0e0;
    --primary-color: #007acc;
    --border-color: #444;
    --input-bg-color: #333;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

.container {
    max-width: 800px;
    margin: 2rem auto;
    padding: 2rem;
}

header {
    text-align: center;
    margin-bottom: 2rem;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.card {
    background-color: var(--card-bg-color);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}

.file-input-wrapper {
    display: flex;
    align-items: center;
}

.file-input-label {
    background-color: var(--primary-color);
    color: white;
    padding: 0.6rem 1rem;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s;
}

.file-input-label:hover {
    background-color: #005a9e;
}

#file-input {
    display: none;
}

#file-name {
    margin-left: 1rem;
    font-style: italic;
    color: #aaa;
}

.tabs {
    display: flex;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 1.5rem;
}

.tab-link {
    background: none;
    border: none;
    color: var(--text-color);
    padding: 1rem 1.5rem;
    cursor: pointer;
    font-size: 1rem;
    transition: background-color 0.3s, border-bottom 0.3s;
    border-bottom: 3px solid transparent;
}

.tab-link.active, .tab-link:hover {
    border-bottom: 3px solid var(--primary-color);
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

.form-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
}

.field-group {
    display: flex;
    flex-direction: column;
}

.field-group label {
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.field-group input[type="text"], .field-group select {
    width: 100%;
    padding: 0.7rem;
    background-color: var(--input-bg-color);
    border: 1px solid var(--border-color);
    color: var(--text-color);
    border-radius: 5px;
    font-size: 1rem;
}

.options-group {
    display: flex;
    gap: 1.5rem;
    align-items: center;
    margin-top: 1rem;
}

.generate-btn {
    width: 100%;
    padding: 1rem;
    font-size: 1.2rem;
    font-weight: 600;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s;
}

.generate-btn:hover {
    background-color: #005a9e;
}