:root {
    --primary: #4f46e5;
    --primary-hover: #4338ca;
    --secondary: #10b981;
    --secondary-hover: #059669;
    --background: #f3f4f6;
    --surface: #ffffff;
    --text-main: #111827;
    --text-muted: #6b7280;
    --border: #e5e7eb;
    --error: #ef4444;
    --radius-lg: 12px;
    --radius-md: 8px;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--background);
    color: var(--text-main);
    line-height: 1.5;
    padding: 2rem;
}

.container {
    max-width: 900px;
    margin: 0 auto;
}

header {
    text-align: center;
    margin-bottom: 3rem;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, var(--primary), #9333ea);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

header p {
    color: var(--text-muted);
    font-size: 1.1rem;
}

.upload-section {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    margin-bottom: 1.5rem;
}

@media (max-width: 768px) {
    .upload-section {
        grid-template-columns: 1fr;
    }
}

.card {
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border);
    transition: box-shadow 0.3s ease;
}

.card:hover {
    box-shadow: var(--shadow-md);
}

.card h2 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.card p {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.drop-zone {
    border: 2px dashed var(--border);
    border-radius: var(--radius-md);
    padding: 2rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s ease;
    background-color: #fafafa;
}

.drop-zone:hover, .drop-zone.dragover {
    border-color: var(--primary);
    background-color: #eff6ff;
}

.drop-zone .icon {
    font-size: 2.5rem;
    display: block;
    margin-bottom: 0.5rem;
}

.browse-link {
    color: var(--primary);
    font-weight: 500;
    text-decoration: underline;
}

.file-list {
    margin-top: 1rem;
}

.file-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--background);
    padding: 0.5rem 0.75rem;
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    margin-bottom: 0.5rem;
}

.file-item .remove {
    color: var(--error);
    cursor: pointer;
    font-weight: bold;
}

.options-section {
    margin-bottom: 2rem;
}

.option-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.option-group label {
    font-weight: 500;
}

.option-group select {
    padding: 0.6rem;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    font-family: inherit;
    font-size: 1rem;
    max-width: 400px;
}

.hint {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.action-section {
    text-align: center;
}

.primary-btn {
    background-color: var(--primary);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    padding: 1rem 2.5rem;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s;
    box-shadow: var(--shadow-md);
}

.primary-btn:hover:not(:disabled) {
    background-color: var(--primary-hover);
}

.primary-btn:disabled {
    background-color: var(--text-muted);
    cursor: not-allowed;
    opacity: 0.7;
    box-shadow: none;
}

.status-message {
    margin-top: 1.5rem;
    padding: 1rem;
    border-radius: var(--radius-md);
    text-align: center;
    font-weight: 500;
}

.status-message.hidden {
    display: none;
}

.status-message.success {
    background-color: #d1fae5;
    color: #065f46;
    border: 1px solid #34d399;
}

.status-message.error {
    background-color: #fee2e2;
    color: #991b1b;
    border: 1px solid #f87171;
}

.status-message.loading {
    background-color: #e0e7ff;
    color: #3730a3;
    border: 1px solid #818cf8;
}