:root {
    --bg-color: #0f172a;
    --card-bg: #1e293b;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --primary: #8b5cf6;
    --primary-hover: #7c3aed;
    --success: #10b981;
    --border: #334155;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 100vh;
}

.container {
    background-color: var(--card-bg);
    border-radius: 12px;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.5), 0 4px 6px -2px rgba(0, 0, 0, 0.25);
    width: 100%;
    max-width: 550px;
    padding: 2rem;
    margin: 4rem auto 2rem auto;
}

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

header h1 {
    font-size: 1.75rem;
    margin-bottom: 0.5rem;
    background: linear-gradient(to right, #a78bfa, #8b5cf6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

header p {
    color: var(--text-muted);
    font-size: 0.9rem;
}

.upload-section {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 2rem;
    border: 2px dashed var(--border);
    border-radius: 8px;
    margin-bottom: 1.5rem;
    transition: border-color 0.2s;
}

.upload-section:hover {
    border-color: var(--primary);
}

input[type="file"] {
    display: none;
}

.upload-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    background-color: var(--primary);
    color: white;
    padding: 0.75rem 1.5rem;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 500;
    transition: background-color 0.2s;
}

.upload-btn:hover {
    background-color: var(--primary-hover);
}

#fileName {
    margin-top: 1rem;
    color: var(--text-muted);
    font-size: 0.85rem;
    word-break: break-all;
}

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

label {
    display: block;
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-muted);
}

select, input[type="number"] {
    width: 100%;
    padding: 0.75rem;
    border-radius: 6px;
    border: 1px solid var(--border);
    background-color: var(--bg-color);
    color: var(--text-main);
    font-size: 1rem;
}

select:focus, input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 2px rgba(139, 92, 246, 0.2);
}

.actions {
    margin-top: 2rem;
}

button {
    width: 100%;
    padding: 1rem;
    border: none;
    border-radius: 6px;
    background-color: var(--success);
    color: white;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: opacity 0.2s;
}

button:hover:not(:disabled) {
    opacity: 0.9;
}

button:disabled {
    background-color: var(--border);
    color: var(--text-muted);
    cursor: not-allowed;
}

.status-area {
    margin-top: 1.5rem;
    text-align: center;
}

#statusText {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.spinner {
    border: 3px solid rgba(255, 255, 255, 0.1);
    width: 24px;
    height: 24px;
    border-radius: 50%;
    border-left-color: var(--primary);
    animation: spin 1s linear infinite;
    margin: 0 auto 1rem;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.download-btn {
    display: inline-block;
    background-color: var(--primary);
    color: white;
    text-decoration: none;
    padding: 0.75rem 1.5rem;
    border-radius: 6px;
    font-weight: 500;
    transition: background-color 0.2s;
}

.download-btn:hover {
    background-color: var(--primary-hover);
}