:root {
    --bg-color: #0f172a;
    --surface-color: #1e293b;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent-color: #3b82f6;
    --accent-hover: #2563eb;
    --border-color: #334155;
    --success-color: #10b981;
    --radius: 12px;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background-image: radial-gradient(circle at top right, rgba(59, 130, 246, 0.15), transparent 400px),
                      radial-gradient(circle at bottom left, rgba(16, 185, 129, 0.1), transparent 400px);
}

.container {
    width: 100%;
    max-width: 800px;
    padding: 2rem;
    background: rgba(30, 41, 59, 0.7);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
}

header {
    text-align: center;
    margin-bottom: 2.5rem;
}

h1 {
    font-size: 2.5rem;
    font-weight: 800;
    letter-spacing: -0.05em;
    margin-bottom: 0.5rem;
}

.highlight {
    color: var(--accent-color);
}

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

.drop-zone {
    border: 2px dashed var(--border-color);
    border-radius: var(--radius);
    padding: 4rem 2rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    background: rgba(51, 65, 85, 0.2);
}

.drop-zone:hover, .drop-zone.dragover {
    border-color: var(--accent-color);
    background: rgba(59, 130, 246, 0.05);
}

.upload-icon {
    color: var(--accent-color);
    margin-bottom: 1rem;
    transition: transform 0.3s ease;
}

.drop-zone:hover .upload-icon {
    transform: translateY(-5px);
}

.drop-text {
    font-size: 1.2rem;
    color: var(--text-secondary);
}

.drop-text span {
    color: var(--accent-color);
    font-weight: 600;
}

.hidden {
    display: none !important;
}

.file-list {
    margin-top: 2rem;
}

.file-list h3 {
    margin-bottom: 1rem;
    font-weight: 600;
}

#files-preview {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

#files-preview li {
    background: var(--surface-color);
    padding: 0.5rem;
    border-radius: 8px;
    font-size: 0.8rem;
    color: var(--text-secondary);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    border: 1px solid var(--border-color);
    text-align: center;
}

.primary-btn, .secondary-btn {
    display: inline-block;
    width: 100%;
    padding: 1rem;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    text-align: center;
    transition: all 0.3s ease;
}

.primary-btn {
    background: var(--accent-color);
    color: white;
}

.primary-btn:hover {
    background: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 10px 15px -3px rgba(59, 130, 246, 0.4);
}

.secondary-btn {
    background: var(--surface-color);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    margin-top: 1rem;
}

.secondary-btn:hover {
    background: var(--border-color);
}

.loading-state, .result-state {
    text-align: center;
    padding: 3rem 0;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid var(--border-color);
    border-top-color: var(--accent-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 1.5rem auto;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.result-state h3 {
    color: var(--success-color);
    font-size: 1.8rem;
    margin-bottom: 0.5rem;
}

.result-state p {
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.download-btn {
    text-decoration: none;
    margin-bottom: 1rem;
}