:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --bg-color: #f3f4f6;
    --card-bg: #ffffff;
    --text-main: #1f2937;
    --text-secondary: #6b7280;
    --border-color: #e5e7eb;
    --error-color: #ef4444;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.5;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.container {
    background: var(--card-bg);
    width: 100%;
    max-width: 600px;
    border-radius: 16px;
    box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
    padding: 2rem;
}

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

h1 {
    font-size: 1.875rem;
    font-weight: 700;
    color: var(--text-main);
    margin-bottom: 0.5rem;
}

header p {
    color: var(--text-secondary);
}

.upload-area {
    border: 2px dashed var(--border-color);
    border-radius: 12px;
    padding: 3rem 1rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    background-color: #f9fafb;
}

.upload-area:hover, .upload-area.drag-over {
    border-color: var(--primary-color);
    background-color: #eef2ff;
}

.upload-icon {
    width: 48px;
    height: 48px;
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.browse-btn {
    color: var(--primary-color);
    font-weight: 600;
    text-decoration: underline;
}

.file-types {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-top: 0.5rem;
}

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

.list-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.list-header h2 {
    font-size: 1.125rem;
    font-weight: 600;
}

.text-btn {
    background: none;
    border: none;
    color: var(--error-color);
    font-size: 0.875rem;
    cursor: pointer;
    font-weight: 500;
}

.text-btn:hover {
    text-decoration: underline;
}

.file-list {
    list-style: none;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    overflow: hidden;
}

.file-item {
    background: var(--card-bg);
    padding: 0.75rem 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
    cursor: grab;
    transition: background-color 0.2s;
}

.file-item:last-child {
    border-bottom: none;
}

.file-item:hover {
    background-color: #f9fafb;
}

.file-info {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    overflow: hidden;
}

.drag-handle {
    color: var(--text-secondary);
    cursor: grab;
}

.file-name {
    font-weight: 500;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 300px;
}

.remove-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 4px;
    border-radius: 4px;
    transition: all 0.2s;
}

.remove-btn:hover {
    color: var(--error-color);
    background-color: #fee2e2;
}

.actions {
    margin-top: 2rem;
    text-align: center;
}

.primary-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 0.75rem 2rem;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.3s;
    width: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 0.5rem;
}

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

.primary-btn:disabled {
    background-color: #9ca3af;
    cursor: not-allowed;
    opacity: 0.7;
}

.spinner {
    display: none;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255,255,255,0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 1s ease-in-out infinite;
}

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

/* Sortable ghost class */
.sortable-ghost {
    opacity: 0.4;
    background-color: #eef2ff;
}

.play-btn {
    background: none;
    border: none;
    color: var(--primary-color);
    cursor: pointer;
    padding: 4px;
    border-radius: 50%;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-right: 0.5rem;
}

.play-btn:hover {
    background-color: #eef2ff;
    transform: scale(1.1);
}

.play-btn.playing {
    color: var(--primary-hover);
    background-color: #e0e7ff;
}

.file-info {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    overflow: hidden;
    flex: 1;
}

footer {
    margin-top: 3rem;
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background-color: var(--border-color);
    border-radius: 4px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background-color: var(--primary-color);
    width: 0%;
    transition: width 0.3s ease;
}

.seek-bar {
    width: 100%;
    margin: 0 10px;
    cursor: pointer;
}

.time-display {
    font-size: 0.8em;
    color: #6b7280;
    min-width: 35px;
    text-align: center;
}