:root {
    --primary-color: #007bff;
    --bg-color: #f4f4f9;
    --panel-bg: #ffffff;
    --border-color: #ddd;
    --text-color: #333;
}

* {
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: var(--bg-color);
    color: var(--text-color);
    height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    display: flex;
    flex-direction: column;
    height: 100%;
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
    background-color: var(--panel-bg);
    box-shadow: 0 0 10px rgba(0,0,0,0.1);
}

header {
    padding: 20px;
    border-bottom: 1px solid var(--border-color);
    text-align: center;
}

h1 {
    margin: 0 0 10px 0;
    font-size: 1.5rem;
}

.upload-area {
    border: 2px dashed var(--border-color);
    padding: 20px;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.2s;
}

.upload-area:hover {
    background-color: #f9f9f9;
}

.upload-area.dragover {
    background-color: #eef;
    border-color: var(--primary-color);
}

.hidden {
    display: none !important;
}

main {
    display: flex;
    flex: 1;
    overflow: hidden; /* Prevent main scroll, scroll inside panels */
}

.sidebar {
    width: 300px;
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    background-color: #fafafa;
}

.sidebar h2 {
    padding: 10px;
    margin: 0;
    font-size: 1.2rem;
    border-bottom: 1px solid var(--border-color);
}

.frame-list {
    flex: 1;
    overflow-y: auto;
    padding: 10px;
}

.frame-item {
    display: flex;
    align-items: center;
    background: white;
    border: 1px solid var(--border-color);
    margin-bottom: 8px;
    padding: 5px;
    border-radius: 4px;
    cursor: grab;
}

.frame-item:active {
    cursor: grabbing;
}

.frame-thumb {
    width: 60px;
    height: 40px;
    object-fit: cover;
    margin-right: 10px;
    background: #eee;
}

.frame-info {
    flex: 1;
    font-size: 0.9rem;
}

.frame-delay {
    font-size: 0.8rem;
    color: #666;
}

.btn-delete {
    background: none;
    border: none;
    color: #ff4444;
    cursor: pointer;
    font-size: 1.2rem;
    padding: 0 5px;
}

.preview-area {
    flex: 1;
    padding: 20px;
    display: flex;
    flex-direction: column;
    overflow-y: auto;
}

.preview-container {
    width: 100%;
    height: 300px;
    background-color: #000;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
    border-radius: 4px;
    overflow: hidden;
}

#preview-img {
    max-width: 100%;
    max-height: 100%;
}

#preview-placeholder {
    color: #666;
}

.controls {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
    justify-content: center;
}

.settings-group {
    margin-bottom: 20px;
    padding: 15px;
    background: #f8f9fa;
    border-radius: 8px;
}

.settings-group h3 {
    margin-top: 0;
    font-size: 1rem;
    margin-bottom: 10px;
}

.control-row {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 10px;
}

input[type="number"] {
    padding: 5px;
    border: 1px solid #ccc;
    border-radius: 4px;
    width: 80px;
}

footer {
    padding: 20px;
    border-top: 1px solid var(--border-color);
    background-color: #f8f9fa;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 20px;
}

.export-settings {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
}

.setting-item {
    display: flex;
    align-items: center;
    gap: 5px;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary:disabled {
    background-color: #ccc;
    cursor: not-allowed;
}

.btn-primary:hover:not(:disabled) {
    background-color: #0056b3;
}

#download-link {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: bold;
}