* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: 'Segoe UI', sans-serif;
    background-color: #121212;
    color: #e0e0e0;
}

header {
    background-color: #1e1e1e;
    border-bottom: 1px solid #333;
    padding: 10px 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: sticky;
    top: 0;
    z-index: 100;
}

header h1 {
    font-size: 20px;
    margin: 0;
    color: #ffffff;
}

nav a {
    color: #bbb;
    text-decoration: none;
    margin-left: 20px;
    font-size: 14px;
    transition: color 0.3s;
}

nav a:hover {
    color: #ffffff;
}

.container {
    display: flex;
    height: calc(100vh - 60px);
}

.panel {
    flex: 1;
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.left-panel {
    border-right: 1px solid #333;
    align-items: center;
    justify-content: center;
    position: relative;
    border: 2px dashed #444;
    transition: background-color 0.3s ease;
}

.left-panel.dragover {
    background-color: #1f1f1f;
    border-color: #888;
}

.right-panel {
    background-color: #1e1e1e;
}

textarea {
    width: 100%;
    height: 100%;
    resize: none;
    background-color: #2b2b2b;
    color: #ffffff;
    border: none;
    padding: 10px;
    font-family: monospace;
    font-size: 14px;
    border-radius: 4px;
}

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

label.upload-btn {
    padding: 10px 20px;
    background-color: #3a3a3a;
    border: 1px solid #555;
    border-radius: 4px;
    cursor: pointer;
    transition: 0.3s;
}

label.upload-btn:hover {
    background-color: #555;
}

.image-preview {
    max-width: 100%;
    max-height: 400px;
    object-fit: contain;
    background-color: #000;
    border: 1px solid #444;
    padding: 10px;
    border-radius: 4px;
}

.drop-instruction {
    font-size: 14px;
    color: #aaa;
}